B11539, Monitoring Marine Environ of Long Island Sound at Millstone Nuclear Power Station Waterford,Ct,Annual Rept 1984

Monitoring Marine Environ of Long Island Sound at Millstone Nuclear Power Station Waterford,Ct,Annual Rept 1984

ML20128E761
Person / Time
Site:	Millstone
Issue date:	12/31/1984
From:	Opeka J NORTHEAST UTILITIES, NORTHEAST UTILITIES SERVICE CO.
To:	John Miller, Youngblood B Office of Nuclear Reactor Regulation
References
B11539, NUDOCS 8505290463
Download: ML20128E761 (284)

Text

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k AlVlV[JAL REPORT 22 1984

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of Long Islan'd Sound at Millstone Nuclear Power Station Waterford, p-Connecticut - / * 'N 4

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NORTHEAST UTILITIES SERVICE COMPANY

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MONITORING

'THE MARINE ENVIRONMENT OF i- LONG ISLAND SOUND AT

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E MILLSTONE NUCLEAR POWER STATION

-WATERFORD, CONNECTICUT l

ANNUAL REPORT 1984 I

i Northeast Utilities Service Company April.1985 b

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i EXECUTIVE

SUMMARY

Table of Contents Section Page ROCKY INTERTIDAL STUDIES...................................... 1 BENTHIC INFAUNA..... ......................................... 2 LOBSTER POPULATION DYNAMICS................................... 3 FISH EC0 LOGY.................................................. 4 WINTER FLOUNDER POPULATION STUDIES............................ 6 0SPREY........................................................ 9 AC KN 0WL EDG EMENT S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

EXECUTIVE

SUMMARY

The Millstone Nuclear Power Station (MNPS) is located on the north shore of Long Island Sound in Waterford, Connecticut. The station consists of two operational units with a combined cooling water flow of' ,

2,155 cfs, and a third unit under construction.

Extensive studies of the potential impact of MNPS on Long Island Sound were initiated in 1968. They have been modified and updated to assure that the best currently available monitoring procedures were used. This report presents 1984 results and provides comparisons with previous years as a basis for impact assessment.

ROCKY INTERTIDAL STUDIES Rocky intertidal communities in the vicinity of MNPS, as represented by plants and animals found at 10 rocky shore study stations, continued to be monitored during 1984. With the exception of Fox Island-Exposed, the station nearest the discharge, community parameters (qualitative algal species composition, percent substratum coverage, recolonization rates and patterns) at all stations in 1984 were similar to those reported in the past, and those of other areas of New England.

At Fox Island-Exposed (ca. 150 m from MNPS discharge), a change in the established Ascophy11um - Fucus - Chondrus - Balanus community was noted in 1984. This change was attributed to thermal incursion resulting from an altered thermal plume. In August 1983, a second quarry discharge cut was opened; this produced a broader plume that increased water temperature along the share near the discharges. The change in temperature caused the elimination of populations of several perennial algae, and their replacement by a suite of species previously found most commonly in the quarry.

The observed effects of the thermal incursion were restricted to 150 m of shore near the discharge and none of the impacted species were unique to that area; excepting this region, detrimental changes to the local rocky intertidal community resulting from operation of HNPS did not occur in 1984, i

BENTHIC INFAUNA The intertidal and subtidal infaunal communities were sampled trom September 1983 through June 1984 and described in terms of sediment characteristics, community composition, density, numbers of species, dominance and trophic structure. These parameters were used to identify spatial and temporal differences observed at potentially impacted and non-impacted communities in 1984 relative to previous years.

Of the three intertidal sampling stations, Jordan Cove sediments continued to be of larger grain size and contain higher amounts of silt-clay than those of Giants Neck and White Point. At subtidal stations, the nost notable sedimentary change in 1984 occurred at Intake, where grain size was finer and silt-clay content higher than values reported in recent years. Similarly, some of the highest values for silt-clay were observed at Effluent in the December through June collections. The increased silt-clay at both stations was related to the Unit 3 intake construction.

Intertidal and subtidal communities continued to be dominated by deposit-feeding annelids, (i.e., polychaetes and oligochaetes). In 1984, the most obvious change at intertidri stations was the abundance of oligochaetes, which declined substantially at Jordan Cove and increased at Giants Neck. At subtidal stations, the number of polychaete species and the total number of molluscs and arthropods collected in 1984 cxceeded previous observations at Effluent, Giants Neck and Jordan Cove.

Changes in the dominance structure of both intertidal and subtidal communities occurred in 1984. At the Jordan Cove intertidal station, oligochaete abundance was substantially lower than the seven yeat average. In addition, the numbers of Capite11a spp., Streblospio benedictii and Microphthalmus sczelkowii were unusually low during 1984; in most previous years they have been among the ten numerically dominant forms. At subtidal stations, localized and widespread changes occurred to the infaunal dominance structure. Construction activities near the Intake station resulted in lower numbers of species and individuals in September through March collections. In addition to the localized changes related to power plant construction, there was a large increase in the abundance of Mediomastus ambisuta at all sampling stationn.

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l During 1984, there were no changes in intertidal or subtidal communities that could be attributed to the operation of Millstone Unit 1 or 2. Spatial and temporal differences observed at intertidal stations were believed reflective of natural year to year changes in physical environmental' variables. Subtidally, some localized changes in sedimentary characteristics and infaunal communities occurred as a result of the Unit 3 construction program. These changes were observed only at stations in the immediate vicinity of the power plant. In addition, an area-wide increase occurred in the density of Mediomastus ambiseta in 1984; this influenced many of the parameters used to characterize subtidal communities. Since the increased abundance of Mediomastus ambiseta occurred throughout the area, it was considered a natural event and not caused by plant operation.

LOEcTER POPULATION DYNAMICS The lobster population in the Millstone Point area was sampled from May through October 1984 using wire traps. Lobsters were tagged and released to monitor growth and movement and to estimate the population size. All lobsters >55 mm carapace length were tagged, and data on sex, presence of eggs, carapace length, missing claws and molt stage were recorded before releasing lobsters at the site of capture. In addition, impingement and lobster larvae entrainment studies were conducted to assess the impacts on the lobster population associated with the operation of Millstone Units 1 and 2.

The 1984 values for total and legal catch and catch per unit effort were within the range of values reported since 1978, when wire pots were first used. Ca:ch per 100 pot hauls was 170 for all sizes of lobsters and 16 for legal-sized lobsters (>81 mm carapace length). Our catch data continue to indicate a high rate of exploitation for lobsters in the Millstone Point area. Several factors were found to cause variability in the catch over the sampling period: 1) seasonal change in water temperature, 2) amount of time between pothauls (soaktime), 3) incidental catch of spider crabs.

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Values for the 1984 lobster size structure, sex ratio, and growth per molt were within the range of values reported for wire pots in previous years. A higher percentage of egg-bearing females was found in 1984 (6.2%) relative to previous values (range 3.1-4.9%). Molting was higher throughout the summer months and a secondary molt occurred in the fall. The percentage of cul) observed in the 1984 catch was significantly lower than the percentage observed in previous years. The percentage of recaptures caught in commercial traps decreased. The reduction in culls and the different recapture rates reported in 1984 were attributed to a new trap regulation instituted in April 1984 which required that commercial traps contain vents to allow escapement of sublegal-sized lobsters. Reducing the number of sublegal-sized lobsters retained by commercial traps reduced the number of tag-returns and increased our recapture rate for sublegals since our traps do not have escape vents.

Entrainment studies indicated that lobster larvae were susceptible to entrainment only during the early summer and coincided with the peak abundance of berried females and with the development of their egg-masses. More larvac were collected in night samples (82%) than in day samples (18%).

The Unit 1 fish return system (sluiceway) was operating during 1984 and thus minimized lobster mortality associated with impingement at Unit

1. Although the combined two unit impingement estimate for lobsters was lower in 1984, the estimated number of lobsters impinged at Unit 2 was greater in 1984 than in previous years. Survival of impinged lobsters during 1984 (79.3%) was similar to the survival reported in 1983 (79.8%).

FISil ECOLOGY Tinfish are an important local marine resource and are found in a vaticty of habitats in the area around MNPS. To determine whether the construction and operation of HNPS cffect local finfish populations, compinmentary sampling programa were conducted to collect data on the available life history stages. For 1984, nine taxa of finfiah were 4

selected for detailed discussion due to their susceptibility to entrainment and impingement. They were the anchovy, American sand lance, stickleback, silverside, grubby, tomcod, windowpane, tautog, and cunner. Fluctuations in abundance of their predominant life history stages in piankton, impingement, trawl and seine samples were examined.

Distinct seasonal patterns of abundance were found for several taxa due to spawning migrations. The tomcod and stickleback leave the Millstone area to spawn in brackish waters. Anchovies were only present during the warmer months when they migrate inshore to spawn.

Differences in the spatial distribution of finfish throughout the Millstone area were evident and could be related to the behavior of predominant life history stages. Silverside juveniles dominated the shore zone during warmer morths; during the winter, adults were collected in deeper waters by trawls. Windowpane juveniles were primarily found in deeper offshore waters and adults were more prevalent in near shore areas. Juvenile tautog and cunner were most abundant in shallow near shore waters.

During 1984, the abundances of several taxa changed in comparison to previous years. An estimated 390,000 juvenile sand lance were impinged during July at Unit 2, an event not previously observed at Millstone. Larval sand lance abundance continued to be low since a decrease in 1982. Silverside abundance was the lowest since 1979.

There was a concurrent decrease in the abundance of larval anchovy, tautog, and cunner which was attributed to predation by etenophores.

Time-series modeling was useful in describing seasonal patterns and natural fluctuations in abundance. For most taxa the 1984 abundance of predominant life history stages was similar to that predicted based on the models. The decline in silverside abundance in 1984 was predicted well with a three year cycle term. The decrease in larval anchovy, tautog, and cunner in 1984 was also identified by the time-series predictions. Based on the comparisons of actual abundance data for 1984 and time-series forecasts, there was no indication that the operation of MNPS had impacted finfish populations in the area.

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WINTER FLOUNDER POPULATION STUDIES The winter flounder (Pseudopleuronectes americanus) is a valuable sport and commercial finfish in Connecticut and is the most abundant demersal fish in the vicinity of MNPS. Because the population of winter flounder is composed of reproductively isolated stocks spawning in specific estuaries of coastal areas, special emphasis has been placed on understanding the dynamics of the winter flounder stock spawning in the nearby Niantic River.

Results of the studies ~ conducted during 1984 were presented and, whenever possible compared to previous years. Included were the adult, larval, and juvenile winter flounder sampling programs and data from the impingement, ichthyoplankton, and trawl monitoring programs.

The 1984 adult winter flounder abundance survey in the Niantic River began on February 14, the earliest start since 1976. The 8-week survey was completed on April 4. Using the Jolly model, the number of winter flounder larger than 20 cm was estimated as 51,819 1 27,134.

Abundance of winter flounder larger than 15 cm was also estimated using the median trawl CPUE. The 1984 median was 14.3, the smallest during the 9 years of study (range of 16.7-35.0). However, capture efficiency of the trawl in the upper river was affected by the large amounts of macroalgae and detritus present; this reduced the catch to an unknown degree and probably underestimated the abundance of winter flounder.

Directly comparable annual CPUE medians were calculated for the period 1977-84 using data restricted from mid-Harch through mid-April and to fish larger than 20 cm. Catch data from the trawl monitoring program were also examined. Abundance increased from 1978 and peaked in 1981. A decreasing trend followed through 1984.

Comparisons were made among adult, larval, and age 1 juvenile indices of abundance. Little correspondence was found between the relative abundance of adults spawning in the Niantic River and the number of larvae produced. A more obvious relationship was found between larvae and juveniles with trends in abundance generally parallel. This suggests that the strength of a winter flounder 6 ,

year-class is established early in their life history. The 1980 year-class was apparently the strongest produced since our studies began.

As in previous years, spawning was essentially completed by early April and apparently began in January or early February under the ice in the upper river. The length at which 50% of the females were sexually mature was 25.6 cm, which was very similar to the 1963 estimate of 25.1 cm. The sex ratio of females to males was 1.07 in 1984, the lowest of the 9-year period.

Recapture rates of adults released with Petersen disc tags were similar among years (15-17%) and stations (11-25%). About 1.67 times as many winter flounder were taken by the sport than the commercial fishery. Most recaptures (70%) were made in local waters. Three times as many returns were received from more distant locations to the east' the, to the west, showing a greater movement of fish outside of Long Island Sound.

The effects of mesh size (0.202 and 0.333 mm) and tow duration (6 and 15 min) on the collection density of winter flounder larvae were examined in 1984. No differences in the collection density of Stage 1 or 2 larvae were found for the two tow durations, but significantly more Stage 1 larvae were taken with the smaller mesh. This indicated that Stage 1 larvae were most likely undersampled in previous years because of net extrusion.

The temporal and spatial distributions of larvae were similar to those found in 1983 with successive increases and decreases occurring sequentially from the upper Niantic River to Niantic Bay. More larvae were collected during the early part of the season in 1984 than in 1983.

A concentration of early developmental stages in the mid and lower portions of the Niantic River suggested that most spawning took place there in 1984.

Using the cumulative Comportz growth model, peak abundance of Stage 2 larvae in the bay was estimated to have occurred 23 days later than in the river, which agreed with the 25 to 27 day average residence time of particles in the river. Eatimated densities at peak abundance for Stages 3 and 4 were similar in both locations. Based on the greater volume of the bay, most of the standing stock of these stages was in ,

Niantic Bay.

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Developmental time was estimated as!9 days for Stage 1, 39 days for Stage 2, 26 days for Stage 3, and approximately 10 to 15 days for Stage

4. Total developmental time from hatching to Stage 4 was less in 1983 (53 days) than in 1984 (73 days), probably due to lower water ,

temperature during 1984. This slower developmental time was also seen in the estimated age of a 7.5-mm larva, which was 59 days in 1983 and 73 days in 1984. Otoliths from vinter flounder larvae were examined for the first time to determine if the number of increments could be used to develope an age-length key. However, we found that the rate of increment deposition cannot be determined until we examine laboratocy-reared known-age larvae.

In tidal import and export studies, an estimated 65% of the Stage 2 larvae that were flushed from the Niantic River on an ebb tide returned' on the flood. The return of Stage 3 larvae increased from 63% carly in the season to 92% a month later. This suggests that older larvae use tidal currents as an estuarine retention mechanism.

Abundance of post-larval young in the Niantic River peaked in early June and leveled off by early August. Although more variable in 1983, densities at station LR appeared to be greater last year than in 1984.

Crowth of young at LR in 1984 was less than in 1983, with weekly mean lengths about 6 mm less after mid-July. Monthly mortality was greater in 1984 (53.7%) than in 1983 (44.5%). This may have been the result of increased predation by the summer flounder, which was 2.75 times iaore abundant in the Niantic River this year than last.

The impingement of winter flounder at MNPS during 1983-84 was 5,246, about half that of 1982-83. A fish-return sluiceway was installed at Unit 1 in mid-December which reduced the impact of MNPS operations on juvenile and adult winter flounder. Impingement sampling effort was reallocated this year and resulted in more samples collected during winter and fewer during other months. The precision of the estimates remained similar to previous years while effort was reduced by about 50%.

I'ntrainment of larvae at MNPS occurred from late February through late June with greatest densities during the first week of May. The median density of 49 larvae por 100 m* was the second highest since 1916, but no significant differences were apparent among the years.

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Fluctuations in abundance from the impingement, ichthyoplankton, and trawl monitoring programs were analyzed using time-based harr.cnic regression models. The best models were developed using impingement and entrainment data and reliably described the catches actually made.

Although R2 values were higher than in 1982-83, the trawl station models remained generally inadequate. Additional years of data vill be necessary to determine and describe cyclical trends in abundance. With increasing ability to successfully model and predict changes in abundance, we should be able to describe changes due to natural fluctuations and assess the impact of 3-unit operations of MNPS.

OSPREY The American osprey (Pandion halinctus) returned to the power plant site in 1984 and produced 4 young in 4 active nests. The number of active nests increased from 2 to 4 this year. Nests active for the first time were located on Fox Island and Bay Point. This years annual production rate of 1.0 per nest is lower than previous years because of the introduction of additional nesting platforms. Only one platform i-remains inactive on the power plant site.

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ACKNOWLEDGEMENTS The following report was prepared by the Environmental Laboratory staff (NUEL) of Northeast Utilities Service Company. All contributors to this report are acknowledged below, according to their respective disciplines.

Laboratory Manager: Paul M. Jacobson Secretarial Support: Dian Audoin Benthic Ecology: Jeffery Blonar Donald Landers Robin Ethier Richard Larsen Bette Fields Douglas Morgan James Focrtch Henry Paul Raymond Heller Joseph Vozarik ,

Dr. Milan Keser Fish Ecology Dr. Linda Bireley David Dodge John Castleman Christine Gauthier David Colby Dorothy Haggan Donald Danila JoAnne Konefal Greg Decker Dale Miller Robert Richter ...

Osprey Greg Decker Statistical Support: Dr. Ernest Lorda NUEL Halling address: Northeast Utilities Environmental Laboratory P.O. Box 128 Waterford, Connecticut 06385 10 ,

I Special thanks are extended Dr. William Renfro, Director Environmental Programs Department (NUSCo) and the following members of the Millstone

) Ecological Advisory Committee for their critical review of this report:

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Dr. Nelson, Marshall - University of Rhode Island, Dr. William Pearcy - Oregon State University, Dr. Saul Saila - University of Rhode Island, Dr. John Tietjen - City College of New York.

Dr. Robert Wilce (University of Massachusetts) is gratefully acknowledged for verifying species identifications and for providing critical reviews of early drafts of the Rocky Shore report, e

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l INTRODUCTION Table of Contents Section Pages I NT ROD U CT ION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 REFERENCES CITED........................................... 4

7 INTRODUCTION Millstone Nuclear Power Station (MNPS) is located on the north shore of-Long Island Sound (LIS) in Waterford, Connecticut. The station consists of three units located on a peninsula bounded by Jordan Cove on the east and by Niantic Bay on the west (Fig. 1). Millstone Unit 1, which commenced operation November 29, 1970, is a 652-MWe boiling water reactor (BWR). Unit 2 is an 870-MWe pressurized water reactor (PWR) that began operating October 17, 1975. Construction of Unit 3. a 1,150-MWe PWR, began in August 1974; commercial operation is planned for 1986.

O 250 L f f f f I meters Jordan Cove Unit C. W. Discharges 3

(N ( Dlscharge Unit Quarry .s ,

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Niontic Bay Figure 1. Site-plan of the Millstone Nucicar Power Station.

All three units use once-through condenser cooling water systema.

Cooling water in generally drawn from depths greater than four feet below mean sea level by neparate shoreline intakes located niong Ninntic Bay. The intake structures are typical of shoreline installations having coarse bar racks and traveling screens. The rated circulating flown for Units 1. 2 and 3 nre 935,1.220 and 2,000 cfs, respectively.

From discharge structures, the heated (25*F A T) cooling water flows through an abandoned granite quarry and into LIS through two channels equipped with fish barriers.

The potential impact of MNPS on LIS has been the focus of study since 1968. The early biological investigations included exposure panel monitoring of woodboring and fouling communities, and surveys of the intertidal sand, rocky shore and shore-zone fish communities. The program scope increased considerably between 1970 and 1973 with the addition of heavy metal analyses of seawater and mollusc tissue, studies of pelagic (gill net) and demersal fishes (trawls), lobster and winter flounder (Niantic River) population studies, subtidal benthos and offshore ichthyoplankton (Battelle - W. F. Clapp Laboratories 1975; NUSCo 1975).

Studies of entrained plankton began in 1970 when Unit 1 became operational (Carpenter 1975); studies at Unit 2 began in 1975. To date, the routine monitoring and special investigations have covered nearly all aspects of plankton, including ichthyoplankton, phytoplankton, and zooplankton. Effects of chlorination and temperature on entrained phytoplankton were addressed as well as latent mortality of zooplankton after condenser passage (Carpenter et al. 1972; Carpenter et al. 1974). Emphasis was placed on entrained ichthyoplankton and the relative impact on fish populations in surrounding waters (NUSCo 1976, 1983).

Impingement monitoring began at Unit 1 in 1971 and at Unit 2 in 1975. The program scope has varied from counting all impinged organisms (1972-1976) to the current program of selected numbers of 24-hour counts per week. Special studies have evaluated the effectiveness of several fish deterrent systems at the intakes, including acoustic stimuli, underwater lighting and a surface and bottom barrier (NUSCo 1976, 1979, 1980). In December 1983, a fish return system (uluiceway) began operating at Unit I reducing impingement related impacts on fish and shellfish.

The potential effect of three-unit operation on selected species was also considered. K1thematical population dynamics models were developed for the Niantic River winter flounder population (lless et al,.

1975) and for the regional menhaden population (NUSCo 1976). These 2

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.models incorporated the predicted entrainment and impingement losses

over the life of the power station.

) A number of hydrographic studies were conducted starting as early l

) as 1966 (NUSCo 1976). Predictive models for 1, 2 and 3 unit thermal plumes were developed based on hydrographic measurements taken from field surveys. A tidal circulation model was developed, not only to predict current patterns and thermal distributions, but also to simulate dispersal and entrainment of winter flounder larvae (Hess g al,. 1975).

As a result of these studies, the hydrographic and ecological characteristics of surrounding waters are described. Studies have been intensified and modified to provide the most representative data with respect to the changing concerns and state-of-the-art techniques. The present report provides results of 1984 studies and summarizes results of previous years as a basis for evaluating any long-term impacts. The report also satisfies certain license and permit conditions stipulated by the Connecticut State Department of Environmental Protection and the Connecticut State Power Facility Evaluation Council.

All ecological and hydrographic studies through 1976 were conducted by consulting laboratories, most notably Battelle - W. F. Clapp Laboratories, Woods Hole Oceanographic Institution (Entrainment, 1970-1975) and Normadeau Associates (Entrainment, 1975-76). In 1977, Northeast Utilities Service Company (NUSCo) began a phased, in-house takeover beginning with the entrainment and impingement programs. Some benthic and lobster program responsibilitics were added in 1978. As of' January 1980, all studies (excluding heavy metals) were being conducted and reported by NUSCo biolohists based at the Northeast Utilities Environmental Laboratory. Critical scientific review is provided by a four-member, Ecological Advisory Committee (see acknowledgements) which has provided continuing support since 1968.

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REFERENCES CITED Battelle - William F. Clapp Laboratories. 1975. Annual Report on a monitoring program on the ecology of the marine environment of the Millstone Point, Connecticut area. Report No. 14592.

Carpenter, E.J. 1975. Integrated summary report to NUSCo on entrainment of marine organisms. Woods Hole Oceanographic Institution.

. S.J. Anderson, and B.B. Peck. 1974. Survival of copepods passing through a nuclear power station on the Northwest shore of Long Island Sound, U.S.A. Mar. Biol. 24:49-55.

. Peck, and S.J. Anderson. 1972. Cooling water chlorination and productivity of entrained phytoplankton. Mar. Biol. 16:37-40.

Hess, K.W., M.P. Sissenwine, and S.B. Saila, 1975. Simulating the impact of the entrainment of winter flounder larvae. -In: Fisheries and Energy Production. S.B. Saila, ed. D.D. Health Co. Lexington, Mass.

298 pp.

NUSCo (Northeast Utilities Service Company), 1975. Summary report, Ecological and hydrographic studies, May 1966 through December 1974, Millstone Power Station.

. 1976. Environmental assessment of the condenser cooling water intake structures (316 (b) Demonstration), Vols. I and 2, submitted to the Connecticut State Dept. Environmental Protection.

. 1979. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1979.

. 1980. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1980.

. 1983. Monitoring the marine environment of Long Island Sound at Hillstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1983.

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ROCKY INTERTIDAL STUDIES Table of Contents Section Pages INTRODUCTION.............................................. 1 MATERIALS AND METH0DS..................................... 2 Sampling Procedures.................................... 2 RESULTS AND DISCUSSION.................................... 7 Qualitative Collections................................ 7 f Quarry Study........................................... 14 Undisturbed Transects.................................. 17 Recolonization Transects............................... 24 Ascophyllum Crowth Studies............................. 29

SUMMARY

AND CONCLUSIONS................................... 35 REFERENCES CITED.......................................... 37

l ROCKY INTERTIDAL STUDIES INTRODUCTION l Benthic communities on rocky shores are important components of the northeastern North American marine ecosystem. Per unit area, the intertidal zone and near-shore waters are among the most productive regions of the world (Mann 1973). Intertidal algae provide food directly and indirectly to snails, crabs, and other benthic invertebrates, as well as to fish, shore-birds, and man (Bold and Wynne 1978; Edwards et al. 1982; Menge 1982). The large perennial shore algae in particular contribute to the physical structure of intertidal communities by providing shade and protection to plants and animals living beneath them, and attachment space for epiphytes growing upon them (Stephenson and Stephenson 1972; Menge 1975). Some algae, e.g.,

Ascophy11um nodosum, return over 50% of their annual biomass as detritus and dissolved nutrients (Josselyn and Mathieson 1978).

In addition to their intrinsic values to the marine ecosystem, rocky intertidal communities have attributes that are important to a program of biological monitoring. Some species that make up the shore community are long-lived, capable of integrating effects of environmental conditions over their life spans, and thus serve as bioaccumulators. Other species are ephemeral; their presence and abundance respond quickly to changing conditions. They, too, may provide evidence of environmental change or instability. Some species l are sessile or slow-moving, and are continuously exposed to potential impacts; others are motile, and their abundance and distribution at any locality may be an indication of the suitability of the environment at a j given time. Many intertidal organisms show precise seasonal patterns in their occurrence, abundance, and reproductive status; these patterns allow a multitude of biological comparisons between sites and between l l

years. Finally, many environmental parameters affecting shore populations (e.g., immersion time, exposure to wave action, predation and grazing pressure) occur in gradients (Chapman 1946; Lewis 1964; Zaneveld 1969; Stephenson and Stephenson 1972). Some of these parameters can be  ;

quantified and characterized over time, others can be experimentally

l manipulated in an effort to determine causal relationships (Connell 1961; Paine 1966; Dayton 1975; Menge 1975). Perturbation of the marine environment, particularly thermal pollution, has been evident in the intertidal region at other power stations (e.g., Maine Yankee, Shoreham, Pilgrim), and these stations have included rocky intertidal studies in their biological monitoring programs.

The objectives of the MNPS Rocky Intertidal Studies are:

1) to identify the attached plant and animal species found at sites in the vicinity of Millstone Nuclear Power Station (MNPS),

2) to establish temporal and spatial patterns of occurrence and abundance of benthic species at these sites, and

3) to recognize the physical and biological factors that induce variability at these sites.

More specifically, we must determine if there are differences in the biota of these sites that could be attributed to the operation of the  ;

power station.

To achieve these objectives, our monitoring program includes qualitative algal collections, determination of percentage of substratum coverage by intertidal organisms, measurement of recolonization rates and patterns following small-scale perturbation, experimental exclusion of predators and grazers from selected areas, and growth studies of Ascophyllum nodosum. In addition to evaluating the biological impact of operation of Millstone Units 1 and 2, this monitoring program is providing base-line data that will allow us to assess the additional impact of construction and operation of Unit 3, expected to go on line in 1986.

MATERIALS AND METHODS Sampling Procedures Collection of plants and animals from the rocky intertidal stations continued throughout the 1984 reporting year (October 1983-September 1984). Sampling techniques have remained relatively constant since March 1979 (NUSCo 1980); present procedures call for monthly qualitative algal collections at nine sampling sites (Fig. 1), and bimonthly 2

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1 mi i Niontic Bar WNPS BP pg E

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O 1T k Figure 1. Location of rocky intertidal sampling sites. GN-Giants Neck, BP-Bay Point, MP= Millstone Point, FE-Fox Island (Exposed),

FS-Fox Island (Sheltered), TT-Twotree Island,-WP-White Point, SE-Seaside Exposed, SS-Seaside Sheltered.

quantitative collections at eight stations-(those listed in Fig. 1, less Twotree Island). Denuded transects and exclusion cages at the recolonization stations (GN, FE, FS, WP) were sampled monthly until March.1984 (the end of the seasonal cycle), and bimonthly thereafter.

The physical character and other relevant features of the rocky shore stations have been described in previous reports (Battelle 1977; NUSCo 1983a, 1983b). Qualitative collections were made over an area sufficiently wide to characterize the flora found at each site during each month. Samples were identified fresh, or after short-term freezing. Voucher specimens were preserved with various methods, depending on the material: in 4% formalin / seawater, as dried herbarium mounts, or on microscope slides.

Qualitative algal collections were also made from the Millstone effluent quarry, to permit examination of species composition over a broader range of water temperatures. Collections from three sites within the quarry (regions 2-4;-Fig. 2) were pooled to represent an 3

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150 new cut feet ' 5d0 original cut NUEL <

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Figure 2. Location of qualitative algal collection sites within MNPS effluent quarry.

' undiluted' effluent flora, while a collection site on the west bank of the original quarry cut (region 1; Fig. 2) represented a transition zone between effluent and ambient water temperatures. The quarry samples were processed as described for the qualitative collections from the rocky shore stations.

Quantitative studies (percent cover determinations) of the intertidal communities have continued since March 1979, with the addition of Millstone Point in September 1981. At each station, five previously established half-meter wide strips, perpendicular to the waterline and extending from Mean High Water to Mean Low Water levels, were maintained as study areas. These strips (referred to as undisturbed transects) were marked with stainless steel screws. The transects were defined by paired lines marked at half-meter intervals, and the resulting 50 x 50 cm quadrats were non-destructively sampled.

Six times per year (Jan., Mar., May, Jul., Sep., Nov.), at low tide, the percent cover of all organisms and remaining free space were determined and recorded. To accurately represent species that were partially or totally obscured by canopy species, an additional percentage was given for the occurrence of understory species.

4

The horizontal zonation pattern of the shore is represented by the division of each transect into three zones; each zone is characterized by a distinctive species complex. For example, Zone I (upper intertidal) is dominated by blue-green algae and Balanus; Zone II (mid intertidal) is largely covered by the rockweeds, Fucus vesiculosus and Ascophy11um nodosum; and Zone Ill (low intertidal) is dominated by Irish Moss, Chondrus crispus.

Data from all transects at each station were pooled to estimate an average percent cover for each organism in each zone. Each organism and subtratum type was then assigned to one of eight habit categories (classes):

Class 1 - free space; includes rock, sand, and mud.

Class 2 - barnacles; mostly Balanus balanoides.

Class 3 - mussels; mostly Mytilus edulis.

Class 4 - fucoids; Ascophyllum nodosum and Fucus spp.

Class 5 - carrageenoids; mostly Chondrus crispus.

Class 6 - other algae (mostly ephemeral); includes host specific epiphytes, non-specific epiphytes, lithophytes, and crusts.

Class 7 - grazers; mostly Littorina spp., but includes any primary consumer.

Class 8 - predators; mostly Urosalpinx cinerea and Thais lapillus, but includes any carnivore that preys upon barnacles, mussels, or herbivores.

Studies to determine rates and patterns of community recolonization following perturbation were completed (for 2-Unit operating conditions) in March 1984. At each recolonization station (GN, FE, FS, WP), three recolonization transects were scraped and burned with and LPG torch in April 1979 and again in September 1981, to remove all algal and faunal cover. These transects were sampled monthly, as described for the undisturbed transects.

At the four recolonization stations, the fourth series of exclusion cage studies (begun in December 1982, representing a winter denuding) was completed in March 1984. This study was identical in design to previous experiments run from April 1979 to May 1980 (NUSCo 1981), from 5

May 1980 to September 1981 (NUSCo 1982), and from September 1981 to December 1982 (NUSCo 1983a) except for the season in which denuding occurred.

At each recolonization station, nine exclusion cages were attached to rock, three cages in each tidal zone, i.e., upper, middle, and lower tidal level. The cages (20 x 20 x 5 cm) were constructed from 3 mm stainless steel mesh and were fastened with stainless steel screws to rock surfaces which had been burned and cleared in the same way as had the recolonization transects. Each cage had a gasket-like strip around its bottom edge to discourage entry of predators and grazers. Adj acent to each cage, a 20 x 20 cm control patch was burned and cleared.

Percent coverage by benthic plants and animals in the experimental and control areas was determined and recorded on a monthly basis. Cages were inspected, and cleaned as necessary. When growth of algae or invertebrates under a cage had progressed to the point at which further growth was inhibited by crowding, the cage was permanently removed.

Replication of both recolonization and exclusion cage studies were undertaken to determine the effect of seasonality on recolonization; i.e_., to see if denudings at different times of the year would develop into different communities. This report will describe the patterns of recolonization following small-scale denuding in each season, and the effect of grazing and predation on these patterns. All the experiments were run under 2-Unit operating conditions; the sequence of experiments will be repeated af ter Unit 3 becomes operational.

Ascophyllum growth studies initiated in April 1979 were continued.

This report emphasizes data collected from plants tagged in 1983, but includes information from plants tagged in previous years. Each group of tagged Ascophyllum plants was followed for an entire year of growth, from new bladder formation in April until the following April. Plants tagged in spring 1984 will be monitored through April 1985. Growth data from April-September 1984 are included in this report, to aid in the explanation of the effects of the opening of the second quarry cut on Ascophyllum populations.

To determine growth, Ascophyllum tip length was measured at three stations (Giants Neck White Point, and Fox Island-Exposed). Fifty plants at each of the three sites were tagged; a numbered plastic tag 6

was fastened to the base of each plant, and five apices were marked with colored plastic tape. Measurements were made from the top of the most recently formed bladder to the apex, or apices if branching had occurred. In April and May, bladders had not yet developed sufficiently to be securely tagged, so five tips were measured on each of 50 randomly chosen plants. Monthly measurements of tagged plants began in June.

Lost tags were not replaced, and the pattern of loss was used as a measure of Ascophyllum mortality. Loss of the entire plant was assumed when the base tag and tip tags were missing; tip survival was measured both in terms of remaining tapes, and remaining tips with viable apices.

The rationale for this distinction will be dealt with in the Ascophyllum growth section.

RESULTS AND DISCUSSION Qualitative Collections A total of 132 algal taxa (exclusive of blue-greens and diatoms) were identified from the qualitative collections at the rocky shore sites during the 1984 sampling year. Since the inception of this monitoring program in March 1979, a cumulative total of 152 taxa been reported. Differences between the species lists from year to year have been minor, and are summarized in Table 1.

Most of the changes among years represent small or rarely found plants. Of the species reported in the past but not found in 1984, only Enteromorpha groenlandica had been found more than ten times (out of almost 500 collections). Of the additions to the list, several represent nomenclatural revisions, rather than floristic change. Fer example, Trailliella intricata is the tetrasporic stage of Bonnemaisonia hamifera, and as such, it is not taxonomically independent. Because it is so morphologically distinct and ecologically significant, however, we record it as a separate taxon. Similarly, Codiolum gregarium has been reported as a sporophyte in the life cycle of Urospora wormskjoldii.

Other listed taxa (Rhizoclonium kerneri, Cladophora crystallina, Urospora collabens) have been synonymized with Rhizoclonium riparium, Cladophora sericea, and Urospora wormskjoldii, respectively, but owing 1 7 i

. -.. . _ - . . _ - . . = . . - ..

1 l

. Table 1. Changes in the Millstone rocky intertidal species lists, 1984.

Species listed in past reports, Species found for first time not found in 1984. in 1984.

~

j Porphyropsis coccinea Porphyra linearis Audouinella purpurea Audouinella dasyae

, Audouinella sp. .

'Trailliella intricata'"

Petrocelis middendorfii Gracilaria tikvahiae Gloisiphonia capillaris Antithamnion sp.

Antithamnion americanum Delamarea attenuata Antithamnion pylaisii Sphacelaria furcigera Callithamnion corymbosum 'Uruspora collabens' Ceramium fastigiatum 'Codiolum gregarium' Chondria tenuissima 'Cladophora crystallina' Entonema aecidioides 'Rhizoclonium kerneri' Acinetospora sp.

3 Feldmannia sp.

~

Eudesme zosterae Capsosiphon fulvescens Enteromorpha groenlandica Ulvaria oxysperma Chaetomorpha melagonium Cladophora glaucescens Cladophora laetevirens a

Taxa in quotes represent distinct life-stages or morphological forms of other species; the rationale for their inclusion here and in Table 2 7 is discussed in the text.

to their usefulness in characterizing the flora at a particular place or time, we feel it is warranted to list these ecotypes as separate entities.

The local flora, as represented by the 1984 qualitative collections, I is summarized in Table 2. Temporal and spatial distributions that have been noted in the past (NUSCo 1983b) are again apparent. Some species

. (e.g., Chondrus crispus, Fucus,vesiculosus, Ascophyllum nodosum) are dominant components of the intertidal community throughout the region, ,

and trroughout the year. Other species (e.g. , Ceramium rubrum, Ulva 1actuca, Codium fragile) are aseasonal annuals; populations of these

~

species are represented in almost every collection, even though the individuals are ephemeral. Some species are site-specific (e.g.,

Gelidium crinale, Prasiola stipitata), and are common at only one or a

.few stations. Others are characteristic of a particular time of year, 1 1

8 e y.-.---3 - .,e,mm..~ , - , y- -my,_.a 3 . - ,- w - - . .

e.g., Dumontia contorta and Monostroma_ pulchrum in late winter and spring, or Champia parvula and Dasya baillouviana in late summer and autumn.

Temporal and spatial distribution patterns are also seen when the qualitative algal collections are presented as number of species in each5 division (Table 3). The greatest number of species collected in any month was 83 in May, and.the most at any station was 93 at White Point.

In general, all stations had a rich and diverse flora throughout the year.

Of the 132 taxa collected in 1984, 60 were red algae, 35 were browns, and 37 greens; proportionally, this flora is virtually identics1 to those reported in past years (NUSCo 1980, 1981, 1982, 1983a, 1984),

and very similar to those reported by other researchers (e_.g., Vadas 1972; Mathieson et al.1981; Schneider 1981). The relative percent occurrence of local reds, browns, and greens in 1984 were 45:27:28; Vadas, on an open coast in Maine, found that 45% of the algal. species were reds, 32% browns, and 23% greens. Mathieson, working in the Great

. Bay estuary system and adjacent open coast of New Hampshire-Maine, reported ratios of 47:28:25. Schneider sampled algae from the MNPS effluent quarry over an 18 month period, and reported total percentage ratios of 45:24:31.

The proportions of species in each division have been used as a measure of phytogeographic affinity (Druehl 1981). Generally, brown algae predominate under boreal and arctic conditions; reds and greens are more common in tropical and subtropical regions. Comparison of our-data with those of '.Vadas (1972) and Mathieson et al. (1981) shows a

' latitudinal gradient; as water temperatures warm from north to south, the relative proportion of brown algae decreases. This phenomenon was also seen in the MNPS quarry. In his investigation of quarry algae, Schneider (1981) included the range of water temperatures over which each species occurred. He found,that as temperatures increased, fewer species were collected, but that' brown algae disappeared most rapidly.

At water temperatures exceeding 25'C, the relative percentages o*s reds, browns, and greens were 50:12:38; at 30'C and above, the ratios ' sere 57:5:38. .

4 9

-Table'2. -Qualitative algal collections (Oct. 1983 - Sep. 1984) by month and station. Values represent number of stations at which each species was found in each month, and number of months that each species was found at each station.

j'l

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Table 2. (Cont'd)

Oc t. 98ev. Dec, Jan. Feb. Mar. Apr. May Jts'e July Aug. Sep. Gil OP ttP TT FE FS NP St SS Tlees thaeophyta 1933 1933 1963 1984 1984 1984 1984 1934 1964 1954 1934 1934 Found tetocarpus fasciculatus 3 3 i L 7 2 5 6 6 6 2 3 5 5 8 6 5 3 4 6 3 45 tetocarpers siliculosis 5 2 2 2 3 3 5 5 4 3 4 3 7 5 3 4 4 7 6 3 2 41 ratocarpus ep. O I O 2 0 3 0 0 3 3 1 1 0 2 5 2 I t 0 0 2 14 Giifordia granulosa 0 0 0 0 0 I 2 1 2 0 0 0 2 8 I e 3 0 0 0 1 6 Giffordia oltcheillae 6 2 2 1 1 1 1 3 2 2 3 3 1 3 1 2 10 3 4 1-t 27 Filaye!!a 11ttoratia 3 1 2 2 3 3 4 4 3 0 1 I 10 1 1 4 0 9 2 0 0 27 Spengona=a ta*entosum 1 0 0 4 8 5 3 1 0 1 0 0 3 5 t t I t t 4 2 23 6 5 4 1 7 1 3 5 I 5 4 4 9 9 I L 6 5 0 3 4 46 entfsla verrucosa 5 3 4 6 7 9 0 8 9 6 7 9 le 8 8 5 0 10 it 8 78 tiechista fucicola 6 0 0 0 0 0 0 0 0 1 0 0 t pietothrlu lu Wricalle 0 0 0 0 1 0 0 0 0 0 teethesia difformis 0 0 0 0 0 0 0 1 2 3 3 0 0 0 4 1 0 0 1 1 0 7 Chordaria flagalliferals 0 0 0 0 0 0 0 1 3 I t 0 0 0 2 1 0 0 1 1 0 5 Sphaerotrichia divaricata 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 $ t 0 0 t Asperococcus fistulosus 0 0 0 0 2 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 t l 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 1 0 1 0 t Desmotrichum twic61stue t Phacesaccion collinsil 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 punetaria latifella t 0 0 0 1 4 3 1 1 0 0 0 t t 1 2 1 2 0 t i It Pteictaria plantaginen 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 2 6 6 9 3 8 6 7 7 0 0 6 8 8 5 6 3 7 7 4 54 Petalonia fascia 9 8 7 8 9 5 5 4 7 7 6 4 55 teytosiphen tonentaria 0 1 2 3 8 8 8 1 0 Celaeares attnugata 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 Desmarestle seulente 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 Ocznarestia viridis 0 0 0 0 e t 5 5 6 0 0 0 2 3 2 2 I I t 1 4 le Chorda fils,. 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 t Chords to*entosu, 0 0 0 0 0 1 3 3 0 0 0 0 0 0 1 1 0 0 1 0 2 7 Laminscia dititata 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 2 0 0 0 0 0 t Leninaria longieruris 2 2 1 2 I I O 5 2 3 0 0 4 3 2 3 0 1 4 1 3 19 Laminaria seetherina 6 4 5 4 4 4 6 0 5 7 8 5 5 9 8 it 4 7 6 8 7 66 Schacelaria enrross 2 3 2 1 0 0 0 1 0 0 0 0 3 0 t t I t 1 0 0 9 fphacelaria furcigers 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 1 Ascephyllut nodesvae 9 9 9 9 9 9 9 9 9 9 9 9 12 It 12 12 12 !! It 12 It IOS t 0 0 t 0 2 0 1 3 0 0 0 0 0 6 Fucus distichus e edentatus 0 0 0 i 1 1 1 Fucus distiehus s evanescens 0 0 0 0 2 3 0 4 0 0 1 0 1 2 0 3 I i 1 8 0 10 Fueus spiralls 0 0 0 0 0 0 0 0 1 1 3 I I 3 1 0 0 $ 0 1 0 6 9 9 9 9 9 9 9 9 9 9 9 9 12 It It It 12 It It I4 12 500 Fueos vesiculosue Oct f8ow. Dee. Jan. Feb. Mar.~Aor. May June July Aug. Sep. Cta OP MP 17 FE FS WP St SS flees Chlororhy ta 1933 1933 1933 1954 8984 1984 1984 1984 1984 1984 1934 1954 Found -

Ulottele flaecs 0 0 2 6 5 6 5 4 0 0 0 0 5 4 8 2 1 3 5 4 3 28 Urospore penientliformis 0 3 5 5 0 5 0 3 0 0 0 0 6 6 6 5 2 2 4 3 3 37 Uro pora sereskjoldil 0 0 0 0 t t 0 0 t I e 0 0 2 2 0 0 1 0 1 0 6 "Jrosrore collat ens' O O 0 t 5 4 1 3 1 1 0 0 1 2 3 2 L 1 I 1 4 16 Monestroaa previllel 0 0 0 0 2 3 3 7 0 0 0 0 1 2 2 2 2 2 1 1 2 15 ft w stre== pulchrve 0 0 0 2 7 9 0 8 8 0 0 0 5 4 4 4 1 3 6 4 4 35 Srenga*serba arcta 0 0 0 0 1 3- t 4 2 0 0 0 3 2 3 2 0 0 1 0 t It Sponysnerbe mere 11nosa 0 0 0 0 0 0 0 t 1 0 0 0 2 0 1 0 0 0 0 0 0 3

'Ceeholue greprium' O O O O 4 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 8 Slidingia minies 3 3 6 6 7 1 6 5 5 5 6 4 7 5 9 9 9 0 8 4 6 57 014dingin esrginata 0 0 0 4 1 0 0 0 0 0 0 0 0 1 0 0 0 0 2 1 1 5 Interewrpha slathe sta 2 0 0 0 0 0 0 3 5 4 4 5 4 1 1 0 4 5 5 0 3 23 Entero-oe pha fleauesa 4 4 3 1 2 1 4 2 6 7 4 3 5 5 4 3 9 3 8 t t 48 Enterc,orphi intestinalis  ! I 3 5 2 2 5 3 4 6 5 5 7 7 6 2 4 2 0 5 3 44 7 4 3 5 8 5 3 5 6 7 2 7 2 10 6 5 52 Intere=orrhe linia 7 5 3 4

1 3

1 0 7 7 6 7 4 le 2 0 59 Entero *serbe prellfere 5 4 6 5 8 5 6 6 5 2 Enterererpha torta 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 1 I l 0 0 0 0 0 0 0 0 1 0 0 0 t t 0 0 4 Enterereerhi entf all 0 0 2 revesesaria percurse 1 0 0 0 0 0 1 0 0 0 0 0 I 1 0 0 0 0 0 0 0 t Ulva !=etuts 9 9 9 0 9 9 8 9 9 9 9 9 It It It 12 It it it le it 306 Prestela s tipitsta 3 2 3 2 2 3 3 3 3 3 2 2 12 0 0 7 0 0 0 It 0 3t Chaete.egha llem 0 0 6 5 5 I i 6 0 7 8 8 6 0 10 9 7 5 7 0 it it Chaetoesepha seres 3 t 1 i 1 3 2 1 3 6 1 2 5 4 2 d 9 3 3 0 0 17 Clad rbers albida 1 0 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 1 1 0 0 3 Cladophora flevuosa L 8 0 0 0 0 3 2 0 4 5 3 3 4 1 0 2 0 3 2 4 19 Clad yhora refracta 5 1 0 t t t 0 1 I 5 1 3 1 6 2 1 2 3 4 1 1 Il Cladschere serisca 2 0 0 0 0 0 0 t t 3 2 3 1 2 0 0 3 3 3 0 t it

'Cla*rhora crystalline' S 0 0 0 0 0 0 0 I i 0 0 0 0 0 0 0 0 0 2 0 t Cla4 rhora butchirs6aa 1 1 0 t t 0 0 3 3 1 2 t i 1 1 0 4 1 5 0 3 16 0 0 0 I 0 0 1 0 0 0 0 2 0 0 1 4 Cladorheea rurestris 0 0 0 0 t L 5 4 I t t 0 3 I I 26 phiroeleniu= eiparive t I t t 5 4 2 3 3 I e 1

'rhirestenlue kernerl* 0 0 0 1 0 2 0 0 2 0 0 0 t 1 0 0 0 1 0 0 8 5 0 0 0 0 0 l 0 0 0 0 0 0 0 0 I Phiteetenisne tor tuosu= 0 0 0 0 0 0 1 Oryepsis plumosa 2 1 0 0 0 0 0 0 0 0 2 1 0 1 0 0 1 0 t 1 1 6 Oryersia bypacides 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 l t 0 0 8 0 0 1 3 3 0 0 0 0 Derbesia rarina 2 3 1 0 0 1 0 0 0 97 codium fragile 9 9 0 9 9 7 0 0 8 7 8 7 lt 9Ititititit 6 le 11

r Table 3. ' Total number of 'airal species from each division in each qualitative collection.

Month Tearly Division Oct Nov' Dee Jan Feb Mar .Apr Hav Jun Jul ~Aug Sep Total Fereent Sta, keds 18 15 15 17 14 13 12 11 15 7 22 15 38 45

.BP Browns 10- .6 6 9 8 10 9 10 10 9 9 6 19 23 Creens 9. 8 8 11 11 11  !! 9 7 9 8 8 27 32 Total 37 29 29 37 33 34 32 30 32 25 39 29 84 100 Reds 15 13 . 17 14  !! 13 10 12 9 9 8 14 32 44 FE Browns. 8 6 5- 5 8 8 11 10 5 5 '3 2 18 -25 Creens- 10 7 7 10 8 10 9 11 9 11 6 6 23 31 Total 33 26 29 29 27 31 30 33 23 25 17 22 73 100 Reds 16 to 13 13  !! 14 - 10 10 12 8 7 15 35 44 FS Browns 6 6 4 4 -8 7 9 10 0 9 7 6 21 26

.Creens 7 11 5 2 8 6 6 9 9 10 5 6 24 3G Total 29 33 27 19 27 27 25 29 30 27 .19 27 80 100 Reds 14 13 16 21 12 8 9 10 14 14 16 14 36 41 CN Browns 8 9 7 7 10 9 8 14 10 10 5 7 21 24 Creens 10 6 12 8 10 8 12 17 16 9 9 8 30 35 Total 32 28 37 36- 32 25 29 41 40 33 - 30 29 87 100 Reds- 16 13 12 12 13 19 15 12 13 11 15 14 32 41 MP Browns 6 2 6 6 10 8 9 11 12 8 8 5 24 30

. Green, 6 5 6 7 11 9 11 10 9 8 9 7 23 29 Total 28 20 24 25 34 36 35 33 34 27 32 26 79 100

.Ecds 13 8 4 15 10 6 5 9 10 9 9 11 31 44 SE Browns 6 5 4 6- 8 9 10 8 9 9 5 4 19 27 Creens 8 7 3 7 11 5 5 8 7 7 5 4 21 29 Total 27 20 11 26 29 22 20 25 26 25 19 19 71 100 Reds 19 15 15 15 20 20 17 15 13 16 12 11 -44 52 SS Browns 4 3 3 2 10 8 9 6 8 9 6 5 17 20 Greens 6 4 5 7 11 8 8 12 10 7 6 9 24 28 Total 29 22 23 24 41 36 34 33 31 32 24 25 85 100 Reds 16 13 14 21 8 15 17 20 15 14 15 21. 37 46 TT Browns 6 4 5 8 11 10 9 14 to 10 5 5 24 30

-Greens 6 5 9 8 5 f. 8 12 6 7 4 6 19- 24 Total 28 22 28 37 24 33 34 46 31 31 24 32 80 100 Reds 16 18 21 15 lb 24 16 22 15 12  !? 15 45 48 WP. -Browns- 6 6 5 7 10 5 11 14 10 9 6 7 23 25 creen, 9 7 7 9 13 10 12 12 12 13 11 10 25 27 Tetal 31 31 33 31 41 39 39 48 37 34 34 32 93 100 Totals Reds 39 31 35 29 24 35 28 34 34 30 35 36 60 132 for Browns 14 14 14 16 16 24 17 24 20 18 15 12 35 132 all Greens. 21 18 14 20 21 20 20 25 25 21 17 18 37 132 Sites Total 74 63 63 63 63 79 65 83 79 69 67 66 132 396 A similar shift in relative proportions of algae is evident in the disappearance of brown algae from Fox Island-Exposed (the station nearest the discharge) in late summer of 1984. From June-September 1984, FE had ' the lowest browntgreen ratio of all stations. In ,

1

-September, only two species of brown algae were collected (Fucus vesiculosus and Ascophyllum nodosum), and these were rare and necrotic.

Other changes to the community at FE were noted in late summer 1984; 12

Chondrus crispus, previously the dominant alga in the low intertidal, became very rare, and _Ahnfeltia plicata, found in almost every collection from March 1979-June 1984, was absent for the remainder of

[ the sampling year. Several species (e_.g., Enteromorpha clathrata, i Agardhiella subulata), previously minor components of the flora, proliferated and occupied most substrata that had been covered with Chondrus, Fucus, and Ascophyllum.

These changes in the intertidal community at Fox Island-Exposed were also seen in other aspects of the rocky shore monitoring program (i.e., percent cover measurements, and Ascophyllum growth studies); they were attributed to the effects of opening a second quarry cut (August 1983).

When the effluent plume was directed through a single quarry cut, its velocity and momentum carried it into Twotree Channel, where it mixed with (and lost heat to) a large volume of tidally flushed water.

With two quarry cuts, however, the same volume of effluent is discharged through twice the area, and the plume loses half its momentum. This broader, slower plume mixes with the smaller volume of water near shore, and remains in the small area bounded by Fox Island on the east, shoreline on the north, and the thermal plume itself on the south and west. This parcel of heated water produces nearly isothermal water temperature along the shore between the cuts and the southwest tip of Fox Island (Fig. 2), only 2-3*C cooler than undiluted effluent in the quarry itself.

Only one reactor was in operation in the period immediately following the second cut opening; Unit 2 was shut down for refueling and maintenance from June 1983 through January 1984. The effluent AT was usually 7-9'C, and the daily average quarry temperature exceeded 30*C only once. In 1984, however, with both units operating, effluent AT was usually 12-14'C; from 4 July to 2 October, average daily quarry temperature fell below 30*C on only 4 days, and maximum water temperatures in the quarry exceeded 35'C.

'lhe intertidal community at Fox Island-Exposed, as represented by the qualitative algal collections, was not affected immediately following the opening of the second cut (summer 1983). The flora at this site appeared to tolerate the effluent resulting from 1-unit operation. The 13

only noted change was the presence of two small, epiphytic red algae, Goniotrichum alsidii and Erythrocladia subintegra, which were identified for the first time at FE (in September and November 1983, respectively).

Even though these species (E. subintegra in particular) have tropical affinities (Taylor 1957, 1960), they have been found at other stations in the past, and may not represent a response to elevated water temperatures.

However, the change in the flora that occurred at Fox Island-Exposed (and only at this site) in summer of 1984 was attributed directly to the thermal incursion following the excavation of the second quarry cut. There was a rapid loss of perennial populations of Fucus, Chondrus, and Ascophyllum; species of these genera were replaced by a suite of species more typically found in warm water of the undiluted effluent. To better characterize the effect of elevated water temperatures on species composition, the following section summarizes the results of five years of qualitative collections from within the effluent quarry and along the quarry cut. This combined flora represents mostly warm water tolerant species, and permits comparisons between quarry sites and the 'outside' rocky shore stations.

Quarry Study The qualitative algal study at the MNPS quar y started in 1979. Of the 111 species collected from the quarry or from the quarry cut (Table 4), only 3 have not been collected at other NUEL sampling sites:

Audouinella flexuosa, Audouinella sagraenum, and Sorocarpus micromorus.

Those species found at other sites, but never in the quarry or cut, are mostly cold-water reds and browns and their epiphytes.

Schneider (1981) identified 42 algal species (excluding blue-greens) in the Millstone quarry over an 18 month period in 1976-77: 19 reds, 10 browns, 13 greens. A summary of algal species numbers per division for his quarry flora study and our own is shown in Table 5.

Schneider (1981) limited his collections to substrata on the floating laboratory (barge; region 4. Fig. 2); ours included other quarry sites.

in All species notes by Schneider except Spongomorpha arcta were present 14

Table 4. Qualitative algal collections from MNPS effluent quarry, 1979-84. Values represent number of times each species was found in the quarry cut (Q1) and in the quarry proper (Q2).

Q1 Q2 NAt1E 1 1 Pilayella littoralis 27 Goniatrichum alsidii 1 9 Acinetospora sp.

13 Feldmannia sp.

1 .

9 12 Erythroteichia ciliaris

. 1 Sorocarpus micromorus 2 Erythrotrichia carnea 5

6 Erythrocladia subintegra 16 . Elachista fucicola

. 2 Erythrepeltis discigera 2 . Leathesia difformin 2 Chordaria flagelliformis 14 16 Bangia atropurpurea .

. 2 Punctaria latifolia 16 10 Porphyra le9cesticta 30 19 Porphyra umbilicalls 12 6 Petalenia fascia 1 Porphyrepsis coccinea 12 7 Scytosiphon lomentaria

. 1 Aud:uinella purpurea 2 2 Desmarestia viridis 4 7 Audouinella secundata . 2 Chorda filum 2 10 Audouinella daviesii 1 1 Chorda tomentosum 12 19 Audouinella saviana 11 11 Laminaria saccharina

. 1 Sphacelaria cirresa 1 1 Audouinella sp.

. 1 Audouinella dasyne . I Sphacelaria furcigera 1 Ascophyllum nodosum 1 . Audouinella flewuosa 4

. Fucus distichus s edentatus 2 2 Audouinella saDraenum Bonnemaisenia h,mifera 1 . Fucus spiralis

. 2 63 152 Agardhiella subulata 37 I Fucus vesiculosus 7 6 Cystoclonium purpureum 10 to Ulothrix flacca 2 Gracilaria tikvahiae 12 8 Urospora penicilliformis 1

. Ahnfeltia plicata 2 . Urospora wormskjoldil 1 1 'Urospora collabens' 10 1 Chondrus crispus 1 1 Dumontia contorta . 2 Monastroma grevillei 5 4 ttonostroma pulchrum I Palmaria painata

. 3 Charnia parvula 4 . Spongamorpha arcta 9 Lementaria baileyana . 2 Spongemorpha aeruginosa 2

4 Capsesiphon fulvescens

. 1 tomentaria clavellosa 1 Blidingia minima 1 1 Lementaria orcadensis 33 9 15 28 Anti thar,nien cruciatum 7 3 Blidingia marginata Callithamnion corymbosum 28 85 Enteromorpha clothrata 7 10 33 99 Enteromorpha flexuosa 22 29 Callithamnion roseum Enteromorpha groenlandica 2 3 4 1 Callithamnion tetragonum 7 18 Callithamnion byssoides 19 41 Enteromorpha intestinalis 1 1 Ceramium deslongchampil 42 52 Enteromorpha lin:a Ceramium diephanum 20 55 Enteromorpha prollfera 15 33 1 6 Enteromorpha torte 20 36 Ceramium rubrum Spermothamnion repens 1 4 Percursaria percursa 2 6 2 13 Spyridia filamentosa 50 100 Ulve lactuca 24 22 Grinnellia americanum . 2 Ulvaria oxysperma 24 57 Dasya baillouviana 14 7 Chaetomorpha linum 26 8 Chaetemorpha aerea 3 6 Chendria baileyana Cladephora albida Polysiphonia denudata 6 16 23 54 39 71 Polysiphonia harveyi 1 1 Cladenhora flexuosa

. 2 Polysiphonia nigra . 4 Cladophora glaucescens 20 48 Cladophora sericea 1 8 Polysiphonia niDrescens 'Cladenhora crystallina' 5 Polysiphonia urceolata 1 3 16

. 1 Cladephora hutchinsiae 2 1 Polysiphonia flexicaulis

. 2 Cladephora rupestris 23 34 Polysiphonia novae-angliae 5 Rhizoclonium riparium 1 1 Rhodomela ccnfervoides .

'phizoclonium kerneri'

. 1 1 1 Ectocarpus fasciculatus 3 7 Ectocarpus siliculosis 5 5 Bryensis plumosa 1 . Ectocarpus sp. . 1 Bryopsis hypnoides 3 Giffordia granulosa 16 28 Derbesia marina 6 11 Giffordia mitchelline 51 64 Codium fragile 15

Table 5. Total number of algal species from each division in HNPS quarry collections.

region

• reds browns greens total Schneider (1980) 4 19 (45)b 10(24) 13(31) 42 July 1976-Dec. 1977 NUEL 1 40(47) 19(22) 27(31) 86

.Apr. 1979-Sep. 1984 2-4 47(48) 17(17) 34(35) 98 1-4 50(45) 25(23) 36(32) 111

a. Regions sampled are shown in Fig. 2.

. b. Numbers in parentheses are percentages, our quarry collections (we found plants of this species in the quarry cut). The relative proportions of species in each algal division are similar in both studies (Table 5). As noted previously, these relative proportions are independent of total species number, and indicate phytogeographic affinity.

Qualitatively, the total quarry flora is very similar to that collected at the rocky shore sites; 97% of the species found in the quarry also occur outside the quarry, and 71% of the species found at the outside stations are also represented in the quarry or quarry cut.

However, differences in temporal distribution, or seasonality, do occur.

In general, species with ' subtropical' affinities (southern centers of distribution, found mostly in summer and autumn in local rocky shore collections) had an extended growing season in the quarry. For example, Agardhiella subulata occurred mostly in summer (May, June, July) at the rocky shore collection sites, but was found in every month in the Millstone quarry. Another red alga, Dasya baillouviana, was rare outside the quarry and found only in August-November qualitative collections in 1984; when found, plants were usually small. Over the course of the study, D,. baillouviana in the quarry could be found in any motith, and sometimes exceeded 1 m in length. Similarly, Enteromorpha~

clathrata and Cladophora sericea, May-October greens at most rocky shore sites, were much more common in the quarry, over a longer period.

In contrast, algae with more northerly distributions (especially browns) were less common in the quarry. Laminaria saccharina occurred each month at qualitative collection sites, but only in March and April 16

1 l

1 at the quarry. Similarly, Petalonia fascia, a November-July brown at l nearby coastal stations, occurred only in January and February at the

. quarry. 1 Several conclusions may be drawn from the qualitative algal collections, both from the rocky shore stations and from the quarry. l The overall flora appears stable, but subsets representing species found ]

at specific sites can respond to changing environmental conditions, and this response may indicate a thermal impact. The qualitative algal collections, as one facet of the rocky intertidal studies, permit identification of species present in the Millstone Point area, and the degree of their seasonal and year to year variability. If change in species composition (relative or absolute) is detected and attributed to thermal incursion (as evident at Fox Island-Exposed in 1984), analyses of qualitative collections will permit delimitation of the magnitude and geographical extent of the impact.

Undisturbed Transects The local rocky intertidal community, as represented by percent cover measurements in our undisturbed transects, has remained stable since 1979. The average yearly values for abundance of each ' functional group' in 1984 are given in Tables 6 and 7, along with a range of values from previous years. Results from this year are within or near those previously reported, and suggest continued stability in the local rocky shore community.

A ' composite' intertidal community is represented by the annual average percent cover at our 8 rocky shore stations (Table 6). On an annual basis, most of the high intertidal (Zone 1) is bare rock.

Ephemeral algae (mostly Ulothrix flacca, Bangia atropupurea, Blidingia minima, or blue-greens) and barnacles (Balanus balanoides) may also be common, and Fucus vesiculosus may be present in small amounts.

Barnacles and fucoids (mostly Fucus vesiculosus and Ascophyllum nodosum) are more common in the mid intertidal (Zone 2) of our ' typical' station. Other algae in Zone 2 may grow directly on rock (e_.g., Ralfsla verrucosa, Enteromorpha spp.) or as epiphytes on fucoids (e_.g.,

Elachista fucicola, Polysiphonia spp.).

17

Tabic 6 Annual average percent cover of undisturbed transects; ,

'cemposite' of all rocky intertidal stations.

C 1979 1980 1981 1982 1983 1984 MEAN t ZONE CLASS" I free space 56 66 71 73 71 72 67 barnacl es 10 10 10 9 12 12 10 mussels t t t t t t t fucoids b 8 7 6 3 2 2 5 Chondrus t t t t t t t ephemerals 24 15 12 13 13 13 15 grazers 1 1 1 1 2 1 1 predators t t t t t t t 2 free space 22 24 29 30 29 31 27 barnacles 23 25 25 26 27 21 25 mussels 2 2 2 1 1 1 2 fucoids 41 37 30 27 30 28 33 Chondrus 4 4 3 3 3 4 3

ephemerals 6 5 8 9 6 13 7 grazers 2 2 2 3 3 2 2 predators t t t t t t t 3 free space 23 25 32 23 24 25 25 barnacles 6 10 11 10 7 8 9 mussels 3 2 2 3 6 1 3 fucoids 14 13 9 8 10 8 11 Chondrus 37 35 31 36 38 41 35 ephemerals 13 12 12 15 12 15 14 grazers 3 3 3 3 3 2 3 predators t t t t t t t

a. See Materials and Methods for additional explanation of classes,

b. Includes both Chondrus crispus and Cigartina stellata,

c. 1979 includes data from Mar. 1979 - Apr. 1980; all other years are Oct. - Sep.

The low intertidal (Zone 3) is typically dominated by Chondrus crispus, though fucoids may also be common. Barnacles are also common, but usually somewhat obscured by an algal canopy. Other algae may be attached to rock (e.g. , Ralfsia, Corallina of ficinalis, Dumontia contorta) or to larger algae. Monostroma pulchrum, Ulva lactuca, polysiphonia spp. are common ephemeral epiphytes.

There is also a typical seasonal periodicity to these abundance patterns. Barnacles settle in early spring (Feb.-Apr.), and coverage increases through early summer as individuals grow. By late summer, barnacle coverage decreases, as individuals are lost to predation, desiccation, or starvation. Percent cover values are lowest in winter, i

18

but the cycle begins again the following spring (Grant 1977; Foertch and Keser 1981).

Ephemeral algae mentioned above also show seasonal cycles; they are usually most abundant in early spring, decrease in summer, peak again in autumn, and decrease again in winter. This periodicity is largely related to photoperiod and water temperature. Temperature also has an important indirect effect on ephemeral algal seasonality, by influencing the abundance and activity of grazers, primarily Littorina littorea.

These snails are rare or absent in winter; if found, they are mostly inactive and confined to crevices in the rock. As temperatures rise in spring, the snails become more active, and feed on the ephemeral algal turf. When temperatures are maximum in late summer-early autumn, Littorina is less common intertidally (at least during the day); it is usually subtidal, or sheltered under an algal canopy when the tide is out. The snails show a second, usually smaller, peak in abundance in autumn, then become e:sentia11y dormant for the winter.

Predators are another functional group of intertidal organisms that show seasonal periodicity. In our study, the most important predators are two carnivorous snails, Urosalpinx cinerea (oyster drill) and Thais lapillus (dog whelk). These snails become most common in summer, around the time of maximum barnacle coverage, and are partially responsible for the subsequent decline in barnacic abundance (Hanks 1957; Bayne and Scu11ard 1978; Foertch and Keser 1981). Other predators (e.g., crabs, fish) play a lesser role in structuring local intertidal communities (cf. Menge 1978, 1982; Edwards et al. 1982).

Mussel (Mytilus edulis) set onto intertidal rocks occurs mainly in mid to late summer, as well. Mussels are a preferred food for Urosalpinx and Thais, and will quickly become prey unless they find a rock crevice, or some other refuge that excludes predators.

The abundances of the perennial macroalgae are generally less variable than those of other functional groups. For example, canopy coverage of Chondrus crispus usually decreases in spring and autumn, as plants are overgrown by epiphytic ephemeral algae (e.g. , Monostroma pulchrum, Polysiphonia spp.), and increases in summer and winter as the epiphytes are removed. Throughout the year, however, understory abundance of Chondrus is relatively stable.

19

Real changes in macroalgal abundance can occur from year to year, however. For exampic,'a period of extremely low tides concurrent with extremely cold temperatures can expose Chondrus to lethal conditions.

Conditions of this type have been noted in our study (e.g., February 1980; NUSCo 1982), and were responsible for a general decline in Chondrus in the area, and the subsequent reported low values in 1981-82.

Regrowth from a surviving crustose holdfast occurs relatively quickly (Prince and Kingsbury 1973), however, and Chondrus remains the dominant organism in the low intertidal at most stations in our area.

A similar recuperation occurs in Ascophy11um nodosum populations (Printz 1956). Individual axes may be lost to senescence or storms, but new growth can occur from the holdfast, and the population is maintained (Keser et al. 1977; Keser 1978). Ascophyllum growth and mortality are

. discussed in more detail in a later section.

The abundance of Fucus vesiculosus is more variable among years than that of Chondrus or Ascophy11um. In our area, there is a 2-4 year I

cycle, based on the growth and life span of Fucus (NUSCo 1983). Unlike Chondrus and Ascophy11um, Fucus does not propagate vegetatively from its basal holdfast; rather, it occupies new substrata following settlement of zygotes and growth of germlings (Knight and Parke 1950). Typically, these germlings will not grow under an established Fucus canopy.

However, if an area in the mid intertidal is cleared (e_.g., by ice-scour), Fucus may settle and grow into a new canopy, comprised of plants of the same age. As these plants mature, they become more susceptible to epiphytism (Menge 1975), storm damage and ice-scouring (Mathieson g g. 1982; Chock and Mathieson 1983). These procestes tend to remove many plants at once; plant loss opens new substrata for Fucus colonization, and the species cycle is maintained (cf. Schonbeck and Norton 1980).

The preceding discussion has been a generalized description of the local intertidal community. Differences in community structure exist among stations, primarily owing to physical and biological differences related to degree of exposure to prevailing winds and waves; the more exposed stations have more available moisture, and support a more diverse community.

20 l r

Relative degree of exposure is consistent from year to year, and each rocky shore station has developed a characteristic community that exhibits considerable stability. Random events that induce variability tend to be temporary. For example, when a winter storm moved masses of mussels into Zone 3 at Seaside in April 1982, Chondrus was buried, in the following year, mussel coverage reached 75%, and Chondrus was as low as 1%. In the past year, however, mussels were lost and Chond(1s recovered; in September 1984, the low intertidal at Seaside Sheltered was covered by 28% Chondrus and 3% mussels. It remains to be acen whether the ' invasion' of mussels was a unique event, or part af a recurring cycle. In either case, analyses of data from undisturbed transects will permit quantitative characterization of the rocky intertidal community, and allow us to follow the development of the community over time.

Owing to the nature of the change at Seaside, and the distance from the power plant (ca. 2.5 km), the mussel invasion was attributed to natural variability, and not to an effect of MNPS operation. However, a change in community structure at a station near the discharge, not present at stations more distant, suggests environmental impact. A change of this type occurred at Fox Island-Exposed, following the opening of the second quarry cut in August 1983. Analyses of rocky shore data permit assessment of the impact.

Percentage of substratum covered by an organism is a measure of its abundance; annual average percent cover by each designated functional group is presented in Table 7. Percent cover values for fucoids at Fox Island-Exposed in 1984 are below the mean; Fucus cover has decreased in undisturbed transects at this station since 1980. This reduction in percent cover (from 1980-1983) had been taken as evidence of the long-term cycle of Fucus abundance discussed previously. The reducticn was not attributed to thermal influence, as Fucus in the recolonization transects and exclusion cage sites at the same station settled and grew rapidly throughout this period. There was some indication that the cycle was entering an upswing at FE in early summer 1983. New Fucus settled, and was expected to develop into a new canopy; however, this did not occur.

21

I N

I Table 7 Annual averare percent cover of undisturbed transects at rocky intertidal stations.

f W? SE MP FE BP TS GN SS 1984  %* range" 1984 1 , range 1984 1 range 1984 I range 1984 I range 1984 I range 1984 I range 1984 I range l ,

54 52 41-61 62 67 66-68 45 27 24-J8 72 71 64-76 1 free space 94 94 86-98 94 83 63-96 78 70 55-76 77 77 64-83 8-12 3 3 2-4 11 9 7-11 10 6 4-8 37 33 27-46 15 16 .12-18 barnacles 1 1 t-2 3 2 1-3 15 10 t t t t c 1 3 2-3 I

t t t t t t t 0-t t mussels 0 0 0 t t t t 2 1-3 t-1 1 22 3-35 t t t 0-1 2 1-4 I 4 1-8 7 7 6-9 2 t I fuccids h t t 1 t 2 e t 0 t 0-t t t 0-1 1 e t Chondrus 0 0 0 0 0 0 t t t-1 t t 16 -16 13-17 9 9 5-14 j

t 12 t-31 5 15 8-26 13 12 6-23 30 36 30-44 28 25 24-25 1-2 ephemerals 1 3 t-13 1 t-1 1 1 1-2 1 2 1-3 1 2 j

1-2 1-2 1 1 I e 1 1 1 t t

grazers 1 1 1 1 0 t 0-t t 0 0 t t t t t t t 0 0 C- t t 0 0 t t t predators 27 19 16-22 29. 21 15-26 32 19 15-26 35 21 14-25 30 36 26-41 31 32 17-40 42 33 25-41 25 32 27-39 8-44 46 56 46-62 2 free space 16 16 12-18 10 15 12-17 18 27 21-34 31 29 25-33 23 21 barnacles 11 18 10-29 15 21 15-28 t-1 t t-1 1 1 t-1 t' t t-1 1 9 3-13 1 2 1-2 t I t-4 t t t 4 41 14-60 t I t-1 mussels t t t-1 49 41 17-62 24 32 27-38 49 42 35-48 35 34 27-39 8 27 22-32 1-3 4 2 2-3 fuccids 55 42 25-41 12 10 6-13 3 4 3-4 5 7 5 4 3 3-4 1 2 4-11 Chor.drus I t C-t t t t-1 3-6 11 4 1-9 13 12 9-15 24 16. 12-20 37 15 13-16 11 7 ephemerals 1 t-2 1 1 1~ 3 4 1-2 3 3 3- 2 2 t-4 3 3. 3 1

2-4 2 3 2-3 1 3 2-3 1 2 t --

u grazers 2 3 2-4 3 3 t t t t t t t t t t t t t-1 0-t 0 0 0 t t t t N predators t t 19 18. 18-19 24 21 19-25 22 20 19-23 14 13 10-15 11 11 5-15 3 free space 42 48 44-56 17 23 16-24 56 41 34-53 5-12 2 3 2-4 6 5 1-8 13 16 12-22 5-17 4 3-7 7 7 5-10 5 9 1-14 barnacles 15 12 6-17 11 11 5 t 0-t t 3 t-15 t t t t t t-1 t 9~

4 0-t 2 4 1-8 5 9 t-30 t 2-3 2 14 9-19 e t t-!

mussels t t 7-17 6 5 4-5 11 10 7-13 t 2 focoids 27 27 21-36 7 11 6-18 10 11 38 39 31-47 74 65 61-69 32 39 34-41 53 .37 28-50 3-7 53 42 34-49 18 20 7-31 51 55 50-59 6-20 46 31- 26-38 13 17 12-24

) chondrus 6 5 3-10 6 8 5-11 9 8 7-9 23 16 13-18 7 14 3 2-3 ephemerals 7 4 3-7 8 7 4 3-4 2 2-3 1 2 2-3 2 1 t-2 2 1

3-4 3 3 3-4 2 5 2-7 2 1 t 1 I 1

grazers 3 3 t t t t t 't t t t t t t I t t t t t t t t predators i s. See Materials and Methods for additienal explanatice cf classes.

b. Includes both Chondrus criswas and Cigartina _stellata,1979 to 1983 (except at MP. which was sampled 1981).

first in Oct.

c. I (mean) and range include data freut 1

l t

t

, , . _ _ _ . _ _ _ . , _ _ , . . - . . . - .m ,__ __ ___

The community at Fox Island-Exposed underwent a structural change, following the opening of the second quarry cut in August 1983. As described in the Qualitative Collections section, the new cut altered the thermal regime at FE. Some results of this alteration are presented i

l in Table 8, as percent cover values in Zones 2 and 3 at FE for each l

l Table 8. Percent coverage of dominant organisms (and rock) in l

mid- and low intertidal transects at Fox Island-Exposed, before and after the opening of the second quarry cut.

1982 1983 pre-opening OCT DEC FEB APR MAY JUL Balanus 19 27 26 45 49 30 rock 33 35 25 6 15 20 13 16 17 12 17 8 Chondrus 12 8 7 7 7 8 Fucus Polysiphonia 7 4 1 0 0 i 2 3 2 3 5 3 Littorina Ralfsia 4 3 1 1 0 7 ulvaccan greens 6 2 1 1 2 1 Total # taxa 24 20 26 24 23 23 1983 1984 post-opening SEP NOV JAN MAR MAY JUL SEP 24 2 25 47 7 0 Balanus 2 26 17 40 34 5 22 16 rock 8 8 20 25 21 18 0 Chondrus 9 5 3 3 3 3 0 Fucus 11 2 3 10 3 Polysiphonia 7 27 3 3 2 2 3 2 0 Littorina 16 6 10 0 Ralfaia 8 10 1 78 ulvacean greens 3 19 2 1 4 23 22 23 28 24 13 Total # taxa 28 24 sampling period in the past two years. By November 1983, barnacle cover f I

at FE decreased sharply; barnacles were overgrown by Ralfsta (a brown algal crust) or replaced by a mixture of opportunistic ulvacean green algal species (e.g. , Ulva lactuca, Enteromorpha linza, E, ficxuosa, E.

clathrata). These effects were temporary, however, ameliorated by single unit operation. The ephemeral algae decreased through the winter, and in spring 1984, a dense set of barnacles occurred. Shortly 23

\

after the opening of the second cut, Polysiphonia spp. (P. harveyi and P. novae-angliae) also increased in abundance, but they occurred mostly as epiphytes on Chondrus, and did not replace it. Values in Table 8 represent canopy coverage; the understory Chondrus cover was consistently high, and exceeded 95% in many low intertidal quadrats through early summer 1984. The number of intertidal taxa was also consistently high through this period. Unit 2 returned to operation in Janaury 1984; by July 1984, the effluent water temperature exceeded 30*C, and the shore community at Fox Island-Exposed began to change. By September, incursion of heated water eliminated populations of Chondrus, Fucus, Balanus, and Littorina; the intertidal area became densely covered by Enteromorpha spp.

The Millstone Point rocky shore station is approximately the same distance to the west of the discharge as Fox Island-Exposed is to the east (ca. 250 m). In 1984, MP had the lowest fucoid cover of any year since sampling began at this station (Table 7), but it is too early to determine whether this is the result of a thermal impact, or natural variability. Continued sampling of the undisturbed transects at this site should permit that determination.

Recolonization Studies Recolonization studies, including those involving exclusion of predators and grazers, have been completed for 2-unit operating conditions. All studies to date have coroborated findings presented in earlier reports; this section will summarize these findings.

Removal of attached plants and animals from intertidal rocks may occur naturally at any time of year. Our denudation experiments, in effect, mimic processes (e.g., storms, ice-scour, grazing, predation, desiccation) that can make space available for recolonization in the intertidal region, during any part of the year. The initial stages of recolonization, whether in experimental areas or on naturally denuded substrata, are dependent primarily on what reproductive units are in the water column at the time (Hook 1981; Peckol and Searles 1983).

Since many intertidal organisms have precise reproductive phenologies, the time of year at which denuding occurs will affect the 24

structure of the early recolonization community; the same patterns of seasonal distribution discussed in the previous section are also seen in the recolonization studies. For example, if denuding occurs in early spring, barnacle = can settle almost immediately. Later, Fucus gernlings settle into crevicen and interstices between barnacles (mostly in the mid intertidal) and, given refuge from grazing, develop into a Fucus canopy. The rate at which the canopy develops is related to degree of exposure; following a spring denuding, Fucus populations reached pre-experimental levels in 8 months at Fox Island-Exposed, in 15 months at White Point, and in 27-30 months at Fox Island-Sheltered and Giants Neck.

If denuding occurs in summer, after the barnacle set, Fucus can settle quickly, but without the surface heterogeneity provided by the barnacles, Fucus germlings are vulnerable to grazing by Littorina.

Ephemeral algae may colonize, particularly at exposed stations, but coverage declines in winter; generally, little community development occurs until spring, when barnacles settle.

Similarly, if substrata are denuded in autumn or winter, recolonization is delayed until spring. Again, using recovery of the Fucus canopy in Zone 2 as a measure of recolonization, recovery from an autumn denuding was faster at exposed stations; ca. 15 month at FE, 25 at WP, and 30-36 at FS and CN. The longer period needed for recovery following denuding in autumn indicates the need for surface heterogeneity in recolonization, and emphasizes the importance of barnacle set as an event influencing community development.

Recovery of the intertidal community following denudation occurs in stages, because different components of the community recover at different rates. As noted previously, many of the ephemeral algae are opportunistic, and can colonize (at least temporarily) available space almost immediately. Most local predators and grazers are mobile, and can tepopulate c1 cared substrata from nearby undisturb d areas, as soon as food availability and weather conditions permit. Therefore, the high intertidal (which is mostly bare rock, on which barnacles and ephemeral algae may be seasonally important) may appear ' recovered' immediately after denuding, and is almost invariably similar in appearance to Zone 1 of nearby undisturbed transects by the end of the first barnacle set.

25

The mid intertidal of our local rocky shore community is dominated by fucoids. As discussed previously, cleared substrata can recover (in terms of Fucus canopy) in as little as 8 months (when denudation occurs prior to barnacle set, at an ecposed station, or as long as 3 years (when denudation occurs after barnacle set, at a sheltered station).

Recovery of the low intertidal (typically, re-establishment of a Chondrus population) may take much longer. Chondrus usually propagates from a basal crust. If the upright axes are removed (e.g., by scraping or freezing) but the crust is intact, recovery may be rapid, as reported in the previous section. If, however, the crust is removed (e_.g., by our methods of scraping and burning), repopulation must occur by settlement of spores, or by expansion of crusts from nearby plants.

Zone 3 of recolonization transects at Giants Neck and White Point prior to initial denuding (March 1979) had 10-15% Chondrus cover; after both spring and autumn denudings, Chondrus reached a maximum of 5% cover after 30 months. Fox Island-Exposed had 45% Chondrus in Zone 3 prior to burning; it recovered to ca. 20% after the spring denuding, and 15%

after the autumn denuding. The last value might have been slightly higher, if the second quarry cut had not opened. The incursion of heated water exceeded the physiological limit for Chondrus; in September 1984 all Chondrus disappeared from the recolonization strips at FE, as it was from the undisturbed transects. Paradoxically, only a trace of Chondrus was found in the recolonization transects at Fox Island-Sheltered prior to the initial denuding, but 3% was found at the end of the spring denuding experiment, and 10% after the autumn denuding.

Part of the explanation for the slow rate of recovery for Chondrus may be interspecific competition for space with Fucus. Regardless of time of year in which denuding occurred, Fucus was the first perennial macroalga to colonize the low intertidal; it usually developed into a dense canopy. Lubchenco (1980) denuded areas in dense Chondrus beds; Fucus could colonize and persist for at least 3 years. Chondrus slowly settled and grew under the Fucus canopy; Lubcheno predicted that when Fucus senesced (after its 3-5 year lifespan), Chondrus would remain and prevent further Fucus settlement. In other words, Fucus would 26

out-compete Chondrus for a short while, but eventually Chondrus would dominate the low intertidal. Neither her experiments, nor ours, continued for a long enough time to definitely test the hypothesis, but preliminary results support it.

Table 9. Comparison of percent coverage at recolonization (R) and undisturbed (T) transects, as of September 1984.

FS GN WP FE Zone Class

• R T R T R T R T 1 free space 84 99 76 96 86 96 39 59 barnacles 6 t 12 1 t 2 0 t mussels 0 0 0 t 0 1 0 0 Fucus 8 0 10 2 t t 0 0 Chondrus 0 0 0 0 0 0 0 0 ephemerals 0 0 1 0 13 1 61 41 grazers 1 t 2 t t t t t predators 0 0 0 t 0 0 0 0 2 free space 9 20 19 30 45 38 22 21 barnacles 22 12 22 14 14 18 0 0 mussels 0 0 0 t t t t t Fucus 64 67 57 54 23 29 0 0 Chondrus t 0 0 t t 3 0 0 ephemerals 1 t 2 1 16 11 77 79 grazers 4 1 1 1 2 2 t 0 predators t 0 0 0 0 t t t 3 free space 8 43 2 4 6 18 3 12 barnacles 11 11 6 10 8 3 0 0 mussels t 1 0 1 t 1 1 1 Fucus 64 30 S2 11 59 3 0 0 Chondrus 10 5 4 62 5 53 0 0 ephemerals 2 6 4 10 20 23 96 87 grazers 4 3 1 1 1 1 t 0 predators t t 0 1 t t t 0

• See Materials and Methods for additional explanation of classes.

Some of the concepts discussed previously, related to the development of a recolonization community, are illustrated in Table 9, where average percent cover values for the recolonization strips in September 1984 are compared sith those from adjacent undisturbed transects. Owing to the effects of the second quarry cut, values at Fox Island-Exposed are atypical of those at other stations, and at FE itself on earlier dates. As the most exposed recolonization station, FE recovered most quickly from the September 1981 denuding. The high 27

intertidal of the cleared strips was indistinguishable from that of undisturbed transects by the time barnacles settled in spring 1982 (ca.

6 months after denuding). As discussed earlier, the Fucus canopy in the mid intertidal re-established itself within 15 months of denuding, and l as reported last year (NUSCo 1984), recolonization of all components of the Zone 2 community was considered complete after ca. 20 months.

Chondrus cover in Zone 3 of the recolonization transects at Fox Island-Exposed was below pre-experimental levels, but (prior to the opening of the second quarry cut) higher than at any other station.

Since the recolonization community at FE so closely resembled that of l the undisturbed transects, it responded to the thermal incursion in l exactly the same way; Chondrus Fucus, and Balanus were removed, and Enteromorpha spp. dominated.

The other stations were unaffected by the opening of the second cut; recovery was slower, but by September 1984, was considered complete (at least in Zones 1 and 2; Table 9). It will be important to see whether the Fucus in the low intertidal will eventually be replaced by Chondrus.

Predators and grazers exert most of their influence on the recolonization community (and intertidal communities in general) by increasing competition, and by preventing the monopolization of space by a single species (Jones 1948; Menge 1976; Connell and Slatyer 1977; Hughes 1980). Initial recolonization in the absence of predation (e_.g.,

under exclusion cages) could occur very quickly. For example, all Fucus germlings in a caged area could grow, rather than only those afforded a spatial refuge by barnacles or rock crevices. On the other hand, persistence of a dense population of the early colonizers could retard or preclude further community development (cf. Lubchenco 1983). In some cases, ' ephemeral' algae could monopolize the space under a cage for 15 months, the duration of each cage experiment.

Sometimes the space monopolizing species was not the initial colonizer. For example, mussels frequently settled into barnacle populations in the low intertidal (cf. Lubchence and Menge 1978). Given the protection from predation afforded by the cages, mussels could overgrow and crowd out the barnacles, and dominate as long as the cages vore in place.

28

The cages also gave the areas under them some protection from desiccation and wave-shock, thereby attenuating several processes that can remove intertidal organisms. The observation that monopolization of space by a single species occurred only under cages is evidence that local intertidal communities are indeed in a state of dynamic equilibrium, a balance between recruitment and growth, and senescence and removal. It will be particularly interesting to see if Fox Island-Exposed proves to be an exception to this generalization; if the thermal incursion excludes Littorina, the suite of warm-water species may persist for a long time.

Ascophyllum Growth Studies As an indicator species, Ascophyllum nodosum has attributes that make it an ideal tool for the NU monitoring program (Foertch et _al_.

1982; Keser and Foertch 1982). It is abundant in mid and low intertidal regions in our area, and individual plants are long-lived (Baardseth 1970; Keser et_ g . 1981). This longevity allows plants (and populations) to integrate the effects of environmental conditions over an entire growing season, or even over several years. In addition, Ascophyllum growth rate is sensitive to changes in water temperature (Vadas et al. 1976, 1978; Stromgren 1977; Wilce et al. 1978), and its mode of growth makes it easy both to determine length, and to identify individual tips (allowing successive length measurements).

Because the mode of growth is unique to Ascophyllum (among plants in our area), and because it has such direct application to our monitoring program, a brief discussion of this plant's typical vegetative phenology follows (cf. Sundene 1973). In early spring (usually Feb.-Mar.), a small swelling forms at the tip of each viable vegetative axis; by late March or April, this swelling develops into a vesicle (air bladder). A new tip extends beyond the bladder, and subsequent growth occurs between the apex and the bladder. Tip elongation can therefore be determined by periodic measurements of this region. A tag placed behind the bladder (tight enough that it will not slip off and loose enough to avoid tissue damage) uniquely identifies 29

each tip, and permits successive measurements. Apical growth continues into autumn, slows during winter, then resumes in spring with the formation of a new bladder.

Ascophy11um growth during the 1983-84 growing season is illustrated in Figure 3. Total tip length (Fig. 3a) was higher at our

'experimenta1' station (Fox Island) than at either ' control' station (White Point or Giants Neck), as it has been since this study began in 1979. Another consistency with past years is the pattern of incremental I growth (Fig. 3b). Since 1979, highest growth rates for plants at the control stations have occurred from late summer to autumn (Aug.-Oct.);

these periods of maximum growth correspond to periods of maximum ambient water temperatures (ca. 21'C). Maximum growth rates at Fox Island, however, usually occurred in spring or early summer. In the past, this temporal shift has been attributed to a slight thermal incursion at Fox Island (a 2-3*C rise), and is considered evidence that water temperatures in excess of 21-22*C are suboptimal for Ascophy11um growth.

These growth patterns are evident in data from the 1983-84 growing season, and permit initial assessment of the effects of opening the second quarry cut (August 1983). From May to August, Ascophy11um tips at Fox Island grew 67 mm (ca. 20 mm/mo). Growth dropped to 8 mm.mo in September, and to 2 mm/mo in October. Crowth rates at the control stations were lower in early summer, but averaged ca. 14 mm/mo through October.

The highest Ascophyllum mortality in the 1983-84 growing season was at Fox Island (Fig.4), whether determined as number of plants, or tip tags, or growing tips. This mortality cannot be directly related to the opening of the second cut, as values at Fox Island were within the range of past years. There has always been a great deal of station-to-station and year-to-year variability in mortality patterns. For example, in terms of surviving plants (over the past 5 years), Fox Island and Giants Neck have each been highest twice. lowest twice, and intermediate once; White Point has been high once, low once, and intermediate 3 times.

The absence of immediate impact from the opening of the second cut was related to MNPS operating status. Unit 2 was shut down for refueling and maintenance from June 1983 to January 1984, so when the second cut was opened (August), a single Unit was in operation. This 30

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32

situation resulted in effluent temperatures 7-9'c above ambient, and maximum water temperature along the shore ca. 26-28'C. As previously demonstrated, these temperatures are above those required for optimal Ascophy11um growth, but not necessarily immediately lethal.

To characterize the effects of a 2-cut effluent when both units are on line, we include data from 1984, illustrated in Fig. 5. With two units in operation, effluent water temperatures averaged 12-13*C above ambient; in spring and early summer, these elevated water temperatures produced high growth rates at Fox Island. However, by the end of June 1984, quarry temperatures exceeded 30*C, and by mid-July, as high as 34*C. This temperature regime sharply reduced growth rates at Fox Island between June and July, and caused irreversible tissue damage. By August, none of the tagged plants had a viable axis, and by September, not a single Ascophy11um plant remained at the Fox Island study site.

For comparison, White Point in September had remaining 193 tagged tips on 47 tagged plants.

Recovery of an Ascophy11um population at Fox Island is dependent on the characteristics of the thermal plume resulting from 3-Unit operation. If the effluent continues to be directed along the shore towards Fox Island, Ascophy11um will not recolonize. If, however, the added momentum of Unit 3 discharge is sufficient to force the plume offshore, conditions may resemble those of 2-unit, singic cut, i.e.,

favorable for Ascophy11um growth. Even under ideal conditions, recovery of Ascophy11um population will be a slow process (Printz 1956; Keser 1978).

In spring of 1985, a new Ascophy11um station will be established, between FE and FS (ca. 250 m from the discharges, around the tip of Fox Island). The Ascophy11um population in this area is qualitatively unaffected by the 2-cut discharge (personal observations); quantitative analyses of Ascophy11um growth and mortality at this site and at sites more distant should permit determination of the effects of MNPS operation, and delimitation of the extent of those effects.

33

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'b) as incremental growth.

34

SUMMARY

AND CONCLUSIONS l

1. The opening of the second cut in August 1983, and resulting thermal incursion, produced structural changes to the rocky intertidal community at Fox Island-Exposed, a station ca. 150 m from the discharges. These changes were evidenced in qualitative algal collections, and in peicent cover measurements in undisturbed and recolenization transects. In 1984, this environmental impact was

-restricted to Fox Island-Exposed; the communities at the other rocky shore stations were typical of rocky coasts throughout the area.

2. Excepting the area immediately surrounding the discharge, the rocky shore in the vicinity of Millstone Nuclear Power Station supports a rich and diverse benthic marine community throughout the year.

This community is stable from year to year, and is similar to those of other areas of New England.

! 3. Degree of exposure to waves and storms plays a determining role in the structuring of rocky intertidal communities, either directly, by minimizing desiccation and providing nutrients, or indirectly, by influencing the distribution of grazers and predators. The abundance and distribution of grazers and predators are also affected by seasonal and year-to-year variability, other major factors influencing the distribution of intertidal algae and sessile invertebrates.

4. Time needed for recolonization of denuded intertidal areas is inversely related to both degree of exposure and intertidal height, i.e., recovery is quickest in the high intertidal of on exposed station, and slowest in the low intertidal of a sheltered station.

5. Denudation of intertidal rock is also a naturally occurring process; substrata can be cleared due to grazing, predation, storms, ice-scouring, etc. Therefore, the typical rocky shore community is not static, but continually undergoing changes.

6. Initial stages of recolonization immediately following denudation are influenced by the availability of spores and larvac in the water column, hence, time of year in which denuding occurs; 35

however, subsequent developmental rates and patterns are determined j hy intertidal height and degree of exposure.

7. Ascophyllum nodosum is a sensitive bioindicator of thermal stress;

-ita growth rate responds to slight changes in water temperature. A population of Ascophy11um 70 m from the MNPS discharge showed enhanced growth from 1979 to 1983 (compared with control sites),

and nortality values within limits of natural variability.

Ilowever, this population was eliminated in 1984 by heated water

(>30*C) following the opening of a second quarry cut.

9 36

1 l

REFERENCES CITED Baardseth, E. 1970. Synopsis of biological data on knobbed wrack Ascophyllum nodosum (Linnaeus) Le Jolis. FOA fisheries, Synopsis

! #38, Rev. 1.

Battelle-William F. Clapp Laboratories. 1977. A monitoring program on the ecology of the marine environment of the Millstone Point, .

I Connecticut area. Annual Report for the year 1976. Presented to the Northeast Utilities Service Company.

Baynes, B.L. and C. Scu11ard. 1978. Rates of feeding by Thais 0;utalin) inpiliwu (L.l. J. Cup. Mar. Util, SA:h 72:!!?-229.

Bold, H.C. and M.J. Wynne. 1978. Introduction to the Algae.

Prentice-Hall, Inc., Englewood Cliffs, N.J., 706 pp.

Chapman. V.J. 1946. Marine algal ecology. Bot. Rev. 12:628-672.

Connell, J.H. 1961. Effects of competition, predation by Thais lapillus and other factors on natural populations of the barnacle, i Balanus balanoides. Ecol. Monogr. 31:61-104.  !

, and R.O. Slatyer. 1977. Mechanisms of succession in natural communities and their role in community stability and organization.

Amer. Natur. 111:1119-114.

1 Dayton, P.K. 1975. Experimental eveluation of dominance in a rocky intertidal algal community. Ecol. Monogr. 45:137-159.

Druehl, L.D. 1981. Geographical distribution. in Lobban, C.S. and M.J. Wynne (eds). The Biology of Seaweeds. University of Calif.

Press, Berkeley and Los Angeles, p. 306-325.

Foertch, J.F. and M. Keser. 1981. Factors influencing development of rocky intertidal communities. Presented at 20th Northeast Algal Symposium, Woods Hole, Massachusetts. April 11, 1981.

, and G.W. Johnson. 1982. Ascophy11um growth in southeastern Connecticut. Presented at 21st Northeast Algal Symposium, Woods Hole, Massachusetts. May 1, 1982.

Edwards, D.C., D.O. Conover and F. Sutter, III. 1982. Mobile predators and the structure of marine intertidal communities. Ecology 63:1175-1180.

Grant, W.S. 1977. High intertidal community development on a rocky headland in Maine, U.S.A. Mar. Biol. 44:15-25.

Hanks, J. 1957. The rate of feeding of the common oyster drill, Urosalpinx cinerea (Say), at controlled water temperatures.

Biological Bulletin Marine Biological Laboratory, Woods Hole, MA.

112:330-335.

i l

37 l

l Hughes, R.N. 1980. Predation and community structure. in Price, J.H.,

D.E.G. Irvine, and W.F. Farnham (eds) . The Shore Environment, Vol. /

2: Ecosystems. Academic Press, London and New York. p. 699-728.

Jones, N.S. 1948. Observations and experiments on the biology of Patella vulgata at Port St. Mary, Isle of Man. Proc. Liverpool Biol. Soc. 56:60-77.

Josselyn, M.N. and A.C. Mathieson. 1978. Contribution of receptacles from the fucoid Ascophy11um nodosum to the detrital pool of a north temperate estuary. Estuaries 1:258-261.

Keser. M. 1978. Ecological effects of harvesting on the growth of Ascophy11um and the growth dynamics'of Tucus. 'r n . 'u . tuests,' univ.

Maine. 138 pp.

, and J. Foertch. 1982. Colonization and growth of Ascophy11um nodosum in New England. Presented at First International Phycological Congress, St. John's, Newfoundland. August 9, 1982.

Keser, M., R.L. Vadas, and B. Larson. 1977. Growth of Ascophy11um nodosum in Maine under various harvesting regimes. Ninth Int.

Seaweed Symp. August 20-28, 1977, Santa Barbara, California. J.

Phycol. 13 (suppl.):82.

. 1981. Regrowth of Ascophy11um nodosum and Fucus vesiculosus under various harvesting regimes in Maine, U.S.A. Bot. Mar.

24:29-38.

Knight, M. and M.W. Parke. 1950. A biological study of Fucus vesiculosus L. and F. serratus L. J. Mar. Biol. Assoc. U.K.

29:437-514.

Lewis, J.R. 1964. The Ecology of Rocky Shores. English Univ. Press, London. 323 pp.

Lubchenco, J. 1980. Algal zonation in the New England rocky intertidal ,

community: an experimental analysis. Ecology 61:333-344.

. 1983. Littorina and Fucus effects of herbivores, substratum heterogeneity, and plant escapes during succession. Ecology 64:1116-1123.

, and B.A. Menge. 1978. Community development and persistence in a low rocky intertidal zone. Ecol Monogr. 59:67-94.

Mann, K.H. 1973. Seaweeds: their productivity and strategy for growth. Science 182:975-981.

Mathieson, A.C. , N.B. Reynolds, and E.J. lichre. 1981. Investigations of New England marine algae II: the species composition, distribution and zonation of seaweeds in the Great Bay estuary system and the adjacent open coast of New Hampshire. Bot. Mar.

24:533-545.

l 38 r

Mathieson, A.C., C.A. Penniman, P.K. Busse, E. Tveter-Callagher. 1982.

Effects of ice on Ascophy11ur nodosum within the Great Bay estuary system of New Hampshire-Maine. J. Phycol. 18:331-336.

Menge, B.A. 1976. Organization of the New England rocky intertidal community: role of predation, competition and environmental heterogeneity. Ecol. Monogr. 46:335-393.

. 1978. Predation int nsity in a rocky intertidal community.

Effect of an algal canopy, wave action and desiccation on predator feeding rates. 0ecologia 34:17-35.

. 1982. Reply to a comment by Edwards, Conover, and Sutter.

Ecology 63:1180-1184.

Menge, J. 1975. Effect of herbivores on community structure on the New England rocky intertidal region: distribution, abundance, and diversity of algae. Ph.D. thesis, Harvard Univ. 164 pp.

Mook, D.H. 1981. Effects of disturbance and initial settlement on fouling community structure. Ecology 62:522-526.

NUSco (Northeast Utilities Service Company). 1980. Rocky Shore. Pages 101-142 1:1 Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station Waterford, Connecticut. Annual report, 1979.

. 1981. Rocky Shore. Pages 1-39 fyL Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station Waterford, Connecticut. Annual report. 1980.

. 1982. Rocky Shore. Pages 1-41 in Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1981.

. 1983a. Rocky Shore. Pages 1-39 in Monitoring the marine environment of Long Island Sound at Millstone Nucicar Power Station, Waterford, Connecticut. Annual report. 1982.

. 1983b. Rocky Shore. Pages 1-30 fyt Monitoring the marine environment of Long Island Sound at Hillstone Nuclear Power Station, Waterford, Connecticut. Resume, 1968-1982.

. 1984. Rocky Shore. Pages 1-31 in Monitoring the marine environment of Long Island Sound at M111stono Nuclear Power Station, Waterford, Connecticut. Annual report, 1983.

Paine, R.T. 1966. Food web complexity and species diversity. Amer.

Natur. 100:65-75.

39

Peckol, P. and R.B. Searles. 1983. Effects of seasonality and ,

I disturbance on population development in a Carolina continental shelf community. Bull. Mar. Sci. 33 67-86.  !

Prince, J.S. and J.M. Kingsbury. 1973. The ecology of Chondrus crispus ,

at Plymouth, Massachusetts. I. Ontogeny, vegetative anatomy, reproduction, and life cycle. II. Field studies. Am. J. Bot.

60:956-975.

Printz, H. 1956. Recuperation and recolonization in Ascophy11um.

Second Int. Seaweed Symp. Braarud, T. and N.A. Sorenson (eds),

Pergamon Press, London. p. 194-197.

Schneider, C.W. 1981. The effect of elevated temperature anr8 reactor shutdown on the benthic marine flora of the Millstone thermal quarry, Connecticut. J. Therm. Biol. 6:1-6.

Schonbeck, M.W. and T.A. Norton. 1980. Factors controlling the lower limits of fucoid algae on the shore. J. Exp. Mar. Biol. Ecol.

43:131-150.

Stephenson, T.A. and A. Stephenson. 1972. Life Between Tide Marks on Rocky shores. Academic Press, London. 383 pp.

Stromgren, T. 1977. Short-term effects of temperature upon the growth of intertidal fucales. J. Exp. Mar. Biol. Ecol. 29:181-195.

Sundene, O. 1973. Growth and reproduction in Ascophy11um nodosum (Phaeophyceae). Norw. J. Bot. 20:249-255.

Taylor, W.R. 1957. Marine Algae of the Northeast Coast of North America. Univ. of Mich. Press. Ann Arbor. 509 pp.

. 1960. Marine Algae of the Eastern Tropical and Subtropical Coat,ts of the Americas. Univ, of Mich. Press Ann Arbor. 870 pp.

Vadas, R.L. 1972. Marine nigae. Pages 250-310 g Third Annual Report on Environmental Studies. Maine Yankee Atomic Powr Company.

. M. Keser, and P.C. Rusanowski. 1976. Influence of thermal loading on the ecology of intertidal algae. M Esch, G.W. and R.W.

MacFarlane (eds). Thermal Ecology II. ERDA Symposium Series, Augusta, CA. p. 202-251.

. 1978. Effect of reduced temperatures on previously stressed populations of an intertidal alga. h Thorp, J.H. and J.W. Gibbons (eds). DOE Symposium Series, Springficid, VA. p. 434-451.

(CONF-771114, NTIS).

40

! Wilce, R.T. , J. Foertch W. Grocki, J. Kilar. H. Levine and J. Wilce.

1978. Flora Marine Algal Studies. _in Benthic studies in the vicinity of Pilgrim Nucicar Power Station, 1969-1977. Summary Report, Boston Edison Co. p. 307-656.

Zaneveld, J.S. 1969. Factors influencing the limitation of littoral benthic marine algal zonation. Amer. Zool. 13:367-390.

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BENTHIC INFAUNA Table of Contents )

l Section Page ,

I INTRODUCTION............................................... I j MATERIALS AND METH0DS...................................... 2

(

DATA ANALYSIS.............................................. 4 INTERTIDAL RESULTS......................................... 5 i l

Sediments............................................... 5 l I

Cencral Community Structure............................. 7 i Density and Numbers of Species ......................... 8 f

Dominance............................................... 12 i Trophic Structure....................................... 14  !

I Species Diversity....................................... 15 Cumulative Number of Species............................ 15 j Cluster Analysis........................................ 16 l

SUBTIDAL RESULTS........................................... 18 l 1 Sediments............................................... 18 ,

General Community Structure............................. 18 f

Density and Numbers of Species ......................... 22 I Dominance............................................... 27 Trophi Structuro....................................... 29 i Species Diversity....................................... 29 l Cumulative Number of Species............................ 30 i l

Cluster Ana1yuls........................................ 30 l DISCUSSION................................................. 33 )

t Intertidal Commun1tien..................................... 33 l

Subtida1 Communitica....................................... 35 l

CONCLUSIONS................................................ 37  !

Intertida1.............................................. 37 l Subtida1................................................ 37 l l

REFERENCES CITED........................................... 39  ;

i l

BENTHIC INFAUNA INTRODUCTION i

Ecological monitoring programs at electrical generating stations frequently include studies of the local infaunal communities (LII.Co 1983: Boston Edison Co. 1983; PSNH 1984) because of the importance of those assemblages in maintaining the functioning of marine ecosystems.

Fcr example, infaunal organisms are an important food source for  ;

demersal fish, particularly juvenile flatfishes (Kuipers 1977; DeVlas 1979 VanBlaricom 1982; Woodin 1982). Sediment reworking by infaunal organisims also contributes to the energy recycling and nutrient regenerating processes that are necessary for maintaining ecosystem l

productivity (Goldhaber e_t,al. t 1977; Aller 1978; Hyllebe g and Maurer 1980; Raine and Patching 1980). Zeitzschel (1980) esticated that l

30-100% of the nutrient requirements of shallow water phytoplankton l

populations comes from the sediments with the activities of the benthon l providing the major source of inorganic nutrient release to the water column. Given the importance of infaunal communities, major shifts in abundsnee or composition could cause changes throughout the ecosystem.

Benthic organisms also provide an excellent monitoring tool, since they are relatively sedentary, sensitive to environmental change, and usually respond to disturbances in a predictable manner (Botsch 1973; Reish 1973: Sanders 3 d. 1980; Gray 1982; Rees 1984). For exampic, ,

1 stressed communities typically exhibit fewer species and individuals. l In addition, shifts in species composition occur as stress resistant organisms and those capable of colonization after stress, (eg .,

Polydora ligni, Cnpitella_ spp. and Mediomantus ambisq), become very abundant (McCall 1977: Reish el al.1980; Sanders 1983).

Operation of the Hillatone Nuclear Power Station (MNPS) creates several changes in the natural environmental conditions that might induce changes in the composition and abundance of local benthic communities. These changes includes current generated scour near the plant intake and dischargo, organism entrainment through the condenser cooling system, chemical and heavy metal additions, and increased water temperatures associated with the plant discharge.

The objectives of the benthic infaunal monitoring program are to (1) establish infaunal composition and abundance at subtidal and intertidal stations located within and beyond the area influenced by operation and construction of the MNPS, (2) identify seasonal and year to year patterns in species composition and abundance and establish the natural variability of these measures, (3) evaluate whether any changes in species composition and abundance (both short and long-term) are due to operation and construction of HNPS.

This report summarizes the results of the 1984 infaunal monitoring study and includes data collected in prior years for comparative purposes.

MATERIALS AND METHODS Benthic infaunal communities were sampled at four subtidal and three intertidal stations in September and December 1983 and March and June 1984 (Fig. 1). The Giants Neck (CN) subtidal and intertidal stations are located 5.5 km west of the plant and serve as reference stations because they are located beyond any projected thermal influence of the plant. The Intake subtidal station (IN) is located 0.1 km seaward of the Millstone Unit 2 intake structure, while the Effluent (EF) subtidal station is located approximately 0.1 km offshore and adjacent to the cooling water discharge in Long Island Sound. This station is positioned as close to the affluent as possible given the current produced by the discharge. The Jordan Cove (JC) subtidal and intertidal stations are located 0.5 km east of the plant and are within the area potentially influenced by the the cooling water discharged during two-unit l operation. The White Point intertidal station is located 1.6 km east of the plant in an area that will potentially be subjected to environmental changes when Millstone Unit 3 becomes operational.

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Jordan Cove subtidal, CNI = Giants Neck intertidal, JCI

. Jordan Cove intertidal WPI = White Point intertidal.

Subtidal samples were obtained by SCUBA divers, using a corer 10 cm (1.d.) by 5 cm deep. Af ter collection each sample was placed in a separate 0.333 mm mesh Nitex bag and brought to the surface. Ten cores were collected at each station four times a year, in September and December 1983 and March and June 1984 (hereafter referred to as 1984).

Intertidal samples were collected along a 5 m transect parallel to the water line at mean low water.

Samples were returned to the laboratory and fixed with a 10%

buffered formalin rose bengal solution. After a minimum of 48 h, organisms were floated from the sediments onto a 0.5 mm mesh sieve and the float and residue preserved separately in 70% ethyl alcohol.

Organisms were removed under dissecting microscopes, sorted into major groups (annelids, arthropods, molluscs, and others), identified to the lowest possible taxon and counted. Organisms not sampled adequately by our methods because of their small size (eg., nematodes, ostracode, copepods, and foraminifera) were not removed from the samples.

3

l i

Sediment analyses were performed on a 3.5 cm (i.d.) x 5 cm deep core taken at each station. The dry sieving method and the method of moments technique was used to calculate the arithmetic mean phi (Folk 1974), which'was then converted to mean particle size in millimeters. l DATA ANALYSIS Specten Diversity Seasonal species diversity for each station was estimated using the Shannon information index (ll'), calculated ass it' . ! "i "i log 2 "~Yf'

< i=1 N (Piciou 1977) where ng = number of individuals of the ith ,p,,g,,,

N = total number of individuals for all species.

S = number of species.

The evenness component of diversity (J) was calculated ant J= 11 '

timax, (Pielou 1977) where limax =1og2S represents the theoretical maximum diversity when all species are equally abundant. Evenness ranges from zero to one; J ,

approaches one as abundance becomes ma,re even among species.

Diversity calculations excluded oligochaetes, rhynchocools and any i other individuals not identified to species (either becanne they were juveniles or in poor condition).

Biological index Value The Biological Index Value (BIV) of McCloskey (1970) was calculated for the 10 most abundant taxa at each station. The species were ranked according to their total abundance in each sampling year and these ranks

> summed for all years. The sum for each taxon was then exprensed as a L

4 i

percentage of a theoretical maximum sum, which would occur if a species ranked first,in abundance in each of seven years.

Numerict,1_ Classification and Cluster Analyses t

l l

The Bray-Curtis similarity coefficient was used to classify otations (nornal analysis), based on transformed species counts (In (count + 1)).

The coefficient was calculated as:

I i 2 min (Xt j, Xik) (Clifford and Stephenson (1975).

S jk =

( (Xi j + Xik)

{

f where Xg ) = abundance of attribute i at entity j, X ik = abundance of attribute i at entity k.

Since Bray-Curtis similarities refer to only pair-wise comparisons, cluster analysen were performed to illustrate relationships among three i or more stations. A flexibic sorting strategy with beta = -0.25 was used to form groups of stations at decreasing levels of similarity (Lance and Williams 1967). Cluster analysis was performed on annual collections l from 1976 to 1984.

l INTERTIDA!, RESUI.TS Sediments Intertidal beach sediments were coarse to medium sands (Fig. 2) with mean grain size ranging from 0.53 to 0.71 mm at JC: 0.33 to 0.60 mm at CN and 0.34 to 0.51 mm at WP. In 1984, grain size at JC and WP increased from September to June and decreased at CN. Although silt-clay content was low at all stations, highest values were consistently observed at JC (0.7 - 2.9%) and lowest at WP (< 0.1%).

There were no unusual changes in the sediment characteristics of intertidal stations during 1984 relative to those observed over the past several years. Sediments at JC continued to be of larger grain size and contained higher amounts of silt-clay than those of CN and WP.

5

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i SEPT 70 SEPT 77 SEPT 78 SEPT 70 SEPT 80 SEPT 81 SEPT 82 SEPf83 Figure 2. Sediment characteristics at the Hillstone intertidal stations September 1976 - June 1984.

6

Figure 2. (Cont'd) 32.0- WHITE POINT GRAIN SIZE (M ) (-*-*-*)

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l l

Ceneral Community Structure During 1984, intertidal communities at all sampling stations were numerically dominated by annelids, both in terms of species and individuals (Table 1). The highest number of polychaete species was collected at CN (24), where they contributed 64.9% to the total species.

Only 12 polychaete species were found at JC, and these accounted for 35.3% of the total. Species of mo11uses (10) and arthropods (12) wero

! sont abundant at JC, where they contributed 29.4% and 35.5%,

l respectively.

polychastes were the dominant group at all sites contributing from i

43.5% (WP) to 60.2% (CN) of the total number of individuals.

j 011gochaetes were most abundant at GN and JC, where they contributed l

I

)

I l

i rette 1. puntos of spectee (3), teletive pottent of tetel (1) euebet of ladtviduelo (N). end telettee percent et totel ll) fot eeth eejer tesen sollested at Mll!stene Pelat latestidal etettese sempted itse Septeater ,

ige) . J,no 190s veth 1994

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30.4% and 40e4% of the totals, respectively. Arthropods (le4%) and j mollusca (2.4%) were most abundant at JC, while rhynchocoals were abundant only at WP (39.6%)e As in previous years, annelids remained the dominant component of intertidal consnunities: and arthropods and molluscs were more common at

JC than CN or WPe The most obvious change from the previous year was the ,

abundance of oligochaetes, which declined substantially at JC and increased at CNe f I

Density _and Numbers of Species .

?

Average number of individuals during 1984 ranged f rom 10 to [

172/ core (Fige 3) and number.of species from 3-8/ core (Fig. 4). The  !

number of individuals and species was consistently higher at JC than at l WP or CN. Densities and numbers of species were highest in June or f September and lowest in December or Marche The largest annual range in both parameters occurred at JCe t

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SEP76 SEo?7 SEP78 SEP70 SEP80 SEP81 SEP82 SEP83 Only one new species, the gastropod Melampus_bidentatue, was collected at intertidal stations during 1984, and it was represented by only one individual (Table $). This species is typical of New England tidal flat coneunities, but is rarely found on intertidal beaches similar to our sampling site.

During 1984 denettles and numbers of species at JC were lower than the previous year, but similar to other years. The observed decline from 1983 was principally due to the lower numbers of oligochaetes present during this year. At GN dnd WP, abundance was similar to that observed in previous years, while the average number of species was generally higher.

10

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, , 7 ,. . 3 -,-, -- r,-,-4 7 SEP70 SEP77 SEP78 SEP70 SEP80 SEP81 SEP82 SEP83 Figure 4. Mean number of species per core (* 2 standard errors) collected at Hillstone intertidal stations maspled from l' September 1976 - June 1984.

11

l.

Figure 4. (Cont'd) 1 i

y 12 5 pp o

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i i i i i i i i SEP70 SEP77 SEP78 SEP70 SEP80 SEP81 SEP82 SEP83 The temporal patterns observed in density and numbers of species during 1984 woro consistent with previous results, i.e. generally high in September and June and low in December and March. The degree of variation was stallar at all sites in 1984 This contrasts with previous years results, which indicated much higher annual variability at JC than at other sites.

I Dominance During 1984, the top ten numerically stundant taxa (primarily species of polychastes, oligochaetes and rhynchocools) accounted for more than 95% of the total individuals collected. 011gochaetes.

l Scolecolepides _ virid _te and rhynchocoals were cosanon to all stations ,

(Table 2). 011gochaetes and Scolocoperiden viridia were the most abundant taxa at CN and JC and contributed from 28.0% to 40.$% of the total individuals collected. Both taxa, however, were found in auch higher density at the JC station (over 30/ core at JC vs. 11/ core at CN).

12

(

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Table 2. Feedin8 IFree, density. (*/eere), percent centettution end Stelesteel lades velve (l!V) of the ten onet numertes!!y obendent tese et Milletene intertidet statione dutieg 1944 Caeserable date overaged ever the previeve seven yeare are else included.

Feedleg 1984 4976-83 1984 1976-83 1976-83 Typeb Density Denetty Foreent Fereent Siv Ciente tech SDF li 2 30.4 4.9 74.6 Olitecheose 13 28.0 H.2 90.9

$3 fjt g viridle SDF 11 2 8.2 4.7 71.0 Iep t'j opp. 80F 3 8.0 1.6 73.0 lieg he _ rigg it,eljjjg SDF 3 3

2 6 7.2 15.1 $4.8 hhyneheseele C 4.0 1.2 $0.8 set 2 l leereljgn 80F 2 2 3.9 9.4 49.0 Le_ertlosive eFr. I 4 3*I 19.4 88g t 8DF

.e * *15 1.*)1'a t e1 0 1.1 . .

Re lne ve pgtse9 tug C 0.6 0.2 .

emmerve levrentierue 80F ei 1 Jerden Ceve SDP 40  !!3 40.5 73.1 97.4 Ollsacheets 49 32.3 11.1 92.9 Je jtte_Jej!d 32 f g yJLlill SDF 20.8 1.3 72.2 0 20 2 t131ul01 2.1 1.5 69.4 M

he djA d d lett 11'a 8DF IF 2

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3. =enue purronetyt SDF ei I 0.2 0.2 39.7 I 0.2 0.8 $3.6 thynMieele C ei Witt 19811

!? $ 39.9 24.1 89.9 Rhyntheceols C 12.4 91.6 9 4 23.3 gerlf?itl?tJ11 f reallil 80F F 4 16.1 14.7 66.3 SDF Olisacheete l 15.1 17.5 89.3 Pegeanie fylgene 80F F e1 2 2.3 9.7 82.4

.yp he d jeg eFp. BDF ei i 1.3 4.5 17.8 C .

0 0,6 .

1[t31?f2 t t !! fait C e1 0.5 3.2 49.5 ta *1 . t fl,1**"ijf g v$M#DF "1

,- ei 1

, t 1*lt eI l 0.4 0.8 39.3 B' 11if1perinae 80F 0.4 0.5 49.8 8DF ei 1 jygg.3 jgggg e a Not among the top ten in leet 7 years, n . Surren dereeli n.teeder, O e *nivore, ser - sae f reee deFeelt Feeder, $F 8verenelen to. der.

heru vere Only one other taxone Hediate diverstenlor was collected in densities e greater than 10/ core (JC)e Rhynchocoals were the most abundant taxa at WP (17/ core) and comprised 39.5% of the total individuals. Other dominant taxa at this station were Haploscoloplos fragilis (9/ core),

oligochaetes (7/ core) and Paraonis fulaens (7/ core)e The dominance structure of intertidal cosaunities during 1984, exhibited several changes from Previous years, both in the kinds of species and in their levels of abundancee A major change was evident in the contribution of oligochaetes at JC, which decreased from the seven year average of 123/ core (1977-1983) to 40/ core in 1984e in contraste densities of this taxon increased substantially at CN; duting 1984, the density was 11/ core compared to the average of 2/ core in previous yearse A smaller increase in density of this taxon also occurred at WPe 13

t, ,

3

• At GN, population changes included a decline in abundance of j Paraonis fulgens and rhynchocoels. These taxa ranked fif th and eighth,  ;

respectively during 1984, compared to their second and third place rankings (based on B1V of 68.9 and 84.1) over the last seven years. In i contrast, tufe taxa were found in higher densities at WP; average density of thynchocoels (17/ core) for example, was more than twice that of the neven year avarage (8/ core).

During 1984, changes also occurred in the abundance of flediste diversicolor, at JC, and 11aploscoloplos fragilis at CN. Higher numbers of both a cies were identified due to the occurrence of larger individuals (small individuals cannot be identified to species). The WP community has been the most consistent over the study period with five t ara having a Blv between 82.0% pd 92.0%.

In terms of compositional changes, five taxa were among the numerical dominants at intortidal stations for the first time. These were 1.cpidonotus a gamstus (CN), Lacuna vincta. Leptocheirus pinguis, and Crepidula pitas (JC) and Sphaerosyllis erinaceus (WP). The three speclan addqd at JC replaced a group of species that had been a relatively consistent part of the dominanco structure at this station in previoca years. This group included C,apitella app., Streblospio benedictl. and Hierophthalmus sczelkowli. These taxa were usually found in high abundances during Septenber, lleuever, the low densities collected in September 1983 caused their exclusion from the group of numerical dominants.

Trophic _ Structure

~

Deposit-feeders were th' ecoinant feeding type at intertidal stations during 1904 (Tablo 2). Surface deposit-feeders (Scolecolepiden viridig, olfgochaetos) were most abundant at JC and CN. Burrowing deposit-feeders,(lty loscoloplos spp., f.gploscoloplos fragilis, Capite11a spp.) and carnivore, (rhynchocoels) wore only abundant at CN and WP.

The trophic. structure and taxa comprising the various categories at intertidal stations have remained relagtvely stable over the years.

Burrow 1"g* deposit-feeders and carnivorun have been consistently more abundant 3t CN and WP, while the JC community has included higher numbers where the sediments contain low amoune9 of nurface deposit-feeders.

14

Species Diversity During 1984, annual species diversity averaged 2.19, 1.47, and 1.44 at GN, JC, and WP, respectively (Table 3). Average evenness (J), ranged f rom 0.44 (WP) to 0.64 (CN) . The average number of species used in diversity estimates was 11,14, and 9 at GN, JC, and WP, respectively.

Both H' and J varied similarly at all intertidal stations reflecting the seasonal abundance of Scolecolepides_ viridis and Haploscoloplos fragilis at GN, Hediste diversicolor_and Scolecolepides viridis at JC, and Haploscoloplos fragilis and Paraonis fulgens at WP. At all stations the average measures of species diversity during 1984 were within the ranges reported over the previous seven years.

Table 3. Species diversity (H'), evenness (J) and number of species (S) for each Millstone intertidal station in 1984 range of means 1976-1983, 1976-83 Range of 1984 Annual Mean Annual Means 2 1 Standard Error Ciants Neck _

2.19 2 1.0L 0.84 - 2.36 N'

0.64 2 0.28 0.26 - 0.73 J

11 2 7 6 - 13 Jordan Cov!

1.47 2 0.79 1.24 - 1.76 H' 0.40 - 0.61 J 0.47 2 0.20 7 - 17 s

14 2 7 n ite Point _

l.44 2 0.42 1.18 - 2.22 H' 0.37 - 0.80 J 0.44 2 0.16 3 - 12 s 921 Cumulative Number of Species Cumulative species curves for the three intertidal communities indicated increases in the collection of additional species in 1984 (Fig. 5). The highest number of additional species occurred at GN and the lowest at WP. Since 1976, the total numbers of species has been 15

highest at JC. The more gradual slope of the JC and WP curves reflects a lower, but constant, addition of species to the total.

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U 0- i i i i i i i i 1977 1978 1979 1980 1981 1982 1983 1984 LEGEND S7A + - + - + GN + 4-0 JC 6-* -o W P YEAR Figure 5. Cumulative species curves for Millstone intertidal stations from 1976 - 1984.

Cluster Analysis Cluster analysis, based on annual collections since 1976, continued to identify the long-term spatial differences among intertidal communities.

Group I contained all JC years and these linked at a low similarity to Group II, which contained all GN and kT years (Fig. 6). This low similarity was reflective of differences in both the kinds of species present at these stations and in the relative abundance of species common to all stations. For example, communities at GN and kT have consistently been characterized by the presence of rhynchocoels, Paraonis fulgens, and Haploscoloples spp., species which are never 16

-3 0 -

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Abundant at JC. Further, even though oligochaetes and Scolecolepides viridis are present at all sites, they are usually more abundant at JC than at other stations. This contributes to_the consistently low similarity between JC collections and those from GN/WP.

The 1984 collections at JC were most similar to those made in 1982 because of the lower densities of oligochaetes and the absence or low abundance of Polydora ligni, Capitella spp., Microphthalmus sczelkowii, Streblospio benedicti and Gammarus mucronatus. This group was a consistent component of the JC community during other sampling years.

The 1984 WP collections were clustered with the previous two years because of similarly high densities of rhynchocoels, Haploscoloplos spp.

and Streptosyllis arenae, relative to other years. The 1984 GN collections chained onto other GN years at a similarity level that was lower than any previous linkages. This low similarity was caused by a 17 c

large increase in the abundance of oligochaetes coupled with substantial decreases in the abundance of Paraonis fulgens and rhynchocoels. )

SUBTIDAL RESULTS Sediments Sediments at subtidal stations were composed of very fine to coarse sands (Fig. 7), ranging in size from 0.07 - 0.23 (IN), 0.22 - 0.29 (EF),

0.33 - 0.59 (CN), and 0.35 - 0.55 mm (JC). Sediments at IN were finest, and had the highest silt-clay content (10-35%); those at JC were coarsest, and lowest silt-clay content was at EF (3-10%).

During 1984, there were no seasonal trends in grain size or silt-clay content that were common to all stations. At EF, GN, and JC, grain size was similar during the four sampling periods, however, silt-clay content varied during the year. At IN, sediment grain size and silt-clay content exhibited marked seasonal change. For example, silt / clay content rose from 14.6 to 30% from September to December, declined to 10.0% in March and then increased to 35.4% in June.

The major differences in the sediment characteristics of subtidal stations in 1984 occurred at IN, where the grain size was finer and silt-clay content higher than values reported in recent years.

Similarly some of the highest values for silt-clay were observed at EF in the December through June collections. At JC and GN, the values for mean grain size and silt-clay content were similar to results from previous years.

General Community Structure Polychaete and arthropod species were the dominant components of subtidal communities in 1984 (Table 4). Of all species collected, polychaetes accounted for 46.6 - 54.8%, arthropods 23.1 - 27.0%, and molluscs 16.3 - 23.0%. In terms of individuals, polychaetes were the most abundant group contributing 53.8 - 79.2% followed by oligochaetes (4.5 - 23.6%), molluscs (2.6 - 7.1%) and arthropods (1.3 - 8.3%).

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September 1976 - June 1984.

19

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Table 4 ~ Number of spec'ies (S). relative p'ercent of total (%), number of individuals (N), and relative percent of -

total (%) for each major taxon collected at Millstone Point, subtidal stations sampled from September 1983 - June 1984 with 1976 - 1983 ranges.

1976 Ranges Stations 1984 N  % S  % N  %

S Z Effluent 69 46.6 7694 61.9 44 45.3 - 68.8 1099 - 5995 40.2 72.8 Polychaetes 444 - 3181 17.9 - 48.9 011gochaetes' - 2930 23.6 - -

34 23.0 887- 7.1 9 - 29 14.0 - 21.3 95 - 478 1.7 - 10.1 Mo11uses Arthropods 40 27.0 738 5.9 11 -- 45 17.2 - 31.7 53 - 799 1.0 - 9.4 167 1.3 .- - 16 - 202 0.7 2.3 Rhynchocoels -- -

Others 5 3.4 11 0.2 - -

Totals 148 12427 Ciants Neck 74 54.8 9262 79.2 44 - 72 51.1 - 65.3 2094 - 8057 54.9 - 71.5 Polychaetes 962 - 2658 15.6 - 41.8 Oligochaetes - - 1514 13.0 - -

2.6 8 - 22 11.3 - 17.7 49 - 281 0.8 - 3.8 Molluscs 22 16.3 302 25.9 507 4.3 17 - 42 18.9 - 31.6 56 - 761 1.0 - 12.4 pa Arthropods 35 16 - 66 0.4 - 0.7

"" Rhynchocoels - - 89 0.8 - -

0.1 1- 4 0.9 - 3.8 1- 13. 1 others 4 3.0 13 Totals 135  !!687 Intake 38 53.5  !!27 58.8 32 - 47 46.7 - 66.2 866 - 1358 43.6 - 71.9 Polychneten - 354 4.7 - 17.4 Oligochaetes - - 86 4.5 -

Mollunes 14 19.7 159 8.3 9 - 22 13.8 - 23.9 53 - 288- 3.3 - 13.6 Arthropods 19 26.8 529 27.6 12 - 31 18.5 - 33.7 115 - 963 8.4 - 46.9 15 0.8 - - 0- 19 0 - 1.4 Rhynchocoels - -

0 2.4 0- 1 1

- - - - 0.- 2 -

others Totals 71 1916 Jordan Cove 13122 73.0 47 - 68 52.7 - 66.2. 1163 - 6412 34.6 - 53.3 Polychaetes 67 51.5 41.5 - 59.1 3800 21.1 - - 1506 - 7811 011gochaetes - -

Molluscs 29 22.3 688- 3.8 9 - 32 12.7 - 24.8 43 - 348 1.1 - 6.1 1.3 15 - 2R 16.1 - 28.9 40 - 352 1.0 - 4.4 Arthropods 30 23.1 23o 15 - -77 0.4 - 1.3 Rhynchocoels - - 125 0.7 - -

. 0.1 0- 4 0 - 3.2 0- 10 0 - 0.2 Othern 4 3.1 8 Totals 130 17981-a - Taxon not ident111ed to specien level T

The total number of polychaetes collected exceeded previous observations at EF, GN, and JC, and was near the high end of the seven year range at IN. 011gochaete density was within the range of previous observations at all stations except IN, where 1984 densities were lower than in previous years. Mollusc and arthropod density and number of species collected at EF, GN and JC were near og above the upper end of the seven year range. Similarly, higher numbers of arthropods were 4 collected at IN and JC during 1984.

Density and Numbers of Species Average quarterly densities of subtidal communities in 1984 ranged from 9-643 individuals / core (Fig. 8). Densities were highest in June

-collections at EF, IN, and JC and in September at GN. Jordan Cove had the highest density and variability among sampling periods. During 1984, the range in average number of species was 5-40/ core (Fig. 9). At

'each station, the seasonal pattern in species number was the same as that for density 1.e., highest number of species occurred in June at EF, IN, and.JC, and in September at GN.

Density and numbers of species per core vere greater in 1984 at EF, GN, and JC than in previous years. At IN, both community parameters were slightly lower in the September, December and March collections, but similar to previous observations in the June collection. Density and numbers.of species have followed a similar pattern over years, (highest in September or June).

Fourteen new species were collected at subtidal stations during 1984 (Table 5), and all were represented by fewer than five individuals

-collected ~during-the year. Most new species have been reported from Long Island Sound (LIS) (Pettibone 1963; Cosner 1971); the polychaete, Microphthalmus fragilis, has not but it has been reported from Georges Bank (Blake personal communication), but not LIS.

22 C: i

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September 1976 - June 1984.

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. September 1976 - June 1984.

25

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Table 5. Species reported for the first time at Millstone subtidal (S) and intertidal (I) stations sampled from September 1983 -

June 1984 Mollusca Sabellidae Gastropoda Enchone incolor S Cerithiidae Sy111dae Cerithiopsis americanus S Exceone naidina S E11obiidae Arthropoda Melampus bidentatus 1 Callianassidae Pyramide111dae callianassa atlantica S Pyranidella fusca S Cammaridae Cammarellus aneulosus S Annelida Hippolytidae Eualus pustolus S Polychaeta Hesionidae Fodoceridae Cyptis vittata S Dulichia spp.

Hesionides sp. S Stenothoidae Microphthalmus franilis S Stenothoe gallensis S Opheliidae Xanthidae Ophelia acuminata S Eurvpanopeus depressus S Dominance During 1984, the ten most abundant taxa accounted for over 75% of all individuals, and of these, the top three taxa at each station comprised between 50.1% and 74.7% of the total. Density ranged from 1-197 individuals / core and was highest at JC and lowest at IN (Table 6).

Mediomastus ambiseta dominated the GN, JC, and IN communities, averaging 73, 197, and 10 individuals / core, respectively. At EF, Polycirrus eximius was the most abundant taxon, and averaged 100 individuals / core over the year.

Based on BIV's several changes and rearrangements occurred in the dominance structure,at subtidal stations. The increased density of Mediomastus ambiseta was the most notable change and was evident in the relatively low BIV and high rank of this species at all stations during 1984. Further, there were seven new taxa among the dominants at IN, and six of these appeared for the first time (no BIV). At other stations the number of different taxa among the top ten was 5 (EF), 3 (GN), and 2 27 L

l 1

Table 6. Feeding types. (x/ core), density, percent contribution and Biological Index valve (B1V) of the ten most numerically abundant taxa at Millstone subtidal stations September 1983 -

June 1984 Comparable data averaged over the previous seven years (September 1976 -

June !?83) are also included.

Feedits 1984 1976-83 1984 1976-83 1976-83 )

Type" Density Density Percent Percent Blv l J

Effluent Polycirrus eximius SDF 100 11 32.0 7.5 87.9 011gochaeta SDF 74 53 23.6 36.9 99.g Mediomastus ambiseta BDF 26 1 8.4 1.0 -

Tellina E lis SF 12 3 3.8 1.8 62.9 Protodorvillea gaspeensis 0 7 6 2.2 4.4 81.4 Aricidea catherinae SDF 6 11 2.1 7.8 83.9 Paguruu acadianus SDF 6 1 1.8 < 1. 0 -

Lumbrineris tenuis BDF 6 1 1.8 < 1. 0 -

Polydora caulleryi SDF 5 1 1.5 < 1. 0 29.3 Leptocheirus pinguis SDF 5 1 1.4 < 1. 0 -

Giants Neck Mediomastus ambiseta BDF 73 6 24.7 3.4 52.4 Tharyx spp. SDF 48 18 16.1 10.3 77.4 Aricidea catherinae SDF 39 37 13.3 21.6 95.2 011gochaeta .

SDF 38 49 12.9 28.6 97.6 Protodorvillea gaspeensis 0 11 4 3.8 2.2 60.3 Polydora caulleryi SDF 10 2 3.4 1.2 39.7 Polvcirrus eximius SDF 9 5 2.9 2.6 62.7 Exogene dispar 0 8 2 2.6 e 1.0 35.3 Polydora quadrilobata SDF 6 1 2.1 < 1. 0 -

Lumbrineris tenuis BDF 6 3 2.1 1.8 52.0 Jordan Cove Mediomastus ambiseta BDF 197 12 43.1 6.3 66.7 011gochaeta SDF 97 95 21.2 50.2 100.0 Aricidea catherinae SDF 46 30 10.1 15.6 92.9 Polycirrus eximius SDF 21 6 4.6 3.0 80.2 Lumbrineris te:uis BDF 20 6 4.3 2.9 76.2 Tharyx spp. SDF 10 3 2.3 1.5 55.2 Tellina agilis SF 8 2 1.8 < 1.0 41.3 Polydora caulleryi SDF 8 4 1.7 2.3 39.7 Chaetozone spp. SDF 4 5 1.0 2.4 -62.7 Prionospio steenstrupi SDF 3 1 1.0 < 1. 0 -

Intake Mediomastus ambiseta BDF 10 1 20.7 2.1 53.7 Polydora 11gni SDF 9 1 18.9 < l .0 -

Leptocheirus pinguis SDF 5 1 10.5 < 1. 0 33.5 Ampelisca abdita SF 3 1 6.8 e 1.0 - I Prionospio steenstrupi SDF 3 1 5.4 1.0 -

Nucula proxima SDF 3 1 5.2 < 1. 0 -

011gochaeta SDF 2 6 4.6 14.1 96.0 Crangen septemspinosus 0 2 1 4.2 < 1.0 -

Pygospio elegans SDF 2 1 3.4 < 1.0 31.7 Ampe11sca vadorum SF 1 1 2.4 < 1.0 -

a - SDF = Surface deposit feeder. BDF - Subsurface deposit Feeder. SF = Suspension Feeder.

0 = Omnivore. H = herbivore b - Taxa not among top ten in last 7 years 28

(JC). At EF, Polycirrus eximius exhibited the largest change in relative abundance, from 7.5% 1976-83 to 32.0% in 1984. At CN, the abundance of Mediomastus ambiseta exhibited the greatest change, increasing from 3.4 to 24.7%. At this station, it ranked first in 1984, while the seven year B1V was only 52.4% reflecting its low abundance in previous years. The dominance structure at JC was the most stable, only two species (Prionospio steenstrupi, Tellina agilis) were listed as dominants for the first time. -

Trophic Structure Deposit-feeders were the dominant feeding type at all subtidal stations (Table 6). Surface deposit-feeders dominated at EF, CN, IN, and subsurface deposit-feeders at JC. At CN and IN, suspension feeders and omnivores also contributed to community trophic structure.

The trophic structure of subtidal communities has remained stable since 1976. Deposit-feeders (surface and subsurface) comprised a majority of the total numbers at subtidal stations. Suspension feeders have contributed more to community trophic structure at IN than any other station. During 1984, there was a large shift in the percent contribution of subsurface deposit-feeders at subtidal stations; this was caused by the increased density of Mediomastus ambiseta.

Species Diversity The range in average species diversity measures of subtidal communities during 1984 was H' 2.60 - 3.64, J, 0.43 - 0.72 and S, 23 - 85 (Table 7). Species diversity was highest at EF and lowest at JC. Due to the dominance of a few species, lower evenness values were obtained at EF, CN, and JC communities than at IN, where the equitable distribution of a low number of species resulted in a high value of J (0.72). The EF community had the highest average number of species and IN the lowest.

During 1984, there were differences in the species diversity measures from those reported in previous years. The values of S were higher than the seven year range at EF and GN and lower at IN. Jordan 29

1 l

Table 7. Species diversity (H'), evenness (J) and number of species (S) !

for each Millstone subtidal station in 1984, range of means 1975-1983.

1984 Annual Mean 1976-83 Range of 2 1 Standard Error Annual Means Effluent H' 3.64 2 0.33 2.69 - 4.61 J 0.57 2 0.04 0.45 - 0.75 S 85210 24 - 76 Giants Neck H' 3.52 2 0.49 2.68 - 3.66

.J 0.57 2 0.05 0.55 - 0.73 S 72 2 18 29 - 69 Intake H' 3.39 2 0.34 2.95 - 4.12 J 0.72 2 0.12 0.60 - 0.76

$ 23 2 2 30 - 46 Jordan cove H' 2.60 2 0.44 2.91 - 3.96 J 0.43 2 0.05 0.52 - 0.71 S 58 2 13 30 - 67 Cove was the only station where H' and J were lower than the seven year average.

Cummulative Numbers of Species Cummulative species curves for subtidal communities from 1976 through 1984 are given in Figure 10. During 1984, there were 11, 16, 22, and 9 species collected for the first time at EF, CN, JC, and IN, respectively. The spatial relationship among stations observed in 1984 was similar to previous years: EF had the highest total number of species collected, IN the lowest, and the totals were similar between JC and CN.

Cluster Analysis Cluster analysis of the 1984 subtidal collections illustrated the spatial differences between the IN station and our other sampling i

30

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• IN +-+- + JC LEGEND: STA YEAR Figure 10. Cumulative species curves for Millstone intertidal stations

from 1976 - 1984.

P stations.. Further, the changes.in community structure that occurred in 1984 resulted in a temporal grouping of the EF, GN, and JC collections rather than the spatial groups that existed in previous years (Fig.11).

In 1984, the suite of species comprising the IN community (Group 1), was different from other subtidal communities. -The' occurrence of amphipod species'among'its dominants and the overall low abundances of E other taxa resulted in the spatial grouping of IN collections. The low densities of'the 1984 IN collections caused this year to chain with the previous five years. In addition, differences in the overall community

' composition resulted in the low similarity of the 1984 collections with previous years.

Group II contained the JC, GN, and EF collections from 1980 to

~1984. A temporal grouping of the JC, GN, and EF 1984 collections ,

(subgroup A) represents a major deoarture from the results of previous 31

I classification analyses and reflects the high abundance of Mediomastus ambiseta at these subtidal communities during this year. Group II was further subdivided into spatial groups of stations. The high percent similarity within each of these smaller clusters reflects the consistency in species composition and abundance at stations in previous years. Group III included annual collections from all subtidal stations between 1976 and 1979. Although composition of these collections were similar to later years, overall abundance was lower. This resulted in the lower similarity between collections from other years (Group II), and the higher similarity to IN, where densities are typically low.

Classification of the 1976 through 1984 subtidal collections illustrated a major change from previous years. The 1984 subtidal collections from GN, EF, and JC formed a temporal group rather than the spatial groups of previous years. The grouping was due primarily to the increased density of Mediomastus ambiseta at the JC, GN and EF subtidal communities, to-20-30-a

$40- g g I H I g 50-y60- - --

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L u 80-90-20ESRg2EEEREEEEEEE2% **SS ESee S**S n-omen n-omo-omNmo-nn ReShe

!!!E2: 5555B3!s590495 05B9_,e5985 2 Figure 11. Dendrogram resulting from classification of annual collections at Millstone subtidal stations, September 1979 - June 1984.

32

1 DISCUSSION In 1984, the intertidal and subtidal sand communities were described in terms of community composition, density, numbers of species, dominance and trophic structure. The following discussions of this year's results will evaluate the structural and compositional differences between communities sampled in potentially impacted and non-impacted areas around the Millstone Nuclear Power Station. In addition, the spatial and temporal characteristics observed during 1984 will be compared to previous years.

Intertidal Communities The 1984 sampling of intertidal communities continued to illustrate the spatial differences among stations that have been evident since the beginning of the monitoring program. Faunal density was much higher at JC than at other stations and the dominant species were small, less mobile forms that use organic material (derived from nearby eelgrass beds) for food and protection from dessication during low tide. At GN and WP, lower densities were observed, and larger burrowing species that could tolerate the unstable conditions, or which required clean unconsolidated sediments were most abundant.

The spatial differences in the structure and composition of Millstone intertidal sand communities reflect the localized differences in the degree to which abiotic environmental factors, e.g. wave scour, influence these communities. These factors can strongly influence sedimentary characteristics and the structure and composition of intertidal sandy beach communities (Holland and Polgar 1976). Exposed beach communities generally include lower numbers of individuals and species (Croker 1977; Withers and Thorpe 1978; oliver 1980) than do sheltered habitats (Maurer and Aprill 1979; Tourtellotte and Dauer 1983).

The influence of abiotic environmental conditions was reflected in the distributional patterns of many of the dominant species collected during 1984 and in the seven previous years. For example, oligochaetes, Hediste diversicolor, Streblospio benedicti, Microphthalmus sczelkovii, 33

Capitella spp. and Polydora ligni are usually most abundant at the more protected JC station, while Haploscoloplos spp., rhynchocoels, Paraonis fulgens, and Streptosyllis arense dominate in the clean, well drained sands of GN and WP. The former group of organisms have often been reported as the dominant components of more sheltered beaches (Sanders et al. 1962; Whitlatch 1977; Casper 1980; Soulsby et al. 1982; Knott 1983) while those in the latter category are generally found only in clean sandy environments (Dexter 1969; Whitlatch 1977; Maurer and Aprill 1979; Tourtellotte and Dauer 1983).

On a temporal basis, large seasonal fluctuations in population densities were again evident during 1984, reflecting the seasonal patterns of reproduction, recruitment, and mortality. These seasonal fluctuations have been consistently observed throughout our studies and are typical of most temperate sandy beach communities (Green 1969; Holland and Polgar 1976; Whitlatch 1977).

There were, however, some notable changes in the structure and composition of the JC intertidal community during 1984 relative to the previous sampling period. At this station, oligochaete abundance during this year was substantially lower than the seven year average and this followed a period (June 1983) in which record numbers were collected.

In addition, the numbers of Capitella spp., Streblospio benedictii and Microphthalmus sczelkowii were unusually low during 1984, when in most previous years they have been among the ten numerically dominant forms.

Densities of Polydora ligni and Gammarus mucronatus were also lower in 1984 although they continued to be among the top ten.

While faunal density and community structure at JC in 1984 were unlike that of most years, they were similar to observations made during 1981-82. For example, in September 1981, lower numbers of oligochaetes were collected following a two year period of very high abundance. In addition, the September 1981 collections also included unusually low numbers of Polydora ligni, Capitella spp., Streblospio benedicti and Microphthalmus sczelkowii, the same suite of species that were of unusually low density in 1984.

The large decline in oligochaete density and the lower densities of the other taxa mentioned above was primarily evident in September collections during both 1984 and in 1982 when there were unusally low 34

amounts of fine silt / clay within the sediments. Since this material is an important food source for oligochaetes (Verdonschot 1981) and for the other species found in low abundance this year (Sanders 1962; Zajac and Whitlatch 1983), the observed decline may have been related to lower levels of food resources at our sampling station.

Subtidal Communities The 1984 subtidal monitoring program identified both power plant induced and natural changes in sedimentary characteristics and community composition. Changes in the sediments were most pronounced at stations located in areas close to the power plant. Shifts in infaunal communities were evident at sites both within and beyond any influence of the power plant.

Major changes in sedimentary characteristics occurred at IN, where mean grain size was lower and silt / clay values higher than in most previous sampling years. Sedimentary changes, principally silt / clay, were first observed at this station in June 1983 (NUSCo 1984). During this period, construction of the Unit 3 intake structure resulted in very turbid conditions in the vicinity of IN station. This material settled and formed a layer of fine sediment approximately 1-2 cm deep; higher silt / clay values and lower mean grain size reflected this change.

The infaunal community at the IN station responded to the changing sedimentary conditions in a predictable manner. During the construction phase, the number of individuals and species collected at IN were lower than those collected since 1976. By June 1984, however, densities and number of species increased to levels higher than any previously obtained at this station. This peak was caused by the large increase in the abundance of opportunistic species, such as Polydora ligni and Mediomastus ambiseta.

Additional changes occurred in the dominance structure of IN. For example, six species (although previously found at IN) were among the top ten numerical dominants for the first time.

35

l Plant induced changes in the sediments and infaunal community were 1

also evident at EF during 1984. Silt / clay content of the sediments in  !

December (1983) and March and June (1984) was higher than usual and occurred as fine sediment, suspended during the construction of the Unit 3 discharge cut. Since the completion of the Unit 3 cut (August 1983) resulted in lower discharge velocity, greater accumulation of fine sediment in the area of our EF station could be expected. Subsequently, several changes in the EF infaunal community were noted. The major change occurred in the abundance of Polycirrus eximius, which increased nine-fold over the seven-year average (100/ core vs. II/ core). This species is a surface deposit feeder, and thus an increase in silt / clay could lead to an increase in abundance. Other infaunal community changes related to the differing sedimentary characteristics included an overall increase in deposit-feeding polychaetes, e.g. Lumbrineris tenuis, and increases in the density of other deposit-feeding organisms such as oligochaetes and the mollusc, Tellina agilis.

In addition to the localized changes related to power plant construction, there was a large increase in the abundance of Mediomastus ambiseta at all subtidal sampling stations. The high rank of this species, relative to the previous years, caused changes in all parameters used to describe the structure and composition of subtidal communities during 1984. For example, the linking of the 1984 EF, GN and JC collections in the cluster analysis was the first year in which the temporal similarity among stations was greater than their spatial similarity. In addition to increases in Mediomastus abundance, increases in density and numbers of species occurred at both potentially impacted (JC, EF) and non-impacted (GN) stations .

The regional changes noted above were the result of natural events, since communities both within and beyond any influence of the power plant were similarly affected. This is not unusual since large temporal fluctuationc in density and composition are typical of benthic communities-subjected to changing environmental conditions (Rainer and Poore 1979; Maurer et al. 1979; Levinton and Stewart 1982). Abiotic factors can strongly influence the structure of shallow water subtidel communities. For example, severe storma and high winds can resuspend sediments and organisms and disperse them over wide areas (Rhoads et al.

36 4 l

1978; Dobbs and Vozarik 1982). Because of these disturbances, the proliferation of short-lived, highly adaptive species, " opportunists",

I such as Mediomastus ambiseta, frequently occurs (Grassle and Crassle 1974; Sanders et,al., 1980; Bamber and Spencer 1984).

Large changes in population density are not unusal at Millstone, and over the last eight years several taxa have exhibited marked fluctuations in density (NUSCo 1983). These year to year cycles are typical of infaunal communities, which include species capable of rapidly exploiting a temporarily abundant resource more efficiently than

-other members of the community. From past studies, these increases are ,

usually temporary and have not led to long-term shifts in the composition of local subtidal communities. ,

CONCLUSIONS Intertidal During 1984, there were no identifiable power plant induced impacts on the intertidal sand communities. Since our stations are located outside the area influenced by the two-unit thermal plume, this observation is not surprising . However, once Unit 3 becomes '

operational, both JC and WP communities will be subjected to direct temperature increases. The long-term data collected during the Unit I and 2 operational studies will provide the information necessary to assess any future impacts during 3-unit operation.

I Subtidal

-During 1984, there were no changes in the subtidal communities that could be attributed to the operation of Millstone Units 1 and 2.

Localized changes in both sedimentary characteristics and infaunal communities occurred as a result of the Unit 3 construction program.

These changes were observed in the immediate vicinity of the power plant and have not influenced the greater Millstone Point area. High densities of Mediomastus ambiseta, throughout the Millstone Point area l

t 37

in 1984 resulted in major shifts in many parameters used to describe the subtidal communities. This change occurred at all of our sampling stations and thus was considered a natural event. i I

1 l

l l

38 i i

REFERENCES CITED Aller, R.C. 1978. Experimental studies of changes produced by deposit feeders on pore water, sediment, and overlying water chemistry.

Am. J. Sci. 278:1185-1234.

Bamber, R.N. and J.F. Spencer. 1984. The benthos of a coastal power -

station thermal discharge canal. J. Mar. Biol. Ass. U.K. 64:603-623.

Boesch, D.F. 1973. Classification and community structure of the Hampton Roads area, Virginia. Mar. Biol. 21:226-244.

Boston Edison Co. 1983. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 22.

Caspers, H._ 1980. The relationship of saprobial conditions to massive populations of tubificids. Pages 503-505 irt R.O. Brinkhurst and D.G.

Cook, eds. Aquatic oligochaete biology. Plenum Publishing Corp., New York.

Clifford, H.T.', and W. Stephenson. 1975. An introduction to numerical classification. Academic Press, New York. 229 pp.

Croker, R.A. 1977. Macrofauna of northern New England marine sand: long term intertidal structure. Pages 439-450 lyL B.C. Coull, ed. Ecology of marine benthos. University of South Carolina Press, Columbia, South-Carolina. .

De Vlas, J.- 1979.- Annual food intake by plaice and. flounder in a tidal flat area in the Dutch Wadden Sea, with special reference to consumption of regenerating parts of macrobenthic prey. Neth. J. Sea Res. 13:117-153.

Dexter, D.M. 1969. Structure of an intertidal sandy-beach community in North Carolina. Estuarine Coast. Mar. Sci. 9:543-558.

Dobbs, F.C. and J.M. Vozarik. 1983. Immediate effects of a storm on coastal infauna. Mar. Ecol. Prog. Ser. 11:273-279.

Folk, D. 1974. Petrology of sedimentary rocks. Hempshill Publishing Company, Austin, Texas. 192 pp.

Goldhaber, M.B., R.C. Aller, J.K. Cochran, J.K. Rosenfield, C.S. Martens, and R.A. Berner. 1977. Sulfate reduction, diffusion, bioturbation in Long Island Sound sediments: Report of the FOAM Group. Am. J. Sci.

277:193-237.

Gosner, K.L. 1971. Guide to identification of marine and estuarine invertebrates - Cape Hatteras to the Bay of Fundy. Wiley-Interscience, New York. 693 pp.

Grassle, J.F. and J. Grassle. 1974. Opportunistic life histories and genetic systems in marine benthic polychaetes. J. Mar. Res. 32:253-284.

39

Gray, J.S. 1982. Effects of pollutants on marine ecosystems. Neth. J. Sea Res. 16:424-443.

Green, R.H. 1969. Population dynamics and environmental variability. Am.

Zool. 9:393-398.

Holland, A.F., and T.T. Polgar. 1976. Seasonal changes in the structure of an intertidal community. Mar. Biol. 37:341-348.

Hylleberg, J., and D. Maurer. 1980. The central role of bioturbation in sediment mineralization and element recycling. Ophelia (Suppl. 1):1-16.

Knott, D.M., D.R. Calder, and R.F. Van Dolah. 1983. Macrobenthos of sandy beach and nearshore environments at Murrells Inlet, South Carolina, USA. Estuar. Coast. Shelf Sci. 16:573-590.

Kuipers, B.R. 1977. On the ecology of juvenile plaice on a tidal flat in the Wadden Sea. Neth J. Sea Res. 11:56-91.

Lance, G.N., and W.R. Williams. 1967. A general theory of classificatory sorting strategies, I. Hierarchical systems. Comput. J. 9:373-380.

Levings, C.D. 1975. Analysis of temporal variation in the structure of a shallow-water benthic community in Nova Scotia. Int. Rev. ges.

Hydrobiol. 55:449-470.

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LILCo (Long Island Lighting Company). 1983. Preoperational aquatic ecology study, Shoreham Nuclear Power Station, Unit 1. Prepared by GeoMet.

Kiurer, D., and G. Aprill. 1979. Intertidal benthic invertebrates and sediment stability at the mouth of Delaware Bay. Int. Rev. ges.

Hydrobiol. 64:379-403.

, D. , W. Leathem, P. Kinner, and J. Tinsman. 1979. Seasonal fluctua-tions in coastal benthic invertebrate assemblages. Estuar. Coastal Mar. Sci. 8:181-193.

McCall, P.L. 1977. Community pattern and adaptive strategies of the infaunal benthos of Long Island Sound J. Mar. Res. 35:221-266.

McCloskey, L.R. 1970. The dynamics of the community associated with a marine scleractinian coral. Int. Rev. ges Hydrobiol. 55:13-81.

NUSCo (Northeast Utilities Service Company). 1983. Benthic infauna. Pages 1-47 in Monitoring the marine environment of Long Island Sound at Millstone

! Nuclear Power Station, Waterford, Connecticut. Annual Report 1982.

l

. 1984. Benthic infauna. Pages 1-57 in Monitoring the marine environ-ment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual Report 1983.

, 40 f

Oliver, J.S., P.N. Slattery, L.W. Hulberg, and J.W. Nybakken. 1980.

Relationship between wave disturbance and zonation of benthic inverte brate communities along a subtidal high-energy beach in Monterey Bay, California. Fish. Bull., U.S. 78:437-454.

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Aphroditidne through Trochochaetidae. U.S. Nat. Mus., Bull. 227:1-356.

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385 pp.

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Spionid polychaete examples. J. Exp. Mar. Biol. Ecol. 60:35-45.

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Pages 195-218 in K.R. Tenore and B.C. Coull, eds. Benthic dynamics.

University of South Carolina Press, Columbia, South Carolina.

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LOBSTER POPULATION DYNAMICS Table'of Contents l

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l INTRODUCTION.................................................... 1 MATERI ALS AND METH0D S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 RESULTS AND DISCUSSION.......................................... 4 Abundance and Catch Per Unit Effort.......................... 4 Population Characteristics................................... 7 Size Frequencies........................................... 7 Sex Ratios................................................. 7 Reproductive Activities.................................... 10 Mo lt in g and G row th . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Cu11s...................................................... 14 Tagging Program.............................................. 16 Population Estimates......................................... 17

! Entrainment.................................................. 17 Impingement.................................................. 20

SUMMARY

........................................................ 22 CONCLUSION..................................................... 24 REF ER ENC E S C IT ED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 l

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LOBSTER POPULATION DYNAMICS INTRODUCTION The American lobster (Homarus americanus) fishery in Long Island Sound (LIS) is the most economically valuable commercial fishery in the State of Connecticut; 1984 landings reached a record 2.16 million pounds The representing an exvessel value in excess of 6 million dollars.

Connecticut Marine Fisheries Information System indicates that over 30%

of the 1984 catch was landed in New London County, the region that includes Millstone Point. Because of intense fishing pressure in the area, local lobsters are nearly 100% exploited upon reaching legal size.

Therefore, lobster catch in the Millstone Point area is a function of the pre-recruit size class and it has been necessary to assess whether the operation of the Millstone Nuclear Power Station (MNPS) influences recruitment patterns.

The dynamics of the lobster population in the vicinity of Millstone Point have been monitored since 1969 with the objective of identifying changes in population characteristics that may be attributable to the construction and operation of the MNPS. The lobster program was designed to assess structural changes in the local population by quantifying catch per unit effort,. examining population characteristics (size frequencies, sex ratios, female size at sexual maturity, characteristics of egg-bearing females, and growth rates), estimating the size of the local population and determining lobster movements.

Changes in the local population are evaluated using year to year, seasonal, and between station comparisons of the population characteristics mentioned above. The results of our studies are compared to other studies conducted throughout the range of American lobsters.

MATERIALS AND METHODS Three stations were established around rock outcrops in the vicinity of the MNPS. From May through October 1984, 20 vinyl coated

wire pots:(76 x 51'x 30-cm; 2.5-cm2 mesh) were set at each station (Fig.

L1). ' Jordan. Cove.(JC) is east of Millstone Point about 500 m from the (

' discharge; Intake-(IN) is along the western shore of Millstone Point

'about 600 m from the discharge and near the power plant intake

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structures, and Twotree (TT) is south.of Millstone Point about 1600 m

' offshore ~near Twotree Island. Four trawls, each consisting of five numbered: pots equally spaced along a 50-75 m line buoyed at both ends, were' fished at:each station. Pots were individually numbered to examine the variability.in catch among pots and to provide a more accurate value of catch-per-pot rather than an average catch-per-pot based on 20 pots.

In addition to recording the number of lobsters caught in each pot, the number of other organisms was recorded to examine the influence of competing species on lobster catch. Catch per unit effort (CPUE) was adjusted for the possible effects of soaktime and catch of crabs and fish by means of covariance analysis (NUSCo.1984).

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Throughout the study, pots were hauled on Monday, Wednesday, and Friday, weather permitting. All vertebrates and invertebrates, with the exception of lobsters, were returned to LIS at each station. Lobsters were removed from the traps and their claws were restrained with rubber bands. The traps were then rebaited with flounder carcasses and reset in the same area. Previously tagged lobsters (recaptures), severely

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injured or sof t individuals, and those < 55 mm carapace length (CL) were -l

. immediately returned to LIS after recording the following data: carapace ,

l length, sex, presence, fullness, and development of egg masses on those females bearing eggs (berried), crusher claw position, missing claws,  !

and molt condition. Molt condition was determined using criteria i established by Aiken (1973). All other lobsters were returned to the laboratory and kept in tanks with a continuous flow of seawater. All lobsters collected that week were examined each Friday and the data J

mentioned above recorded; lobsters were tagged with a serially numbered international orange sphyrion tag (Scarratt and Elson 1965; Cooper 1970; l Scarratt 1970), and returned to the site of capture. Surface and bottom water temperatures and salinities were recorded at each station during each sampling trip.

The size of the local lobster population was estimated using the method of Jolly (1965) as modified by.Seber (1965). This multiple census method uses tag and recapture data collected from an open j population and accounts for the proce'sses of birth, death, and migration. The Jolly-Seber model allows for parameter estimation of I population size, survival rates, recruitment, and capture probability.

In our study, individual lobsters were considered recruited to the population when they grew to a size vulnerable to capture by our traps.

Methods for the collection of lobsters on the intake travelling I screens are described in the Fish Ecology-Impingement Sampling section of this report.

Lobster larvae sampling was coordinated with ichthyoplankton i sampling from May through August. Lobster larvae samples were collected with a 1.0 x 6.0 m conical plankton net (1.0 mm mesh) deployed using a gantry system described previously (NUSco 1978). Sample volumes were estimated from the readings of four General Oceanic flowmeters averaged 3

for each sample. Four-day and four-night samples were collected weekly.

Each sample was placed in a large 1.0 mm mesh sieve and kept in tanks R with a continuous flow of seawater. Most samples were sorted shortly 4 1

after collection (2-4 hr) in a white enamel pan and larvae were examined for movements and classified as either alive or dead. Lobster larvae were also classified by stage according to the criteria established by Herrick (1911) and sected in 70% ethyl alcohol.

A probability level of significance a =0.05 was used in all statistical tests.

RESULTS AND DISCUSSION Abundance and Catch Per Unit Effort Monthly catch statistics for 1984 are presented for each station in Table 1. Annual catch statistics, for each station, are presented in Table 2 (1978-84). A total of 7587 lobsters were caught in 4490 pothauls from May through October (1984). In the Millstone Point area, as temperature increased, catch increased, and as temperature decreased, catch decreased (Fig. 2). This relationship between CPUE and water temperature has been reported by other researchers (McLeese and Wilder 1958; Dow 1966, 1969, 1976; Flowers and Saila 1972). The total CPUE was highest in July at JC and 1N, and in August at TT. CPUE for legal size lobsters was greatest in May at TT, and in July at IN and JC.

From 1978 to 1982 CPUE was calculated as follows: (CPUE=(Total number caught / Total number of traps hauled) x 100). This formula does not account for soaktime which has been found to affect trap efficiency (NUSCo 1984). In addition to soaktime, the number of crabs and fish caught in lobster traps was shown to significantly influence lobster catch (Richards et al. 1983; NUSCo 1984). The total number of vertebrates and invertebrates caught in our traps are presented in Table 3, for each station. Spider crabs (Libinia spp.) had the greatest influence on lobster catch of all competing species caught in our traps.

Since the effects of soaktime and the incidental catch of spider crabs significantly biased the values of lobster CPUE, we adjusted our mean monthly CPUE by performing an analysis of covariance where soaktime and i

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Table 1. Catch statistics for lobsters cauthe at each statien May-October durint 1984 Number of . Total Number CFCE Adjusted Total Le8als CPUE rots hauled caurht (A) A CFCE A' caught (5) __3_.

Jordan cove MAT 240- 696 2,07 2.07 28 .12 1.94 1.95 29 .11 JrN 260 Sn3 JCL 240 530 2.21 2.16 42 .18

.12 AUG - 280 493 1.76 1.78 33 219 303 1,38 1.33 24 .11 SEF 255 332 1.30 1.23 15 .06 OCT Intake MAY 240 309 1.29 1.50 20 ~ .08 260 486 1.87 1.90 37 .14 JUN .

239 515 2.16 2.17 36 .15 Jtt AUG 280 397 1.42 1.44 - 22 .08 220 249 1.13 1.09 20 .09 SEF OCT 260 282 1.09 1.05 12 .05 Twottee 239 436 1.82 1.80 84 .35 MAY 260 443 1.70 .1.72 59 .23 JUN 240 438 1.83 1.77 67 .28 JUL 2.08 2.08 70 .25 Ato 279 579

.26 SEP 220 382 1.74 1.68 56 414 1.60 1.55 56 .22 Oct 259 a CPUE values adjusted for the effects of soaktime and apider crab catenes.

Table 2. Catch ststistics for lobsters caught in wire pots at each station 1978-84 Number of Total Number CPUE Total Legals CPUE pots hauled caueht (A) A caught (B) ,_B ,

Jordan Cove 1978 349 634 1.82 34 .10 1979 701 1337 1.91 97 .14 -

1980 722 966 1.34 63 .09 1981 724 640 0.88 51 .07 1982 1473 2816 1.91 152 .10 1983 1449 2368 1.63 218 .15 1984 1494 2657 1.78 171 .12 Intake 1978 348 720 2.07 77 .22 f 709 1184 1.67 98 .14 1979 1980 721 903 8.25 60 .08 1981 130 749 1.03 39 .C5 1982 1449 2740 1.89 153 .11 1983 1439 1646 1.14 126 .09 1984 1499 2238 1.49 147 .!O Twottee 1978 329 470 1.43 67 .20 1979 641 738 1.15 72 .11 1980 673 987 1.47 109 .16 1981 733 847 1.16 127 .17 1982 1418 3567 2.52 403 .28 1983 1456 2350 1.61 308 .21 1984 1497 2692 1.80 392 .26 5

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Table 3. Total number of invertebrates and vertebrates caught in lobster traps at each station May-October during 1984.

Jordan Cove intake Twottee Lobster 2657 2238 2692 Rock crab 71 208 112 ,

Jonah crab 12 26 36 Spider crab 437 2729 71 Hermit crab 28 323 77 Blue crab 7 32 1 Winter flounder 34 8 3 Summer flounder 24 27 9 Skates 2 6 7 Oyster toadfish 38 37 i Scup 3 23 1 Cunner 33 28 80 Tautog. 1 27 11 Sea raven 7 11 2 Whelks 4 21 41 6

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' Table 1.

Population Characteristics Size Frequencies The yearly size distribution of male and female lobsters caught from 1979 to 1984 is presented in Figure 3. Percent legal catch, mean carapace lengths, sex ratios, percent of berried females, and size frequency distributions for the 1984 catch are presented for each station in Figure 4. The percentage of legal-sized lobsters in -1984 was 9.6% (14.4% at TT,i6.7% at JC and IN) and was within the range of values reported since 1979 (7.2-10.1%). The percentage of legal-sized individuals in our catch was lower than that reported by other studies in LIS, in which wood traps were used (Smith 1977; Briggs and Mushacke 1979) and for wire traps used in Block Island Sound (Marcello et al.

1979). The mean CL of lobsters caught in 1984 was 71.8 mm. This length 1s very similar to previous values for mean CL since wire pots were first used (range 70.8-71.7 mm).

Sex Ratios The sex ratio of males to females during 1984 was 1.0:0.82 and was

- within the range reported in previous years (1.0:0.79-1.0:0.93) (Fig.

3). . Females predominated at the deeper offshore TT station (1.0:1.22) whereas more males were found at the shallow inshore stations (IN 1.0:0.68, JC 1.0:0.60) (Fig. 4). .This relationship between sex ratio and depth has been consistent since 1975 (Keser eti al.1983). Ennis

-(1980) indicated that sex ratios are very much dependent on the size

. composition of the catch which in turn depends on the method and depth of sampling. After females become sexually mature they tend to

. predominate in the catch due to changes in trapping behavior related to molting and. reproduction, legal restrictions of landing egg-bearing females, and the fact that mature females molt less frequently than males (Skud and Perkins 1969; Cooper et al. 1975; Ennis 1980).

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Figure 4. Size frequency distribution for male and female lobsters caught at each station during 1984. (Male: Female = M:F, Percent berried females = %BF, Mean carapace length = X, Percent legals = %L). 9

Reproductive Activities i 1 Several methods can be used to determine sexual maturity of female lobsters. The presence of external eggs is an obvious indication that females are_ mature. Another method of determining sexual maturity is to measure the width of the second abdominal segment, and plot the ratio of abdominal width to carapace length against the carapace length (Skud and

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Perkins 1969; Krouse 1973). The morphometric relationship between carapace _ length and abdominal width (second segment) for data collected during 1984 is presented in Figure 5. The curve shows that females begin to mature at about 50 mm CL and that all females are mature at about 95 mm CL. On the south shore of Long Island females begin to mature at a size larger than in the MNPS area, 81 mm CL (Briggs and Mushacke 1979). Additionally, in northern waters, Newfoundland, females also mature at a larger size 60-70 mm CL (Ennis 1980). The size range of berried females was 62-95 mm CL (mean CL 79.1 mm) confirming the small size at which females mature in our area (NUSCo 1984). 0 75-

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c------ - -- -- t The percentage of berried females caught in 1984 (6.2%) was greater than the percent caught since 1978 when wire traps were first used (range 3.1-4.9%). Twotree continued to yield the greatest proportion of berried females (9.6%) followed by JC (3.5%) and IN (3.4%). The mean CL of berried females (79.1 mm) was within the range of values reported in previous years (79.1-82.9 mm) (Keser et,al. 1983). Sixty-seven percent of the berried females caught in 1984 were of sublegal size (Fig. 6). In the past, about half of the berried females were of sublegal size; the 1984 mean CL and the number of sublegal sized. berried females provides further evidence for the small size at which females become mature in our area. 18-15-12-  ! 9 D 5' O , e 5: 'l i 3- , 0' i i . i i i . . . . 70 75 80 85 90 95 100 105 55 60 65 CARAPACE LENGTH (mm) Figure 6. Size frequency distribution for berried females caught during 1984. The Connecticut Department of Environmental Protection has been investigating the extent of the apparent low fecundity of female lobsters in western LIS (Smith 1977). To gain more insight into the reproductive cycle of lobsters in eastern LIS, we recorded both the fullness using the following scale (full, 3/4 full,1/2 full,1/4 full, < 1/4 full), and the developmental stage of egg masses carried by berried females during 1984. Egg mass fullness and egg mass development from May through October are summarized in Table 4. Based on embryo development, berried 11

I l' Table 4 The number of berried fesales examined for e,e pass fullness and development May-October during 1984. Number of Number with Number with Number with Number with Developmental l Number with Betried Fatales 1/2 3/4 Full Stage i

                        < t/4              1/4 Complement Month Examined        Corole,,pg       c.m le-e t       C anlement       Cneolement                                 j MAY          28             0                t                4                11          12        Light-Green wicptical disks AN           16             4                1                2                 1           8 KL            4             0                0                1                 1           2 AUG          18             0                0                0                 4          14      Black-Dark Creen SEP         48              1               5               16                10          16 OCT         50              t               5                7                16          21 TOTAL      164             6               12               30                (3          73 females caught in May and June carried eggs ready to hatch. The low number of berried females caught in July indicated the completion of the biennial spawning cycle. Females that were fertilized in the previous year (1983) began extruding eggs in August and the number of berried females carrying newly extruded eggs peaked in September and October.

About 90% of the berried females examined for egg mass fullness had 1/2 or more the normal full complement of eggs according to the description provided by Smith (1977). Only 3.7% of the berried females we examined itad less than 1/4 the normal (full) complement of eggs which compared to 10-14% found in western LIS (Smith 1977). Molting and Growth In 1984, molting peaked in June and remained at high levels through mid-August.(Fig. 7). In previous years molting reached a peak in early summer and decreased rapidly through the warmer sun:mer months. We , observed a secondary peak in autumn as we have in the past three years. Two molting peaks were also observed by Lund et al. (1973) in LIS and by Russell e_t,t al_. (1978) in Narragansett Bay. The average growth per molt (CL increment), in 1984, was 12.7%, (13.0% males; 12.4% females). Growth per molt varied with size class (Table 5). In general, smaller lobsters exhibit a greater percent growth than the larger ones. Other researchers working in inshore waters found growth per molt ranging between 12.0-17.5% (Wilder 1953; Cooper 1970; Ennis 1972; Fair 1977). In deeper offshore waters growth 12

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          -Table 5. Average percent growth for males, females and sexes combined for different carapace leneths using data collected from 1978-84 Tag Recapture Studies                                          1.ab Observations Males           Females                Both            Males             Females-      Both 50-60 m N                     6                    6                 12                  6                    5       11
            % Crowth           15.3                14.5                 14.9               11.5               20.8       15.7 61-63 mm N                   23                   60                  83                  7                  19        26
            % Crowth           14.1                 14.5                14.4               11.9               13.8        13.3 66-70 m N                   45                   90                 135                 18                  12        30
            % Crowth           13.8                 14.0                13.9               13.3               10.8        12.3 71-75 m N                   18                   40                  58                 12                    8       20
            % Crowth           13.0                 13.6                13.4                12.8              11.4        12.2 76-80 m N                     8                   17                  25                 8                    5       13
            % Crowth           12.7                  12.4               12.5                11.5              11.3        11.4 81-85 m N                     0                     t                   i                1                    0         i
            % Crowth                -                12.2               12.2                14.8                    -     14.8
            > 85 m N                    O                     I                   I                -                    -        -
            % Crowth                -                10.1                10.1                  -

13

increments are greater-(18.7% males; 16.7%' females) (Cooper and Uzmann 1980). The smaller growth of inshore lobsters is attributed to their relative inactivity during the colder months of the' year (Cooper and Uzmann 1980). Linear regression models were used to describe male and female lobster growth per molt (Fig. R). The data used were the pre- and post-molt carapace lengths from our tag and recapture studies. The post-molt sizes (Y) were regressed on the pre-moit sizes (X) assuming random variability in both measurements (i.e., functional regression). The' equations and growth parameters estimated for male and female lobsters were: Male growth: Y = 3.688 + (1.082) X; n=100; R 2=0.94 Female growth: Y = 3.309 + (1.090) X; n=215; R 2=0.93 One hundred and two lobsters molted in our holding tanks and we measured both the new and cast. shells of these individuals. These pre-and post-molt lobster sia.es are included in Figure 8 and confirm that the growth of tagged lobsters is similar to that of untagged lobsters

                                           -(Cooper 1970; Ennis 1972).

Culls The total percentage of culls, missing either one (10.1%) or both claws (0.7%) in 1984 was 10.8% of the total catch and was significantly lower than the value of 12.4% reported in 1983 (log-likelihood ratio test , G=8.347; p < 0.005) . Table 6 summarizes cull rates from 1979-84 ] for wood and wire traps and for different size classes. The CT DEP instituted an escape vent regulation in April 1984 requiring that lobster traps contain in each parlor one of the following: 1) a horizontal, rectangular escape vent with an unobstructed opening not less than 1 3/4 in by 6 in (44 x 152 mm); or 2) two circular escape-vents with an unobstructed. opening not less than 2 1/4 in (57 mm) in diameter. This regulation was intended to allow the escape of sublegal (> 81 mm carapace length) lobsters from pots thereby reducing mortality 14

MALES I10-3 100 ' i Squore=Tcnk NoI ter O 90' Dof= Tog-Reccoture Moiter O O pP 3 d 0 E 80J C W5?"d'$c a i .- 0 64 3 J MN ?

• n ~

70 T2" sm J C 00 U E i E 605 v 4 i I (3 502 Z La to 40- ~r'- m r-~-- - ' i F- i i U r - r ' '- " -

• T- r ' "~'

t (1. S. FEMALES 0:

     -t, U

110] t  ; 9 -

     .2     100-

• d Squer e= Tank Me I ter ,.

v1 / O Dot = Tog-Recepture Molter a

                                                                            ' LvWb[

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                                                          . . t:

fG 6 @

                                                 -: d 70-i o n. O 60-50--

40- i i i (- i r" i i i 55 60 65 70 75 80 85 90 50 PRE-MOLT CARAPACE LENGTH (mm) Figure 8. Functional regression for pre-molt vs. post-molt lobster size. 15

Table 6. Percentage of culls caueht in wood and wire pots 1979-81 and wire pots 1982-84. Percent Cull I.egal-Size Prerecruits Sublegals All Sizes (;3 3/16" 81 m) ( 71 - 81 m) ( < 81 m) Vood Wire Wood Wire Wood Wire Wood Wire 1979 20.5 16.1 17.8 15.9 16.9 15.5 17.4 15.5 1980 16.5 12.9 17.2 13.8 17.0 13.4 16.9 13.4 , j 1981 18.2 12.4 14.4 12.4 13.5 12.1 14.0 12.1 1982 - 14.3 - 12.1 - 11.2 - 11.3 1983 - 12.3 - 12.9 - 12.4 - 12.4 1984 - 11.0 - 10.9 - 10.7 - 10.8 and damage due to handling by lobstermen. The effectiveness of this new regulation was apparent from our observations of reduced cull rates during 1984. Tagging Program From May to October, 1984, 7587 lobsters were caught of which 5992 were tagged; 1431 were subsequently recaptured (24%). The recapture percentage in 1984 was higher than in previous years (range 14-19%), possibly due to the escape vent regulation. This regulation allows sublegal-sized lobsters (the majority of our tagged lobsters) to escape from commercial traps, thereby increasing the probability of capture by our traps, which do not contain escape vents. Most lobsters were recaptured once (84%); 12% were recaptured twice, 3% were recaptured 3 times, 1% were recaptured four times, and only 3 lobsters were recaptured more than 4 times. Tag losses were detected by the presence of tag scars during tagging procedures. Percent tag loss was 11.8% in 1984 and was within the range reported in previous years (11.4-15.0%). Ninety-four percent of our recaptures were caught at the stations where they were released. Most (82%) of the lobsters that moved from the site of release moved between JC and IN. The average time between tagging and first recapture was 36 days. Because of the vent regulation, the percentage of tags returned to us by commercial fishermen in 1984 (18%) was much lower than that returned in previous years 1978-83 (Ave. = 36%). In addition, the 16

L i r mean size of lobsters returned by one fisherman increased from 72 mm'in 1983 to 78 mm in 1984. These data and the reduction in the percentage of culls observed in 1984 indicate that implementation of the vent regulation will immediately benefit-lobstermen by 1), decreasing handling time 2), reducing the number of culls and 3), minimizing trap related i mortality of sublegal lobsters. Population' Estimates The monthly population estimates for 1984 are presented in Table 7. The total population size (26,261) was within the range reported since

     ' 1975 (16,506-44,761). The population peaked in September, whereas
    ' maximum recruitment occurred in June, reflecting the spring molt. The i

estimates were consistent over months, in contrast to previous years when population estimates were higher in the early summer and decreased. as fishing pressure increased through mid and late summer. The standard deviations associated with the monthly estimates were much smaller than ! those in previous years, because the higher percent recapture in 1984 ! resulted in more accurate estimates. The probability of survival averaged 53% and was within the range of average values reported since

         ~

1975 (48-73%). [ Table 7. Estimated monthly lobster population site. number of recruits. and probability of survival in the the Millstone Point area 1964. Standard Estimated Standard Estimated Standard Estimated f . of Recruits Deviation of Probability of Deviation of Month. Population Site Deviation of Survivat Survival 8 8 8 8 3 I 1 t 1 1 1 1 , 5841 1145 0.52 0.07 June 9380 15C5 3863 931 0.42 0.05 July 9752 1317 4961 1133 0.54 0.06 August 9097 1169 2216 940 0.54 0.07 i September 9888 1492 l 0.62 0.12 October 8373 1578 Total Population

• June pg + Recruits Bi b -5 td.

      . Total Population Sire 2 2 standard errors = 26.261 2 5312 Entrainment Lobster larvae entrainment samples were collected at 11 nits 1 and 2 8

from May through August. Each sample filtered an average of 4000 m of cooling water (sample n=114; volume range =2241-6145m ). 8 A total of 102 17

1hbster larvae were found in.27 samples. The first lobster larvae were collected on 21 May and the last larva was collected on 10 July. l Although stage duration is temperature dependent (Templeman 1936), the ) larval phase is completed in 25-35 d under normal conditions. In contrast to the photopositive behavior of lobster larvae observed by many researchers, more lobster larvae were found in night samples than

                   -in day samples (Table 8). Diurnal vertical distribution is apparently
                    'related.to light intensity and larvae tend to disperse from surface waters during night except under bright moonlight (Templeman 1939). The f act that' more lar.rae were collected at night when . surface densities are lowest may be due to the fact that the power plant intake structures
                   . generally draw cooling water from depths greater than 3 m below mean sea level.
                                                                                    ~

Table 8. Sumar r of data collected during 1984 lobster larvae entrainment study. Day Night

                       '4eek                         . Number of Stage                         Number of Stage                                   Total Date'                           I II III IV                   Total     I II III IV      Total                         Dav/ Night 21 May                         7          0  0       0          7      2   0   0    0          2                                9 28 May                         0          0  0       0          0     21 - 0   0    0      21                                21 4 June                         4          0  0       0.         4     38 0     0    0      38                                42 11 June                        1          0  0       0          1      4   0   0    0          4                                 5 18 June                        3          0  0       0         .3      1   1   0    0          2                                 5 25 June                        0 0            0      0          0      7   0   1     3      11                                11 8

2 July 0' O. 0 3 3 0 0 0 5 5 8

                      -9 July                          0          0    0      0         0      0   0   0     l'         1                                 1 Total                       15            0    0      3        18     73    1   1    9      84                         ~102 1

one inrva collected alive. Lobster larvae entrainment was related to the occurrence of berried females-and to the developmental stage of the eggs carried by them (Fig. 9). In May, the number of berried females collected in traps was high and the development of the eggs indicated that hatching was imminent.

                                 -More stage I larvae (n=88) were collected than any other stages.

Inter-stage mortality was not calculated due to the paucity of stage II (n=1) and III (n=1) larvae and the fact that more stage IV (n=12) larvae 18

                                   ~.

i-

                                                                                                                                                                ~50 50J                                          Numce- of LarvceC-*-)

Bottom Tevoe-alureC-i ',- ir - Mudea, of 3er-;ed FemotesC- + -) l '.

                            ;                                                                                                         Ii                        L 40
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                                                                                   '                                                                              -0 0-l:  .
                                            ^
                                                                                                                                                .                6 Jul                 Aq                     See                     Get Mcy                    Jun MONTH Figure 9.               Bottom water temperatures and the number of berried females and lobster larvae collected during 1984.

i .- were collected than stages II and III. Two stage IV. larvae survived after passing through the plant and lived several days indicating that lobster larvae (Stage IV) entrainment mortality is lower than the assumed 100%. Collings et al. (1981) reported 28% survival of entrained

              ' lobster larvae, (Stage I and II), collected at the Canal Electric Company, Sandwich MA.

Table 9 presents lobster larvae entrainment data from our ichthyoplankton monitoring programs 1977-84 and from the 1984 lobster larvae study. The total entrainment estimates were calculated by summing the volumes of all samples collected f rom May through August, dividing that volume into the total plant volume over the same period and multiplying that proportion by the number of larvae collected over the hatching season. The disparity between the two 1984 values for total entrainment is primarily due to the difference in sample volumes. 8 of cooling Ichthyoplankton samples, on the average, filter about 400 m S water whereas the lobster larvae samples filter 4000 m . Because

               ~1obster larvae are so rare in the water column, large volumes of water l~

l I 19

       . _.     .    -                                   _                   _       ,_                  - - - _ - , . ~ . _ . _. .                                       . _,

Table 9. sumary of entrainment estimates for lobster larvae collected in ichthyoplankton sasiples 1977-84 and ] in 1964 lobster larvae entrainment study. 4 Total Tolume (m') a l of samolas Total U1 + U2 g,,,,g,,,,, Number Year -Dates ' Collected collected 0 3 estimate j Volume (m May-Aug (x10)6 ) May-Aug Found (number samples) May-Aug (x10 ) i 1977 _ .8Jun-6Jul 19 (10). .125 $17.9 78.721 1978- -. 5Jun-10Aug 74'(24). .121 662.9 405.410 1979 11Jun-11Jul 60 (17) .151 467.3 185.762 1980 29May-3Jul 37 (14) .133 534.8 148.780

                         .1981        27May-l3Jul                                    18 (13)                          .138                                       556.3                                                   72.361
                         ' 1982            IJun-28Jul                               45 (26)                           .128                                       677.9                                                  238.324 1983      31May-20Jul                                      9 (8)                             060                                     516.0                                                   77.400
                           '1984      '2May-19Jun                                      2 (2)                          .060                                       538,0'                                                  17.933
                         - 1984-Lobster 21May-10Jul                                   102 (27)                            .!05                                       538.0                                                  108.665
                         ' 1.arvae
                         - Study.

Ut

• Millstone $tation Unit 1; U2 a Millstone $tatice Unit 2.

                                                           ~

must be filtered to collect them. Our ichthyoplankton monitoring program was not. designed to collect lobster larvae, and with the reduction in ichthyoplankton sampling effort implemented in 1983 (from 18 samples /wk to 8 samples /uk), our probability of collecting them was

                         . reduced as evidenced by the numbers collected in 1983-84.                                                                                                                                                             ,

Because no lobster-larvae were collected after July 1984, in 1985 we will suspend sampling at the end of July and reallocate the August  ; sampling effort to perform several 24 hr special studies during the peak abundance of lobster larvae (May-July) to determine the peak daily abundance in the cooling waters.'and to' substantiate the diurnal variation observed in-1984. 1 Impingement The Unit 1 fish return system (sluiceway) began operating on 16 December 1983. Lobsters caught on the Unit 1 traveling screens are

                                                      ~

returned to Niantic-Bay shortly after being impinged, thus minimizing the lobster mortality associated with impingement at Unit 1. A survival

                           - study is being conducted to assess the effectiveness of this new system.
                                                                                                                       ~

f 20-b

                                                                                                                                                                                                                           =       +-_<<-,-_m-.-_._mm_,..___._                               _

The'.1984 monthly' impingement estimates for lobsters caught on the Unit 2 traveling screens are presented in Table 10. The annual total estimate for lobsters impinged at Unit 2 (1220) was higher than any previous value for total impingement at Unit 2, 1976-83 (range 261-1041). The standard deviation in 1984 was 8.52% of the mean while in 1983 the standard deviation was 6.85% of the mean. In the past, 3 samples per week were collected to assess impacts due to impingement, in 1984 the sampling schedule was reduced to 4 samples per month during the peak abundance.of lobsters (May-November). The impingement sampling sch'edule was modified to maximize precision in the estimation of the number of winter flounder impinged during peak flounder abundance. Over

                          ~

all months, survival of impinged lobsters averaged 79.3% and was similar to survival in 1983 (79.8%). Survival was lowest during the summer months, coinciding with increased wnter temperature and peak molting. Table 10. Number of impingement samples collected, number of lobsters collected and the total estimated' impingement for lobsters by month in 1984 at, Unit 2. Number- Number Estimated Percent Month Samples collected Number Survival 4 100 January 8 1 4 8 100 yebruary .15 14 5 11 100 March 5 3 18 100 April 4 8 50 100 May 4 40 294 70 June 40 305 -78

       . July                     4 4                  13          101                 69 August 4                   9           67                 67 September 16          124                 88 October'                 4 4                 19          145                 74 November 10                  30           93                 87 December 80                 188         1220                 79 Total

• Impingement estimates are calculated based on cooling water flow ratest Number lobsters
• Estimate Sample volume Total volume 21

                                                      ._m        -._                    .           .             . _ . _ _ _ _ _ _ - _ . _

e The size frequency, mean carapace length, and sex ratio of lobsters caught on the Unit 2 travelling screens in 1984 are presented in Figure 10.. The mean carapace length .(58.1 mm) was similar to previous years. The male: female sex ratio (1:0.47) of' impinged lobsters reflected the higher abundance of males in near shore waters. 10-i

6l i i 4-

                   )

{ MALE 3 CL=53 4 1 10 t N=128 ,! lj' l l - 3, lf; e i: j.1 I!l. .{f . g 2- 1 6 p ,jt{ l, l!l l l ll

                                                                                               ,             ll     l
          @      " JI                           (       11        ll[liliqlli                         h 11
          '                                                                           l i 2-l                                                Ilr               **
                     !                                       l b

i FEMALES CL=55 2 : la 5 l N=62 l 61 . . . . .- . . i , i 20 25 30 35 40 45 50 55 62 65 70 75. 80 85 CARADACE LENGTH (m-0  ; Figure 10. Size frequency distribution for male and female lobsters impinged at Unit 2 during 1984. The lower cull rate observed in the trap catch valess for 1984 was also apparent in the number of culls observed in impingement samples. , The percentage of culled lobsters impinged at Unit 2, during 1984, (29.5%) was much lower than in 1983 (43.6%).

SUMMARY

h Since l'982, both our legal CPUE and the commercial landings in , L L Connecticut have been increasing annually, while in other New England i states and in some maritime provinces lobster landings have declined during the same period. The increased number of legal lobsters was ] l l 22 l

anticipated from our observations of a very strong pre-recruit (one molt from legal-size) size class in 1982. The lobster population characteristics in the Millstone Point area, during 1984, remained relatively consistent with previous results. The 1984 values for total and legal CPUE were within the range of values reported since this study began. The 1984 values for mean carapace length, sex ratio, and growth were similar to previous years. A higher percentage of berried females was observed in 1984 and was higher than any year since wire pots were first used in 1978. Molting was high throughout the summer months in contrast to previous years when molting peaked in early summer and decreased through the later summer months. A secondary autumn molt occurred in 1984 as observed in the past three years. The percentage of culls was significantly lower in 1984 than in previous years. Percent recapture increased during 1984. The reduction in culls and the higher recapture rate was attributed to a new trap regulation instituted in April 1984 which required that traps contain , escape vents to allow the escape of sublegal-sized lobsters. Reducing the number of sublegal-sized lobsters retained by commercial traps increases our capture rate for sublegals since our traps do not have escape vents. Lobster-larvae entrainment studies indicated that lobster larvae were only susceptible to entrainment for a short period (8 wk) during the early summer (mid-May to mid-July). The majority of larvae were collected in night samples. The occurrence of larvae in the cooling -waters corresponded to the abundance of berried females and the development of their egg-masses which was induced by the seasonal change in water temperature. The estimated number of lobsters impinged at Unit 2 was greater in 1984 than in previous years. Population characteristics of lobsters impinged during 1984 were within the range of values reported in previous years and similar to the characteristics of the inshore (JC,1N) populations. 23

  ,                                                                                                         -1 CONCLUSION     l I
                                                                                                             .i Our results indicate that the local population continues to be                               ]
          -highly exploited. The commercial and recreational catch (legal-sized lobsters) was highly dependent on the abundance of sublegal-sized lobsters. Potential changes in-the lobster population due to the start-up'and operation of Unit 3 should be detected through the analysis of the basic population characteristics now being co11ceted (population size, growth, movement, size structure, sex' ratios, and the number of egg-bearing ^ females). In addition, lobster larvae entrainment studies and impingement studies will be performed after Unit 3 becomes operational to assess.the impacts on the local fishery.from operating three units. The stability of these population parameters during Unit 1.

and 2 operation and after the start-up of Unit 3 will demonstrate the effects (if any) of operating plants on the lobster population in the vicinity of Millstone Point. 24

REFERENCES CITED Aiken, D.E. 1973. Procedysis, setal development, and molt prediction in the American lobster (Homarus americanus). J. Fish. Res. Board Can. 30:1337-1344. Briggs, P.T., and F.M. Mushacke, 1979. The American Lobster in Western Long Island Sound. New York Fish and Game J. 26:59-86. Collings, W.S., C.C. Sheehan, S.C. Hughes, and J.L. Buckley. 1981. The effects of power generation on some of the living marine resources of the Cape Cod Canal and approaches. Massachusetts Department of Fisheries, Wildlife, and Recreational Vehicles, Div. Mar. Fish., 100 Cambridge Street, Boston, Mass., 212pp. Cooper, R.A. 1970. Retention of marks and their effects on growth, behavior, and migration of the American lobster, Homarus americanus Trans. Amer. Fish. Soc. 99:409-417.

      , R.A. Clifford, and C.D. Newell. 1975. Seasonal abundance of the American lobster, Homarus americanus, in the Boothbay Region of Maine.

Trans. Amer. Fish. Soc. 104:669-674. Cooper, R.A., and J.R. Uzmann. 1980. Ecology of Juvenile and Adult Homarus. Pages 97-142 131 J.S. Cobb, and B.F. Phillips eds. The Biology and Management of Lobsters, Vol. II, Academic Press, Inc., New York. Dow, R.L. 1966. The use of biological, environmental and economic data to predict supply and to manage a selected marine resource. The Amer. Biol. Teacher 28:26-30. 1969. Cyclic and geographic trends in sea water temperature and abundance of American lobster. Science. 164:1060-1063.

       . 1976. Yield trends of the American lobster resource with increased fishing effort. Mar. Technol. Soc. 10:17-25.

Ennis, G.P. 1972. Growth per molt of tagged lobsters (Homarus americanus) in Bonavista Bay, Newfoundland. J. Fish. Res. Board Can. 29:143-148.

       . 1980. Size-maturity relations and related observations in Newfound-land populations of the lobster (Homarus americanus). Can. J. Fish.

Aquat. Sci. 37:945-956. Fair, J.J., Jr. 1977. Lobster investigation in management area I; Southern Gulf of Maine. Mass. Div. of Mar. Fish. 8pp. Flowers, J.M., and S.B. Saila. 1972. An analysis of temperature effects on the inshore lobster fishery. J. Fish Res. Board Can. 29:1221-1225. Herrick, F.H. 1911. Natural History of the American lobster. Bull. U.S. Bureau Fish. 29:149-408. 25

9 Jolly, C.M. 1965. Explicit estimates from capture-recapture data with both death and immigration-stochastic model. Biometrika 52:225-247. Keser, M. , D.F. Landers Jr. , and J.D. Morris. 1983. Population charac-teristics of the American lobster, Homarus americanus, in Eastern Long Island Sound, Connecticut. NOAA Tech. Rep. NMFS SSRF-770, 7pp. Krouse, J.S. 1973. Maturity, sex ratio, and size composition of the natural population of American lobster, Homarus americanus, along the Maine coast. Fish. Bull. 71:165-173. Lund, W.A., L.L. Stewart, and C.J. Rathbun. 1973. Investigation of the lobster. NOAA Tech. Rep. NMFS Project No. 3-130-R, 189p. Marcello, R.A., Jr., W. Davis III, T. O'Hara, and J. Hartley. 1979. Population statistics and commercial catch rate of American lobster (Homarus americanus) in the Charlestown-Manatuck, Rhode Island region of Block Island Sound. Yankee Atomic Electric Company. Submitted to New England Power Company YAEC1175, 40pp. McLeese, D.W., and D.G. Wilder. 1958. The activity and catchability of the lobster (Homarus americanto) in relation to temperature. J. Fish. Res. Board gan. 15:1345-1354. NUSCo-(Northeast Utilities Service Company). 1978. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Cormecticut. Annual report,.1977, 1984. Lobster Population Dynamics. Pages 1-25 JLjl Monitoring the Marine Environment of Long Island Sound at Millstone Nuclear Power Station, Waterferd, Connecticut. . Annual Report 1983. Richards, R.A., J.S. Cobb, and M.J. Fogarty. 1983. Effects of behavioral ,' interactions on the catchability of American lobster, Homarus americanus, and two species of Cancer crab. Fish. Bull. 81:51-60. Russell, H.J., C.V.D. Borden, and M.J. Fogarty. 1978. Management studies of inshore lobster resources completion report. No. LO74-1-R1(1):1. R.I. Fish and Game, 75pp. Scarratt, D.J. 1970. Laboratory and field tests of radified sphyrion tags on lobsters (Homarus americanus). J. Fish. Res. Board Can. 27:257-264.

           , and P.F. Elson.      1965. Preliminary trials of a tag for salmon and lobsters. J. Fish. Res. Board Can. 2:421-432.

Sebht..G.A.F. 1965. A note on the multiple-recapture census. Biometrika 52:249-259. Skud, B.E., and H.C. Perkins. 1969. Size composition, sex ratio and size at maturity of offshore northern lobsters. U.S. Fish W11dl. Spec. Sci Rept. Fish. 598, 10pp. 26 s 4

i t Smith, E.M. 1977. Some aspects of catch /ef fort, biology, and the economics of the Long Island lobster fishery during 1976. NOAA Tech. Rep. NMFS Project No. 3-253-R-1, 97pp. Templeman, W. 1936. The influence of temperature, salinity, light and food conditions on the survival and growth of the larvae of the lobster 2:485-497. (Homarus americanus). J. Biol. Board Can. ' . 1939. Investigations into the life history of the lobster (Homarus americanus) on the west coast of Newfoundland, 1938. Newfoundland Dep. Natl. Resour. Res. Bull. (Fish) 7, 52pp. Wilder, D.G. 1953. The growth rate of the American lobster (Homarus americanus). J. Fish. Res. Board Can. 10:371-412. 27

P.A * -4m. - e. a . 5 t L e

                                                                                                      ~\

a } d S i ) i e J 4 f 1 l I k e b a i 5 t I I 1 .l ' t i l y 1 4 f l 2 + h 'f t i H mi i M O O s

3 FISH ECOLOGY I 1 1 Table of Contents  ; i l Section Pages INTRODUCTION.............................................. 1 MATERI ALS AND METH0D S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Ichthyoplankton...................................... 2 Impingement.......................................... 4 Trawl................................................ 5 Seine................................................ 5 Data Analyses........................................ 5 RESULTS AND DISCUSSION.................................... 8 Ammodytes americanus................................. 8 Anchoa spp........................................... 12-Gasterosteus wheatlandi and Casterosteus aculeatus............................. 15 Menidia spp.......................................... 19 Microgadus tomcod.................................... 25 Myoxocephalus aenaeus........'........................ 26 Scophthalmus aquosus................................. 31 Tautoga onitis....................................... 34 Tautogolabrus adspersus.............................. 36

SUMMARY

................................................... 43 R EF ER ENC ES C IT ED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 APPENDICES................................................ 48 i-A Ih -

                                                         ,      -,,e                      m                  ,w        . - - -

FISH ECOLOGY INTRODUCTION The construction and operation of Millstone Nuclear Power Station (MNPS) could impact local finfish populations. The station withdraws water from Niantic Bay for once through cooling and discharges the heated effluent into Long Island Sound. Due to the withdrawal of cooling water, mortality may occur to fish eggs, larvae, juveniles and adults that are entrained or impinged. Entrainment mortalities occur when eggs, larvae, and small fish pass through the condenser cooling systems of the plants, where they are subjected to mechanical, chemical, and heat stresses. Impingement mortalities occur when adult and juvenile fish are trapped on intake screens and are -eventually washed into collection baskets. Other potential impacts could result from construction activities at MNPS and the velocity and volume of the heated effluent, which could alter habitats and affect the distribution of local fishes. Finfish are an important local marine resource and are found in a variety of habitats in the area around MNPS. Some species occur seasonally to use the area for feeding, spawning, or nursery activities and other species are year-around residents of the area. All the available life history stages of finfish are studied by various programs at the Northeast Utilities Environmental Laboratory (NUEL) to determine if any detrimental effects have occurred to the populations due to the construction and operation of MNPS. The objectives of the fish ecology programs at NUEL are:

1) To sample, identify and enumerate finfish found in the area;

2) To determine which finfish species may be susceptible to entrainment, impingement, or exposure to the heated effluent.:

3) To describe the fluctuations in abundance of life history stages of species that are potentially impacted; and

4) To evaluate whether the fluctuations in abundance are within the expected historical range.

To meet these objectives complementary sampling programs were designed for the collection of data on the available life history stages of those fish susceptible to impact. Traditionally, adult fish p0Pulation abundance has been the focus in assessments of population  ! stability. However, the abundance fluctuations of early life history , stages,.which can reflect changes in reproductive potential, also serve as a good indicator of population stability. In this report the life history and population characteristics of potentially impacted species are presented and evaluated to determine if MNPS has had any detrimental effects on those species. MATERIALS AND METHODS Data included in this report are from October 1976 through September 1984. A reporting-year includes data collected from October of the previous year through September of the reporting year. Report year 1984 includes October 1983'through September 1984. The materials and. methods presented are for 1984 and any changes from 1983 are described. Historical changes to procedures in the fish ecology programs'were presented in NUSCo (1983b). Ichthvoplankton

       .Finfish eggs and larvae entrained by MNPS were. sampled one day and
                    ~

one' night weekly from October through December, and four days and four nights weekly from January through September. Samples were collected at the discharges of Unit,1 and 2 (EN). Sampling alternated weekly between the two. units when plant operations permitted. A 1.0 x 3.6-m conical plankton net with 0.333-mm mesh was deployed with a gantry system. Four General Oceanic flovmeters (Model 2030g) were positioned in the mouth of the net.to account-for horizontal and vertical flow variations. Sample volume (ca. 400 m8 ) was determined-by averaging the four volume estimates from the flowmeters. Finfish larvae were also collected at station NB located in mid-Niantic Bay (Fig.E1). One day and one night sample were taken biweekly from September through March, and two day and two night samples 2

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                          - i,,.;egjg'.g' PLANKTON------

TRAWLS SEINES M Figure 1. Location of plankton, trawl and seine sampling sites. were taken weekly from April through August. Paired 0.61- x 3.3-m conical plankton nets (0.333-m mesh), mounted on a bongo frame, were used to take stepwise oblique tows. Sampling duration was 5 min at each surface, mid, and bottom depths. Sample volumes were measured using one 8 General Oceanics flowmeter in each net and approximately 300 m of seawater were filtered for each sample. Plankton samples were split using a NOAA-Bourne splitter (Botelho and Donnelly 1978) and sorted for ichthyoplantkon using dissecting microscopes. Successive splits were completely sorted until at least 50 larvae and 50 eggs (for samples processed for eggs) were found, or until one-half of the sample was examined. EN samples collected in April through September were sorted for fish eggs and larvae. EN samples collected during all other months, when egg abundance was low, and all NB samples were sorted only for larvae. Fish eggs and larvae were 3

i l identified to the lowest practical taxon. Cunner (Tautogolabrus adspersus) and tautog (Tautoga onitis) eggs were differentiated weekly using the criterion of bimodality of egg diameters (Williams 1967). Ichthyoplankton density was expressed as numbers per 500 m8 . 1 Impingement Finfish impinged on the intake screens at Units 1 and 2 were washed into 1.5 x 0.8 x 1.75-m perforated collection baskets. Screens were washed at least once every eight hours. Impingement sampling consisted of sorting the finfish from all material washed from the screens during a 24-h period. All finfish were identified to the lowest possible taxon, counted, and up to 50 specimcas of each species were measured to the nearest millimeter, total length. Catch was calculated as number impinged per 24-h period. Three samples were collected weekly from 1 October 1983 through 16 December 1983 at Unit 1, and through 31 December 1983 at Unit 2. After 16 December impingement sampling was discontinued at Unit I when a fish-return sluiceway began operating. After 1 January 1984, sampling effort at Unit 2 was stratified by month so that 8 samples were collected in January, 15 in February, 14 in March, 5 in April 4 per month in May thraugh November, and 10 in December. This sample design resulted from a resource allocation analysis based on the variability of winter flounder (Pseudopleuronectes americanus) impingement. More samples were collected in those months with high variances in impingement counts and fewer samples in months with low variances. The sampling effort was reduced.by approximately 50%. Estimated variances based on the new sampling schedule were expected to be at or below historic levels. Annual impingement estimates of each species of finfish were calculated by summing the monthly estimates. Estimates for each day not sampled in a month were calculated by multiplying the species impingement density (number of fish per cubic meter of cooling water) on the days sampled in that month times the volume of cooling water on the day not sampled. These estimates were then combined with the actual counts to arrive at the monthly totals for each species. Impingement 4

estimates included October 1983 through September 1984 at Unit 2 and only through 16 December 1983 at Unit I due to the operation of the sluiceway. 4 Trawls Demersal finfishes were collected using a 9.1-m otter trawl with a 0.6-cm cod end liner. Triplicate tows were made biweekly at six stations: Niantic River (NR), Jordan Cove (JC), Twotree (TT), Bartlett Reef .(BR), Intake (IN), and Niantic Bay (NB) (Fig.1). A standard tow covered 0.69 km and this distance was measured using radar. Up to 50 individuals of each species per station were measured to the nearest millimeter, total length. Catch was expressed as number per tow. Seines Shore-zone finfishes were samples using a 9.1- x 1.2-m knotless nylon seine net of 0.6-cm mesh. Triplicate 30-m tows were made parallel to the shoreline at Seaside Point (SS), White Point (WP), Jordan Cover

                                                        ~

(JC), and Giants Neck (GN), at least monthly (Fig.1). In addition, from April through October sampling was increased t'o biweekly at WP, JC, and GN. Collections were made during the time interval of 2 h before to 1 h after high tide. Fish in each haul were identified to the lowest possible taxon, counted, and up to 50 individuals of each species in each replicate were measured to the nearest millimeter, total length. Catch was calculated as number per haul. Data Analyses In order to assess impact it is necessary to identify potentially affected species, documeat their spatial distribution, and describe the natural temporal fluctuations of their predominant life history stages.near MNPS. Potentially affected species were selected because they dominated entrainment or impingement samples. Spatia: distribution patterns were documented from the percentage of the tc tal 5 .

c-

                                                                              ]

l l catch for a species found at each station. Temporal fluctuations were considered in two ways: by annual median catches and through time-series q regression forecasts. The predominant life history stages in impingement, trawl, and seine collections were determined from ) length-frequency distributions. In addition, median lengths were used to identify spatial and temporal differences in length-frequency distribution. The median was used as the parameter to examine changes in abundance and length frequency because it is a better estimate of central tendency than the mean when the data distribution is skewed. A nonparameteric 95% confidence interval (Snedecor and Cochran 1967) was calculated for each median. Sampling effort beginning in January 1984 was stratified by season for seine sampling and by month for impingement sampling. Therefore, the length-frequency data had to be weighted to equalize effort during the year. Since the seining effort was doubled in April through October, each length measurement in November through March was weighted by two. For impingement which was stratified by month, a monthly weight of: January (X4), February and March (X2), April (X6), May through November (X7), and December (X3) was used to equalize the monthly effort close to 30, ranging from 28 to 32. Time-series models were developed to describe the natural temporal fluctuations of potentially impacted species in the MNPS area and determine if the operation of the station had affected these finfish

   . populations. A detailed discussion of the time-series technique is
   . presented by Bireley (1985) and provided in Appendix 1, but is briefly reviewed here. Models were fitted only to data from selected stations and life history stages that would best represent the natural fluctuations of the populations. All data used for the time-series modeling were log transformed to stabilize variances (Glass et al.

1975). After transformation, data within a sampling period were averaged: sampling periods were a week for impingement and ichthyoplankton samples, two weeks for trawl samples, and a month for seine samples. The deterministic portion of the model considered variables such as time, season, and flow. The variable time entered the 6 L_

model as a sine-cosine function describing cycles of 2, 3, 4, 5, or 6 months; or 1, 2, 3, 4, 5, 6, or 7 years;oor combinations of these harmonic components. Cooling water flow and season were multiplicative dummy variables that scaled the overall shape of some mcdels. Flow was a variable in the impingement models and scaled predicted impingement catches by the amount of cooling water withdrawn. The variable season had a value of zero during the times when a species was known to be absent from the MNPS area and a value of one otherwise (Table 1). Table 1. The species and program combinations that had the dummy variable season in their time-series models with the months that were set equal to one. PROGRAM SEASON SPECIES Larval November - July Ammodytes americanus Anchoa spp. Larval May - November Egg April - August Menidia spp. Seine May - December Trawl September - May Microgadus tomcod Trawl October - April -Myoxocephalus aenaeus Larval January - June Tautogolabrus adspersus Larval May - October Egg April - August Tautoga onitis Larval May - October Egg April - August Stepwise regression was used to determine the best combination of the above variables to include as deterministic components. Model selection was based on maximizing the R values but with the restriction that all parameter estimates had to be significantly different from zero. Stochastic terms were included in the model if the residuals from the

-deterministic portion were autocorrelated. The time-series model was The data used to f orecast the 1984 catch with 95% confidence intervals.

from 1984 (which were not used to estimate the model parameters) were then compared with forecasted data to determine if current populaticn abundance was within the bounds of historic variation and a percent forecast error calculated. 7

1 l RESULTS AND DISCUSSION The finfish studies at 100?S include data on 125 species in seines, plankton, trawls, and impingement samples from October 1976 through September 1984 (Appendix 2). The relative abundances of these finfish

 . species are indicated by the percent species composition (Table 2).

Because all the finfish could not be discussed in the same detail,

           ~

certain taxa were selected for further discussion based on their susceptibility to impact of impingement and entrainment. The species selected were those that contributed at least 1% to either impingement or entrainment samples and were among the top 80% impinged or entrained. Ten taxa were selected for detailed analysis and discussion based on our selection criteria and nine of these will be discussed in this report section. Because the winter flounder (Pseudopleuronectes americanus) has been studied extensively, it is discussed in a separate section (Winter Flounder Population Studies). American sand lance (Ammodytes americanus) ranked first among impinged taxa and third among entrained larval taxa. Larval anchovies (Anchoa spp.) ranked first in entrainment. Eggs of cunner (Tautogolabrus adspersus) and tautog (Tautoga onitis) were the two most abundant egg taxa entrained; cunner was also well represented in other sampling programs. Silversides (Menidia spp.) ranked fifth in impingement and trawls and was the dominant shore-zone taxon in seines. The grubby (Myoxocephalus aenaeus) contributed over 4% to the impingement and entrainment species compositions. Sticklebacks (Casterosteus spp.) and tomcod (Microgadus tomcod) ranked sixth and seventh, respectively among impinged species and each contributed over 2% to the impingement percent species composition. The windowpane (Scophthalmus aquosus) ranked tenth in impingement and fifth among trawled species. These nine species are discussed in detail below. Ammocytes americanus, American sand lance The American sand lance is found from the Arctic to Cape Hatteras (Bigelow and Schroeder 1953). Individuals form large schools and are found over sandy bottoms from near shore to the edge of the continental 8

Table 2. Finfish percent species composition as recorded f rom impingen'ent, plankton, trawl and seine programs during the period 1 October 1976 through 30 September 1984 PLANKTON TRAWL SEINE SPECIES IMPINGEMENT Entrainment Niantic Bay Eggs Larvae Larvae 60.35 0.01 9.28 8.40 0.19 2.65 Ammodytes americanus (p) 45.25 0.06 6.69 0.10 11.84 7.67 Pseudopleuronectes americanus 2.15 0.06 6.57 12.21 55.10 55.57 Anchoa spp. (a) 2.20 2.33 0.01 Myoxocephalus aenaeus 4.63 0.08 4.19 0.39 0.14 0.18 4.50 76.82 Menidia spp. (b) 4.14 0.06 2.67 0 0.01 0 trace Casterosteus wheatlandi 0.05 3.26 0.20-Microgadus tomcod (p) 2.33 0.41 0.07 0.02 0.01 0.55 0.66 casterosteus aculeatus 2.28 trace 0.01 1.40 51.80 2.61 6.51 2.83 Tautogolabrus adspersus 14.56 trace 1.37 0.86 0.69 1.24 Scophthalmus aquosus 0.62 0.57 0.52 Syngnathus fuscus 1.19 0 0.82 0 0.06 0.15 1.07 0 Merluccius bilinearis 1.04 1.01 0.07 1.07 1.71 0.58 trace Peprilus triacanthus 0.83 0.01 0.59 23.03 2.25 3.98 Tautoga onitis 0.27 0.08 0.58 4.87 0.05 0.22 Alosa spp. (c) 0 0 0.02 0 Morone americana 0.54 0.01 0 0.01 0.01 0.06 0 Cyclopterus lumpus 0.35 0.02 0.33 0 0.02 0.02- 0.48 Osmerus mordax 0 0 4.61 0 0.33 0 Raja spp. (d) 0.03 0.10 1.51 0 Paralichthys dentatus 0.17 0.03 ya 0.14 0.88 1.69 0.01 0.16 Brevoortia tyrannus 0.16 0.01 0.15 trace 0.06 0.06 0.03 Sphoeroides maculatus 0.04 0 0 0.13 trace 0.01 Pollachius virens 0 0.08 0 0.13 0 0 Opsanus 3 0.43 0.65 0.04 0 Cynoscion regalis 0.12 0.14 0 0.17 0.03 0.07 0.03 Anguilla rostrata 0.12 10.34 Fundulus spp. (e) 0.11 0.03 0.01 trace trace 1.78 0.56 0.06 0 Liparis atlanticus (p) 0.10 0 0.41 0.06 0.08 0.86 0.01 Urophycis spp. (f) 0.10 0.26 0.10 0 0 0 trace Pomatomus saltatrix 0.42 1.05 1.78 0 Prionotus spp. (g) 0.10 2.36 0 1.21 0.51 0.63 15.56 Stenotomus chrysops 0.08 0 0.08 0 2.29 1.18 0.66 Pholis gunnelius

• Impingement percents have been corrected for variations in flow includes U. regia. U. chuss and U_. tenuie (f) trace- 0.01% (g) includes P. carolinus and P_. evolans (p) indicates most probable identification (a) includes A. mitchilli and A. hepsetus (b) includes M. menidia and M. beryllina (c) includes A_. aestivalis, A. mediocris, A. pseudoharengus and A. sapidissima

                                                                           ~

(d) includes R. erinacea, R. ocellata and R. eglanteria

                                                      ~

(e) F_. majalis and F. heteroclitus

l shelf (Richards 1963; Leim and Scott 1966). The taxonomy of sand lance has not been resolved and the numbers of species found in the North  ; Atlantic is questionable (Bigelow and Schroeder 1953; Leim and Scott 1966; Scott 1972; Fritzsche.1978). However, all specimens collected near MNPS are believed to be the American sand lance, (Ammodytes americanus). The sand lance has been collected in all finfish programs (Table 2). Historically, it accounted for less than 1% of the species composition for impinged species (NUSCo 1984). However, in 1984, such a large number of sand lance was impinged, that they accounted for over 60% of the species composition from 1977 to 1984. The sand lance is a winter spawner and its larvae were collected in the plankton program from January to May; the taxon ranked second at NB and third at EN. Because their eggs are demersal and adhesive (Frizsche 1978), they were rarely collected. Sand lance were collected infrequently in the trawl and seine samples. Juvenile and adult sand lance burrow into the sand (Leim and Scott 1966) and this behavior may account for the low numbers in the trawl and seine programs. When present in these programs adults were found in the trawl collections in the winter, January through March, and were collected primarily at BR ( > 60%) and young-of-the-year were collected by seine sampling during July through October. An estimated 390,000 sand lance were impinged at Unit 2 during the week of July 18, 1984 (Appendix 3). This estimate was based on a single 24-h sample, but qualitative observations made during the remainder of the week indicated that the numbers of impinged sand lance decreased rapidly. Over the previous six years, impingement estimates for sand lance (Unit 1 and 2 combined) ranged from 68 in 1977 to 321 in 1981 (NUSCo 1983a). The sand lance is a schooling species (Leim and Scott 1966) and possibly a large school encountered the intake structure. Reay (1970) reported that sand lance individuals are generally segregated into schools containing fish of approximately the same size. Randomly selected individuals collected during this impingement event ranged in length from 60 to 90 mm, and were juvenile fish (Frizsche 1978). Because the sluiceway was in operation there were no estimates of the number impinged at Unit 1. However, some sand lance passed 10

through the intake screens and were collected in the plankton samples at EN. During that week, plankton nets were deployed simultaneously at Units 1 and-2 for sampling lobster larvae (see lobster Section) and .ichthyoplankton. While no quantitative data on sand lance were available from the lobster larvae sampling at Unit 2, it was observed that approximately twenty times as many juvenile sand lance were entrained through Unit 2 than through Unit I which was sampled for ichthyoplankton. This indicated that it was primarily a one unit phenomenon. Time-series models of impinged sand lance were not useful in explaining. trends since previous impingement abundances were low (Appendix 4). A similar short-term large impingement of a schooling species, Atlantic menhaden (Brevoortia tryannus) occurred in 1971 (NUSCo 1982b). At that time, an estimated 50 million juvenile menhaden were impinged during August at Unit _1 (the only unit operating then). This mass

                  ~

impingement of menhaden has not recurred in 12 years. Thus, we believe the larger than normal impingement of sand lance in 1984 was a rare event and is not expected to recur often. Iatrval sand lance were abundant in plankton collections, but a marked decrease occurred in densities since 1982 (Fig. 2). Meyer et al. (1979) reported that although there were large annual fluctuations of sand lance abundance, there was an. upward trend along the Atlantic coast during the late 1970's. The high larval abundance from 1977 to 1980 in the MNPS collections may have been a result of the increased regional abundance. .The decrease in abundance since 1982 may indicate a regional decline in the sand lance population. Time-series models of larval density at EN and NB fit observed data well and had R 2 values of 0.91 and 0.93, respectively (Fig. 3) . The short term cycle (4.mo) was evidence of seasonal occurrence within each year. The forecast errors at NB (13.7%) and EN (37.0%) were low, indicating that actual data were close to the forecast. Most of the 1984 data fell below the model predicted average as would be expected from the overall decreased observed since 1982, but were generally above the lower 95% confidence limit. 11

                                                                                                                      'l l

60; 50 '

                           ~~___

40 , b

      '5     .

E 30 8 5 5 20,. 1 10 , , , , ,- ,. ... ., 77 78 79 80 81 2a 83 84 YEAR Figure 2. The annual median densities (#/500m 3) and 95% confidence intervals of larval sand lance collected at EN and NB combined from 1977 through 1984. Anchoa spp., anchovies Two anchovy species the bay anchovy (Anchoa mitchilli) and the striped anchovy (Anchoa hepsetus) have been collected in the MNPS area. Based on egg data, the life stage in which the two species can be easily distinguished, the bay anchovy was the most common and made up over 84% of all anchovy eggs collected at MNPS. McHugh (1977) stated that the bay anchovy is perhaps the most numerous fish found along the Atlantic

 . Coast of the U.S. They are most commonly found inshore during the warmer months and move offshore in the winter. Hilderbrand (1943) believed that each section of the coast had a distinctive population and all migrations were inshore and offshore movements. In Long Island Sound-(LIS), spawning takes place in depths of less than 20 m from June to September (Richards 1959). Eggs are pelagic and hatch in 24 h at approximately 27 C (Kuntz 1914). Development is rapid and individuals may mature within 2.5 months of hatching, at a size of 34 to 40 mm; its life span is probably not more than 2 or 3 years (Stevenson 1958).

12

(a) ii'o_ R2 = o,91 Fcrecast Error = 37.05% 9.0-m 7.0-T , ,,

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1984 t983 (b) tt.0- R2 = 0.93 Forecast Error = 13.78% 9.0-

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       .D
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_,,gj Z=S(14Cos(ly)+ Sin (ly) -Si n(dJn)) i i i i i s i i i a i i i F u A M J J A S O 5 0 N D J 1983 1984 Figure 3. The forecast ( ), 95% confidence limits (---), and 1984 data (+) for sand lance larvae at EN (a) and NB (b). 13

( - o 1 l l l l Anchovies were among the top nine most abundant taxa collected in all programs except seines (Table 2). They were the most abundant I finfish impinged in 1983 '(NUSCo 1984) .and although their numbers decreased in 1984, they ranked third in total impingement catch since 1977. Near MNPS anchovies migrate inshore in spring and thus are only briefly'available to capture by the various sampling methods. Adults (median length of 77 mm) were impinged primarily from May through June

 -(Fig. 4),'the time of their spawning migration. Eggs were abundant 100 -

2W99Ws TRAWL

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Lwww IMP!NGEMENT

[ i 80 i i PLANKTON-LARVAE

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4 5 6 7 8 9 10 11 12 MONTH Figure 4. The monthly percent distribution of anchovies collected in trawls, impingement and plankton sampling. primarily June through July at EN and larvae primarily July through

                                    ~

Young-of-the-year (median length 30 mm) were

          ~
  . August at EN and NB.

caught in' trawls during August through_0ctober primarily at NB (47%) and IN (33%). The trawl catch of anchovies varied greatly from year to

  . year, and may have depended on a chance match of our sampling efforts
  -and'the sporadic spatial and temporal-presence of anchovies.

14

The seasonal occurrences of anchovy catches in plankton and aimpingement programs were modeled using harmonic regression techniques. A11'models contained terms describing a 6-mo cycle (Fig. 5). The models of egg and larval: abundance explained more of the -variation (Ra> 0.90) 8 2 than1the impingement:model (R =0.68). 'The lower R value of the

                   ' impingement model-was probably the result of the unusually high 1983 catches-(NUSCo 1984). Forecast errors for eggs and larvae (16-29%) in 1984.were' larger than errors for. 1983 (7.9-19.6%; NUSCo 1984). This can be attributed to greater than normal abundance of-eggs and a lower

abundance of larvae' in 1984. Concurrent with the decrease in larval '

anchovy abundance, there was a decrease of other plankton (including

                   . larval tautog and cunner) during July 1984 at NB and EN. This decrease was observed in other parts of_ northeastern LIS-(per. com. University _of
                                                                ~
                     . Connecticut, Noank, Ct. and Little Harbor Laboratory, Inc., Guilford, Ct.). -The; reasons for this decline were not known but during July 1984 ctenophores, a zooplankton predator (Denson and Smayda 1982), were-abnormally abundant.
                    . Gasterosteus1aculeatus, threespine stickleback and Gasterosteus wheatlandi, blackspotted stickleback The threespine stickleback (Gasterosteus aculeatus) are small,
                                          ~

near-shore' fishes. The threespine stickleback is euryhaline and

                     . circumpolar in distribution. In the Western North Atlantic.it ranges from Newfoundland to Cheasapeake Bay.(Perlmutter 1963). - The blackspotted stickleback (G. wheatlandi) is restricted to coastal or                                                                ,

brackish water-from Newfoundland to LIS (Perlmutter 1963). Both species move-into fresh.or brackish water in the spring where they construct

                     ; nests and spawn (Worgan and Fitzgerald.1981). Adults and
                      ' young-of-the-year remain in the nesting areas until late summer (Fitzgerald 1983). Threespine and blackspotted sticklebacks are-very similar in appearance-and are easily confused (Bigelow and Schroeder 1

1953). ' Because of this similarity, the blackspotted stickleback was not identified until October 1981 (NUSCo 1982a). The percent species composition of the two species was based on impingement data collected ' 7

                       'after this date.

15

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l i 11.0- R2 = 0.92 (a) Forecast Error = 21.04% 9.0-n - +* +

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             -5.0-i            i    i      i           I            i              I           I          I 1             I     4         i    I S            0     N      D   J    F   M    A     u           J            J              A           5          0 1983                                                                                                1984 1i.0-             R2 = 0.96                                                                                                        (b)

Forecast Error = 16.40% 9.0- . m  :

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O -1.0-D E .

              -3,0-
              ,,,g_ Z=S (1+Cos (6m) + Sin (6m) + Sin ( 3m) + Sin (2m) ) -Al+A8 i            i     i. i      i    i   i    i      i            e            i               i           i        i S             O     N     D   J    F   M    A      M            J           J               A           $         0 1983                                                                                              1984 Figure 5. The forecaat ( ), 95% confidence limits (---), and 1984 data (+) for anchovy eggs at EN (a), larvae at EN (b) and NB (c), and individuals impinged (d).

16

(c) 11.0- R2 = 0.92

Forecast Error 28.87% ,' 's 9.0- ',

    ^            .

s'

     -                                                                                                                  s 7.0-                                                                                      ,a s,
      +                                                                                               ,     r.
                                                                                                           # s s

g I  % h 5.0-

                                                                                                    #                              s
     'Ui              ',                                                                         ,

ll,*gt, + c s

• 8 s O 3.0- ' ,' ,/ , ', ,

O ~... ,. y ~...........

                                                               ....:                 ' ' .l s,

s g 1.0- i + C 's

                                                                                             *l 0

o

            -1.0-                   . . ,
                                          ~~...............' ~.'

2

            -3.0-
            -5.o       Z=S (1+Cos (6m) + Sin (6m) + Sin ( 3m) + Sin ( 2m) )

I i i i i i l i 4 i I I I i M A u J J A S O S O N D J F 1984 198J (d) 11.0- R2 = 0.69 Forecast error = 21.16 9.0-

                                                                                      +f. ' .,. +' ,

s' + + ',

        "     7.0-                                                             ,'                                   s, i                                             s
        +                                                               ,
                                                                                                             +              'n
                                                                      '           +                             +                 '..

g 5.o- ,. .-...., ,

                                                                                +                                 + + +

c , ,a* y , 3 i, ~~.- O 3.0-O v Z

                               ,             +
                                                         ++
                                                                                      , ' . .'s, a     1.0-            ~                                                     ,                         ,
                             + ++++++ +++++++++                  +"+++,'                                         '+- ++ +++

c ,' 's r 0 1.o- i o ' 's ' 2 -

             -J.0- ,'''''''r,
                                                         ~.. . . '

Z=F (14Cos (ly) -Sin (6m) +Cos (6m) ) -Al-A2

             -5.0_                                                                                                                          i i      i   i           6           i         i                       i            i           a 6         6 J      F    M          A         M            J          J            A           S    O S         O       N      D 1983                                                                                                        1984 Figure 5. (Cont'd) 17

Sticklebacks were collected in all programs, but the-blackspotted and threespine sticklebacks were most prevalent in impingement samples ranking sixth and eighth, respectively (Table 2). The length frequencies of the two species in impingement samples were different, with the mode for the blackspotted stickleback at 45 mm and for the threespine stickleback at 55 mm (Fig. 6). Their eggs and larvae were c 10 (a) (b) 15 20 25 30 35 29 40 3 MHFMM<1 r fg & XXH/M M M MFM71 E, 50 M'xWC E E 55 MWhWe *l 3 60 72C9CC<MMMl 65 'N 70 29 75 3 0 400 800 1E00 0 400 800 1200 FREGUENCY FREGUENCY Figure 6. Length-frequency distribution of impinged blackspotted (a) and threespine (b) sticklebacks from 1982 through 1984. rarely collected in plankton samples because they spawn in brackish waters and the young remain near the nesting site through the summer. Sticklebacks were found in low abundance in seine and trawl samples, and were primarily the threespine stickleback. There was a distinct seasonal occurrence of sticklebacks in-the impingement and trawl samples (Fig. 7). In impingement samples the threespine stickleback was collected primarily in December through April and the blackspotted stickleback in March and April. In trawls samples, most sticklebacks were collected during two separate periods of the year; 35% of the catch in March and April and 53% of the catch in August through October. In addition, nearly all (98%) trawled sticklebacks were collected from the near-shore station, NR and JC. Rowland (1983) was unsure where the sticklebacks were prior to their spring spawning season. Our data suggested, based on their occurrence in late winter and early spring in impingement and trawl samples, that they reside in near-shore areas prior to the spawning migration into brackish waters. 18

          '100 -                                        TRAWL i       i THREESPINE STICKLEBACK b              IMPINCEMENT e0 -                              gggg THREESPINE ST!cKLEDACK
                                          %    N BLACKSPOTTED STICKLEBACK i-z ' ~                           %

W  % o \ m w  % 1 40 - g 0 % 5 ~ N zo- n p  % 2 6 R-s _ 3 8 5 5  % f _,x h1 h ) l$) , , , , R, , 3 4 5 6 7 8 9 10 11 12 1 2 MONTH Figure 7. Monthly percent distribution of blackspotted and threespine sticklebacks in impingement from 1982 through 1984 and threespine sticklebacks in trawls from 1977 through 1984. The similarity in the length-frequency distributions for spring and fall trawl samples indicated that the young-of-the-year had reached a mature size by the time they returned to more saline waters to overwinter (Fig. 8). Sticklebacks were sufficiently abundant only in impingement samples for time-series modeling (Fig. 9). However, because the blackspotted' stickleback was'only recently recognized, data from both species were combined. Model R2 for impingement: data was 0.88 demonstrating a good fit to the data. Forecast error (29%) showed that the population abundance in 1984 remained within the historical bounds. Menidia spp., silversides Two silverside species have been found in the Millstone area. the -Atlantic silverside (Menidia menidia)-and the inland silverside (M. beryllina). Since 1980, silversides were separated by species; most were Atlantic silversides. In order to determine long-term trends, these two species were analyzed together. 19

e Wet Ape' 10 15' 20 2S 30

                                                                                                                          .J$                -

40 . 4S WNvWi SO XXXXXXXXXXXXX]

                                                                                                                 ,          70
                                                                                                                 *-         75 Aug Oct' 'y                                                         10 w          IS
                                                                                                                          .20 25 N
                                                                                                                            +0 b

ntp7erwesw 95 M SC 3 SS 40 l sS-70 75 '

                                                                                                                                                           .         i              ,                                       ,

0 50 100 150 200 FR(OWENCY Figure 8. Length-frequency distribution of threespined sticklebacks trawled during March through April and August through October

                                                  ^from.1977 to'1984.                                                 -
                                                                  -R2 = 0.88'
                                                  -11.0-                  Forecast error = 28 4Q%                                                      ,               '
                                                                 ~

e,,'# g' _ 9.0- ,8 5,

                                                                 .                                                                             +                       +- '
                                           'R                                                                                       0 e        7.0-      '
                                                                                                                                ,,.'                         +
                                                                                                                                                               +,           +      \  r
                                            ~h                   "

f t g ,,

                                               "b0T                                                                ,"           *,                             ' , .~                    ++t
                                                                                                                                                                                                                              +,

5 ,' , + , s, --, O .-3,0- ,,# , . .', s ', O +,'++ i, v-3 'i.of -

                                                                                                        ++++ + , "*+

[ 's,

                                                                                                                                                                            ~ ++t                                                      & ++++ +++++

0 -1,0- # s s q) . ,' c- 2  : ,' , 's ,

                                                   -3,0-                      .,;,'                                                                                                                                                                           ,
                                                      - - --                 Z=F (1+ Sin (ly) +Cos (ly) -Sin (4m) ) -Al                                                                                                                                                 --
                                                   -S.0-
                                                                   .i                                     i             i        i      i             i           i       i            i                                 i                         i           i        i  i

S 0 N- 0 'J F M A u J J. A S 0

- 1983 1984

                 - Figure 9.                       The forecast ( ), 95% confidence                                                                                                                             limits (---), and 1984 data (+) for sticklebacks impinged.

20 E - - - . - - _ - - _ _ - . _ _ _ _ _

Silversides are found in tidal river mouths, creeks, channels and bays along the Atlantic coast from Canada to Mexico (Bigelow and Schroeder 1953; Johnson 1975). They were the dominant species in the shore-zone seine program and ranked fifth in both trawls and impingement. Silversides were not abundant in plankton samples because their eggs are adhesive (Bigelow and Schroeder 1953) and larvae and juveniles stay close to shore (Bayliff 1950). Seined, trawled and impinged silversides had pronounced seasonal patterns of abundance (Fig. 10). They were found in seines primarily in July through November and in trawls and impingement in December through March. Greater than 98% of the silversides trawled in July through November were found at the near-shore stations (NR, IN, and JC), while those trawled from December through July were more evenly distributed over all stations. Winter offshore migrations of silversides are well documented (Bayliff 1950; Bigelow and Schroeder 1953; Conover 1979). Larger fish (60-120 mm) dominanted the winter trawl and impingement collections, while juveniles (20-50 mm) were abundant in the summer seine catches. The median abundance of silversides in 1984 at JC, where over 65% were seined since 1977, was the lowest recorded since 1979 (Fig. 11). The medians were based on collections during May through October from 1978 to 1984, when JC was sampled at least once a month. The time-series model of seined silversides at JC had a 3-yr cycle (Fig. 12), which was also reported in 1983 (NUSCo 1984). The JC seine forecast fit the 1984 data well (forecast error 32.2%), indicating that the decline in 1984 abundance was probably a naturally occurring population fluctuation that the model accounted for with the-3-yr cycle term. The increased susceptibility to trawling and impingement during the winter offshore migration was evident in the time-series models for 2 trawls at JC (R 2=0.58) and impingement (R =0.81) (Fig. 13). At trawl station JC the forecast error (39.6%) was lower than the actual modeling error (41.7%), indicating 1984 deviated little from historical average variability. The forecast error for the 1984 data was high (66.8%), but most of the 1984 data were within the forecast 95% confidence intervals. 21

4 r i O p _O u v. 5 ~: a  : . k a -:: 3

                                                                                                       ! ",,    8

. c-

                                                                                                            "   M
                                                                                   ,                            m l               .   $

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m. 3 wa bk a  :"O: . U M Nii q - - a MN w in s 3 m

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                                                    .                                                 '$         ch 0%

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                                                                                                       -O       ~M C "i
                                                   "a                                                  - +

[ 'O C x ce n . _ _ _ > 'O .. Oe4 4 3 w'c-SN ceE SoSSSS m S.EeSoSSES eS eoS g, an

                           '                                                                                      CJ C3 AW
                               .-                         e                        E S
                         - 3., .:                         i E

a CC ar4 4s 22 l:

e-800 700 600 500-g 400 z a

      'O    300 I

9 280-2 100 L 0 ,. ,. , ,. .,- .,. .,. ., 1977 1978 1979 1980 1981 198a 1983 1984 YEAR Figure 11. The annual median counts and 95% confidence intervals of silversides collected in seines from May through October in 1978 to 1984. 11 0~ R2 = 0.88 I'orecast error = 32.25% 9.0- , A , e 1.0- 's ,s'

                                              ,                                     .                         +
             +                                   '                                          ,'
            ,       5.0-                           \                                    ,'     +

C \ '

                                                                                      <                                 +

3 i ,

                                                                                  ,                        +

0 3.0- '-~~~----

• o ~~. '

O

                                  ', +                                 +                                            ',

Z ,

                                                                                                   ,i g       1.0-                                                   +                     ,
                                             't            -    -

c- ,e 0 -1.0- s i o r o 2 \

                 -3.0-                                      __________-
                 -5   0- Z=S (1+ Sin (3y) + Sin (6m)-Cos (4m) )                                                                  !

I I I i i i i i i i i i i l l S O u 0 J F M A M J J A S O 1983 1984 l l Figure 12. The forecast ( ), 95% confidence limits (---), and 1984 l data (+) for silversides seined at JC. l 23

E i1.o- R2 .= 0.58 (a)

Forecast error = 39.62%

9,0-

           .n
            -                                    .'      's r 7.0.                          ,
             +                               ,'           +
            ,     s.o-
                            -V,'
                                    +,                               ~ - . . '~ ,                                           ,r,     ,

c s , + 2 O 3,0- -' O v

                                                                     ++

Z 1.0-g

                                       + +        ,#   ,'N                  + ++ + ++++                              +        ++

0 -1,0- e 's o ..,,,' , ~... . 7 . s, , _ s , .

                -3.0-                                                                   s.__..                   ,
                -5.0- Z=S (14Cos (6m)+ Sin (3m)) +Al-A21 i        i       e           i         e         i       i         i       i      i          i        i     i       i S        O      N           D          J        F        u        A       u       J         J         A     S       O 1983                                                                                                       1984 11.o-      R2 = 0.81                                                                                                            (b)

Forecast error =,,,66.86% , 9.0- ,e '. s

                                                              ,                       s n                                                ,                          s
             -    7.0-                                      e                             \

l  %

             +                                      ,

u 5.0- ,' ' + ,. \ C s

                                        *           *                  +         *+                '

• 3 ,

                                  '                                  +      +                         's,                ',,. -

o 3.o-

                                                      +            .
                                                                     ,             ++                         -

O + r' s v + -

                                                                                    ~

f 1.0- ,

                              +++++ ++                                                    ++, ++++4                              ..++..

c ' f+. . O.-t.0-e ,

                                                                                              \.
            ~s
                                                                                                    ~
                                                                                                       's, 3.0-                                                                                          .. ,...          .
                -5.o-       Z=F (l+ Sin (ly) +Cos (ly) + Sin (6m) ) -Al-A2 i        i        i          i          i        .        i. i             i       i         i         i    i        i S        O-     N           D          J        F        u        A       u       J         J         A     S       O-1983                                                                                                       1984 Figure 13. The forecast (                               ), 95% confidence limit (---), and 1984 data (+) for silversides trawled at JC (a) and itopinged (b).

24

n;  ;

           /J-
               .Microgadus tomcod, Atlantic toscod The Atlantic tomcod (Microgadus tomcod) is the most abundant member of the cod family collected in the monitoring programs at MNPS. Its range extends along the Atlantic coast of North America from                                  -

Newfoundland to Virginia (Bigelow and Schroeder 1953). Howe (1971) reporteh that tomcod reach sexual maturity at about 130 mm; they migrate up rivera to spawn in fresh or brackish water from November through Februarl7 Eggs are adhesive and attach to the substrate. After spawning adult and larval tomcod remain in or near the estuary. They move off to cooler waters during the summer months. The ::omcod has' been observed in all finfish programs, but was only abundant. in the trawl and impingement samples (Ta'ble 2) . In trawl samples, tomcod' abundance ranked sixth and individuals were caught predominantly at IN .and JC ( > 72%) . Catches in trawls were seasonal and 4 s over 88% were collected during April through June. These catches-consisted mostly of young-of-the year (Fig. 14). In impingement samples i ., 3 s ki ' C SEASON m N nar June 30 ymewm 60 (b) 90 120 3 (aM') l 150 S - 2 180 3 M 9 i- 210 ' mox Julg Oct E 30 0

                                                       ~

d' 60

                                   '90     9 120      I 150 '

180' ] 210 3 ^ Si5i'R1 Nov Feb 30 , N 60 90 I 120 150 (. 1 ZiD wwmm 180 N wwMwwwl 210 > P ? . . .,. ,. mxmm) _, ,. 0 100 200 300 400 500 0 400 800 1200

                                                . FREQUENCY                         FREQUENCY Figure 14. Length-frequency distrubution by season for tomcod collected in trawls (a) and impingement (b) from 1977 through 1984.

25

tomcod ranked seventh, and were seasonally abundant with over 75% collected during their spawning season in November through January (Fig. 14). Because tomcod eggs are adhesive they were infrequently collected in plankton samples. Larval tomcod were also rarely observed in

   -plankton samples because the larvae remain in or near the spawning areas which were not sampled.

Time-series models fit the trawl data at IN and JC, and impingement data well with R2 values ranging from 0.68 to 0.75 (Fig. 15). Model terms include 1- and 7-yr cycles. However, the 7-yr cycle may be an artifact of the length of the data base (7 yr). A bimodal seasonal peak occurrence was evident in both programs (Fig. 14). In the trawl models, the primary peak was due to the early spring appearance of juvenile tomcod and a secondary peak due to the appearance of both adult and juvenile tomcod in the spring. Forecast errors of all models ranged from 25% at JC to 96% for impingement. The high error for impingement was probably caused by a concentration of data points near or above the upper confidence limit during the summer months. This appeared to be a later summer occurrence than predicted from historical data and may indicate a later migration from their spawning area in 1984. Myoxocephalus aenaeus, grubby The grubby (Myoxocephalus aenaeus) is a small fish from the sculpin family. It is an inshore species found over a variety of substrates but predominantly in eelgrass habitats. Its range extends from the Gulf of St. Lawrence south to New Jersey (Bigelow and Schroeder 1953). The grubby spawns from late fall through winter, attaching its eggs to the substrate (Lund and Marcy 1975). The grubby is a resident fish with all life history stages collected at MNPS (Table 2). In impingement and trawl samples, the grubby ranked fourth and eighth, respectively. Greater than 80% of the individuals caught in both programs were taken during the spawning season in December through March. In trawls, most were caught at the near-shore stations IN, JC, and NR (73%). Grubby length-frequency

    -distributions in trawls and impingement had modes of 60 and 90 mm.

respectively (Fig. 16). Grubby larvae ranked fourth at EN at NB, and 26

s I

                        '?1.0- R2 = 0.76                                                                                                                   ()

Forecast error = 36.67%

9.02 m _

                   "       7.0-                                                                              +
                                                                                                          +,
                                                                                                +, ' '          '(,,,
                   +              -                                                                              -         ,
                                                                                                '                      +          i u       5.0-                                                                                                     ',

C s' ----- a ,, ,a ,

                                                        ,'              '                                                 +

3.0- --s, _,,-

                 ]v
                                                          +++

7 1.0-g C s' ' o -1,0-

                                                                                                  ,'                '-       ' s, e              -                                                           ,                                    ,

2 ,' '....

                          -3.0-          --.'s     . , ,..
                          -5.0; Z=S (1+Cos (7y) -Cos (ly) +Cos'(4m) ) +Al+A2 i       i     i             i          i        i      i      i             i      i     i i       e     i J     F             M'         A       M      J      J             A       S     0 S       O     N        D 1983                                                                                                    1984 (b) 11.0-         R2 = 0.73 Forecast error = 24.85%

9.0-n ,i's,,' ~ ._ e 7.0- ,

                                                                                                                +++ s,
                                                                                                ,'                       +           's,
                      +'                                                                  '         *                                        '

a c 5.0-r + 3 s....

                                                                                          +               +                                +

O 3.0- + 0

            ,~

v Z 1.0- , ,'s,,. 3 ' '

                                                                                                                                               +++

c

                                              ++                 ++++++                          +
                                                                                                    ,'                         's+.

O -1.0-

                                                                                                  '                                   's
                                                                                             .'                                             ~, '

o - 2  : 's ,N _ ' .

                            -3.0-             s,,,,'                        ..,'
                 ;                           Z=S (l-Cos (ly)+Cos (4m) )+Al+A2+A26 l            -5.0}                                                                             T'     i        i            i     i     i e       i       i        i       i       i            I J     F                                M      J       J             A     S     O S       O       N        D 1983                                                                                                     1984 Figure 15. The forecast ( ), 95% confidence limits (---), and 1984 data (+) for tomcod trawled at IN (a) and JC (b), and                                                                     '

impinged (c). 27

7 L r. 1 11.o- R2= 0.68. (c) 7 Forecast error = 93.78% 9.0-N. A v 1.0- ,,_l ', , . ,

                                    .+.                                              ,-                            s,.        ,',             ,             ,

5,o- ,- + ,_,- ~ , +! _+_ ! - - { C , 2 ~

                                                                                          +                            '

0- 3,0-O V t

2J- ,0- ,

                                                                                                                  +

c ++"**++/,'+*+"+**++** * " " o -1.0- ,..- N ,

                                                                                                                                      ,s y                                                ,'                             ',         ,

_3,g;

                                                            .,, '                 '                                    's.,'                            .__,
                                           ,3,,; Z=F (1+Cos (ly) +Cos (4m) -Sin (6m) +Cos (6m) ) -Al-A2 i               i            i        i               i      i     i       i     i      i         i       i      i    i S             0              N       D               J       F     M       A     W      J         J      A-     S    O 1983                                                                                                           1984               ,

Figure 15. (Cont'd) (b)

                                     .40-           M                                                                                 (a) ]

50 W20000000M61 E 60 70. 80 90

                                  -100               M 110              M                                                                                     M 120-            h                                                                                      M 130             h                                                                                      M 140             h                                                                                      M                               .,.       ..

O. . E00 400 600 800 0 500 1000 1500 FREQUENCY FREQUENCY Figure 16.- Length-frequency distribution of the grubby collected in trawls. (a) and impingement (b) from 1977 through 1984. 28

were collected from February through May. Because the eggs are

                                                                                                         ~

adhesive, few were collected in plankton samples. The grubby was rarely _ collected'in seine samples. Time-series modeling of grubby catch from impingement, trawl, and

         > larval collections had mixed results. In general, plankton and impingement'models. accurately described those data and had R2 values 2

ranging from 0.87 to 0.97 (Fig. 17). However, trawl models had R values less than 0.59 (Appendix 4). Larval and impingement models had low forecast errors (9% to 26%) indicating that the 1984 pattern of grubby abundance was similar.co historical levels. (a) 11.0- R2= 0.97

Forecast error = 9.53%

9.0-m 7.0-N 5.0A i '~'s m _ 3+ * - s, C . .+ / r +,bj( s 0 3.0- g s, s a-v ' e4' ,,' ' ~ s

                                                          , r'                         ~------- --

f 1.0- _, ------ - g

                              -                        ,#                        +4,++-

o - 1 . 0.' "'-------- e 2  :

                        -3.0-Z=S (Sin (ly) -Sin (4m) ) +Al-A3+A6-A7-Al2

_3,o_ i i i i i i i .i i i i I i i S O N D J F M A M J J A S O 1983 1984 Figure.17. The forecast ( ). 95% confidence limit (---), and 1984 data .(+) for-grubby larvae at EN (a) and NB (b), and individuals impinged (c).  ! e 29

(b) 11.0- R2 = 0.93 Forecast error = 12.79% 9.0-m s** 7.0-Y l

                   >s
                 .t     5.0-y)                                                                    +,,r c                                                                  ,' +,       '

O 3.0- e

                                                                                           ,,       \

Q V

                                                                                 ,' ,, ++ +,+s            '

Z '

                                                                                  ,e is       's a      1.0- _____ ..... _,,                                   ,                      s,          -....______

c ,'

                                                                            ,                              *t+-,

0 -t.o-O E .

                      -3.c-
                      ,3,g_

Z=S (Sin (ly)-Sin (4m)) i i i i i i i i i i i i i i S 0 N D J F M A M J J A S O 1983 1984 R2 = 0.87 (c) Forecast error = 25.63% 11.0- - ,._ l '... ,, 9.0- +, \ _ l .

                                                                                                          \,
                 ^             .                         + ,'            + ,+ +

e 7 . 0 -- ,p + + , s,

                                                   ,'                      + +                       ++ '

4 - , ,

                                                                                                                   "++

c 5.0. .

                                     ,,s,,'            +
                                                                                    +
                                                                                           +
                                                                                                                                     +
                                                   +                                                                          ,,

O 3.0- + , O , , , v - , i Z g 1.0-C

                               ~
                                        +        **e#                                           + +
                                                                                                              \*                 " " "

o -1.o- ,e ,'

                                                                                                                \,

y O -

                                    ,'s-        ,-
                      - 3 . o --                                                                                        (,,'
                      ,3,g, Z=P (1+ Sin (ly) 4Cos (ly) +Cos (4m) ) -Al i         i       i       i          i       i         i      i         i        i        I       i      i   i S        0       N       D          J        F        M       A        W         J       J        A     S    0 1983                                                                                                   1984 Figure 17. (Cont'd) 30 I

r p-Scophthalmus aquosus, windowpane. The windowpane (Scophthalmus_ aquosus) is found in coastal waters on sandy bottoms along the Atlantic coast of North American from the Gulf

of St. Lawrence' to Florida (Gutherz 1967) . - It is found year-round off the coast of Southern New England-(Moore 1947). The windowpane has a wide temperature tolerance (Bigelow and Schroeder 1953). Austin et al.

                               ~
           -(1973) observed an inshore-offshore migration of windowpane off
          .Northport, L.I.,-and this seasonal movement was believed to be the result of avoidance of extreme temperatures.-

The windowpane was most abundant-in trawls and impingement where it ranked third.and ninth, respectively (Table 2). Individuals were l infrequently. collected-in the planktou and seine programs. Because

           . spawning takes. place in deeper water (Moore'1947), eggs and larvae were not susceptible-to entrainment. Windowpane juveniles are . found in the sublittoral zone (Martin and Drewry 1978) which may explain their
           ' absence from seine samples.

a.

                  -The windowpane was found in trawl and impingement collections year-round at MNPS. Over 50% of the windowpane caught in trawls were found at BR.- The median-length of trawled windowpane was consistently larger at NR than at BR (Fig. 18). Median lengths at the other trawl stations (IN, JC, NB and TT) ranged between these two extremes.

Windowpanes mature at 230 to 250 am, therefore primarily juveniles were found at BR, and adults at NR. The annual median lengths of impinged

           -windowpanes were similar to thoses trawled at NR except in 1979 and-1983
           .when.apparently large numbers of juveniles were impinged.-

Time-series models were developed from trawl-and impingement-windowpane catch data. Data from trawls were not modeled well as evidenced by the low model 2R values and high forecast errors (Fig. 19; Appendix 4). Trawled f_ish. species that have no seasonal pattern of occurrence 'are not modeled well with harmonic regressions (NUSCo 1984). Windowpane catch at BR had a 7-yr, 2-yr and 1-yr cycle; models done in 1983 had 6-yr and 1-yr cycle. The long-term, 6-yr (1977-82) and 7-yr -

(1977-83), cycles may be an artifact of our data base indicating possibly longer term cycles. Although the BR trawl model did not 31

305i . (a) 295- ,, 285 ,, f 275: - t 265i  ? 255_ 2

   $c    245 d                      i 3     235q                       t
   .0 B

2251 7 f I s 215 . T

                                                          ?

2057 " a 7 l [ 195 185 _ m 1 175 ,. , .,. , ., .,. .,_ .,. ., 1976 1977 1978 1979 1980 1981 1982 1983 1984 YEAR 305i (b) 295 1 285 275: 265 1 255 _

     $C   245i K

3 235 C

    .9    225-2 s     215 205:

1 195 1 185 _ 1752 - ,- . ,- .. 1976 1977 1978 1979 1980 1981 1982 1983 1984 YEAR Figure 18. The annual median length (n:m) and 95% confidence interval for the windowpane trawled (a) at BR (E) and NR (9) and impinged (b) from 1977 through 1984. 32

s LR2 =-0.38 . (a) 1i 0 , Forecast error = 225.96% N

                                    .9.0-                                     ,
                                                                      +
                                                                                 ~
                                                                                                                             ; ,+ ' . , , ,

m +

                                                                                              - " ~~,                              '

7.0. ++ ,', ,

                                                                                                                                             + +
                          ~+           .      .             +                                                                                 +

a 5 ~. 0 - +

                                                      '+                                                      +

C' , 3 + O 3,o_

                        .O-v                                               -                              +

z

g. t.0-

                                                                                       ~,                                   , -
                          .c.                 .                                                    _,,,,

O -1,0-e 1 .

                                   -3.0-

_3; g j Z=I+ Sin (7y) +Cos (7y) -Sin ( 2y) -Sin (ly) +Al i i e i e i i i .i i i i i i 5 .0 N D , J F M A W J J A 5- 0 1983 1984 11.0- R2 = 0.78 (b) Forecast error - 37.65% 9.0- -

                                                                                                           , -~,

e- 7.0- < - 's

                                                                        +                                                      .
                                              '                                              .*                              s
                                                                                        ,-                                     s, +
                           +                                               .  ;                             +          +

3,o_ +

                                                              ,,                       +
                                                                                                    +                    ++',                   +
                        .,                               '                                                      ++          ++ +     - L+ ' +

c .- .,,

3. +

O 3,0- + ,

                                                                 +                           , +

0-. - s l

                         %,,,o*

Z.

                                                                                      ++ 4+,'o                         's s.                                        .j i

g- 1.0. # i r s

                                             =
                                                      + ' + +                +#4=#
                                                                                                          ++       +           'g     ++++

0 , - - ' 's , e -3,o. . ',,,- 2 a- -3.0.

                                  .3,oj            Z=F (1+ Sin (ly) +Cos (4y) -Sin (6m) -Al i        i       i      i      i       i      i .i              i        i       i        i    i      i S       O       N;      D      J      F       M          A~M            J       J        A     S     O 1983                                                                                         1984 Figure 19. The forecast (.                                   ), 95% confidence limit                                      (---)     and 1984 data-(+) for the windowpane trawled at BR (a) and impinged (b).
                                                                                                                     ~

l 33

l describe observed patterns well, most of the 1984 data fell within the 95% confidence intervals. The impingement model of windowpane catch described patterns of abundance well (R2 =0.78) and had a 4-yr and a 1-yr cycle (Fig. 19). The forecast error was low (37.6%), for a species that has little seasonal pattern, and most of the 1984 data were within the 95% confidence intervals. Tautoga onitis, tautog The tautog (Tautoga onitis) is found from New Brunswick to South Carolina, but is most common from Cape Cod to Delaware Bay (Cooper 1965). Adult and juvenile tautog are found inshore near rocky areas, ledges, musselbeds, breakwaters, and other similar habitats from early May until late October (Bigelow and Schroeder 1953; Cooper 1965). Juveniles are also found in eelgrass beds and among macroalgae in coves and channels (Tracy 1910; Briggs and O' Conner 1971). Both juveniles and adults have a home site where they remain inactive under cover at night; during the day larger fish move to other locations to feed, but juveniles remain close to their home sites (011a et al. 1974). During winter, adults move to deeper water and remain inactive while juveniles stay inshore to overwinter in a torpid state (Cooper 1965; Olla et al. 1974). Tautog males become sexually mature at age 3 and females at age 4 (Chenoweth 1963). Spawning occurs from mid-M a y until mid-August in LIS (Wheatland 1956; Chenoweth 1963). The eggs are pelagic and are concentrated in the upper 5 m of the water column (Williams 1967). Metamorphosis of larvae is complete by 10 mm when young become benthic and move inshore (Fritzsche 1978). The tautog was found in all programs, but was dominant only in the plankton samples (Table 2). Tautog eggs ranked second and larvac ranked fif th (NB) and seventh (EN). Tautog catches-were low in trawls and impingement samples. Tautog prefer rocky shores such as those surrounding MNPS; this type of habitat cannot be sampled effectively by either trawl or seine; Even though the intakes are located near preferred habitat, tautog individuals were not impinged in large numbers. 34

7.- Tautog catches were higher at near-shore trawl stations (JC, IN, NR) than offshore (TT, BR) or mid-bay (NB) stations. Although tautog-were present year-round, catches were lower from November through April-in trawls'and impingement. The season of peak occurrence of tautog in

   -impingement collections (May and June) preceded the peak in trawls (June I

through August). Both' eggs and larvae were abundant in plankton samples from June through August.

         !The length distribution (1977-1984) of impinged tautog was unimodal, while that of. trawled fish (all stations and years combined) ~

was bimodal (Fig. 20) . Smaller adult tautog probably stay near the EO I l, 40 N u

                  %WNXONNY2                        ^ * *Yf 60                                    MDMA 80   WW1 DNl                             MMMMM1 100                                    NAMNM^WN3
          '120    ^^WW ga0    %WYY/XYMOW'I                    NNNWWWNWNNNWN3 gga    :<xoyxoyxxxcoxo)Xo:              M/MM/MM/MMJ
                  ^N'WWWNMM#'3                    WMANWWMMi 180                                     %wwwW<'s ggg    /H/ H////7 M M H///h MWMWMMANA                        MMMMM3 220                                     FN/H/MN1 g4g    /////////7MAM//1 LODXXJXUXXXAD]                   XX/X/X/ X1 z    550 5    280    MWWWAN3 5    200    M^WNeh3                          M
      "    320    C'XGX4XXXGC                      FA 340     ^^N N 3g3     t/Mn 3

380 fee /l 3 400 2525IS 420 p i 440 460 M 480 29 500 W , . , , . , ,.

                                                    }    .       .,.    .,.    ,.

O 20 40 60 80 100 120 140 0 50 100 150 200 FREQUENCY FREQUENCY _ Figure 20. Length-frequency distribution of~tautog collected in trawls (a) and impingement (b) from 1977 through 1984. rocks and shoreline and are thus more susceptible to impingement. Larger tautog move out to open water to feed during the day and can be caught by trawls. In addition, juveniles ( < 80 mm) were caught in trawls primarily at near-shore NR and JC ( > 70%), ideal nursery areas for tautog (Briggs per. comm.). This spatial difference in the distribution of juveniles and adults accounted for the bimodal length distribution _of trawled tautog. 35

l Tautog eggs and larvae abundance are probably the best life history stages to determine. population stability for this species in the MNPS area. Tautog eggs and larvae in the plankton programs were modeled using harmonic regression techniques (Fig. 21). The time-series models had high R2 values ( > 0.82) . The 1984 egg data followed model predictions very closely (3% forecast error). The 1984 larval data were not predicted well at NB (39% forecast error) and at EN (183% forecast error) due to a large decrease in larval abundance during July and August - This was the same pattern as discussed for the anchovy larvae. Tautogolabrus adspersus, cunner The cunner (Tautogolabrus adspersus) is predominantly a coastal marine fish which prefers reef habitats (Bigelow and Schroeder 1953; Olla-1975, 1979; Pottle and Green 1979; Serchuck 1972; Dew 1976). It ranges from northern Newfoundland to the mouth of the Chesapeake Bay (Leim and Scott 1966). Most cunner have limited home ranges and are active only during the day. Activity in cold weather declines and individuals become dormant at a temperature of about 5 to 8'C and lie torpid among and under rocks (Green and Farwell 1971; Dew 1976; Olla 1979). The cunner becomes mature in its first year (Dew 1976) and spawning occurs inshore from May through August, occasionally to mid-October (Wheatland 1956). .The eggs are pelagic and are usually found in the' upper 5 m of the water column (Williams 1967). Metamorphosis of larvae is complete by 10 mm and juveniles move to the bottom'(Miller 1958). The cunner was among the top ten ranked finfish in all MNPS monitoring programs except seines (Table 2). This species had the most abundant eggs found in plankton samples and larvae ranked fourth at NB and fifth at EN. It ranked seventh in abundance among the trawl catches and ninth among the impinged finfish. Over 75% of trawled cunner were caught at IN and JC, primarily during June and July. Impingement catches were highest in June through October. The length-frequency distribution of cunner from the trawl and impingement programs differed (Fig. 22). The distribution of trawled 36

7m 11 0- R2 = 0.98 . (a)-

Forecast error = 2.86%-

9.0- ,.., n o 9'

   -                                                                                   4     4 tg
                      .7.0-
                                                                                                     's , 9 y s          -
                 +.-:          -

g ,,'

                                                                                                            ~

s . 0 -- ,o o' ',

C . o, '* O. O 3.0- '8

                                                                              , 8
                                                                                                                    , s' s

v ',. ., s Z. ,,o _'----.------------- ,,l ,o' 's, e

                                      ,.                             ...+.                                                 ,

O.-1.0- ------------------, ' s,

                .o             -

I .

                      -3.'O-
                      -5.O b Z=S (-Cos (ly) +Cos (6m) + Sin (6m) -Sin (3m) )

i- i i i  ! i i i i i i i. i. i S 0 'N D' J F M A M J J A S 0 1983 1984

                                        ?

11.0- R~ = 0.85 (b) Forecast error = 183.51% 9.0-n 1.0-

                 ,b s.o us C                                                                               ,,' ' , *
                .O      3.0-                            '
              .Q                -

i i ',

                .v              -

s

                                                                                                    ,'y\, '," '-
                .Z.

a ,,o_ ,

                                       .... ------------------ ,, -++++. + +g ++ + h
                                                                                +

C' J++: : ., ., O -1.0- ,s ,------------------

                                             ,                                  s, o

3

                      -3.0.
                      -3,o
                          -j           Z=S (Sin (Sy) -Cos (ly) + Sin ( 6m) -Cos (4m) + Sin ( 2m) +Cos (2m) ) +Al-A2 i      .i       i  i    i    i  i        i        i         i         i        i       i     i S-       0    .N   D    J. F  M'       A        M         J         J        A       S     0 1983                                                                                 1984
       - Figure 21. The forecast ( ) 95% confidence limit (---), and 1984 data (+) for tautog eggs at EN (a) and larvae at EN (b)-and NB'(c).

37

Y tit.0- R2 = 0.85 .(c) Forecast error = 35.27% 9.0-

                   ^                     .

e-

                    .} -     7.0.
                                                                                                                             ,~,
                          '5.0-                                                                                           '
                                                                                                                                   .'s,
                   *m l

C- .  : , g

                   -C'

a. 3.0. ..

g' ,/ ,\ r,

                                                                                                                   ,                           s, .- ..
                 .a                       .
                                                    , ,........              ____......s_,                            f               ,

c

a. n , ..

                          -1.0               .',',..................,,,',

2 ', l

                         ' -3.0-                        g
                          -5.0                Z=S (-Cos (ly)-Sin (4m)+Cos (3m))

i i i i i i i i i i i i i. i S' O N D J F M A M J J A S 0 1983 1984 , Figure 21 (Cont'd) 10 20 (a) (b) 30 l. A0 M 3 50 M N 60 N N'vWWNxN3 70 N NmWNYxN 80 W7W73 MNXNXXXN1 90 MWWWxWW WMWMANM71 100 Wx NNNNN 110 MmMm^Xmi mmm>Wm 120 ^NWMWNJ NNWMJ 2: 130 B<wmWNI.od ^NWxNNel 73 140 M W N W W YxY! - M^M MAM^NN

          -E        150-                WNMM                                                          WNNNN 160                 MNWM                                                          DNA 170-                XummJ                                                         mm                                                                                                1 180                 NmN                                                           WM 190                 WWWi                                                          'XZD]                                                                                            

200 TN Z33 1 210 M256 8 220 M 230 - 2 23 @s 240 M 3 Ese WNNI ).. ,. 0 100 200 300 400 500 0 100 200 300 400 FREQUENCY FREQUENCY Figure 22. Length-frequency distribution of cunner collected in trawls (a) and impingement (b) from 1977 through 1984. I 38 f _ ~ , -

cunner at'all stations combined was bimodal and the impingement.had a single mode. This was similar to the tautog length,_ distributions discussed ~previously, and both species have a similar behavior pattern.

Smaller cunner adults' stay near the rocky. shore and are more susceptible to' impingement. Larger' adults. move offshore and are found in trawls.

Cunner juveniles (< 75 mm) were trawled primarily from near-shore NR and JC (>70%),'as were tautog; the spatial differences in the distribution aof juveniles and adults ac' counted for the-biomodal length distribution

    .oft
       .-. raw el d cunner.

The time-series models described seasonal occurrence in catch reasonably well as indicated by R2 values greater than 0.85 for all 2

models except impingement (R -0.61) (Fig. 23, Appendix 4). The 1984 egg.

data did not deviate greatly from model predictions (9% forecast error). Fewer-cunner were caught during 1984 in impingement, trawls (IN) and entrainment (larvae) and accounted for the higher forecast errorssat

   - these sites-(Fig. 23). The decreases in trawl catches at l[N and impingement may have been due to the removal in 1983 of the coffer dam (an excellent reef habitat for cunner) at the' Unit 3 intake. The decrease in larval abundance in July was similar to that found for
    - larval anchovies and tautog and was discussed previously in the anchovy section.

a t 39

L i1.O_ R2','0.96' (a) Forecast error = 7.49%- /~N .I o s i 9.0- i

                          ^
                                                                                                               .,?+,++.si,,

7.0- < i s

                          .+                                                                                ,
                                                                                                                   ,e         s, i,
                          .b s.'o_                                                             ,! l'                  l\, \

m , ,

                          -C                                                                                                        i w

[

                                                                                                                                     \ \'r+

O- 3.02  : O - ~r .

                                                   .,______.____________l                               ,                           \ ', , ,

C '*N+ \ ** O . _1 ~. 0 - 's , - o , ____________________/ _. 1 ~

                                   -3.0.
                                   -3     . O      Z-S (-Cos(ly)-Sin (6m)-Cos (4m))

i .i i i i i i i i i i i i i S 0 N D J F M A M J J A S O 1983 1984 11.0- R2 = 0.84 (b). Forecast error = 195.87% 9.0-

                           ^                   .

7.0-D 5.0-Tn C - s' 0 3.0- ,\ v o ,/ .

                                                                                                                                     -s
                          -z          .,,o_               _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ,    ,'             ,,_,                _._

a , , , C.

                                                        + " =                                           ' + "/ " +                  +b, + **

g -1.0- -'____________________,,/ ' 2 _3.0-

                                   -3.0; z=s (-cos (ly) + sin (6m) -cos (4m) ) +Al-A5+A6+A8 i          i     i     i     i            i  i      i         i                 i       i        i   i
                                                 $         0     N     D      J           F  M     A          W         J       J       A        S   O 1983                                                                                         1984              .
                .. Figure 23.          The forecast ( ), 95% confidence limit (---), and.1984 data (+) for cunner eggs at EN (a), larvae at EN (b) and                                                             -

NB -(c), .and individuals impinged (d) and trawled at IN (e) and JC (f). 40

FE tt.o- R2 = 0.83 (c) Forecast error = 39.17% 9.0-

         ^          .

7.0-

         ,D     5.0-                                                                                 a             .

w * '. C 0 3.0- / *

                                                                                                            ,-          5
                                                                                                                          's C                   .,                                                                 ,i      a        's                -

w Z _3 1.0- \o----------------,' ,-vvvv$7 +/

                                                                                                   ,/               's
                                                                                                                  ,s,
                                                                                                                    ++w c                 -+ + q' , , , , , , , ,

O -1.0- ' s, ,__________________s_ 2 ', l

               -3.o,
                      . Z=S (-Cos (ly)-Sin (4m)+Cos (3m))
               -s.0-                                                                                                       i       i     i i       i      i               i      i         :          i i         i         6 6

J F M A M J J A S 0 S O N D 1984 1983 11.0- R2 = 0.61 (d)

Forecast error = 70.54%

9.0-

                                                                                           ,,.              --~~ ,_ '

n  : ' '

           "     7.0-                                                             ,                +
                                                                                    ',               + , +
            +                    s
                                                                                                              +

y 5.o- - 2____- + + + c + 0 3.0- + + ,+ + ++ o v *

                                                        +
                                                +                            +

Z g 1.0- ..__-___

                                                   +            ++     +++ m ,+ne                                    ++ m g+++

c _

                                 ,'s                                             ,-

0 1.0-o _a

                         -          r 2
                -3.0-
                          ~
                -5.o- Z=F (1+Cos (ly) )-Al-A2-A3 i      i               i      i           i        i         .             i i           i       i      i                       e M       A      M          J         J         A       S     O 5         0         N      D       J      F 1983                                                                                                1984 Figure 23. (Cont'd) 41 L

l R2 = 0.88 (e) 11.0- Forecast error = 88.72% 9.0-

                                                                                                           ,'                  \'

o

          /**%          .-

e 7.0- / \ s

           +               -                                                                   /                                            N 5.0-                                                                        l a-C 3                        ','            ,,.- ,
                                                                                                                       ' 'g ,,

s O 3.0-

                                                  +
                                                                                                                                  \,

o -- , s v -

                                       +                                   +                        '

Z 1.0-

                                                                                                /                                         \

g '

                                             ++       ++++                    +        ++,'+                                       +++s c               ^

0 -t 0- l o , 2  % ,,, , N '

               -3.0-                                                       ,,,-
                             ~
               -5.0- Z= Sin (ly)+Cos (ly)4Cos (6m) +Al+A2 i         i     i     -e         i      e      i         i          i           i         i        i         i       i S        0      N       D       J      F       M        A          M            J         J        A         $       0 1983                                                                                                       1984 11.0-              R2 = 0.88                                                                                                         (f)

Forecast error = 22.52% 9.0- * ,,,' m ,' ',

            -        7.0-                                                                                  ,
                                                                                                             ,                             's s
                                                                                                                         +                        ~

4 ,l +

                                                                                                                                          +
            ,        5.0-C s                                                       ,'                           +

s,. - ., , O 3 o 3.0-

                                                       +
                                                                    ,N               '
                                                                                                                          .--t, s

v . ~~' ' Z g 1.0-

                                                                                                           ,'                               's,,
                                                           ++            ++++ + + ,                                                           +
                                          ++++

e s 0 -1.0- ,' f o ' ~~~,, 2 ',,'s

                -3.0-
                                                                        's-- ','
                -5.0-_ Z= Sin (ly) +Cos (ly) +Cos (6m) +Al+A2+All i        i      i       e         i           i           i        i        i          i     i i          i .i M         A           M           J        J         A         $      0
                                   $         0      N      O        J      F 1983                                                                                                       1984 Figure 23. (Cont'd) 42

i

SUMMARY

1. Nine taxa of finfish were selected for detailed discussion due to their susceptibility to entrainment and impingement by the operation of MNPS. They were the anchovy, American sand lance, stickleback, silverside, grubby, tomcod, windowpane, tautog, and cunner. Fluctuations in the abundance of their predominant life history stages in plankton, impingement, trawl and seine samples were examined.

   ~

2. Distinct seasonal-patterns of abundance were found for several taxa due to spawning migrations. The tomcod and stickleback leave the Millstone area to spawn in brackish waters. The anchovy was only present during the warmer months when they migrate inshore to spawn.

3. Differences in the spatial distribution of fish throughout the Millstone area were evident and could be related to the behavior of predominant life history stages. Juvenile silversides dominated the shore zone during warmer months and during the winter adults were collected in deeper waters by trawls. Juvenile windowpanes were primarily found in deeper waters and adults more prevalent in near shore areas. Juvenile tautog and cunner were most abundant in shallow near shore waters.

4. During 1984, the abundances of several taxa changed in comparison to previous years. An estimated 390,000 juvenile sand lance were impinged during July at Unit 2, an event not previously observed at Millstone. Larval sand lance abundance continued to be low since a decrease in 1982. Silverside abundance was the lowest since 1979.

There was a concurrent decrease in the abundance of larval anchovy, tautog, and cunner which was attributed to predation by ctenophores,

5. Time-series modeling was useful in describing seasonal patterns and natural fluctuations in abundance. For most taxa the 1984-abundance of predominant life history stages was similar to that predicted based on the models. The decline in silverside abundance in 1984 was predicted well with a three year cycle term. The decrease in larval anchovy, tautog, and cunner in 1984 was also identified by the time-series predictions. Based on the comparison of actual abundance data for 1984 and time-series forecasts, there was no indication that the operation of MNPS had impacted finfish populations in the area.

43

REFERENCES l Austin, H.M., J.J.1Dickinson, and C. Hickey. . 1973. An ecological study of:the,k.ichthyofauna New Yor Oceanography at the Department, Northport N.Y. Power Station,-Long Ocean Island, Science Laboratory. Contract No.2SR 60.38 72-73 F., 249 pp. Bayliff, W. H. .Jr. 1950. The-life history of the silverside Menidia menidia (Linnaeus).- Md. Board Natur. Resour. Publ. 90:1-27. _Bigelow, H.B., and W.C. Schroeder. 1953. Fishes of the Gulf of Maine. U.S., Fish Wildl. Serv., Fish. Bull. 53:1-577. Bireley, L.E. 1985. Time-series modeling: Applications to.long-term-finfish monitoring data. Ph.D Thesis, Univ. of Rhode Island.- 181 pp. Bothelho, V.M., and G.T. Donnelly.- 1978. A statistical analysis of the performance of the Boure plankton splitter, based on test observations.

                                    'NMFS unpub. ms.-
   ' Briggs, P.T.,                                     and J.S. O' Conner.                                                                            1971. Comparison of shore-zone fishes .
                                    .over natural'vegatated and sand-fille'd bottoms in Great South Bay.

N.Y. Fish and Game Jour. 18:15-41. Chenoweth, S.B. 1063. Spawning and fecundity of the tautog, Tautoga onitis.(Linnaeus). M.S. Thesis, Univ. of Rhode Island. 60 pp. , Conover, D.O.- 1979. Density, growth, production and fecundity of the Atlantic silverside, Menidia menidia (Linnaeus), in a central New England ~ estuary. M.S. Thesis Univ. of Massachusetts. '60 pp.

   -. Cooper, R. A.                                     1955. Life history of the tautog, Tautoga onitis
                                      '(Linnaeus). Ph.D Thesis, Univ. of Rhode Island.- 153 pp.
                                            . 1966. Migration and population estimation of the tautog,-

Tautoga'onitis (Linnaeus), from Rhode Island. Trans. Am. Fish. Soc. 95:239-247. Denson, E.E.'and T.J. Smayda. 1982. Experimental evaluation of herbivory in the etenophore Mnemiopsis leidyi relevant to

                                     -ctenophore-zooplankton-phytoplankten interactions in Narragansett Bay, Rhode Island, USA. J. Plank. Res. 4:219-236.

Dew, C.B. 1976. A contribution of the life history of the cunner, Tautogolabrus adspersus, in Fishers Island Sound. Connecticut. Ches., Sci. 13:101-113. Fitzgerald, G.J. 1983. The reproduction ecology and behavior of three sympatric sticklebacks (Gasterosteidae) in a salt marsh.

                                           'diol. of Behavior 8:67-79.

44

Fritzsche,<R.A. 11978. Development of fishes of the Mid-Atlantic

           ; Bight. An atlas of egg, larval and juvenile stages. Vol V.

Chaetodontidae'through Ophidiidae. FWS/0BS-78/12. 340 pp. Glass, G.V., V.L.. Wilson,.and J.M. Gottman. 1975. Design and analysis of time-series experiments. Colorado Associated University Press,' Boulder, Colorado.'241 pp. Green, J.M., and-M.:Farwell. 1971. Winter habits of the cunner, Tautogolabrus adspersus (Walbaum), in Newfoundland. Can. J. Zool. 49:1497-1499. Gutherz,.E.J. 1967. Field guide.to the flatfishes of the family

           - Bothidae in the western North Atlantic. U.S. Fish Wild 1.-Serv.

Cire. 26.3. 47 pp.

 -    Hilderbrand, S.F.      1943. A review of the American anchovies (Family-JEngraulida'e). Bull. Bingham Oceanogr. Coll. 8:1-165.

Howe,-A.B. 1971. Biological investigation of Atlantic tomcod, Microgadus toscod, in the Weweantic River Esutary, Massachusetts, 1967. M.S. Thesis, Univ. of Massachusetts. 82 pp. LJohnson, M.S. 1975. Biochemical systematics of the atherinid genus Menidia. Copeia 1975:662-691. Kuntz, A. 1914. The embryology and larval development of Fairdiella chrysura and'Anchovia mitchilli. U.S. Bur. Fish., Bull. (1913) 33:1-19. Leim', A.H., and W.B. Scott. 1966. Fishes of the Atlantic coast of Canada. Bull.. Fish. Res. Board Can. 155. 485 pp. Lund, W.A., and B.C. Marcy, Jr. 1975._ Early development of the grubby, Hyoxocephalus aenaeus (Mitchill). Biol. Bull.. 149:573-383. Martin, _ F.D. , and G.E Drewry. 1978. Development of fishes of the Mid-Vol Atlantic Bight. An atlas of egg, larval and juvenile ' stages. Stromateidae through Ogcocephalidae. FWS/0BS-78/12. 416 pp. 6.

      - McHugh, J.L. 1977. Fisheries and fishery resources of New York Bight.

NOAA Tech. Rep. NMFS Cire. 401. 51 pp. 1979. Relative abundance, behavior,

      .Meyer, T., R. Cooper, and R. Langton.

and food habits of the American sand lance, Ammodytes americanus, from the Gulf Maine. Fish. Bull., U.S.' 77:243-253. Miller, D. 1958. A key to some of the more common larval fishes of the Gulf of Maine. Woods Hole Laboratory. M.S. Rep. 58-1. 56 pp. 45

Moore, E. 1947. Studies on the marine resources of southern New England. VI. The sand flounders, Lophopsetta aquosa (Mitchill); a general study of the species with special emphasis on age determination by means of scales and otoliths. Bull. Bingham Oceanogr. Coll. 79 pp. NUSCo (Northeast Utilities Services Company). 1982a. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1981.

     . 1982b. Millstone Nuclear Power Station Unit 3. Interm environ-mental report, operating license stage.
     . 1983a. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1982.
     . 1983b. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Resume 1968-1981.
      . 1984. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1983.

Olla, B.L., A.J. Bejda, and A.D. Martin. 1974. Daily activity, movements, feeding, and seasonal occurrence in the tautog, Tautoga onitis. Fish. Bull., U.S. 72:27-35.

      . 1975. Activity, movements, and feeding behavior of the cunner, Tautogolabrus adspersus, and comparison of food habits with young tautog, Tautoga onitis, of Long Island, New york. Fish. Bull., U.S.

73:895-900.

       . 1979. Seasonal dispersal and habitat selection of cunner, Tautogolabrus adspersus, and young tautog, Tautoga onitis, of Long Island, New York. Fish. Bull., U.S. 73:895-900.

Perlmutter, A. 1963. Observations on fishes of the genus Gasterosteus in the waters of Long Island, New York. Copeia 1963:168-173. Pottle, R.A., and J.M. Green. 1979. Field observations on the reproductive behavior of the cunner, Tautogolabrus adspersus (Walbaum), in Newfoundland. Can. J. Zool. 57:247-256. Reay, P.J. 1970. Synopsis of biological data on North Atlantic sandeels a' of genus Ammodytes FAO Fish, synopsis No. 82. Richards, S.W. 1959. Pelagic fish eggs and larvae of Long Island Sound. Bull. Bingham Oceanogr. Coll. 17:95-124.

        . 1963. The demersal fish population of Long Island Sound. I. Species composition and relative abundance in two localities, 1956-1957. Bull.

Bingham Oceanogr. Coll. 18:5-31. 46 ,

Roland, W.J. 1983. Interspecific aggression and dominance in Gasterosteus. Env. Biol. Fish. 8:269-277. Scott,.J.S. 1972. Morphological and meristic variation in northwest Atlantic sand lances'(Ammodytes). J. Fish. Res. Board Can. 29:1673-1678.

    .Serchuk,.F.M.        1972. The ecology of the cunner, Tautogolabrus adspersus (Walbaum) (Pisces: Labridae), in the Weweantic River Estuary, Wareham, Massachusetts. M.S.' Thesis, Univ. of Massachusetts. 111 pp.

Snedecor, G.W., and W.C. Cochran. 1967. Statistical methods. Iowa State Univ.. Press. Ames, Iowa. 593 pp. Stevenson, R.A. 1958. The biology of the anchovies Anchoa mitchilli and

          -Anchoa hepsetus in Delaware Bay. M.S. Thesis. Univ. of Delaware.

56 pp. Tracy, H.C. 1910. Annotated list of the fishes known to inhabit the

    ;      waters of Rhode Island.         R.I. Annu. Rept. Comm. Inland Fish. 40:35-176.

Williams, G.C. 1967. Identification and seasonal size changes'of eggs of the labrid fishes, Tautogolabrus adspersus and Tautoga onitis, of Long Island sound. Copeia 2:452-453. Worgan, J.P., and G.J. Fitzgerald. 1981. Habitat segregation in a salt marsh among adult sticklebacks. Env. Biol. Fish. 6:105-109. i 5

                       \

47

APPENDIX I. j TIME-SERIES MODELING METHODS Data Preparation Before the selected series were analyzed, the data were prepared so that analytical calculations would be more tractable. This preparation included insuring that the data were equally spaced in time, filling-in

 . missing data and long-transforming all data to stabilize the variance.

The catch data for the selected species were reviewed to establish the time elapsed between observations. The sampling intervals were one week-for impingement and plankton, two weeks for trawls, and a month for seines. All observations within one of these sampling periods were arbitrarily assigned to have been collected on the same date. In the impingement and plankton series, the assigned date was that of the preceding Sunday; in the trawl series, it was the date of the first Sunday in the two-week period. In the seine series, date values were 30.44 days apart beginning with 15 May 1969 so that collected samples could be assigned to one of 12 equally long sampling periods in a year. If, during a sampling period, a sample was collected that contained no representatives of a selected species, a zero was included in the data series for that sample. If no sample was collected in a period, this happened routinely in NB plankton samples and seines, a data point was filled in as described later by estimating its value from the deterministiccomponentofthepodel. Previous investigations (NUSCo 1983a, 1983b) revealed that the plankton, impingement, trawl and seine data come from highly skewed, non-normal distributions, with non-homogeneous variances. Glass et al. (1975) recommends that data like these be log-transformed to stabilize the variances before being subject to time-series modeling. Thus each datum in a series was log-transformed: Y=ln(catch *c + 1) where: catch = numbers of fish per 24 h (for impingement) 8

                 = density of ichthyoplankton per 500 m      (for plankton)
                 = numbers of fish per 0.69 km (for trawl)
                 = numbers of fish per 30 m (for seine) 48 m

and: c=1 for plankton series

                     =100 for all other series The constant, c, was chosen so that incrementing (catch *c) by I added less than 1% to the overall mean catch of a given species. For example
     .if the mean catch, over all time and stations, of a species was greater than-10 but less than 100, a multiplier of 10 was used; if the mean catch was greater than-1 but less than 10, a multiplier of 100 was used.

Because the median tends to be a better choice than the arithmetic mean as a measure of central tendency in a highly skewed distribution and because the geometric mean is an estimate of the median in such a distribution (Sokal and Rolf 1969), all catches from a sampling period were averaged after transformation so that a single value, the geometric mean in the original scale, represented each sampling period and station combination. Deterministic Component It seemed reasonableito expect that the. deterministic component of each model should explain the most obvious variations in a selected catch series and generate a realistic description of the observed patterns. However, it was not clear from the series themselves what variables should be included in the deterministic component to describe the patterns. Thus, many predictor variables were considered as potentially good candidates for describing the general pattern of occurrence of the selected species. These were time, season, flow

      -(water volume entrained by the cooling system--considered only in impingement models), and the following environmental variables: water temperature, deviations from normal water temperatures, barometric pressure, species abundance at other stations and zooplankton abundance.

In a preliminary review of the plotted catches, most series appeared to follow a somewhat cyclic pattern within a year. Thus, it seemed reasonable to use some cyclic function of time to predict the

      -general pattern of catches. A spectral analysis of the impingement and trawl series was used to determine the periodicities that accounted for much of the variation in the series. Cycles with a period of 7, 6, 5, 49

l 4, 3, and 2 years and 12, 6, 4, 3 and 2 months were found to account for much of the variation in many series. Therefore, the time variable was transformed using sine and cosine functions into new variables which could describe the observed periodic fluctuations. The actual argument of these trigonometric functions was the time (in days from the beginning of the series) expressed as radians scaled for the number of days in the cycle being described (see Bliss (1958) and Lorda (1983) for more details): S in (X) = Sin [ t ( 2pi) (X/12) ( 365. 25) ] Cos (X) =Cos [ t (2pi) (X/12) ( 365. 25) ] where t= time (in days) pi=3.1416 X= duration (in months) of a complete cycle 12= number of months in a year 365.25= average number of days in a year Based or. the results of the spectral analysis, the values of X were restricted to multiples or even fractions (or harmonics) of a basic period of one year. This was done because it did not make any biological sense to include a cycle that was not completed a whole number of times a year. Because time could enter the models in either the sine or cosine function (or both), a total of 18 predictor variables based on time alone were available to describe the observed periodic fluctuations. Usually predictor variables included in regression models take values over some continuous range. Sometimes, however, it is necessary to introduce a factor with two or more distinct values to account and scale for separate effects on the response variable. Variables of this sort are called ' dummy variable' (Draper and Smith 1981). Flow and season entered the models as dummy variables that were multiplied by every other term in the models. Cooling water flow entered the impingement models as the weekly mean of the daily average flow rate (m/s) during the days in the week in which a 24-h fish count was made. Season (not related to the calendar season) entered the models as a binary variable, either 0 or 1. The value of season was set equal to 1 during those months when at least 98% of the total annual abundance occurred for each species; it was set to O during other times. Thus, 50 L

f i these dummy variables, season and flow, scaled the underlying seasonal pattern as described by the harmonic terms. When present in the models, season caused a O catch to be predicted when the species was known to be absent from MNPS collections. Predicted impingement counts resulted from the interaction of flow and the within-year pattern of occurrence described by the harmonic term. The catch patterns of the selected species were different at each station. Because of this, the catch data from individual stations were

    ' modeled separately.

Becauce time could enter the model in any of 20 ways, the total number of predictor variables available for inclusion in the deterministic component (including the dummy variables and environmental variables listed above) was 25. Clearly, not all of these variables would probably be useful in every model, and it was necessary to select the combination of variates that gave the best regressien equation for each catch series. However, rather than calculating and looking at all 25 possible combinations (2 = 33,554,431 for each of the series), a stepwise regression procedure was used to find the best combination of predictor variable for each deterministic model (SAS 1982b). The analysis followed the maximum R improvement technique developed by James Goodnight which is considered nearly as good as using all possible regressions (SAS 1982b). This method finds the best one-variable model, 2 the best two variable model and so forth based on maximizing the R , The equations resulting from the stepwise procedure were evaluated further according to these criteria (Draper and Smith 1981):

1. the value of the multiple correlation coefficent (R2 ),

2. the value of the residual (or error) mean square (s2 ),

3. the C statistic P

The C statistic, initially suggested by Mallows (1973), has the form C = RSSp / s -(n-2p) where Ras = resSdual sum of squares from a model containing P p parameters s = the square root of the error mean square p = the number of parameters in the model including the intercept 51 L. -

l l Although some subjectivity was unavoidable during the selection process, some guidelines were followed to promote objectivity and parsimony. The above ' criteria were plotted against the number of variables in the model. Models were selected when R 2 and s2 leveled off and when the C P statistic first approached a minimum close to p, the number of parameters in the model. This model building process revealed that the environmental variables listed above did not predict catches as well as time, season and flow. Two general classes of deterministic models were found most descriptive of the species catches modeled: tim ~e alone: Z = 1 + sine terms + cosine terms multiplicative: Z =M(I + sine terms + cosine terms) where: Z = mean of long-transformed catch I = intercept (sometimes this was not significantly different from 0 and was dropped from the model) M = multiplier, flow (for impingement data) or season (for seasonally occurring data). Because the NB plankton and seine data were not equally spaced in time, these series could not be used in time-series modeling. To correct this prol tem feature, the selected deterministic model was used to predict values for the missing months. However, these predicted data points had no associated error because no observed value actually existed. To correct for this, a 'pseudoresidual' was added to each predicted value. The variance, on, of the residuals from the selected regression model was estimated. It was assumed to represent the 'true error' of the series and come from a N(0,a 2) distril'ition. The

'pseudoresidual',     R*, was generated by multiplying a random variate from the standard normal distrit.ution, N(0,1), by the estimated variance (a2 )

E *=(N) * (o2 ) , This was added to the predicted value for the missing monthly value unless season for that time period had previously been determined to be

0. In that event, a 0 replaced the missing value.

52

m 4 A e Stochastic Component i The best determicistic regression models were used as transfer functions in a classic Box-Jenkins analysis of time-series data. In this way, the deterministic component accounted for the overall catch

                                         ~
                 . pattern before the remaining variation was examined for stochastic
   ~

properties. The form of the error process was first identified as being either autoregressive, moving average, or mixed by evaluating the shape of the computer generated sample autocorrelation function (ACF), and partial autocorrelation function (PACF), for each model. Autoregressive processes are characterized by a direct relationship between\ adjacent e' observations while moving average processes a're characterized by the persistenceofarandomshock(McClainandMcCleary1979}. These processes have distinctive signatures in the ACFkand P,ACF. Box and Jenkins (1976), McCain and McCleary (1979), Glass et al'. (1975), and SAS (1982c) show how these functions are derived from the data and provide guidance for identifying the stochastic process of each series using these diagnostic tools. 7 The values of the ACF and PACF are calculated at various lags (intervals between data pairs that are separated bp one time period contribute to the calculation of the ACF and PACF values at lag 1, all data pairs separated by two time periods contribute to the calculation at lag 2 and so on. In this report, all lags for up to one year (12, 26 or 52, depending on the series) were considered for each model. The values of the ACF and PACF, plotted against the lags at which they were calculated, provide the graphical representations necessary for identifying the stochastic process. . \ The shapes of the ACF and PACF indicate the form (autoregressive, moving average, or mixed) of the stochastic process and what parameters t need to be estimated to account for the stochastic variation. If the

                   , form of the stochastic process is autoregressive, the ACF decays
                   ' exponentially with increasing lag and ' spikes' occur in the PACF at lags for which autoregressive parameters should be estimated. However, if the process is moving average, the PACF decays exponentially and the ACF has ' spikes" at those lags for which moving average parameters need to 53 N

~ ... be estimated. The data used in this research generally had an underlying stochastic process that was autoregressive and the specific autoregressive parameters to be estimated were determined by locating the lag (s) at which ' spikes' occurred in the PACF. Once the form (autoregressive) and order (e.g., lag 1, lag 3) of an error process was determined, the deterministic and stochastic parameters were re-estimated simultaneously. The ACF and PACF of the residuals were used to evaluate the adequacy of the whole model in accounting for both the deterministic and stochastic processes. If any of the deterministic or stochastic parameter estimates were not significantly different from zero, were correlated with other parameters (rho > 0.5), or if significant autocorrelation remained, the identification and estimation processes were repeated until those criteria were met. When all that remained in the series was white noise, the model was used to produce a forecast. The exception to this was the procedure used for the seine and plankton models. Unfortunately the procedure used to generate the errors associated with the predicted missing data in these series was found to seriously affect both the form and substance of the stochastic component. Because of this problem, stochastic parameters were not estimated for the seine or plankton series. Seine and plankton forecasts were generated from models containing only de arministic components. The best time-series models determined from 1977-1983 data provided a description of average abundance fluctuations over those years. These models were used to generate a forecast for 1984 that represented a picture of the expected natural variation. The actual 1984 data were compared to the forecast values through the use of upper and lower 95% confidence intervals and percent error. The percent error was calculated as 100 times the square of difference between the observed and predicted (or forecasted) values divided by the total sum of squares 2 for the forecast period. This statistic is similar to an R *100 except that the data value did not contribute to the calculation of model parameter estimates. In models that include intercept terms, the total sum of squares was corrected for the intercept. Interpretations were then made as to how well the model forecasted the 1984 data. 54

7-Appendix II. Finfish percent species composition from impingement, plankton, trawls and seine programs during the period 1 October 1976 through 30 September 1984. SPECIES aIMPINGEMENT PLANKTCH TRAWL SEINE Entrainment Niantic Bay Eggs Larvae Larvae Ammodytes americanus (p) 60.35 0.01 9.28 8.40 0.19 2.65 Pseudopleuronectes americanus 6.69 0.10 11.84 7.67 45.25 0.06 Anchoa spp.ta) 6.57 12.21 55.10 55.57 2.15 0.02 Nyoxocephalus aenaeus 4.63 0.08 4.19 2.20 2.33 0.01 Henidia spp. (b) 4.14 0.39 0.14 0.18 4.50 76.82 Gasterosteus wheatlandi 2.67 0 0.01 0 trace 0.06 Microgadus toscod (p) 2.33 0.41 0.07 0.05 3.26 0.20 Gasterosteus aculeatus 2.28 trace 0.02 0.01 0.55 0.66 Tautogolabrus adspersus 1.40 51.80 2.61 6.51 2.83 0.01 Scephthalmus aquesus 1.37 0.86 0.69 1.24 14.56 trace Syngnathus fuscus 1.19 0 0.82 0.62 0.57 0.52 Herluccius bilinearis 1.04 0 0.06 0.15 1.01 0 Peprilus triacanthus 1.01 0.07 1.07 1.71 0.$8 trace Tautoga onitis 0.59 23.03 2.25 3 '? 0.33 0.01 Alosa spp. (c) 0.58 4.87 0.05 b, t 0.27 0.08 Norone americana 0.54 0.01 0 0 0.02 0 Cyclepterus lumpus 0.35 0 0.01 0.C1 0.06 0 Osmerus mordax 0.33 0 0.02 0.02 0.48 0.02 Raja spp. (d) 0.33 0 0 0 4.61 0 Paralichthys dentatus 0.17 0.03 0.03 0.10 1.51 0

  .Orevoortia tyrannus                   0.16     0.14    0.88         1.69     0.01     0.16 5phoeroides maculatus                 0.15    trace    0.06         0.06     0.03     0.01 Pollachius virens                     0.13    trace    0.01         0.04         0       0 Opsanus tau                           0.13         0       0            0    0.08        0 Cynoscion regalis                     0.12     0.14    0.43         0.65     0.04        0 Anguilla rostrata                     0.12         0   0.17         0.03     0.07     0.03 Fundulus spp. Ifl                     0.11     0.03    0.01        trace   trace    10.34 Liparis atlanticus (p)                0.10         0   1.78         0.56     0.06        0 Urophycis spp. (g)                    0.10     0.41    0.06         0.08     0.86     0.01 Pomatomus saltatrix                   0.10         0       0            0  trace      0.26 Prionotus spp. (e)                    0.10     2.36    0.42         1.05     1.78        0 Stenotomus chrysops                   0.0S     1.21    0.51         0.63   15.56         0 Pholis gunnellus                      0.08         0   2.29         1.18     0.66        0 Hemitripterus americanus              0.06     0.08    0.01         0.02     0.13        0 Trinectes maculatus                   0.06     0.17    0.11         0.08   trace         O Nyoxocephalus spp.                    0.03     0.01    0.32         0.15         0       0 Gadus morhua                          0.03    trace    0.07         0.12         0       0 Norone saxatilis                      0.02         0       0            0  trace         0 Nelanogrammus aeglefinus              0.02         0       0        0.07   trace          O Caranx hippos                         0.02         0        0           0  trace    trace Apeltes quadracus                     0.02         0 trace              0    0.56     5.21 Clupea harengus                       0.02         0        0           0    0.01   trace Leiostomus wanthurus                  0.01         0   0.01             0   trace         0 Hugil cephalus                        0.01         0 trace              O  trace      0.12 Monacanthus hispidus                  0.01         0        0           0    0.01         0 Etropus microstomus                   0.01         0   0.04         0.09     0.15         0 Centrepristis striata                 0.01          0  0.05         0.24     0.17         0 Sphyraena borealis                   trace          0       0           0   trace         0 Scomber scombrus                     trace     0.11    0.51         0.31    trace         O Cphidion marginatum                  trace          0  0.02         0.03         0        0 Hugil curema                         trace          0       0           0        0    0.01 Aluterus schoepfl                    trace          0       0           0   trace         0 Ulvarla subbifurcata                 trace          0   1.15         0.82   trace         O Pungitius pungitius                  trace          0   0.01             0  trace     0.57 Mustelis canis                       trace          0       0            0    0.03        0
  ~Paralichthys oblongus                trace      0.05    0.16         0.42     0.17        0 Selene vomer                         trace          0       0            0  trace    trace Conger oceanicus                     trace          0   0.01         0.01   trace         O Squalus acanthias                    trace          0       0            0  trace         0 Nyoxocephalus octodecesspinosus      trace      0.01    0.29         0.42     0.27        0 Chaetodon ecellatus                  trace          0 trace              0  trace         0 Alectis ciliaris                     trace          0       0            0        0        0 Trachurus lathami                    trace          0       0            0  trace          O Caranx crysos                        trace          0       0            0  trace          0 Selene setapinnis .                 trace          0       0            0        3        0 55

_ ,2

i Appendix II. (Cont'd) aIMPINGEMENT PLANKTON TRAWL SEINE SPECIES Entrainment Hiantic Bay Eggs Larvae Larvae Cyprinodon variegitus trace 0.02 0 0 0 1.98

   .Decapterus macarellus                           trace        0         0            0    trace          o Fistularia tabacaria                         trace        0         0            0    trace          0 Etrumeus teres                               trace        0 trace            0.01           0         0 Pristigenys alta                             trace        0         0            0    trace           O Chilotycterus schoepfi                       trace        0g        0            0          0         0 Bairdiella chryscura                         trace        0 " 0.26           0.39     trace           0 Dactylepterus volitans                       trace        0         0            0    trace           0 Hippocampus erectus                          trace        0 trace                0          0         0
   -Docapterus punctatus trace        0         0            0          0         0 Priacanthus cruentatus                       trace        0         0            0    trace           0 tophius americanus                            trace       0     0.06         0.02     trace           0 Henticirrhus saxatills                        trace       0     0.33             0    trace      trace Seriola zonata                                trace       0         0            0          0         0 Salmo trutta                                  trace       0         0            0    trace           0 Hacrozoarces americanus                       trace       0          0            0     0.01          0 Monocanthus spp.                              trace       0         0             0         0         0 Ophidion welshi                             . trace       0          0            0          0        0 Priacanthus arenatus                          trace        0         0            0          0        0 Ophidiidae             .

trace 0 0 0 0 0 Selar crumenopthalmus trace 0 0 0 0 0 Ictalurus catus trace 0 0 0 0 0 0 0 0 0 Aulostomus maculatus trace 0 Petromycn marinus trace 0 0 0 0 0 Brosne brosme- trace 0 0 0 0 0 Rhinoptera bonasus trace 0 0 0 0 0 0FHX .

                                                    ' trace       0         0            0          0         0 Acipenser oxyrhynchus                              0       0         0            0    trace           0 Bothus ocellatus                                   0       0 trace                0    trace           O Clupeldae                                          0  trace     0.18          0.11     trace           0 Dasyatis centroura                                 0       0         0            0    trace           0 Enchelyopus cimbrius.                              0   0.32-    0.66          1.16     trace           0 Engraulus eurystole                               0     'O    trace               0         0         0 0            0    trace           0 Gasterosteidae                                     0       0 Glyptocephalus cynoglossus                         0       0          0       0.01            0        0 Gobiidae                                           0   0.02. 0.23          0.10     trace           0 Hippocampus spp.                                   0       0        .0             0   trace           0 0.89      0.09         0.03            0        0 Labridae                                        0 Limanda ferruginea                              0       0     0.01         0.03       0.02           0
     'Lucania parva                                       0        0         0            0          0    0.01 Lumpenus lumpretanformis                        0        0    0.04              0          0         0
     'Nicropogon undulatus 0       0 trace           0.03            0         0
     -Nullus auratus                                       0       0         0            0    trace           O Myliobatis freminvillel                          0       0         0            0    trace           O 0

Pagurus pollicaris 0 0 0 0 trace-0 'O. trace 0 0 0 Peprilis alepidatus Scimenidae 0 0 0.18 0.36 0 0 0 0 0 0 trace O Scyliorhinus rettfer. 0 0 trace Strongylura. marina 0 0 0 0 Synodus footens 0 0 0 0 . trace Trachinocephalus myops 0 0 0 0 trace . 0 Trachinotus falcatus 0 0 0 0 0 0.02

          *Irpingement percents have been corrected for variations in flow trace s(0.01% ~

(ptindicates most probable identification tal includes A. mitchilli..and A. hepsetus tb) includes,M. menidia and M. beryllina (c) includes A. ' aestivalis, A. mediocris, A. pseudoharengus and A. sapidissima (d). includes R. erinaces, R. ocellata and R. eglanteria l' 1(e) includes'P. carolinus and P. evolans-

      -(f) includes F. majalis and F. heteroclitus
        ~
       -(g) includes U. regia, U. chuss and U.. tenuis 56

l~ Appendix III. Estimated total number of fish and shellfish impinged at Millstone f Point units 1 and 2 (combined) from 1 October .1983 through 30 September 1984. SCIENTIFIC NAME TOTAL SCIENTIFIC NAME. TOTAL 392,749 Mugil cephalus 48-Ammodytes americanus 47 16,082 Liparis spp. Loligo pealei Fundulus majalis 43 Ovalipes ocellatus 8,~ 76 2 8,642 Alosa sapidissima' 39 Merluccius bilinearis 7,512 ophidion marginatum 37 Myoxocephalus senaeus 7,269 Argopecten irradians* 36

   - Carcinus maenus                                                                       33
   . Cancer irroratus 6,330       Callinassa atlanticus 5,246       Urophycis tenuis                 32 Pseudopleuronectes americanus                                                         30 4,631       Cancer borealis Menidia menidia                                                                         29 Casterosteus aculeatus                   3,876       Mugil curema

( 3,547 Ulvaria subbifurcata 29 i Anchon mitchilli- 3,185 Chaetodon ocellatus 29 Peprilus triacanthus Squalus acanthias 26 Libinia emarginata 1,762

                                             .1,444        Centropristis striata            24

! Syngnathus fuscus 24

    -Scophthalmus aquosus                     1,413        Urophycis regia l-                                             1,374        Bairdiella chrysoura             23 Homarus americanus                                   Pagurus pollicaris               20 Callinectes sapidus                      1,019 conger oceanicus                 19 Tautogolabrus adspersus-                   952 Cynoscion regalis.                16 Raja spp.                                  910 Pristigenys alta                  15 Neopanope texana                            743
                                                          ~ Caranx hippos                    15 Gasterosteus wheatlandi                     739 l

Decapterus macarellus 12 Paralichthys dentatus 570 [ Tautoga onitis 440 Cyprinodon variegatus 10 ( Illex illecebrosus 9 Morone americana 416  ; l Ophidion marginatum 9 Anchoa spp. 408 l Alectis ciliaris 8 i Microgadus tomcod 357 Alosa spy. 8 Brevoortia-tyrannus 327 Selene vomer 8 Alosa pseudoharengus. 282

     'Pollachius virens                           246       Morone saxatilis                    7 Selene setapinnis                   7 Sphoeroides maculatus                      239 194      -Monacanthus hispidus                7 Alosa aestivalis                                     Chilomycterus schoepfi 6

Trinectes maculatus 192 _ Pungitius pungitius 5 Squilla empusa 181 Caranx crysos 5 Hemitripterus americanus 171 Hippocampus erectus S Urophycis chuss 164 162 Menidia beryllina 4-LLimulus polyphemus 2

     .Etropus microstomus                          160      Alosa mediocris Menticirrhus saxatilis               2 Pomatomus saltatrix                         156 Sphyraena borealis                  2
      -Cadus morhua                                141

[ Cyclopterus lumpus 137 Dactylopterus volitans 2' Monocanthus spp. 2 Prionctus evolans 115 Mustelis canis 2 Osmerus mordax 106 PriacantSus cruentatus 2 . Opsanus tau 86 Apeltes quadracus 2 Pholis'gunnellus 70 Liparis liparis 2

      -Anguilla rostrata                            62 2

! Prionotus carolinus 52 Fundulus heteroclitus Stenotomus chrysops 51 57 i- , L

e e 3 Appendix 'TV. Summary of time based regression models selected to desertbe the occurrence of varinus finfish species in the MNPS monitoring programs. Model Forecast Species Program Station Model Ra Error Ammodvtes spp. Impingement U2 F (1 +COS (lY) +C05 ( 2Y) *COS ( 7Y) +S1N (6M)) + Al + A2 0.44 99.48 Larval EN S ( l + S IN ( l Y) +COS (lY)-$ 1N (4M)) + Al + A2 + Al l 0.91 37.05 La rval NS S(1+COS(1Y)+ SIN (1Y)-SIN (4M)) 0.93 13.78 Anchos spp. Impingement U2 F(1+COS(lY)-SIN (6M)+COS(6M))-Al-A2 0.69 21.16 Egg EN S (-$ 1 N (2Y)-COS ( lY)

• S IN (6M)-COS (4M) + S IN ( 3M)) 0.92 2I.04 La rval EN $ (1 +COS (6M) + S IN ( 6M) + SIN ( 3M) +S IN ( 2M) )- Al + A8 0.96 16.40 Larval NB S ( 1 +COS ( 6M) + S IN ( 6M ) + S I N ( 3M) + S 1 N ( 2M) ) 0.92 28.87 Casteresteus spp. Impingement U2 F(l+ SIN (1Y)+COS(1Y)-SIN (4M))-Al 0.88 28.88

   -M. senaeus       Impingement            U2           F(l+ SIN (!Y)+COS(lY)+COS(4M))-Al                                               0.87     25.63 Larval                 EN          S ($ 1N (lY)-S I N ( 4M)) + Al- A 3+ A6- A 7- A l 2                              0.97      9.53 Larval                 NB           S($1N(lY)-51N(4M))                                                              0.93     12.79 Trawl                  IN           I+ SIN (lY) +COS (lY) +COS(4M)+ A 3                                             0.51     38.83 Trawl                  JC           I+COS(7Y)-SIN (2Y)+S1N(lY)-SIN (6M)+COS(4M)+A2+A3+A21*A24                       0.32    129.57 Trawl                  NR           !

• S IN ( 7Y) +COS ( 7Y) +COS (lY)-S IN ( 6M) + A! + A8 0.59 88.26 M. t osc od Impingement U2 F(1 +COS (1Y) + COS (4M)-SIN (6M) +COS (bM)) A- t -A2 0.68 93.78 Trawl IN $(1+COS(7Y)-COS(lY)+COS(4M))+Al+A2 0.76 36.67 Trawl JC S (1-COS (1Y) +COS(4M))+ Al+A2+ A26 0.73 ' 24.85 Trawl NB S(COS(7Y)+ SIN (lY)-SINf6M))+A1 4.74 56.40 h"o 0.66 42.72 Trawl TT S(SIN (lY)+ SIN (6M)+COS(6M))+A1+A26 Menidia spp. Impingement U2 F(1+S1N(lY)+COS(1Y)+ SIN (6M))-Al-A2 0.81 66.86 Seine CN S(1-SIN (IT)+ SIN (6M)) 0.88 32.47 Seine JC S(l+5IN(3Y)+ SIN (6M)-COS(4M)) 0.88 32.25 Seine SS 5(1-COS(6M)+COS(3M)) 0.65 127.88 Seine WP S(1-SIN (lY)+ SIN (6M)+COS(4M)) 0.90 39.77 Trawl IN S(COS(lY)+$IN(6M)-SIN (4M)+COS(4Y))+A27 0.70 67.31 Trawl JC S(1+COS(6M)+ SIN (3M))+Al-A21 0.58 39.62 Trawl NB S (S IN (lY) +COS ( lY) +$IN (6M) +COS ( 6M) + SIN (4M) +COS ( 3M)) + A2
• A24 0.72 46.44 Trawl NR 5 ( S IN ( lY) +COS ( l Y) +S IN ( 4M)-COS ( 3M) )- A24 + A2 7 0.72 58.71 aquosus Impingement U2 F(l+ SIN (lY)+COS(4Y)-SIN (6M))-Al 0.78 37.65

   -S.                                                                                                                                   0.38    225.96 Trawl                  BR           1+ SIN (7Y)+COS(7Y)-SIN (2Y)-SIN (lY)+Al Trawl                  TT           I+ SIN (7T)+COS(6M)+Al                                                          0.23     86.00 T. adspersus      Impingement           U2           F(l+COSflY))-Al-A2-A3                                                           0.61     70.54 Egg                    EN           S(-COS(!Y)-SIN (6M)-COS(4M))                                                    0.96       7.49 La rval                EN           S(-COS(lY)+5IN(6M)-COS(4N))+Al-A5+A6+A8                                         0.84    195.87 La rval                NB           S(-COS(lY)-51N(4M)+COS(3M))                                                     0.85      35.27 Trawl                   IN          SIN (IT)+COS(lY)+COS(6M)+Al+A2                                                  0.88     88.72 Trawl                  JC           SIN (1Y)+COS(lY)+COS(6M)+Al+A2+All                                              0.88     22.52 Egg                   EN           S ( -COS ( 1 Y ) +COS ( 6M) + S I N ( 6M)-S I N ( 3M) )                         0.98       2.86 T. enttis Larval                 EN           $(SIN (5Y)-COS(lY)+ SIN (6M)-COS(4M)+ SIN (2M)+COS(2M))+Al-A2                  0.85    183.51 Larval                N5           St-COS(IT)-SIN (4M)*COS(3M))                                                    0.83      39.i7 s

8

s , E 9 O E n w s

WINTER FLOUNDER POPULATION STUDIES Table of Contents Section Page INTRODUCTION.................................................... 1 MATERIALS AND METH0DS........................................... 2 Adult Studies................................................ 2 j Early Life History Studies................................... 5 La rv al S t a g e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Post-larval Stage......... ................................ 10 Impingement.................................................. 12 Entrainment....... .......................................... 12 Harmonic Regression Models................................... 13 RESULTS AND DISCUSSION.......................................... 14 Adult Studies................................................ 14 Abundance.................................................. 14 Reproduction............................................... 23 Movements and Exploitation................................. 25 Early Life History Studies................................... 29 Larval Stage............................................... 29 N e t Ex t ru s ion S tudie s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Abundance and Distribution............................... 29 Age and Growth........................................... 42 Tidal Import and Export.................................. 48 24-h Tidal Studies....................................... 50 l Post-larval Stage.......................................... 54 , i Abundance ............................................... 54 Growth and Mortality..................................... 55 Impingement.................................................. 59 1 Entrainment.................................................. 61 Harmonic Regression Models................................... 63

SUMMARY

......................................................... 65 CONCLUSIONS..................................................... 68 REFERENCES CITED.................'............................... 70

y ._ WINTER FLOUNDER POPULATION STUDIES INTRODUCTION The winter flounder (Pseudopleuronectes americanus) ranges from Labrador to' Georgia (Leim and Scott 1966). It is one of the most common

              ~

demersal fishes along the northeastern coast from Nova Scotia to New

      -Jersey-(Perlmutter 1947). It is the most valuable commercial finfish in Connecticut with. annual landings from 1981 through 1984 averaging 320,417 kg (Connecticut Department of Environmental Protection, unpublished data),. about one-fif th of the total finfish catch (Blake and Smith 1984). It is also the most popular marine sport fish in the state
      . with an estimated annual catch in 1979.of almost 1.4 million fish weighing 412,234 kg (Sampson 1981; Blake and Smith 1984).

The abundance of the winter flounder in the vicinity of the

                             ~

x Millstone Nuclear Power Station (MNPS)~has been evident from the beginning of our environmental studies. The species dominates the trawl catch of demersal fishes and is the most numerous fish impinged-on the traveling screens of the MNPS cooling-water intakes. Its larvae are abundant'in. spring, particularly in the Niantic River, and many are entrained through the MNPS cooling-water system. The population of winter flounder is composed of reproductively isolated stocks that spawn in specific estuaries and coastal areas (Lobell 1939; Perlmutter 1947; Sa11a 1961). Consequently,-special-emphasis has been placed-on understanding the dynamics of the winter flounder stock spawning in the nearby Niantic River. The dynamics of this population have been studied extensively to determine if MNPS impacts have caused or would-cause changes in local abundance beyond those expected from natural variation. Winter flounder studies began at Millstone in 1973 and included the development of a predictive mathematical population dynamics model (Sissenwine et al. 1975; Saila 1976). Preliminary field studies to estimate abundance of the-local population spawning in the Niantic River

       -began in 1973 and were expanded in scope in 1975, when surveys using mark and recapture techniques were initiated.      Studies of age structure, L

reproductive activity, growth, length-weight relationships, survival,

  . movements, early. life history, and entrainment were conducted in following years and were reported in greater detail in Battelle-William F. Clapp Laboratories-(1978;'79) and in NUSCo (1975; 1980; 1981; 1982; 1983; 1984). The present report summarizes results of the 1984 adult,
  . larval, 'and juvenile winter flounder sampling. Data from the impingement, entrainment, and trawl monitoring programs are also given.

Results from previous years are included whenever pertinent. MATERIALS AND METHODS Adult Studies The adult winter _ flounder abundance survey in the Niantic River started after ice-out on February 14. Sampling was conducted on 2 days each week until April 4, when the proportion of reproductively active females decreased to less than 10% of all females examined for the second consecutive week. Six stations were sampled in.1984 (Fig. 1). Compared to 1983, station.51 was extended to the south along the eastern shoreline approximately 500 m because heavy accumulations of macroalage and detritus in the deeper portion of the station hindered sampling this year. In addition, occasional tows were made north of station 53 during the latter part of the survey for similar reasons. The 30 to 41 tows made weekly were allocated to stations based on their area and expected

  ' abundance of winter flounder, with more tows taken where fish were most numerous.

Winter flounder were captured with a 9.1-m otter trawl (6.4-mm bar mesh-codend liner) towed 0.55 km. This distance was chosen because it represented the maximum tow length at station 1 and its use at all stations was expected to reduce variability in calculating catch-per-unit-effort (CPUE). However, since catch data from station 2 were also used for the trawl monitoring program, hauls there were maintained at the 0.69 km tow. distance used.for that sampling. Because of tidal currents, wind, and varying amounts of material collected in the trawl, tow times for the standardized distances varied slightly and were usually greater in the lower than in the upper river. Differences 2

r i Niantic River j

                                        ;53 i

North 52 0 1 km 51 l

                                               \\  4 O 2

• 1 R

Figure 1. Location of Niantic River adult and juvenile winter flounder sampling stations. in towtime and boat speed between 1983 and 1984 were compared using a nonparametric Wilcoxon signed-ranks test. The probability level chosen to reject the null hypothesis in these and other statistical tests given below was p 1'.05. 0 Tows made prior to 1983 were not standardized by distance or time. From 1976 through 1982, the mean duration for stations 1 and 2 was 14.7 min and for other stations was 9.8 min (NUSCo 1984). Tows having durations greater or less than two standard deviations of these means were deleted from analysis and calculation of CPUE. For comparisons among years, all catches of winter flounder larger than 15 cm were standardized to either 15-min tows (stations 1 an 2) or 10-min tows (all other stations). The annual mean and median CPUE were determined and a 3

95% confidence interval was calculated for each median using a nonparametric method (Snedecor and Cochran 1967). The catch of winter flounder taken in the trawl monitoring program from October 1976 through September 1984 (see Fish Ecology section) was also used to calculate an index of abundance. The winter flounder caught in each tow during the abundance survey in the Niantic River were held in water-filled containers until processed. All fish 20 cm or larger were marked with a letter made by a 15.9-mm brass brand cooled in a container of liquid nitrogen; the mark was changed weekly. Fish recaptured were noted and remarked with the letter designating the latest week of the survey. Estimates of abundance of all winter flounder 20 cm and larger in the Niantic River during the spawning season were obtained from the mark and recapture data using the Jolly (1965) model. The actual computations were done using a version of a computer program of Davies (1971) with minor modifications as described in NUSCo (1982). Total abundance estimates were obtained by starting with an initial estimate and then adding the total number of fish joining during subsequent weeks. The occurrence of temporary outmigration during the population survey was examined using a series of 2 X 2 tables and the chi-square statistic (NUSCo 1980; Balser 1981). The log-likelihood ratio test (G-test of Sokal and Rohlf 1969) was used to compare the proportions of winter flounder marked and recaptured in each category of sex, length interval, and station. All winter flounder larger than 20 cm and at least 200 smaller specimens were measured to the nearest 0.1 cm in total length during each week of the population abundance survey. The sex and reproductive condition of all mature winter flounder were determined either by observing eggs or milt or by the presence (males) or absence (females) of ctenii on the caudal peduncle scales of the left side. Probit analysis (SAS Institute Inc. 1982) was used to estimate

   .the length at which 50% of all females were mature. The number of females reproducing in the Niantic River each year was estimated by
   . determining their abundance in each 1-cm length increment starting with
   ,25 cm. Fecundity.(annual egg production per female) of Niantic River 4

L__ -

winter flounder was estimated from the length-frequency data and the length-fecundity relationship described by a functional regression (Jolicoeur 1975; Sprent and Dolby 1980), where: fecundity = 0.1179(length in cm) 4.4124 (n=48, r2 =0.76). The mean . fecundity was the sum of all individual fecundities divided by the number of spawning females. The sum of the fecundities gave total egg production for the year. From 1980 through 1983, winter flounder in the study area were tagged with a Petersen disc to determine their movements and exploitation by fishermen. During tagging operations, specimens larger than 20 cm were sexed, scales removed for aging, and length recorded to the nearest 0.1 cm. A white 1.3-cm diameter disc uniquely numbered and printed with information for its return was positioned en the nape of the right side of the fish and a red disc with additional information was used on the left side. A nickel pin was pushed through the musculature, cut to size, and its end was crimped over to connect the tags and hold them in place. Except for specimens released specifically at the MNPS intakes, winter flounder were returned to the location of their capture. Information requested at recapture included date, location, method of capture, length, sex, and additional scales. A reward of $1.00 given to all persons returning a tag. Early Life History Studies Larval Stage Ichthyoplankton samples for winter flounder larvae were taken in Niantic River at stations A, B, and C and in mid-Niantic Bay at station NB (Fig. 2). Data from MNPS entrainment sampling at station EN (methods described below) were also used in many of the analyses. Collections in the river and bay were made with a 60-cm bongo sampler with 3.3-m long nets towed at 2 knots and weighted with a 28.2-kg oceanographic depressor. Volume of water filtered was determined with General Oceanics model 2030 flovmeters. A stepwise oblique tow pattern was used with equal sampling time at surface, mid-water, and bottom strata. The length of tow line necessary to sample the mid-water and bottom strata 5

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TRAWLS Figure 2. Location of stations sampled for winter flounder in the trawl and ichthyoplankton monitoring programs, was based on water depth and the tow line angle as measured with an inclinometer and was determined by the following relationship: tow line length = desired sampling depth / cosine of tow angle. From February 6 through March 19, 0.202-mm and-0.333-mm mesh nets were paired on the bongo sampler and 28 samples were taken to compare net extrusion between the two meshes a the Niantic River stations. Nets were towed for 6 min because the 0.202-mm mesh net clogged when duration was greater. After March 19, all collections were made with 0.333-mm mesh. When time permitted, consecutive 6- and 15-min tows were made at the Niantic River stations with 0.333-mm mesh nets to compare net extrusion for the two durations (16 paired comparisons). A Wilcoxon signed-ranks test was used to compare the paired samples and test for significant differences due to mesh and tow duration. Beginning in April at stations A and B, all tows were 6 min due to clogging by Cyanea spp. hydromedusae. At station NB, 0.333-mm mesh nets and 15-min tows were used throughout the season. 6

Sampling time and frequency varied with station and season and were partly based on information from the 1983 studies described in NUSCo (1984). At NB, single-bongo tows were made day and night biweekly from January through March. From April through the end of the larval winter flounder season in mid-June, single-bongo tows were taken twice weekly during day and night. In the Niantic River, preliminary tows were made during the day in February at stations A, B, and C at weekly intervals to determine when larval winter flounder were present. From March ~through the first week in April, single tows (not including additional tows to examine net extrusion) were made during the day twice weekly within I h of low slack tide. During the second and third weeks of April, single-bongo tows were made twice weekly day and night. The day samples were collected within I h of low slack tide and the night samples during the second half of a flood tide. During the remainder of the season until the disappearance of larvae at each station (last sample taken on June 14), tows were made twice a veck only at night during the second half of a flood tide. Only one collection trip was made during the weeks of March 4 and May 27 because of adverse weather conditions. The effect of tidal current on the collection of Niantic River winter flounder larvae and on their import and export were examined. Two 24-h tidal studies were conducted at station C on March 9-10 and March 18-19. Samples were collected at 2-h intervals during a 24-h period.. Tow durations were 6 min and paired 0.202-mm and 0.333-mm mesh nets were used. Tidal import and export studies were conducted during two tidal cycles on April 4 and May 8. Samples were taken hourly except for 1 h before and after slack tidal currents. Stationary tows were-taken in the middle of the channel adjacent to the Niantic River Highway Bridge. Bengo samplers with 0.333-mm mesh nets were used with an additional 40 kg of veight added as ballast to increase the vertical tow line angle. Bongo samplers were deployed off each side of the boat with one at mid-water and the other near bottom. Sampling duration varied from 6 to 15 min depending on the current velocity and approximately 100 m' of water was sampled. Current velocity at the time of sampling was measured with a flowmeter mounted outside of the bongo opening so that back-pressure due to net clogging would not effect the measurement. 7

0 These current' velocities were used to calculate the net exchange of larvae _ leaving and entering the river. Larval data analyses were based on density per 500 m8 and due to

   -varying sampling frequencies data were reduced to weekly mean density.

Data from all mesh sizes and tow durations were used in calculating the weekly mean densities. For comparisons, daylight samples in 1983 from the last week of April through the end of the season were excluded. These samples underestimated abundance because of diel behavior of the older larvae (NUSCo '1984). Daylight samples were not collected in 1984 during these weeks. Most ichthyoplankton samples were preserved with 10% formalin. Except for tows made to compare net extrusion between 0.202-mm and 0.333-mm mesh nets, only one of the two bongo sampler replicates was processed for Niantic River and Bay samples. Samples were split to at least one-half volume and larvae were identified and counted using a dissecting _ microscope.' Up to 50 winter flounder larvae were measured to 0.1-mm in' standard length (snout tip to' notochord tip). The

    -developmental stage of each larva measured wasurecorded and the five stages were defined as:

Stage 1. The yolk sac was present or the eyes were not pigmented (yolk-sac larvae) Stage 2. The eyes were pigmented, no yolk sac was present, and no fin ray development Stage 3. Fin rays were present, but the left eye had not migrated to the mid-line Stage 4. The left eye had reached the mid-line, but juvenile characteristics were not present Stage 5. Transformation 'to juvenile was complete and intense pigmentation was present near the caudal fin base 8

Otoliths from larval winter flounder were examined to determine if an age-length key could be constructed as deposition of daily increments

      . on otoliths has been reported for many fishes (e._g. , Panella 1971, 1974; Brothers et'a1. 1976; Laroche et al. 1982). One sample each week from
      - all Niantic River stations was preserved and stored using 95% ethanol.

i At least one of the three weekly samples was processed to obtain

 '     ' approximately 50 larvae, if possible. Prior to otolith removal, each
       - larva was measured and its developmental stage was recorded. Otoliths were removed with the aid of a dissecting microscope and a polarized

~

light analyzer. All otoliths removed (1 to 4) from a larva were mounted using Crystal Bond 509 Thermoplastic on a labeled microscope slide. Otoliths were examined with a compound microscope connected to a video monitor that provided a magnification of approximately 5,000X. If

        - individual otoliths differed in size, the larger pair was assumed to be the sagitta and used for counting increments. If no size difference was found,~the otolith with the most distinct increments was used. The margin of the otolith nucleus was identified and increments were counted f' rom the margin to the edge.
               . Times of peak abundance-for each developmental stage and for each-1-mm size-class were estimated from the observed cumulative densities over time using the cumulative Compertz growth model (Draper and Smith
        - 1981):

Cumulative density = a exp(-Be- t) where a = total cumulative density B = location parameter k = shape parameter t = time in days since February 15 ~ Time of peak abundance was estimated as the date (ty ) corresponding to the inflection point of the above cumulative growth curve:

                                 "I = (Ins)/k Time between peak abundance of successive developmental stages was used to estimate developmental time of each stage and peak abundance of size-classes was used to develope a growth curve. The grevth curve was constructed by fitting the regular Gompertz growth function (Ricker 1975) to the length data matched with the estimated times of peak 9

4 - -

abundance for each 1-mm length increment. The form of this growth function was:

                                 ~

length = L eXP(6 ) O where LO= length at hatching (about 3 mm) B = location parameter k = shape parameter t = days from estimated time of peak abundance for the 3-mm size-class Post-larval Stage Information on post-larval young-of-the-year winter flounder in the Niantic River was first gathered during 1983 (NUSCo 1984). Only two of the four stations sampled then, Lower River (LR) and Camp O'Neill (CO), were used in 1984 (Fig. 1). These stations contained habitat preferred by juvenile winter flounder, with sandy to muddy bottoms in shallow water adjacent to eelgrass beds (Bigelow and Schroeder 1953). Due to an extensive summer buildup of benthic algae at CO, quantitative sampling there became impossible in late July. C0 was replaced by a station across the river along the Waterford shoreline (WA) on August 1. All stations were sampled once cach veck from May 24 through September 26 during daylight within about 2 h before to 1 h after high tide. Depths sampled ranged from 1 to 2 m. A 1-m beam trawl was used with interchangable nets of 0.8 , 1.6 , 3.2 , and 6.4-mm bar mesh; a tickler chain was added to increase catch efficiency. Two nets of consecutive mesh size were used during each sampling trip to. insure adequate representation over the entire available size range of young. This helped to eliminate bias in the catch as was found in 1983, when some of the older and larger specimens apparently avoided the smallest mesh net needed to capture the smallest fish (NUSCo 1984). A change to the next larger mesh in sequence was made in 1984 as young grew and became susceptible to it. The larger meshes also reduced the amount of detritus and algae retained. Two replicates with each of the two nets were made at both stations; the order in which the nets were deployed was chosen randomly. Distance of 10

each tow was estimated by letting out a measured line attached to a lead weight as the not was towed. Tow length increased from 50 to 75 m as the number of fish decreased throughout the summer. For data analysis and calculation of CPUE, the catch of both nets used at each station was z summed and standardized to a density per 100 m of bottom covered by the beam trawl. Two flowmeters were mounted to the beam, one inside and one outside of the mouth of the net, to monitor clogging of the meshes and the resulting back-pressure which would have affected sampling. The number of revolutions in each flowmeter was corrected using known calibration factors. Readings from the inside and outside meters were compared using a paired t-test. Young winter flounder were measured to the nearest 0.5 mm in total length'(TL). During the first 4 weeks of the study, standard length (SL) was also measured because many of the specimens had damaged caudal The relationship between fin rays and total length could not be taken. the two' lengths was determined by a functional regression and used to convert standard to total lengths: TL = -0.67 + 1.245(SL)_ (n=90, r 2=0.97) The instantaneous mortality rate (Z) of post-larval' juvenile winter flounder was calculated using the method described by Jones (1981). Parameters required for this procedure included L and K of the von Bertalanffy growth model (Ricker 1975; Gallucci and Quinn 1979): L t " L.(1-exP(-K(t-t0 ))) where L = length in mm at time t Im = asymptotic maximum -length (assumed to be 100 mm) K = instantaneous rate at which size approaches the asymptotic length t 0 " hypothetical date at which a fish would have zero length if it had always grown in the manner described by the equation A nonlinear procedure using the Gauss-Newton iterative method (SAS Institute Inc. 1982) was used to estimate K by fitting the growth 11

function to the weekly length measurements of specimens from station LR. As suggested by Jones (1981), the asymptotic maximum length L. was fixed at 100 mm, or slightly larger than the length of the largest young found in the lower Niantic River. The densities (total number per 100 m2 ) for each 0.5-mm length increment of the size distribution of juveniles were estimated for each date during the sampling season. The natural logarithms of the cumulative catch larger than each 0.5-mm increment were plotted against the logarithms of the values of L= minus each specific length increment. Jones (1981) shows that the resulting slope is an estimate of the ratio Z/K. As he suggested, data points from the lower tail of the plots were eliminated from the regression because they departed from the linear relationship. Since the data used to estimate K had a time scale with weekly increments, the derived value of Z corre'ponded s to the weekly rate of instantaneous mortality. Once Z was determined, daily survival was estimated as exp(-Z/7), weekly as exp(-Z), and monthly as exp((-Z)(30.4/7)). Survival rates for 1983 were recalculated because L. had not been fixed at 100 mm and a larger length interval was used in determining the slope for that year. Catches from the 0.8-mm mesh net in 1983 were excluded from the cumulative plot because, as previously noted, they were biased. Impingement The number of winter flounder impinged on the traveling screens of MNPS from October 1972 through September 1984 was estimated using techniques described in detail in the Fish Ecology section of this report. Length-frequency data of fish impinged from 1976-77 through 1983-84 were also examined. Entrainment Samples for winter flounder larvae entrained by MNPS were taken at station EN on 4 days and 4 nights each week, alternating weekly at the discharge of Units 1 and 2 when plant operations permitted (Fig. 2). 8 Approximately 400 m of water were filtered through a 1.0-m diameter, 12

Additional details may 3.6-m long, 0.333-mm mesh conical plankton net. be found in the Fish Ecology section. Annual entrainment estimates from 1976 through 1984 were calculated 8 using the median density (n/500 m ) of winter flounder larvae collected at EN during the larval season. The entrainment estimate was computed 8 as the median times the total number of 500 m units of seawater withdrawn by MNPS during the larval period for each year. A nonparametric method (Snedecor and Cochran 1967) was used to construct a 95% confidence interval around each median and corresponding entrainment estinate, assuming no error in the measurements of seawater withdrawn by MNPS. Harmonic Regression Models Fluctuations in the log-transformed catches of winter flounder taken in various monitoring programs were analyzed using harmonic regression techniques described in the Fish Ecology section. Data from the trawl monitoring program were used to calculate the catch of winter flounder for a standard tow of 0.69 km at six stations (Fig. 2), including Niantic River (NR), Niantic Bay (NB), Intake (IN), Twotree Island Channel (TT), Jordan Cove (JC), and Bartlett Reef (BR) . Three replicate tows were taken every other week and the log-transformed catches were averaged to obtain a single biweekly mean. Weekly means of the log-transformed catches were calculated from the impingement (Unit

               ~

2), entrainment (station EN), and ichthyoplankton (NB) monitoring programs. These values were used to construct various models describing catches from October 1976 through September 1983. The models were used to forecast log-transformed catches for October 1983 through September 1984. These forecasts were compared to the actual catches during the same period. 13

RESULTS AND DISCUSSION Adult Studies Abundance The 1984 winter flounder population abundance survey in the Niantic River began on February 14, the earliest start since the beginning of the surveys in 1976. Changes in sampling methodology initiated in 1983 and described in detail in NUSCo (1984) were continued this year. These included a 20-cm minimum size for branding, standardization of tows and effort, and ending the survey when spawning was essentially completed. During the 8-week sampling period, 4,278 winter flounder were branded and released; 197 vere subsequently recaptured (Table 1) . These totals were the lowest to date as were the percent recaptured (4.6%) and the percent of the estimated population sampled (8.6%). Table 1. Yearl, mark and recapture data for Miantic River vinter flounder studies from 1976 throueh 1984 Deres Number of Number Number Percent Percent of a pooulation samoted Year sasoled weeks marked recaotured recaptured 1976 March 1 - May 4 10 9,856 699 7.1 11.2 1977 March 7 - h y 10 10 6.860 623 9.1 13.3 1978 h rch 6 - b y 16 11 8,403 729 8.7 16.1 1979 March 12 - May 15 to 8,105 491 6.1 15.1 1980 hrch 17 - May 6 8 7.625 961 12.6 23.4 1981 March 2 - b y 3 10 10,458 822 7.9 11.8 1982 February 22 - May 11 12 11,076 901 8.1 10.9 1983 February 21 - April 6 7 5.196 363 7.0 12.4 1984 February 14 - April 4 8 4.278 197 4.6 8.6

• Minimum size for marking was 13 cm during 1976-82 and 20 cm thereaf ter.

The weekly mark and recapture data (Table 2) were used in the Jolly model for estimating population abundance. Following the first week of t sampling, when winter flounder were relatively scarce, the number marked was consistent from week to week because of the uniform spatial and temporal sampling effort. The one exception was a decrease in the number of marked and recaptured fish during the week of March 13. After several days of very cold weather, ice completely covered the western 14

Table 2. ' Weekiv catch' data used for estimating pooulation abundance ofRecaptures Niantic River winter flounder durins 1984 (ween maraed) Recap.. Total Week . Date Total Number. Number Number Number 2 3 4 5 6 7 8 9 recao no. (week of) esteh unmarked marked removed examined 1977-83 5 356 31 - 2 2/14 672 316 351 to - 10 534 0 534 53

  '3      2/21       1.284     750

,, 677 52 5 9 - 14

   ~4'    3/1        1.269     693     676         0 45    5 14.14     -                         33 605                 607
  '5. 3/7        1.237     651                 1 17 6     3/13          740    348      391        1       393       20    1 3 9 4 -

23 6 5 8 9 8 - 36 588 0 588

   .7     3/20        1.609  1.021 23    2 5 6 11 9 12 -                       45 453      595        1       598 8     3/27        1.049 16    2 6 5 5 8 6 10 -                      42 4/3         1.074    532      538        4       543 f    9 31 42 42 29 25 18 to -                 197 4,764   4,278        12     4.296      263 Total            9.054 The ice arm of the river (stations 52 and 53) and much of station 51.

broke up on March 14, which permitted most, but not all, of the scheduled tows to be made in the upper river. Although some of the decrease in catch may have been due to less effort, the extreme weather and ice formation may have temporarily altered the distribution of winter flounder in the river during the week. For the purposes of abundance estimation, these data were combined with the catch from the following week in order to reduce the standard errors of the parameters estimated using the Jolly model and to obtain phi values less than 1.00 (Cormack 1973).

           .The data were examined for potential sources of bias or error in the abundance estimate by comparing proportions of marked and recaptured fish in.each category'of sex, length, and station. Neither the proportions of females and males marked _(52, 48%) and' recaptured (54,
    -46%) nor the number marked and recaptured by station were significantly
    -different. A significantly larger proportion of 25 through 27-cm
                   ~

females was recaptured (14%) than branded (6%). More recapture, were made in the upper arm of the river than would have been exp seted, ' although the reasons for this were unknown. No bias occurred because of capture-prone fish; only five winter flounder (3% of the total) were recaptured twice. Data presented in NUSCo (1984) indicated that the

     -number of brands obscured or lost was probably small and, according to Arnason.and Mills (1981), should not have biased the results.

Movements of marked fish out of and back into the Niantic River The movements,. during the survey can affect the population estimate. termed temporary outmigration, were examined using a chi-square test 15

l developed b'y Balser (1981). No significant temporary outmigration was found in 1984; the'only other year that this occurred was 1980. Apparently the decrease in catch during the week of March 13 was similar  ! among marked and unmarked fish and did not affect the results. Significant differences found in previous years were suspected to have been mostly due'to sampling error rather than actual temporary outmigration (NUSCo 1984). An estimated 51,819 27,134 winter flounder larger than 20 cm were present in the Niantic River during the 1984 sampling period (Table 3) . Table 3. . The 1984 abundance estimate of winter flounder larger than 20 cm during the spawning period in the Niantic River. Date Total Standard Probability of Calculated number Standard Week (week number error of. survival Standard error joining error Actual number (N) N (phi) of cht (B) of 8 joinint no. of) 0.793. 0.198 14,955 2 2/14 3 '2/21 14.955 5,904 0.997 0.217 23.912 12.380 23.912 0.206 -10,076 10.144 0 4 3/t 38,815 12,801 0.849 0.175 10,924 5,213 10,924 5 '3/7 22,864 6,244 0.667 26,167 6,785 0.912 0.339 2,028 5,536 2,028 6-7 3/13-20 8 3/27 25,900 9.803 Total abundance 51.819

? 2 standard errors                                                                                 227.134

-This abundance estimate should not be directly compared to population estimates from years prior to 1983 (Fig. 3). The latter estimates were for winter flounder 15 cm and larger, which included many immature fish; > duration of surveys differed; and surveys in 1979 and 1980 started in 'mid-March, relatively late in the spawning season. The Jolly model has been criticized because its flexibility is provided by many unknown parameters which must be estimated. These estimates are usually. imprecise unless sampling intensity is high ((Cormack'1979; Buckland 1980; Nichols et al. 1981; Hightower and Gilbert 1984). Sampling intensity is defined as the probability that an individual will be captured on a given sampling trip (Manly 1971) or as the proportion of the population sampled on each trip (Bishop and Sheppard 1973). Based on our estimated abundance and sampling intensity and using information provided by Hightower and Gilbert (1984), we can assume with 95% confidence that our estimate was within 50% of the true population size. Substantially greater levels of effort would be needed l

.to obtain more precise estimates.

16

                                               >15 cm                                  > 20 cm 120-m e

tn D 90-O ~ I H - E W 60-- O . Z

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        ?

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                           ,.      3     3      3        7 77      78       73         80       81    82    83       84 75      76 YEAR Figure 3.          Population abundance estimates ( 2 standard errors) for winter flounder taken during surveys in the Niantic River from 1976 through 1984 Other measures of abundance were investigated to supplement the Jolly population estimates. Abundance of winter flounder larger than 15 cm was also measured since 1976 by trawl CPUE (Table 4; Fig. 4). As these data were non-normally distributed and positively skewed, the Table 4     Mean and median CPUI of Niantic River winter flounder latter than 15 es from 1976 thrcush 1984 1981     1982        1983  1984 1977      1978       1979       1980 1976 256        322       233   281 412      289       265         228 Total tows made                    390 273       285        228   276 260        247        173 349      355 Tows used for CPUE 87        98    98 86       90         93         76       95

% of tows used 89 41.3 30.6 26.9 15.3 37.5 22.1 38.2 38.4 34.2 Mean CPt:t 31.2 31.3 13.8 8.4 36.9 19.6 33.1 33.7 27.3 standard deviation 76% 1021 51% 552 88 80% Coef ficient of 98% 89: 87 variation 19.5 26.4 14.3 16.7 27.3 26.7 26.3 35.0 Median CPtiE 27.5 16-24.4 24-28 13-16 24-31 22-12 22-31 31-38 95% CI 24-31.5 15-18 1.94 1.26 1.07 2.09 1.45 1.33 1.40 2.96 Coefftetent of skewness

• 2.51

'  2ero when data is distributed symmetrically 17

40-J

                       . ,$_                                     -                                                                                                                                                     i o

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                                                  ' ~

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1 10-3 6' 'i' ' n' '6 '3' 'l' 'l' 'A' 'l 78' 81 82 83 84 75' 76 77 79 80 YEAR

                ; Figure 4.                            Median CPUE ( 2 standard errors) for winter flounder larger than 15 cm taken during surveys in the Niantic River from -

1976 through 1984. median was chosen as the most appropriate catch statistic (NUSCo 1984). A 15-cm minimum length was necessary for year-to-year comparisons because'alll fish larger than this. length were branded before 1983, but not all individual length measurements were recorded. The standardization of trawling effort. lessened the variability in CPUE during the past two years. Fewer tows were excluded from the calculations and the coefficients of variation and skewness were reduced. The 1984 abundance. estimate and median CPUE showed conflicting trends when compared to 1983 (Figs. 3 and 4). The Jolly estimate-may have been less certain because the confidence interval around the

                 -estimate increased from the previous year. The median CPUE of 14.3 in 1984 was the smallest of the nine estimates made since 1976; the others ranged from 16.7.in 1977 to 35.0 in 1981. The 95% confidence interval
                 .in 1984 was also the smallest among all the years.

18

Observations made during the 1983 and 1984 surveys indicated that capture efficiency of the trawl may have decreased during the latter year because of an increase in the amount of benthic algae and detritus in the upper river. Quantitative comparisons showed that tow time was significantly greater (increase of 0.8-1.9 min) and boat speed significantly less (0.12-0.27 knots) in 1984 than 1983. This was most likely the result of the net filling with material as it was towed. Therefore, the 1984 decline in abundance may not have been as large as indicated by the CPUE. Culland (1983) noted that the standardization of fishing effort is difficult and although the catchability of a species (or certain size groups, reproductive stages, and so forth) is presumed constant, the fishing gear can vary in efficiency and can be affected by subtle changes in its use, rigging, or deployment from different vessels. Nevertheless, he further stated that repeated surveys using consistent methods can provide an index of abundance free of difficulties caused by possibic changes in catchability. Since 1976, the number of weeks samples and starting and ending dates varied for each annual survey. To provide a more directly comparable measure of abundance, the annual CPUE medians were recalculated using data restricted to the 4-week period between mid-March and mid-April. Since adult abundance indices were most desirable, the medians were also adjusted using length frequency data to give an annual median catch of Niantic River winter flounder (CPUE-NR) larger than 20 cm. No confidence intervals could be calculated for the 1077 through 1982 surveys because not all fish were measured. An additional adjustment to the 1980 CPUE-NR was necessary. Winter aunder larger than 20 cm made up 61 to 77% of all fish 15 cm and

 .arger from 1977 through 1982 with the exception of 1980 (50%). The proportions in 1983 and=1984 were even greater (96% and 92%,

respectively) and this will be discussed below. A previous re-examination of the 1980 survey suggested that only a fraction of the adults in the river were sampled (NUSCo 1983). Only one tow was made in upper river (sta. 51-53) in 1980, but in 1981 adults were very abundant there. Consequently, the 1977-82 average value of 72% was used to adjust the median in 1980 for length of fish larger than 20 cm. 19

A second measure of adult abundance was provided by an annual (October through September) median CPUE calculated using the trawl monitoring program data (CPUE-TMP) from all six stations shown in Figure

2. These estimates were also made using only winter flounder 20 cm and larger.

The two CPUE abundance indices are shown in Figure 5, which also includes for comparison the weekly Petersen abundance estimates during the spawning season as generated from the Jolly model (NUSCo 1984). In general, the two CPUE indices follow each other with increasing abundance occurring from 1978 through 1981. A second peak in the CPUE-TMP. occurred in 1983, but not in the CPUE-NR. The small CPUE-NR found in 1984 noted previously. The Petersen estimates also increased after 1978, but largest values were found in 1982 instead of 1981. A decrease in population followed in 1983 and 1984. 60 d

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                    ,..   .,,   .,.     ...  .,.        ...             .i.              .i 75      76    77      78   79       80          81    82      83       84 YEAR Figure 5. Comparison of adult winter flounder abundance in the Niantic River from 1976 through 1984 using CPUE-NR                      (---), CPUE-TMP

( ), and weekly Petersen estimates from the Jolly model (+). 20

The CPUE-TMP most likely included winter flounde,r from a number of different stocks, especially at the BR, TT, and JC stations. Unless trends in abundance were similar over the entire region, varying stock abundance could have influenced the annual medians. Other factors, such as water temperature, probably affected the CPUE-TMP more than the CPUE-NR since our data shows that local spawning occurs almost exclusively in the Niantic River and fish are concentrated there when our surveys take place. Movements of winter flounder which might have affected the CPUE-NR were only found during adverse weather. Some of the Petersen estimates of abundance had large standard errors and may have been less reliable. An examination of available abundance data was made to see if a relationship existed among the stock size of adults spawning in the Niantic River, the number of larvae produced, and the corresponding abundance of juveniles 1 year later. The adult CPUE-NR was used and a similar median was calculated for age 1 (smaller than 12.5 cm) winter flounder during the same mid-March through mid-April time period. The medians for age 1 fish were lagged 1 year to match the larval numbers for the year in which they were produced. The annual median entrainment density (number of larvae entrained per 500 m of cooling-water flow at MNPS) was used as the index of larval abundance. However, these medians have relatively large confidence intervals (see Table 15 below) and are less precise than the adult and juvenile indices. Little correspondence was seen between the relative abundance of

 -         the adult stock and the number of larvac produced (Fig. 6). Peak adult abundance in 1981 and 1982 did not result in the largest number of larvae, indicating that perhaps egg and early larval mortality or egg production changed due to year-to-year environmental variability.

Cushing and Harris (1973) and Roff (1981) noted that the recruitment of v most flatfishes in independent of parental ' stock and that the number of offspring is related to environmental factors. Although many hypotheses can be developed to explain year-class fluctuations in terms of some environmental factor, it is difficult to demonstrate this with statistical significance (Gulland 1965) . Changes in abundance may also take place following the larval stage and both density-dependent and s 21

                                      ^6 l

density-independent processes can affect year-class abundance (Bannister et al. 1974;-Cushing 1974'; Lockwood 1980). 70-4

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g. .g. .,. ,,. .,. .,. ,,. 6' 't 75 76 77 78 79 80 81 82 83 YEAR Figure 6. Comparison of median adult (catch / standardized tow), larval -

(no/500 mS ), and juvenile (catch / standardized tow) abundance in the Niantic River. An obvious relationship was found between larvae and age 1 juveniles with trends in abundance generally parallel. A strong year-class of larvae in 1980 was reflected by a peak in juveniles taken - in 1981, although the larval peak in 1978 and decline in 1981 were not reflected as strongly by the juvenile index. The largest difference was found for the 1983 year-class in which the larvae increased by about 25% from 1982, but the juveniles decreased by two-thirds. The increase in juvenile abundance beginning with the 1977 year-class culminated in the 1980 year-class, the strongest to date. This resulted in an increasing trend.of adult abundance, which peaked in 1981. The previously noted low (4-8%) proportion of subadults (15-20 cm) in 1983 and 1984 as compared to previous years (mean of 28%) was probably a result of the strong 1980 year-class and its dominance in the length-frequency distributions during those years. Changes in the abundance and 22

(i ~ ~ mortality of post-larval young-of-the-year Niantic River winter. flounder in'1983 and 1984 will be-discussed in a separate section below. The: lesser variability.in-adult abundance is not surprising given

                                                                  ~

the relatively long--(about-9 to 12_yr)-life span of the winter flounder. The adult stock is also subject to variable. fishing pressure. The

            -entrance of a strong year-class into the fishery could result in more pressure on'the stock as fishermen take advantage'of their increased availability. This would tend to decrease abundance more rapidly than for averagefor; weak 1 year-classes.

Reproduction Winter flounder spawning activity was monitored by weekly examination'of reproductively active females. Based on the decline in gravid-females, spawning was essentially completed by early April (Fig. L7). :Althoughithe 1984 survey began on February 14, a week' earlier than

                                                                                                         +
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n;  ; MARCH APRIL MAY FEBRUARY Figure 7. Percentage of female adult winter flounder in spawning condition by week in the Niantic River from 1981 through;1984, 23 L'<

i any previous survey, about 40% of the females present had already l spawned, presumably under the ice in the river. More gravid females were observed in 1984 at mid-river station 2 than during the past few years. The sex ratio in 1984 (1.07 females for every male) declined from 1983 (1.52) and was the lowest for the 9-year period (Table 5) . Overall, the ratios were similar to those reported by Saila (1962a, b) and How and Coates (1975) for other populations. Table 5. Female to male sex ratios of vinter flourder taken during the spawning period in the Niantic River from 1977 throueh 1984 1077 1978 1979 1960 1981 1982 1983 1984 Mean C.7. All fish eactured 1.03 2.22 1.37 2.66 1. 2 1.16 1.52 1.07 1.56 38: Measured fish

 .farrer than 20 en       1.26     1.95     1.21      2.03      t.61      1.50       1.52    1.07   1.52      23%

Sexual maturity in the female winter flounder occurs when individuals are at least 3 years old and 25 cm in length (Dunn and Tyler 1969; Dunn 1970; NUSCo 1983). A probit analysis of the 1984 data indicated that the length of 50% sexual maturation was 25.6 cm tiith an 95% confidence interval of 24.9 to 26.1 cm. This estimate was very similar to the 25.1 0.9 cm reported for 1983 (NUSCo 1984). Niantic River females probably have reached the physiological lower limits for age and size of first reproduction. Male flounder mature at smaller sizes and earlier ages; even some age 1 males were observed to have been mature. The proportion of females larger than 25 cm was used with the Jolly abundance estimates to determine the annual number of spawners and egg production (Table 6). Egg production seemingly peaked in 1982 and Table 6. Annual estimates of spawning population abundance and total egg production for Niantic River vinter flounder from 1977 throveh 1984 Numeer of Number of Population of 21 standard Population of 22 standard spawning Mean Total egg weeks for winter flounder errors vinter flounder errors females fecundity production 3 3 5 Year estimates 115 cm (x10 ) (x10 ) 120 cm (x10 ) (x10 ) (x10 ) (x10 ) (xt0') 1977 4 37.4 19.4 27.7 - 12.4 5.7 7.0 1978 6 25.4 12.1 17.3 - 9.9 6.2 6.1 1979 4 26.7 - 14.0 - 7.4 6.3 4.6 1980 3 27.2 15.3 13.1 - 6.0 5.4 3.3 1981 5 62.9 10.8 49.3 - 25.1 6.3 15.8 1982 5 77.5 13.4 58.8 - 30.3 7.0 21.2 1983 5 49.4 - 42.0 15.6 22.0 6.8 15.0 1984 6 62.1 - 52.0 27.1 23.1 6.9 16.0 24

estimates for 1981, 1983, and 1984 were similar. Mean fecundity (average number of eggs per female) has varied little among recent years. However, the same length-fecundity relationship determined , during 1977 has been used with data from all subsequent years. This relationship for the winter flounder may vary from year to year, , depending upon prevailing environmental conditions, as females were reported to sacrifice egg production to maintain body weight (Tyler and.. Dunn 1976). Movements and Exploitation Adult winter flounder were tagged with a Petersen disc from December 1980 through September 1983 (Table 7). Most of the 4,978 tagged fish were released in the Niantic River (46%) and in Niantic Bay (31%). Sixty-one percent of the fish tagged were females, 29% were males, and 10% were fish of unknown sex. The percentage of fish recaptured from each year of tagging ranged from 18% in 1981 to 30% in 1983. Only two fish tagged in 1980 or 1981 were taken during the past year. Recaptures made during various NUSCo sampling activities (excluding impingement on the MNPS screens) accounted for 14 to 49% of the recaptures made. Almost all (96%) of these were released again, mostly in the Niantic River. Ignoring the NUSCo-caught fish, the recapture rates for fish tagged in each year were remarkably similar (15-17%), as were the rates for those released in the Niantic River (16%), Bay (16%), and Twotree (17%). Fish tagged at Bartlett Reef and the MNPS intakes both had a 11% rate of return. The greatest return was from Jordan Cove, where 25% of the tagged fish have been recaptured through September 1984. Two-thirds of all recaptured winter flounder were females, 30% were males, and 4% were fish of unknown sex. The percent return within each sex was 26, 25, and 10%, respectively; significantly fewer fish of unknown sex were recaptured. These fish were smaller at the time of tagging and may have had greater initial mortality, shed tags at a greater rate than larger fish, or were less vulnerable to capture. Many of these fish were probably small females since their movements were 25

Table 7. Susanary of winter flounder dise tagging and recapture data free December 1980 throush Septeeler 1984 tmPS Niantle Bay Niantic River Twotree Intakes Bartlett Beef Jordan Cove Miscellaneous' Tot al , 0 68 IG O' 844 Number tagged 1980 309 410 47 198 4 0 0 1,309 1981 970 108 29 61 206 131 10 1,997 1982 280 1,015 294 828 0 40 12 6 0 1983 0 770 4,978 299 290 147 10 Total ,1,559 2.303 370 0 8 0 0 185 Number recaptured 1980 74 88 15 0 0 0 230 179 21 3 27 1981 45 2 521 1982 53 334 54 11 22. 4 2 1 0 249 1983 0 242 0 42 32 46 2 1,18$ Total 306 685 72 Method recaptured 0 0 67 1980 31 28 7 0 1 Sport fishing 8 0 0 0 80 1981 64 8 0 5 27 1 233 28 144 19 5 1982 0 0 0 97 0 97 0 0 1983 10 27 1 477 277 26 13 Total 123 0 7 0 0 57 22 21 7 Commercial 1980 0 0 0 105 9 3 2 fishing 1981 91 9 1 100 40 23 2 11 1982 14 0 0 24 y 0 23 0 0 1 1983 286 m Total 127 93 33 .4 19 9 1 0 0 0 56 18 37 1 0 NUSCo sampling 1980 0 0 0 32 4 0 7 1981 21 8 0 175 146 9 1 0 1982 11 1 0 123 0 119 0 2 1 1983 1 9 0 386 50 306 to 10 Total 0 0 0 0 3 1980 2 0 10 1spingement 1 0 10 0 0 0 1981 0 0 0 8 at MNPS 1 1 1 1982 0 3 0 2 0 0 0 5 1983 0 3 0 26

                                                                                       -15               1               1             0 Total                    1             8          0 0                0             0                  2 2             0          0               0 Hiscellaneous*       1980 0               0             0                0             0                  3 1981                   3             0                                                                                          5 3              0              1               0 ;           O 1982                   0             1 0               0-            0                  0 0             0           0              0 1983                                                                                           0             0                 10 3              0              1 Total                    5              1

• Includes various locations along shoreline west of Slack Point to the Connecticut B1,er.

Number recaptured includes 381 released alive (mostly by NUSCo), 77 of which we Year here and f ollowing ref ers to year in which fish were tagged. caught again.

• Includes recaptures from the CT DEP, Project Oceanology, and unknown sources.

similar to those of adult females. Also, since many small males were mature, most of-them were probably identified during tagging operations. Few (0.5%) of the tagged winter flounder were impinged at MNPS. More than half of the fish impinged had been released specifically near the discharge of the Unit 1 fish-return sluiceway to evaluate their ability to avoid re-impingement. Of the winter flounder released near MNPS, only 5% were impinged, about the same fraction as taken by sport fishermen (Table 7). The sport fishery took about 1.67 times as many winter flounder as did the commercial fishery. This was greater than the 1.17:1 sport to commercial ratio based on 1979 reported annual landings (NMFS 1980; Blake and Smith'1984). The local sport fishery is concentrated in the Niantic River where nearly half of the flounder were released; three times as many of these fish were taken by sport than commercial

 ' fishermen. A similar ratio was seen for the Jordan Cove and Millstone Intake releases. Equal numbers were taken by the two fisheries for Niantic Bay releases and more of the winter flounder tagged in deeper waters at Twotree and Bartlett Reef were taken by commercial fishermen.

About 90% of the winter flounder caught by sport fishing were taken locally in our study area or in New London county waters, but only one-third of those taken by the commercial fishery were. Sport catches were greatest in spring and early summer when winter flounder were most available inshore; commercial catches were made mostly in summer and early f all when many of these fish were in' deeper water and vulnerable to trawlers. The local commercial fishery also maintained unequal effort since our study began. Most catches occurred in 1980 and 1981 when one trawler was operating extensively in Niantic Bay. Most (70%) of the recaptures were made in local waters (Table 8). Three times as many winter flounder tag returns were received from east of MNPS than from the west, indicating a much greater movement of fish out of Long island Sound. The number of returns generally fell off as a function of distance with many fish taken in Fishers and Block Island Sounds and fewer farther east. Eleven winter flounder each were taken in waters around Martha's Vineyard and Nantucket Islands. More females (0.5% of the total tagged) and fish of unknown sex (1.2%) were taken from distant locations than males (0.2%). 27

Table 8. Location of recaptures of dise-tag ed winter flovnder from December 1990_thronsh September 1984 ll%$"S.10E.[tyn MNPS Niantic River Twotree intakes Bartlett teef Jordan Cove Miscellaneous Total Recapture location Niantic Bav Local 14 4 4 - 219 Niantic Bay 126 58 13 4 - 3 - 519 N1 antic River 36 472 4 2 - -

                                                                                                                           -           15 2                  -               !!

Twotree - 26

                                   !                 8                -         15            1               1 IctPS Intakes                                                                               2               -             -             3
                                                                      -            1 Bartlett Reef                    -                  -
                                                                                  -          -             24              -           45 Jordan Cove                      5                 16                -

East 2 9 11 1 116 New London Co., CT 43 34 16 4 - 2 - - 26 Suffolk Co.. NY 6 14 - 84 liashington Co. , Rl* , 35 35 9 I 4 -

                                                                                             -               -             -            1 Newport Co.. 21                   1
                                                                       -          -          -               -             -            1 Barnstable Co., MA              -                    1 I              -             1           11 Dukes I"o. , MA                   4                  3                2          -
                                                                                  -            1
                                                                                                             -             -           11 Nantucket Co., MA                 3                 6                 1 M

I I - 19 M New London Co., CT 10 5 I I

                                                                                                             -              -          17

• MidJlesex Co. CT 4 10 1 2 -

                                                                                                              -             -          20 6                 2         -           2 Suffolk Co., NY                10                                                                           -             -          20 2                 8          -           3 New Haven Co., CT                 7
                                                                                   -          -                1
                                                                                                                            -            4 Fair field Co. , NY              2                   1 1

Brona Co. , NY - - - - I - - Unknown

                                                                                   -          -                -            -            2 Connecticut                       i                  1                -
                                                                                               -               -            -             1 New York                          1
                                                                                   -           1
                                                                                                               -             -          Il Rhode Island                      4                  6                -
                                                                                                                             -          12
                                                                                    -          -                1 Massachusetts                     5                  6                -
                                                                                               -               -             -            1
                                    -                   1 Virginia 32             46                2     1,185 306                685                72         42 Total

• Corrects 19 returns misclassified as Newport County in MUSCo (1984).

Mostly f rom fist: markets.

• Most likely caught in Rhode Island.

Early Life History Studies. Larval Stage Net Extrusion Studies The effects of tow duration and mesh size on net extrusion of early developmental stages of winter flounder larvae were examined in 1984. Sixteen paired comparisons were made between 6- and 15-min tow durations with 0.333-mm mesh nets and 28 between the 0.333- and 0.202-mm meshes (6-min duration). ~No differences in the collection density of Stage 1 or 2 larvae were found between the 6- and 15-min tow durations. In the comparisons between the two mesh sizes, Stage 1 larvae were collected in greater densities with the 0.202-mm mesh in 21 of the 28 trials; this represented a significant difference. No difference was found for Stage 2 larvae with their density in the 0.202-mm mesh greater in only 13 of the 28 comparisons. Since 1976, ichthyoplankton sampling at MNPS has been conducted with 0.333-mm mesh nets and early larval developmental stages were probably undersampled because of net extrusion. This was evident for winter flounder larvae collected i 1983, the first year that developmental staging was conducted, as fewer Stage 1 larvae were collected than Stage 2 (NUSCo 1984). Abundance and Distribution The abundance (number per 500 m ) of larval vinter flounder showed a successive pattern in the Niantic River and Bay during 1984 (Fig. 8). Abundance in the Niantic River increased from weekly mean densities near 0 to more than 300 during the last 2 weeks of February. Abundance at station A was generally lower than at B and C and also was the first to decline in late March. The greatest weekly mean density (2,200) was at station B during the first week of March. Larvae increased in abundance at station C to a peak of 2,050 during the first week of April and the mean density remained above 400 through mid-May. The last decline in abundance occurred at Station C in late May. In Niantic Bay, the number of larvae increased more slowly and required more than 2 months to reach densities greater than 300. Peak abundance at NB occurred approximately 3 weeks earlier than at station EN. 29

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a- l l l l l o ,. .,. ,. .,. ,. .. .. , o8FEB 23rt8 19 WAR o8APR 28APR 18WAY 07JUN 27JUN DATE Figure 8. Weekly mean density per 5008 m of larval winter flounder in the Niantic River and Bay during 1984. 30

i The temporal and spatial distributions of winter flounder larvae in 1984 were similar to those found in 1983 (NUSCo 1984). A rapid increase in abundance occurred in the Niantic River with a slower increase in the bay. The successive decline at stations A, B, and C along with a similar pattern of abundance seen during the latter portion of the season at C, NB, and EN was similar to the seaward flushing reported by Pearcy (1962) in the Mystic River. More larvae were collected during the early_ part of the season in the river during 1984 compared to 1983, with peak weekly mean densities exceeding 2,000 in 1984 compared to approximately 600 in 1983. Spatial distribution of developmental stages was compared with 1983 (Fig. 9). More larvae of the earlier developmental stages (1 and 2) were collected in 1984, primarily at stations B and C in the river and as in 1983, few were found in Niantic Bay (EN and NB). For Stage 1, this could be attributed, in part, to less net extrusion with the 0.202-mm mesh. The numbers of Stage 2 larvae collected in 1983 and 1984 were similar at stations A, EN, and NB, but larvae were approximately The concentration of early twice as abundant in 1984 at B and C. developmental stages at stations B and C indicated that spawning activity was greatest in the mid and lower portion of the Niantic River in 1984. This confirmed observations made during the adult survey. During 1984, Stage 3 larvae were concentrated at station C compared with a more uniform distribution at C, EN, and NB in 1983. Stage 2 and 3 1arvae remained more abundant in the river with less dispersion into Niantic Bay. Stage 4 larvae were less common at all stations in 1984 except A, which had few in both years. Stage 5 larvae were collected infrequently in 1984, but in 1983 this developmental stage was also rare and then caught primarily at EN. This indicated that transformed larvae, primarily benthic in nature, were more susceptible to entrainment than The to capture by the bongo sampler used at the other four stations. spatial distribution of developmental stages supported the previous discussion on temporal abundance with earlier developmental stages occurring primarily in the river, in higher densities during 1984 compared to 1983, and with the older larvac mostly found in the lower river and the bay in both years. 31

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                                                                                                                                $IA Figure _9. . Cumulative density by' developmental stage for larval winter flounder at each station during 1983 and 1984.

32 I

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0 es s. es s. es e+ es es as s. vtan A e C (N Ne STA Figure 9. (Cont'd) The temporal distribution of each developmental stage was modeled by fitting the cumulative Compertz growth model to the cumulative density of each stage over time in the Niantic River (stations A, B, and C combined) and Niantic Bay (stations EN and NB combined) (Fig. 10). No attempt was made to fit the model to Stage I larvac in the bay since so few were collected. The model fit the sigmoid-shaped data distribution extremely well with all R values 2 exceeding 0.97. The estimated total cumulative density (a ) approximated the average of the actual cumulative densities observed in the river and bay for each developmental stage (Fig. 9). In the Niantic River, Stages 1 and 2 were most abundant during March, Stage 3 in April, and Stage 4 in May. Stage 2 larvac in the bay occurred later, mostly in April. Stage 3 larvac were found in the first half and Stage 4 during the last half of May. 34

RIVER STAGE 1 acco-E acoo; ~ 8 a = 4075 + + + + o + 2 m .

                            # = 3.2 3   2000,        k = 0.052 o

y R8 = 0.997 2 E +

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Soo-o-r + .,. .,. ., i- .,. .,. .,. .. oorte torte iguAn otAP4 2eArm teuAv o7JUN IIJUN DATE Figure 10. Cumulative density of larval winter flounder for each developmental stage in the Niantic River (stations A, B, and C) and Niantic Bay (stations NB and EN) during 1984 with the lines fitted from the cumulative Gomportz growth model, 35

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4 s 3' o loo-oA .,. ., o8FES 20FEB $9WAN 08APR 20APR 88WAY 07JUN 27JUM DATE~ Figure 10 (Cont'd) The daily density of each stage was estimated from the Compertz models in the river and bay by calculating the cumulative density for each day and subtracting the estimated cumulative density for the previous day (Fig. 11). In addition, the date of peak abundance was estimated by determining the point of inficction of each curve. In the Niantic River, the estimated peak abundance of Stages 1 and 2 overlapped and for Stage 2 was 9 days after Stage 1. No large overlap was found for Stage 3 and 4 larvae, which occurred sequentially. In Niantic Bay, peak abundance of' Stage 2 was 23 days later than in the river. This lag agreed with the average particle retention time in the river estimated by Moore and Marshall (1967) as 25 days and Ko11meyer (1972) as 27 days. In addition, the estimated Stage 2 density at peak abundance in the bay was approximately half that found in the river. The estimated densities at maximum abundance for Stages 3 and 4 were similar in the bay and river. Based on the greater volume of the bay in comparison to the river, most of the standing stock of Stage 3 and 4 larvae was probably in Niantic Bay. 38

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0- ., .,. .,. ., carce seres seuan Osare  ::arn isuay orsvu risu= DATE Figure 11. Estimated abundance curves for each developmental stage in the Niantic River (stations A, B, and C) and Niantic Bay (stations NB and EN) from the cumulative Compertz growth models with estimated dates of peak abundance in 1984. 39

1 The developmental time for each stage was estimated by determining the number of days between the peak abundances of successive stages in the Niantic River (Fig. 11). For 1984, the estimated time of development was 9 days for Stage 1, 39 days for Stage 2, and 26 days for Stage 3. A precise estimate for Stage 4 was not possible because an insufficient number of Stage 5 1arvae was collected to determine peak abundance. However, 39 of the 49 Stage 5 larvae collected were from EN and all but 5 of these were taken during the last week of May and the first week of June. This suggested an approximate 10 to 15 day developmental time for Stage 4 larvae. The short developmental time of Stage 1 larvae would have accounted for their scarcity in Niantic Bay due to the approximate 25-day retention period in the Niantic River. Peak abundance in 1983 was also estimated using the .aulative Gompertz growth model for comparisons with 1984 (Table 9). The estimated dates of peak abundance for Stage 1 in the river and Stage 2 in the river and bay were similar between the two years. Also, maximum Stage 2 abundance in the bay occurred 23 days after that in the river during both years. A progressively later date of peak abundance in both river and bay was found for Stages 3 and 4 in 1984 compared to 1983. The estimated developmental time from hatching to Stage 4 in 1983 was 56 days as compared to 73 days in 1984. The largest difference in develop-mental time was for Stage 3 with an additional 14 days needed in 1984. Table 9. Estimated date of peak abundance in the Niantic River and Bay with the estimated duration for each winter flounder developmental stage in 1983 and 19.C4 1983 1984 Developmental Estimated Estimated" Estimated Estimated stage p ak abundance developr. ental peak abundance developmental Bay River time (days) Bay River time (days) 1 - Mar 5 11 - Mar 8 9 2 Apr 8 Mar 16 33 Apr 9 Mar 17 38 3 Apr 21 Apr 18 12 Apr 30 Apr 24 26 4 May 8 Apr 30 - May 22 May 20 - Days from hatching 73 to State 4 $6

• Based on estimated peak abundance in the Niantic River.

40

7_ Developmental time is controlled by numerous environmental and biological factors. For poikilothermal organisms, temperature can have a profound effect (Warren 1971). In a laboratory study, Laurence (1975) found that temperature influenced development of larval winter flounder and that the time to metamorphosis decreased from 80 days at 5*C to 49 days to 8'C. A running mean water temperature for the Niantic River was calculated for each week of 1983 and 1984, starting from the second week in March when Stage 1 larvae were most abundant (Fig. 12). The mean temperature plotted for any date represented the average temperature since the second week of March. Because of low water temperatures in mid-March of 1984, the running mean water temperature was approximately l'C lower after the end of March in 1984 than in 1983. Developmental time appeared to be closely related to water temperature. The date of peak abundance for Stage 4 larvae was April 30 in 1983 and corresponded to a mean water temperature of 6.4*C. This temperature was not reached until May 21 in 1984, which corresponded with maximum Stage 4 abundance on May 20. Based on the difference in developmental time between 1983 and 1984, development did not appear to follow any particular schedule, but it may have been regulated by environmental conditions such as water temperature. Io-9A g aJ ' W ' y i: g ' y .: ,,,... y . 2 s- - g '

             .:        1g83 a-        1984  .

2E .,, .,. ,,. 1, 20 Ape 10uAf 30WAY 19JUN

• 19Ftg fluAA JtuAR DATE Figure 12. Running average water temperature ('C) in the Niantic River beginning during the second week of March in 1983 and 1984.

41

l 1 Age and Growth An examination of the length-frequency distribution of all larvae measured during 1984 showed a separation between the first three developmental stages (Fig. 13). Stage 1 larvae were predominantly between 2.5 and 3.0 mm (80% of the total), Stage 2 were 3.0 to 5.0 mm (81%), and Stage 3 were 5.0 to 7.5 mm (88%). Lengths of Stages 4 and 5 overlapped with predomiaant size-classes for Stage 4 of 6.5 to 8.5 mm (84%) and Stage 5 of 7.0 to 8.0 mm (92%), although only 49 of the latter were measured. Even though estimated larval developmental time in 1984 was longer than in 1983 (Table 9), the length-frequency distribution by developmental stage was similar (NUSCo 1984). Thus, stage of development and length were closely related. The spatial distribution of mean lengths for each developmental stage provided additional information on dispersion (Table 10). Stage 1 larvae, mostly_found in the Niantic River (Fig. 9), had a similar mean length at all stations. Stage 2 larvae were noticeably larger in the bay compared to the river, which supported the lag in occurrence due to tidal flushing into the bay (Table 9). Mean lengths of Stages 3 and 4 1arvae showed no spatial pattern, although Stage 4 larvae at station EN were much smaller than the others. 60 - STAGE I 40 - e s E 30 - U h E 8 , d to -  % g io- g h d 7 s s f kl / , o - -- rd A ^ ~ l 2 3 4 0 6 7 8 9 10 11 12 LENGTH (MM) Figure 13. Length-frequency distribution of larval winter flounder by 0.5-inm size classes for all stations combined during 1984. 42

s.

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Figure 13. (Cont'd) 43 l-L.E

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                 ,                           e                                                  al t  2  s    +  a     e             t                         e                                   o                               to       it  it LENGTH (MM)

Figure 13. (Cont'd) 44

Table 10. Mean length by stage of all measured larval winter flounder taken at stations in the Niantic River and Bay and at MNPS. Developmental Number Mean Standard stage Station measured length (mm) error i A 445 2.8 0.02 B 807 2.8 0.01 C 686 2.9 0.01 EN 15 2.8 0.14 NB 85 2.8 0.05 2 A 296 3.4 0.03 B 554 3.5 0.03 C 490 3.7 0.03 EN 1057 4.5 0.03 NB 681 4.1 0.03 3 A 47 6.5 0.21 B 216 6.0 0.06 C 496 6.6 0.05 EN 1188 6.2 0.03 NB 614 6.0 0.04

                                                       ~

4 A 10 8.3 0.25 B 44 8.0 0.08 C 116 8.0 0.07 EN 377 7.1 0.04 NB - 107 8.4 0.09 5 A 0 - B 6 7.8 0.23 C 3 7.8 0.61 EN 39 7.5 0.08 NB 1 7.5 - Radtke and Scherer (1982) reported that a winter flounder larva deposited a daily growth increment on its otoliths following yolk-sac absorption. Otoliths from Niantic River larvae were examined to determine if the number of observed increments could be used to develop an age-length key. The otoliths from 104 larvac were examined and 81 of these were sufficiently cicar to count the number of increments. Totals ranged from 0 to 1 for Stage 1, O to 6 for Stage 2, 5 to 35 for Stage 3, and 17 to 50 for Stage 4 (Fig. 14). Our data indicated that no incremental deposition took place during yolk-sac absorption and based on the low counts found for Stage 2 larvae, daily deposition also did not occur during that stage of development. Until known-age larvae from laboratory rearing are examined we cannot determine the rate of 45 L -__ ._m_______________s

I ioo-eo-4 4# 4 k3 '3 so. 4 1 44 44 3 20-4 3 4

       "                                                             3 33    3$ $

h to-3 33 33 3 2 3 w 6 3 3 3 2 22 3 2 2 2 2 s- 22 2 222 2 2 2- 2 222 2 1 21 2 8 ,- "",.1 2 .,. _,_ .,. .,. .- 2 a 4 s s 7 s e LD CH Figure 14. Otolith increment count by length (mm) for each developmental stage of larval winter flounder from 1984 samples. increment deposition. Since the increments were not deposited daily, no attempt was made to fit a growth curve to the otolith data. Another approach to the construction of a larval winter flounder growth curve was based on size-class abundance. The cumulative Compertz growth model was used in a similar manner as for the estimation of the dates of peak abundance for each developmental stage. However, instead of developmental stages, 1-mm size-classes from 3 to 8 mm were used and the date of peak abundance for each size-class was estimated (Table 11). Subsequently, a regular Compertz model was fit to the data points corresponding to the time of estimated peak abundance for each size-class (Fig. 15). The length (L O) at the beginning of the growth curve, which represented egg hatch, was 3 mm. The time (t) required to enter each of the size-classes was in days from the date of estimated peak abundance of the 3-mm size-class. Slower growth occurred this year compared to 1983, which agreed with the previously discussed longer developmental time in 1984. The predominant length-frequency of Stage 4 larvae was 7.5 mm (Fig. 13) and from the growth curves a 7.5-mm larva in 1983 was 49 days old and in 1984 was 63 days old. This 14-day 46

Table 11. Estimated date of peak abundance and the Ra of the Compertz model fit to cumulative density over tirne for 1-mm size classes of larval winter flounder collected in the Niantic River in 1983 and 1984. 1983 1984 Size Peak Peak class (mm) abundance Ra abundance Ra 3 Mar 11 0.998 Mar 6 0.990 4 Mar 21 0.996 Mar 25 0.991 5 Apr 10 0.984 Apr 6 0.994 6 Apr 15 0.994 Apr IT 0.987 7 Apr 25 0.991 May 5 0.987 8 Apr 29 0.992 May !! 0.988 4 3 4.,.* eJ. *

                                                                                                                               ~

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                                                                                    ,-                   ,-      i-         i-        i-           i 18 to 2S 30 38                          40        si to SS                       to 48 70 e      a to DAYS
 '  Figure 15, 1.arval winter flounder growth curves' based on estimated peak abundance of 1-mm size classes in 1983 ( ) and 1984 (-~; with the lines fitted from the Comportz growth model.

47

7 -- difference agreed well with the 17-day difference in developmental time to Stage 4 between the two years (Table 9). The estimated time from hatching to Stage 4 in 1983 and 1984 was 56 and 73 days, respectively. This was longer than the estimated 49 and 63 days needed for growth from 3 mm to 7.5 mm in 1983 and 1984, respectively. f Although day 1 was defined at a length of 3 mm, it did not necessarily represent the date of hatching because little growth was expected during yolk-sac absorption. Cetta and Capuzzo (1982) reported that in a laboratory study total body weight of winter flounder larvae decreased during the first 2.5 weeks after hatching and after 1 week, larvae appeared to be metabolizing body tissue following depletion of the yolk sac. Therefore, an additional 10 days may pass during yolk-sac absorption when larvae are in the 3-mm size-class. Based on the growth curves, these additional days would increase the age of a 7.5-mm larva to 59 days in 1983 and 73 days in 1984, which agreed with the estimated developmental time to reach Stage 4 of 56 days in 1983 and 73 days in 1984. Tidal Import and Export Sampling was conducted at the Niantic River liighway Bridge on April 5 and May 8 during two tidal cycles to estimate the tidal import and export of winter flounder. On April 5, mostly Stage 1 and 2 larvae were collected and on May 8 the larvae were primarily Stage 3 (Fig. 16). More Stage 1 larvae were collected during ebb rather than flood tide in April, although about 40% (1,521 per 500 m8 ) of the former were collected in one sample taken near the bottom. Slightly fewer Stcge 2 and 3 larvae were collected during flood tide. On May 8, similar numbers of Stage 3 larvae were collected on the two tides and most of the Stage 4 larvac were collected during the flood. Net tidal flushing for the predominant developmental stages on each sampling date was estimated by multiplying the density (average of mid and bottom samples) by the estimated water velocity during the time of sample collection. This density adjustment accounted for changes in discharge volume during the tidal cycle. A harmonic regression equation using a 12-h tidal cycle was fit to densities adjusted for 48 c- _. _.

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!q Figure 16. Frequency of larval winter flounder by developmental stage collected at the mouth of the Niantic River during ebb and flood tides on' April 5 and May 8, 1984. 49 L__

n. _ _ . _ _

velocity. Good fits were obtained for Stage 2 and 3 larvae on April 5  ; and for Stage 3 larvae on May 8 (Fig. 17). Densities of Stage 1 larvae - on-April 5 could not be modeled (R =0.38) 2 because larvae were scarce during-flood tide and the one sample with a very high density was collected during ebb tide. The area under the curve for each tidal stage was assumed to be a good estimate of net flushing and the areas were approximated by numerical integration of the respective harmonic regression equations using 5-min increments. On April 5, an estimated 65 and 63% of the Stage 2 and 3 larvae, respectively, returned to the Niantic River on a flood tide. The return of a flood tide increased to 92% for Stage 3 larvae on May 8. The larval dispersion model developed for vinter flounder larvac in the Niantic River used a 72% return of passive particles to the river on a flood tide (Saila 1976). This model underestimated larval retention because older larvae used flood currents to increase their return to the river. The data for May 8 showed a net loss of Stage 3 larvae from the river during a tidal cycle. This did not agree with the tidal import-export studies conducted in 1983, when many more larvae were found entering the river than leaving (NUSCo 1984). In 1983, sampling was conducted on May 9 and 18 and Stage 3 (45%) and 4 (48%) larvae

  . predominated. Although they May 8 sampling in 1984 was conducted during a similar time period, larval development was slower this year (Table 9). Because of slower development in 1984, few Stage 4 larvae were present during the early part of May and the younger Stage 3 larvae may not have had fully developed fins. This lack of complete fin development possibly prevented the larvae from using tidal currents to enter the river as it was postulated in 1983.

24-h Tidal Studies Two 24-h tidal studies were conducted in 1984 to examine the effect of tide on the observed abundance of early developmental stages (Stages 1 and 2). These studies were used to most efficiently schedule sampling for winter flounder larvae of various developmental stages. The 1983 24-h sampling was conducted when Stage 3 and 4 larvae predominated and 1 50

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R8 = 0.64 '

                      -7s002             -.,-         ,       . , - -

4 7 8 9 to il 12 o 1 2' 3 4 s HOUR Figure-17. Estimated exchange of larval winter flounder at the mouth of the Niantic River for Stage 2 and 3 larvae on April 5 and Stage 3 larvae on May 8 with the line fitted from a harmonic regression model. 51

MAY 8 STAGE 3 92 % RETURN 2cocoy tonoof EBB g of .

• z
• 5 G
• U . .

                 -'    7

• FLOOD

                 -20000f                             ,

Exch = -430 + 3289 cos(h) - 14328 sin (h) R8 = 0.74

                 -30"0"2         ,.   ,-   ,. .,.      ,.     ,. .,. .,. ,. .,. .,.                                                                  ,. .,

o 1 2 3 4 S 6 7 8 9 10 11 12 13 HCUR Figure 17. (Cont'd) their collection densities increased during flood tides. This was attributed to a vertical movement in relation to tidal currenes, which served as an estuarine retention mechanism. In 1984, densities of Stage 1 and 2 larvae on March 12 were unrelated to tide (Fig. 18). Although the greatest density (746 per 500 m 8 ) was found during one of three low slack tidal stages sampled, the remaining collection densities ranged from approximately 100 to 300. Collection densities evidently changed in relation to tidal stage on March 19. The greatest densities were found during an ebb tide and the lowest during a flood tide. Also, collection densities were smaller on March 12 than on March 19, as the largest ones from the first study were smaller than almost all those found a week later. A harmonic regression with a 12-h period was used in an attempt to relate changes in density to tidal stage. A satisfactory fit was achieved for Stage 1 larvae (R2 =0.58), but not for Stage 2 (R 2=0.01) (Fig. 19). The increased abundance of Stage 1 larvae found during an ebb tide on March 19 agreed with.the results of the previously presented tidal import-export study on April 4, when few Stage 1 larvae returned to the 52

i 100- MARCH 12 P 500-SOC-D ' 400-8 300-* i A . 200- -

                         '**-                      HicH            LCW                   . HIG:i          LOW tow
                                                                                             .    . a-    a     i i-                   .

12 na se la 20 22 24 26' 0 2 6 6 5- 10 HCLR 1100-MARCH 19

                       -1000-9002 m       a00-o            .

N 700-p .

@ . . {

g s00-500-400A I: .l J00-LCW HlCH LOW HIGH 200j HICH to 12 14 14 18 -20 22- 24 26-0 2- 4 e 8 HCUR f 8 Figure 18.. Larval winter flounder density per 500 m and the time of high _and low slack tidal currents during the March 12 and 19, ic84 24-h studies at station C. 53

n. _ __ _

6.J-6.o- . s . 7-j

       '8 s 41 .

S? I ' h 3 g 3.iJ cI l 5 . 4.H . 3 1 2

s. J i

J LCW HIGH LCW HIGH HICH 0 2 4 6 8 IC 12 14 16 18 23 22 24 HOUR Figure 19. Stage 1 larval winter flounder abundance (in density per 500 m 8

                                             ) and the time of high and low slack tidal currents for the March 19, 1984 24-h study at station C with the line fitted from a harmonic regression (in density = 5.39 - 0.55 cos(h) + 0.34 sin (h);

R2 = 0.58). Niantic River on a flood tide (Fig. 16). Although the same tidal flushing study indicated a net loss of Stage.2 larvae, apparently the difference in density between ebb and flood tides at station C was not sufficient to have been detected using the harmonic ' regression model. Post-larval Stage Abundance A 1-m beam trawl was used at stations LR and CO in the Niantic River during 1984 to sample for young-of-the-year winter flounder . following larval metamorphosis. As in 1983, dense mats of the alga Enteromorpha clathrata developed at CO and hampered sampling there beginning in mid-July. Much algae collected on the tickler chain and 54

trawl frame and filled the net. Sampling at CO became impossible by the end of July and the replacement station WA was established on August 1. A comparison of readings from flowmeters mounted inside and outside of the net indicated no significant net clogging at LR and WA throughout the survey and none at C0 early in the season. Catch of young winter flounder peaked in early June, most likely when recruitment from larvae began to be offset by natural mortality (Figs. 20 ). Initial densities were greater at CO (81 per 100 m2 ) than LR (43.5), but declined to similar levels (about 20) in late. June and July. However, densities at CO were probably underestimated during the last few weeks of sampling there because of the decreasing efficiency of the net due to clogging. Densities at LR leveled off at about 6 young per 100 m2 by early August. Young appeared to have been more common at WA than LR, although catches at WA were more variable and fluctuated more from week to week. An initial density of 32 decreased to about 6 to 13 in September. Because of sampling problems previously mentioned, comparisons to 1983 are limited to LR from late June through September. Initial densities in 1983 were higher (23-46) than in 1984 (about 21), but were similar from mid-July through early August (10-17). Abundance was more variable during the remainder of the survey in 1983, but on the average young appeared to be twice as numerous in 1983 than in 1984. Growth and Mortality Growth of young at LR was followed over the entire season by observing changes in their weekly mean length (Fig. 21). Mean lengths increased regularly until early August when growth slowed and weekly means during September were similar. As was found for larvae (Fig. 15), growth in 1984 was less than in 1983. After mid-July mean lengths averaged about 6 mm smaller, but the reasons for the lesser growth were not apparent. Water temperatures appeared to be similar between the years during the late spring and summer. Food habits, rates of feeding, and size-selective predation upon the young were not studied and could possibly have caused the differences found. Differential movement of larger specimens into deeper water did not occur as only a few young of average sizes were taken at trawl station NR. 55

i

                        -                                                                                                      i i
                '100-                                 CO
                        ^
                                                                                                                               \
                        ~
      "E
                        ~
       .g
                 .75-R.

5 6 - z 50- *^ 5*

3x

                                                  .I    ,

y . K.. 3 25- / 1 /.

                     ~0-
                               ,,       ,,,        ,            .,.         .,.      .,.....g.              .c       i MAY          JUNE                     . JULY              AUGUST         SEPTEMBER 60-50-
            ~
         ~ E'                                                               ~ O.
         -g         ..40-
           .R                .

5 .

         ', 6         30-p 6

a _20-

                                                                     /%                                                       1 x

d.  :

                                                                                    ../1\\

10 2

                                                                                                \   - -

1

                       ' ~
                                                     ,,..           .g.       .g-      .g-      g-    l'      '6'      'I' 'I 4

WAY JUNg- JULY ' AUGUST SEPTEMBER Figure-20. Weekly CPUE (22 standard errors) for juvenile winter flounder taken in..the Niantic River during 1984, 56

                             -100-h                               7 1983 y                                                    _

gf1 50-k T W D '/ , x- 25-

d. -

3. -

0- , ,

                                                                                                         ,,.   .,. ,,. .g.   '6' 'l JULY              AUGUST      SEPTEMBER WAY     JUNE Figure 21.                                               Weekly mean length' ( 2. standard errors) of juvenile winter flounder taken at station LR in 1983 and 1984.

Since growth of young-was apparently seasonal and reached.a plateau in September, the von Bertalanf fy growth model was fit' to both 1983 and 1984 data from station LR. As the growth coefficient K was necessary for the calculation of mortality, fixing I. at 100 mm in the model also allowed K to vary from year to year as did rates of growth. Good fits 2 (n=716, R2 =0.79 for 1983; n=740, R -0.85 for 1984) were obtained for'the growth models. Following Jones (1981), the slope of the logarithms of the cumulative catches plotted against the logarithms of L. minus each 0.5-mm length increment was determined (Fig. 22) . The parameter.K was used with the. slope to calculate the instantaneous mortality coefficient

                             ~

Z; weekly mortality rates were 12.7% in 1983 and 16.3% in 1984 (Table

12) . Corresponding monthly rates were 44.5 and 53.7%, respectively.

The monthly survival rates of young Niantic River winter flounder were lower than the 69% reported by Pearcy (1962) for the Mystic River. He suggested that predation may have been a major cause of mortality and

               -included the summer flounder (Paralichtvs dentatus), oyster toadfish
               .(0psanus tau), double-crested cormorant (Phalocrocorax auritus), and mergansers (Mergus spp.) as likely predators. The catch of summer 57

C 5 ,_ 1983 s a r = 0,97 g o - E

                                                                                                  /

5 g s: U 2 S: '

                                                                                 /

7

 'n       .

o 4-

 =.                                                                     #

y . f w s- ++ n ,+

                                                            +*
                                                     +

g 2-w i-E-

            .        +

0 g ,. ., .,- ., .,. ., .,. .,- ., I} O.S 1.0 8.S 2.0 2.5 3.0 J.S 4.0 4.4 S s C 5 ,_ 3 1984

  .d r = 0.96 g

g 7-E5 $_ z d - E

             *~                                                           /

4 O 4-

                                                                       /

5 ++ 6 2: /* n ,+ ++

                                                   +

l, ~~. ,- .

    $a         0;
                   ,.         ,.                 ,                 ,.             ,-      i i

3.0 3.$ 4.0 4.S 3 g.S 2.0 2.5 O Y_ in(L , - LENGTH INCREMENT IN MM) Figure 22. Plot of log of cumulative length of juvenile winter flounder against the log of the difference between L. and the length increments for 1983 and 1984 data. The estimated slope corresponds to the ratio Z/K (Jones 1981). 58

Table 12. Survival of juvenile vinter flounder taken at station LR in in the Niantic River during 1983 and 1984 1983 1984 8 0.0701 0.0635 Growth coefficient t Slope of in(number > length) vs in(1.= - length) 1.9353 2.7940 l i Z = (slope)(K) 0.1356 0.1774 Daily survival = e I~ I } 0.9808 0.9750 Daily mortality 1.92% 2.50% Weekly survival - e~ 0.8732 0.8374 Weekly mortality 12.7% 16.3%

                                                                                                    ~

Monthly surviva' =e 0.5549 0.4627 Monthly mortality 44.5% 53.7%

• 1=. fixed at 100 mm and time unit equal to 1 week flounder at trawl station NR in 1984 was the greatest in 9 years and ras 2.75 times that of 1983. Their increased abundance might have caused the increase in juvenile winter flounder mortality seen this year.

Cormorants and gulls (Larus spp.), which have been observed feeding on winter flounder in the Niantic River, were also common at LR throughout-the survey. Impingement The estimated impingement in 1983-84 was 5,246, about half the total for 1982-83 (Table 13). The actual rate at which winter flounder were impinged was probably similar during the past 3 years, but samples have been taken only at Unit 2 following installation of a fish-return Table 13. Estimated total number of winter flounder impinged on the. intake screen , of HNPS Units 1 and 2 by season and year from October 1972 thrergh September 1984 Winter Spring Summer Total I by year t of all fish Year Fall 1972-73 405 4,404 1,184 170 6,163 6.4 37.9 462 2.663 564 124 3,813 4.0 28.9 1971-74 384 1.666 354 185 2.589 2.7 27.0 1974-75 764 107 4.037 4.2 15.6 1975-16 757 2.409 2,388 4,857 2.243 142 9.630 10.1 32.4 1976-77 373 3,984 1.673 152 6.182 6.5 16.9 1977-78 1,712 17,434 3.809 1.123 24.078 25.1 32.9 1978-79 699 2,989 2.352 380 6.420 6.7 20.4 1979-80 988 4,365 1.360 378 7,091 7.4 12.5 1980-81 1981-82 1.493 6.225 1,508 525 9.751 10.2 15.7 586 7.500 1.962 720 10.768 11.2 7.4 1982-83 1,840 303 103 5.246 5.5 1.2 a l983-84 3,000 Total 13.247 60.336 18,076 4.109 95,768 - - t by season 13.8 63.0 18.9 4.3 - - 59

sluiceway at Unit 1 in mid-December of.1983. We believe that the impact

   .on juvenile and adult winter flounder has decreased considerabl y at MNPS with the sluiceway in operation because.the species has demonstrated good survival when immediately returned to the water following.

impingement (Miller 1978; NUSCo 1981b). Tagging studies also suggested

   . that few. winter flounder returned via the sluiceway would be re-impinged.

The percentage that winter flounder contributed to the total of all fish impinged in.1983-84 was 1.2%, by far the lowest in 12 years. This was the result'of an anomalously large catch of sand lance this year (see Fish Ecology section). Overall, the winter flounder ranked second (14.5% of the total) among all fish impinged from 1976 through 1984. Since.1976-77, about one-fourth of all impinged winter flounder have been taken during February (NUSCo 1984) . However, unlike previous

      . years, more winter flounder in 1983-84 were taken during the fall than in winter. This occurred even though Unit 2 was shut down until January 16 and had reduced-cooling-water flow throughout the fall. The total was influenced by one large catch made on December 29 during a storm in which wind velocities averaged 12.8 m/sec (about 30 mi/h). Large impingement catches following storms have occurred infrequently, but
     . usually made up a large proportion of each annual impingement total (NUSCo 1983) . For example, six such events during the winter of 1979 resulted in the large estimate for that year.

The length-frequency distribution of impinged winter flounder has

varied somewhat from year to year (Table 14). The percentage of larger Table 14. Annual mean length and percent length-frequency distribution by 5-cm size intervals of winter flounder impieted at $0iPS Units I and 2 free Octeber 1976 throush September 1984 Mean i length-frequency

 ' Year -     Number       lensth (ca)        CV      e10       10-14        15-19     20-24 25-29    > 29
                             .19.7            45%       22      -16           15         17   17         13 1976-77    5.247 16.9            43%. 22       21           29         16    8           4 1977-78   2.670 16.2            51%      31       25           14         14   11           5 1978-79    5.040 22.3                      5       21            19        16   21       . 18 1979-60    2.935                           36%

19 14 16 17 15 1980 2.197 20.0 45% 19 1981-82 2.945 20.0 42" 11 24 23 lb 12 14 27 25 11 11 12 14 1982-83 3.374 17.7 52%

                                             '40%      .19        19           22        21   11           7 1983-84    1.010           20.1 60

adults impinged was the lowest since 1978-79 and the catch of mid-size (15-24 cm) winter flounder made up almost half of the total. This was in contrast to 1982-83 when small (less than 15 cm) fish comprised over half the catch and mid-size fish were relatively uncommon. Since weather and plant operating conditions influence impingement catches as well as abundance, the relative differences in numbers and sizes impinged annually may not always reflect actual changes in the

      . population.

An examination of winter flounder impingement by month from 1976 through 1983 indicated that estimates were least precise from December through March, the period when catches were highest, and most precise from July through November when fewer were impinged (Fig. 23) . Therefore, the impingement sampling effort was reallocated in 1983-84 to improve the precision of the estimates while reducing unnecessary sampling effort. Instead of uniform sampling effort year-round, the number of samples was increased in winter and generally reduced during the rest of the year. Even though sample sizes were smaller when using data from a single year, the standard errors were similar or decreased during all month of 1983-84 when compared to 1976-83, with the exception of December and March. The large confidence interval in December was the result of the unusually large catch previously noted. Thus, the 50% reduction in sampling effort in 1983-84 provided an adequately precise estimate of winter flounder impingement and should continue to do so in the future. Entrainment Larval winter flounder were collected in entrainment samples at EN from late February through late June (Fig. 8). Greatest densities (exceeding 500 per 500 2m ) occurred during the first week of May. Predominantly Stage 3 larvae were entrained (Fig. 9), which also occurred in 1983 (NUSCo 1984). The median entrainment density of 49 per 500 m8 was the second highest recorded since 1976 and the total entrainment estimate of 50.8 million was the third highest (Table 15). However, due to the overlap in confidence intervals, no significant differences were noted in annual entrainment estimates among the years. I 61

1976-1983 175-w

                                                                              $        isol, s

d K ins 2 I_ - g.iool s

                                                                           .; @         -rel 8

nol [ , si 25-

                                                                                                                                    /N
                                                                                            '02            -

MAR- APR MAY JUN JUL AUG SEP OCT NOV OEC JAN FEB 1983-1984 irs-E w -,so: 3 o 12 5

                                                                                  .f 2
                                                                                  -Q _ tool
                                                                                  .g               _

2 FS-

                                                                                  .S.

g so-

                                                                                   .p-rs-
                                                                                                                                                  \
                                                                                                                                                                                           =            ;

a.. _ OCT NOV DEC JAN FES MAR APR MAY JUN JUL AUG SEP Figure 23.- Estimated monthly impingement (12 standard errors) of winter . flounder at MNPS for 1976-83 and 1983-84. 62 . _ - _ _ _ _ - _ _ _ _ _ - = _ _ . - - _ _ _ _ _ _ _ - - - - _ _ - _ - _ _ _ _ _

Table 15. Yearly .nedian densities of winter flounder larvae in entrainment samples during their season of occurrence and annual entrainment estimates with 95% confidence intervals for MNPS IJnits 1 and 2 from 1976 through 1984. 6 6 Year Median

• 95% CI Estimate (x 10 ) 95% C1 (x 10 )

1976 38.8 25.9-83.3 45.5 30.4-97.7 1977 23.4 12.0-43.8 20.8 10.7-39.0 1978 46.9 23.2-84.9 47.5 23.5-85.9 1979 28.7 14.2-56.8 24.5 15.1-57.7 1980 58.6 31.7-116.4 72.7 32.9-117.6 1981 20.1 9.8-47.6 14.1 10.5-48.3 1982 33.7 19.1-49.8 47.6 20.5-51.2 1983 47.5 31.0-109.6 54.7 35.7-126.1 1984 49.0 25.0-84.0 50.8 25.9-87.2 n/500 m 8 1 Harmonic Regression Models The fluctuations in abundance of winter flounder in three monitoring programs (impingement at Unit 2, larval sampling, and trawling) were described using time-based harmonic regression models with log-transformed data from October 1976 through September 1983 (Table 16). The models were used to forecast catches from October 1983 through September 1984 and actual catches were then compared to those predicted. The impingement model had only 1-yr and autoregressive terms as well as MNPS cooling-water flow as significant predictive regressors. The high R 2 (0.87) indicated that the model reliably described the impingement catch. Flow, representing plant operations, obviously affected impingement and was necessary to correctly predict little or no catch when flow was low or when the unit was shut down. The forecast error of 27% was an increase from the 12% calculated last year (NUSCo 1984). This again demonstrated the somewhat uncertain nature of impingement, which can be influenced by factors independent of abundance and previous trends. 63

Table 16. Summary of time-based regression models selected.to best describe the occurrence of winter flounder in various MNPS nonitorfift programs. Model Forecast Monitoring R2  % error program Station Model" 0.87 27 Impingement Unit 2 F*(1 + sin (lY) + cos(!Y)) - Al - A3 0.95 4 Entrainment EN S*(1 - sin (6M) - cos(6M) + cos(3M)) + A1 + A2 - A3 + A5 0.90 13 Ichthyoplankton NB S*(1 - sin (1Y) - cos(1Y) - sin (4M)) 0.55 353 Trawl BR I + sin (7Y) + cos(7Y) + cos(6Y) + sin (lY) + Al - A21 0.38 139 cm Trawl IN I + sin (7Y) + sin (6Y) - sin (1Y) - cos(lY) - sin (6M) + Al + A8 s~ 0.42 141 Trawl JC I + cos(6Y) + cos(4Y) - sin (6M) - sin (4M) + cos(4M) + Al - A19 0.53 95 Trawl NB I + cos(7Y) - sin (2Y) - cos(1Y) - sin (6M) 0.70 224 Trawl NR I + sin (7Y) + sin (6Y) - sin (lY) - sin (6M) - sin (4M) + Al - A3 - A10 0.50 98 Trawl TT I + sin (7Y) + cos(7Y) + sin (6Y) + sin (1Y) - cos(lY) + Al - A12 F = flow S = season nY. nM = period in years or months An = autoregression coefficients I = intercept

The two larval models had seasonal components as winter flounder larvae were only present for up to 7 months of the year. These models also had high R2 values (0.95, 0.90), which was expected for species having a very seasonal pattern of occurrence (NUSCo 1984). Only terms with shorter periods (6 and 3 mo) were included in the entrainment model. Forecast percent errors were very low (4,13%) for these models, which suggested an accurate prediction for 1983-84. Most of the trawl models contained terms with 6- and 7-yr periods. This was probably an artifact of the analysis as we may not yet have enough data to observe a repeatable pattern. However, because 6-yr terms found significant in 1983 (NUSCo 1984) remained so for almost all stations in 1984, a cyclical pattern of abundance may be emerging from the data. However, this cycle can only be confirmed by additional data in the coming years. The models for the inshore trawl stations (NR, NB, IN, and JC) also contained shorter terms which probably reflected annual cycles of abundance due to local movements and recruitment of juveniles into the trawl catch. The R for each trawl mocel improved from 1982-83, but except for NR (0.70) the variability of the trawl models was high. This is typical for species caught year-round, such as the winter flounder. The forecast percent errors were also large for all models, although except for BR they decreased considerably or remained the same as 1982-83 (NUSCo 1984). Insufficient data and inherent variability of trawl catches probably contributed to the inadequacies of the models. With additional data, the reductions in R2 and in forecast errors seen this year may continue. With increasing ability to successfully model and predict trends in abundance, we should be able to describe changes due to natural fluctuations and assess the impact of 3-unit operations of MNPS.

SUMMARY

1. The 1984 adult winter flounder abundance survey in the Niantic River began on February 14, the earliest start since 1976. The number of winter flounder larger than 20 cm was estimated as 51,819 1 27,134.

65 1 L. . . . . . . . .

r

     .- 2.

Abun'anced of winter flounder larger than 15.ca was also estimated using the. median' trawl CPUE. The 1984 median was 14.3, the smallest-during thel 9 years of stdy. However, capture efficiency of1the trawl in the upper river was affected by the large amounts-

                                 ~
             -of;macroalgae and detritus present; this reduced the catch to an
             . unknown degree and probably underestimated the abundance of winter flounder.-
     ~3.       Directly comparable annual CPUE medians were calculated for the period 1977-84 using'da'ta restricted from mid-March through mid-April and to fish larger.than 20 cm.      Abundance peaked in 1981 with decreases seen in 1983 and 1984.

Comparisons were made among adult, larval, and age 1 juvenivle

      ~
      .4..

indices.of abundance. Little corresponsdence was found between the

              ' relative-abundance of adults and the number of larvae produced.- A more obvious relationship was found between larvae and juveniles with trends in' abundance generally parallel. This suggests that the strength of a year-class _is established early during the winter-flounder life history.

5.  ; As inLprevious years, spawning was essentially completed by early April: and apparently began in. January or early February -under the ice in.the upper river. The length-at which 50% of.the females were sexually mature was 26.6 cm, very similar to the 1983 estimate of 25.1 cm.

               -Recapture rates of adults released with Petersen disc tags' were
                     ~

6.

           -     similar among years and stations. .About 1.67 times as many winter flounder wereitaken by the sport than the commercial fishery. Most recaptures (70%) were made in local waters. Three times as many returns were received from more distant locations to the east than to the west.

66

7. The effects of mesh size (0.202 and 0.333 mm) and tow duration (6 and 15 min) on the collection density of winter flounder larvae were examined. No differences in the collection density of Stage 1 and 2 larvae were found for the two tow durations, but significantly more Stage 1 larvae were taken with the smaller mesh.

8. The temporal and spatial distributions of larvae were similar to those found in 1983 with successive increases and decreases occurring sequentially from the upper Niantic River to Niantic Bay.

More larvae were collected during the early part of the season in 1984 than in 1983.

9. Peak abundance of Stage 2 larvae in the bay occurred 23 days later.

than in the river, which agreed with the 25 and 27 day average

               -residence time of particles in the river. Estimated densities at peak abundance for Stages 3 and 4 were similar in both locations, which indicated that most of the standing stock of these stages was in the bay.

10. Developmental time was estimated as 9 days for Stage 1, 39 days for Stage 2, 26 days for Stage 3, and approximately 10 to 15 days for Stage 4. Total developmental time from hatching to Stage 4 was less in 1983 (53 days) than in 1984 (73 days), probably due to lower water temperature d' iring 1984. This slower developmental time was also seen in the estimated age of a 7.5-mm larva, which was 59 days in 1983 and 73 days in 1984.

11. An estimated 65%'of the Stage 2 larvae that were flushed from the Niantic River on an ebb tide returned of the flood. The return of Stage 3 larvae increased from 63% early in the season to 92% a month later. This suggests that older larvae use tidal currents as an estuarine retention mechanism.

12. Abundance of post-larval young peaked in early June and leveled off by early August. Although more vaiable, densities at station LR in 1983 were greater than in 1984.

67

13. Growth of young in 1984 was less than in 1983 and mortality was greater. The latter may have been the result of increased predation by the summer flounder, which over the past 9 years reached its greatest abundance in the Niantic River during 1984.

14. The impingement of winter flounder at MNPS during 1983-84 was half that of 1982-83 as a fish-return sluiceway was installed at Unit 1 in mid-December. Impingement sampling effort was reallocated this year and resulted in more samples collected dur'ing winter and fewer during other months. The precision of the estimates remained similar to previous years while effort was reduced by about 50%.

15. Entrainment of larvae at MNPS occurred from late February through late June with greatest densities during the first week of May.

The median density of 49 larvae per 500 m8 was the second highest since 1976, but no significant differences were apparent among the years.

16. Fluctuations in abundance from the impingement, ichthyoplankton, and trawl monitoring programs were analyzed using time-based harmonic regression models. The best models were developed using impingement and entrainment data. Although R2 values were higher than in 1982-83, the trawl station models remained generally inadequate. Additional years of data will be necessary to

     ' determine and describe cyclical trends in abundance.

CONCLUSIONS Special emphasis has been placed on understanding the dynamics of the winter flounder spawning in the Niantic River because the winter flounder is a valuable sport and commercial finfish and the Niantic River stock is reproductively isolated. During 1984, information was

. collected to determine the factors related to the natural fluctuations

'in the abundance of the stock. Although adult abundance has decreased since 1981, there has been no indication of a decline in the 68 l

t reproductive potential based on the abundance of early life history stages. The documentation of the material fluctuations in the life history characteristics provide the bases for assessing the impact of 3-unit operation at MNPS. 69

REFERENCES CITED Arnason,(A.N.,and'K.H. Mills. 1981. Bias and loss of precision due to

                  . tag-loss in Jolly-Seber estimates for mark-recapture experiments.
                  'Can. J. Fish. Aquat. Sci. 38:1077-1095.

Balser, J.P. -1981. . Confidence interval estimation and tests for temporary outmigration in tag-recapture studies. Ph.D. Thesis, Cornell University. 205 pp. Bannister, R.C.A., D. Harding, and S.'J. Lockwood. 1974. Larval

                  . mortality'and subsequent year-class strength in the plaice (Pleuronectes platessa L.). 'Pages 21-37 ijl J.H.S. Blaxter, ed.

The early life history of fish.' Springer-Verlag, New York. Battelle-William'F. Clapp Laboratories. 1978. A monitoring program on the ecology of the marine environment of the Millstone Point,. Connecticut area.- Annual report, 1977. Presented to Northeast Utilities Service Company.

                     .__1979. -A monitoring program on the ecology of the' marine environment of the Millstone Point, Connecticut area. Annual report, 1978. Presented to Northeast Utilities Service Company.
           'Bigelow, H.B., and W.C. Schroeder.                       1953. Fishes of                                the Gulf of Maine.

U.S. Fish. Wildl. Serv., Fish. Bull. 53:1-577. Bishop, J.A., and P.M. Sheppard. 1973. An evaluation of two capture-recapture models using the technique of computer-simulation. -Pages 235-252jyL M.S. Bartlett and R.W. Hiorns, eds. The mathematical theory of the dynamics of biological populations. Academic Press, London. Blake, M.M., and E.M. Smith. . 1984. .A marine resources management plan for the state of Connecticut. Connecticut Dept. of Environmental Protection, Mar. Fish. 244 pp. Brothers, E.B., C.P. Mathews, and R. Lasker. 1976. Daily growth increments in otoliths from larval and adult fishes. Fish. Bull., U.S. 74:1-8. Buckland, S.T. 1980. A modified analysis of the Jolly-Seber capture-recapture'model. Biometrics 16:419-435. Cetta, C.M., and J.M. Capuzzo. 1982. Physiological and biochemical aspects of embryonic and larval development of the winter flounder Pseudopleuronectes americanus. Mar. Biol. 71:327-337. Cormack, R.M. 1973. Commonsense estimates from capture-recapture studies. Pages 225-234 jyt M.S. Bartlett and R.W. Hiorns, eds. The mathematical theory of the dynamics of biological populations. Academic Press, London. 70

1979. Models for capture-recapture. Pages 217-255 it! R.H. Cormack and D.S. Robson, eds. Statistical ecology. Vol 5. Sampling biological populations. International Co-operative Publishing House, Fairland, MD. (not seen, cited by Hightower and Gilbert 1984). Cushing, D.H. 1974. The possible density-dependence of larval mortality and adult mortality in fishes. Pages 103-111 iyt J.H.S. Blaxter, ed. The early life history of fish. Springer-Verlag, New York.

                                                  , and J.G.K. Harris.                            1973. Stock and recruitment and the problem of density dependence. Pages 142-155 jj! B.B. Parrish, ed. Fish stocks and recruitment. ICES Rapp. P.V. Reun. 164.

Davies, R.G. 1971. Computer programming in quantitative biology. Academic Press, New York, N.Y. Draper, N., and H. Smith. 1981. Applied regression analysis. John Wiley and Sons, New York. 709 pp. Dunn, R.S. 1970. Further evidence for a three-year oocyte maturation time in the winter flounder (Pseudopleuronectes americanus). J. Fish. Res. Board Can. 27:957-960.

                                                      , and A.V. Tyler.                         1969. Aspects of the anatomy of the winter flounder ovary with hypothesis on oocyte maturation time.                    J.

Fish. Res. Board Can. 26:1943-1947. Gallucci, V.F., and T.J. Quinn II. 1979. Reparameterizing, fitting, and testing a simple growth model. Trans. Am. Fish. Soc. 108:14-25. Gulland, J.A. 1965. Survival of the youngest stages of fish, and its relation to year-class strength. Spec. Publ. ICNAF 6:363-371.

                                                         . 1983. Fish stock assessment: a manual of basic methods. John Wiley and Sons, New York.                        223 pp.

Hightower, J.E., and R.J. Gilbert. 1984. Using the Jolly-Seber model to estimate population size, mortality, and recruitment for a reservoir fish population. Trans. Am. Fish. Soc. 113:633-641. Howe, A.B., and P.G. Coates. 1975. Winter flounder movements, growth, and mortality off Massachusetts. Trans. Am. Fish. Soc. 104:13-29. Jolicoeur, P. 1975. Linear regressions in fisheries research: some comments. J. Fish. Res. Board Can. 32:1491-1494. Jolly, G.M. 1965. Explicit estimates from capture-recapture data with death and immigration stochastic model. Biometrika 52:225-247. 71 w___-__-___- = _ _ _ _ _ _ _ - _ _ _ _ _ _ - - _ _ _ _ _ _ _

Jones, R. .1981. The use of length composition data in fish stock assessments (with notes on VPA and cohort analysis). FAO Fish. Circ. 734:1-60. Kollmeyer, R.C. 1972. A study of the Niantic River estuary, Niantic, Connecticut. Final report phases I and II, physical aspects of the Niantic River estuary. Rep. No. RDCGA 18. U.S. Coast Guard Academy, New London, CT. 78 pp. Laroche, J.L., S.L. Richardson, and A.A. Rosenberg. 1982. Age and growth of a pleuronectid, Parophrys vetulus, during the pelagic larval period in Oregon coastal waters. Fish. Bull., U.S. 80:93-104. Laurence, G.C. 1975. Laboratory growth and metabolism of winter flounder, Pseudopleuronects americanus, from hatching through metamorphosis through three temperatures. Mar. Biol. (Berl.) 32:223-229. Leim, A.H., and W.B. Scott. 1966. Fishes of the Atlantic coast of Canada. Bull. Fish. Res. Board Can. 155:1-485. Lobell, M.J. 1939. A biological survey of the salt waters of Long Island, 1938. Report on certain fishes. Winter flounder (Pseudopleuronectes americanus). Suppl. 28th Ann. Rep., N.Y. Cons. Dep., Pt. .I:63-96. Lockwood, S.J. 1980. Density-dependent mortality in 0-group plaice (Pleuronectes platess L.) populations. J. Cons. Int. Explor. Mer 39:148-153. Manly. B.F.J. 1971. A simulation study of Jolly's method for analyzing capture-recapture data. Biometrics 27:415-424. Miller, G.J. 1978. Impingement of fishes and macroinvertebrates on the traveling screens. Pages 16-51 in T.R. Tatham, D.J. Danila, D.L. Thomas, and Associates. Ecological studies for the Oyster Creek Generating Station. Progress report for the period September 1976-August 1977. Vol. One. Fin- and shellfish. Ichthyological Associates, Inc., Ithaca, N.Y. Moore, J.K., and N. Marshall, 1967. The retention of lamellibranch larvae in the Niantic estuary. The Veliger 10:10-12. I Nichols, J.D., B.R. Noon, S.L. Stokes, and J.E. Hines. 1981. Remarks on the use of capture-recapture methodology in estimating avian population size.- Studies in Avian Biol. 6:121-136. (not seen, cited by Hightower and Gilbert 1984). , NMFS (National Marine Fisheries Service). 1980. Marine recreational fishery statistics survey, Atlantic and Gulf coasts, 1979. Current fishery statistics No. 8063. NMFS, U.S. Dept. of Commerce, NOAA. (not seen, cited by Blake and Smith 1984). 72

NUSCo (Northeast Utilities Service Company). 1975. Summary report, ecological and hydrographic studies, May 1966 through December 1974, Millstone Nuclear Power Station. 1980. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1979. 1981a. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station Waterford, Connecticut. Annual report, 1979. 1981b. Feasibility of modifying the Millstone Units 1 and 2 cooling water intake screen wash system to improve the return of fish to Long Island Sound. 67 pp. 1982. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1982. 1983. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1982. 1984. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1983. Pannella, G. 1971. Fish otoliths: daily growth layers and periodical patterns. Science (Wash., D.C.) 173:1124-1127. 1974. Otolith growth patterns: an aid in age determination in temperate and tropical fishes. Pages 28-39 in T.B. Bagenal, ed. The ageing of fish. Unwin Brothers, Ltd., Surrey, U.K. Pearcy, W.G. 1962. Ecology of an estuarine population of winter flounder Pseudopleuronectes americanus (Walbaum). Bull. Bingham Oceanogr. Coll. 18(1):1-78. i Perlmutter, A. 1947. The blackback flounder and its fishery in New England and New York. Bull. Bingham Oceanogr. Coll. 11:1-92. Radtke, R.L., and M.D. Scherer. 1982. Differential growth of winter flounder (Pseudopleuronectes americanus) larvae in the Plymouth Harbor estuary. Pages 1-5 irl C.F. Bryan, J.V. Conner, and F.M. Truesdale, eds. Proceedings of the fif th annual larval fish conference. Louisiana Coop. Fish. Res. Unit, Baton Rouge, LA. Ricker, W.E. 1975. Computation and interpretation of biological statistics of fish populations. Bull. Fish. Res. Board Can. 191:1-382. Roff, D.A. 1981. Reproductive uncertainty and the evolution of iteroparity: why don't flatfish put all their eggs in one basket? Can. J. Fish. Aquat. Sci. 38:968-977. 73

Saila, S.B. 1961. A study of winter flounder movements. Limnol. Oceanogr. 6:292-298.

       . 1962a. .The contribution of estuaries to the offshore winter flounder fishery in Rhode Island. Proc. Gulf Caribb. Fish. Inst.

14th Annu. Sess. 1961:95-109.

       . 1962b. Proposed hurricane barriers related to winter flounder movements in Narragansett Bay. Trans. Am. Fish. Soc. 91:189-195.
        . 1976. Effects of power plant entrainment of winter flounder populations near Millstone Point, Connecticut. URI-NUSCo Rep. No.

5. 134 pp.

Sampson, R. 1981. Connecticut marine recreational fisheries survey 1979-1980. Connecticut Dept. of Environmental Protection, Mar. Fish. 49 pp. SAS Institute Inc. 1982. SAS user's guide: statistics, 1982 edition. SAS Institute Inc., Cary, NC. 584 pp. Sissenwine, M.B., K.W. Hess, and S.B. Saila. 1975. A mathematical model for evaluating the effect of power plant entrainment of populations near Millstone Point, Connecticut. MES-NUSCo Rep. No.

1. 77 pp.

Snedecor, G.W., and W.C. Cochran. 1967. Statistical methods. The Iowa State University Press, Ames, Iowa. 593 pp. Sokal, R.R., and F.J. Rohlf. 1969. Biometry. W.H. Freeman and Company, San Francisco. 775 pp. Sprent, P., and G.R. Dolby. 1980. Query: the geometric mean functional relationship. Biometrics 36:547-550. Tyler, A.V., and R.S..Dunn. 1976. Ration, growth, and measures of somatic and organ condition in relation to meal frequency in winter flounder, Pseudopleuronectes americanus, with hypotheses regarding population homeostais. J. Fish. Res. Board Can. 33:62-75. Warren, C.E. 1971. Biology and water pollution control. W.B. Saunders Co., Philadelphia. 434 pp. 74

O in

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1 I l OSPREY Table of Contents Section Page INTRODUCTION...................................................... 1 MATERIALS AND METH0DS............................................. 2 Existing Platforms.............................................. 2 N ew P l a t f o rm s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Observations.................................................... 3 RESULTS........................................................... 4 Wildlife Area Nest.............................................. 4 Quarry Nest..................................................... 4 Fox Island Nest................................................. 6 North Bay Point Nest............................................ 6 Wildlife Area Marsh Nest........................................ 6 Other Observations.............................................. 6 DISCUSSION........................................................ 7 R E F ER ENC ES C I T ED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1 OSPREY INTRODUCTION

        \

The osprey (Pandion haliaetus) is a fish eating raptor found fu many estuarine areas along the East Coast of North America (Wicceyer et al. 1980). They form colonies along shallow bays and rivexs where there is an abundance of fish and available nesting sites. Coastal c

       ,\    Connecticut once supported one of the largest known colonies of the osprey (Spitzer 1979). An estimated 1,000 nesting sites existed here in the 1940's.(Spitzer et al. 1983).

Pesticides, including DDT, heavily used in the 1950's and 1960's,

           -became-incorporated into the food chain and eventually into the
           -reproductive system of the osprey, causing massive reproductive failures iby eggshell thinning. Osprey colonies declined to alarmingly low levels and it was feared they would be eliminated as a breeding species in our region. Populations along the Connecticut River estuary decreased by 30% per year (Ames 1966) and by 1974 only nine active nests were lef t producing seven young (Spitzer 1979). Reproductive rates began to increase following a federal ban on DDT in 1972. The number of fledglings in-1976 was double that of 1974 and the reproductive rate of nesting osprey in the Northeast produced 1.55 young per active. nest in
            '1981 (Spitzer 1983). The osprey have survived the use of DDT and now have a production rate sufficient to sustain a stable population (0.8-1.3 young per active nest) (Henry and Wright 1969; Spitzer et al.

1983). I Although the osprey lives in close association with humans and-exhihits a great deal of tolerance for human activity, it was not until-their decline that osprey generated so much concern. Because ospreys feed primarily on fish, Weimeyer et al. (1980) and Spitzer et al.'(1983) have recommended that ospreys be closely monitored as a-biological e indicator of pollutants in estuarine ecosystems. Federal officials have also placed the osprey on the 11et of spc.cies of management concern. Millstone Point and the adjacent area is an established breeding

             -ground for osprey. Jordan Cove and the Niantic River provide the opportunistic feeder with a reliable food resource. The objectives of L

4 d'. I

       .- our program are to monitor the reproductive success of active osprey                                                          '

nests on site of the Millstone Nuclear Power Station (MNPS), and to  ! encourage the growth of the local osprey population by providing artificial nesting platforms. MATERIALS AND METHODS Existing Platforms Between 1967 and 1983 Northeast Utilities erected five artificial nesting platforms,on HNPS.(Fig. 1). The first three platforms were set on top of utility poles ranging in height from 30' to 50'. The other

         ' two were mounted on top of 14'x4"x4" pressure treated posts and were similar.to those used by the Connecticut Department of Environmental Protection (DEP) in their nesting program. These shorter platforms are sheathed with aluminum flashing to prevent climbing by predators such'as raccoons, who can easily climb to the nest and eat the eggs.
                                  ^^t _          **
                          *^
                                          .         m A                                                                      fon tsiend g
                                                 *A                                                            -'

Jordon Cove nactive Piotforrrt W '*

                        ~                                 bree Active Picteo rm O

Guarry

                                             /                           Generot;ng
                                             '\ North                         Units 2     1 3

Niontic Bay

                                                               -                                       ,               i obt la^^                     D Figure 1.      Location of osprey artificial nesting platforms at Millstone Nuclear Power Station.

2

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                                                                 ~

The quarry nest, the first platform, was erected in 1967, on the eastern. rim of the granite quarry, to replace a nest.that had been built upon anfunused derrick dismantled during the construction.of Unit 1. ~ In 1969, this nest was part' of ~an-egg transfer program, in which eggs from Lthe nests'of the less threatened osprey-of the Chesapeake Bay were exchanged.for.-those of-local birds. .In 1972, this nest alone produced

three: of the nine fledglings in Connecticut.

                      'A second' platform, the' Wildlife Area Nest, was erected in 1974 on       '
               'the' southern edge of a 50 acre, wildlife' refuge, set aside by Northeast' x

Utilities as a conservation area. This nest. -50 m' from the water, became active in 1976 and-the;-pair that occupy'it hads consistently

             -produced-young every year.

In 1979, a third nesting platform was erected on Fox Island.

               -Although-the Fox Island platform. remained inactive through ,1983, it was-used-by-thebirds;oftheQuarryNestas'afeedingandroostingsitag ThisLyear it became an active nesting platform.

The.last two platforms were erected in'1983,:.V One was located-in a marsh ~ on the' eastern edge of the wildlife refuFei (Wildlife Area Marsh Nest) and:the.other was on the west side'of-the plant by Niantic. Bay,

 .                                          ~

just north of. Bay Point (North Bay Point Nest)..

                'N'ew Platforms Northeast Utilities Environmental: Laboratory (NUEL) ' assisted the Connecticut DEP in 1984, in erecting four new nesting platforms along x

coastal: Connecticut in Guilford, Old Saybrook..Waterford and Stonington. The Waterford platform is,on the eastern shore of Niantic Bayfon

                -property that borders MNPS. This platform was erected to attract a pair-ofbirdsthathadbuiltanesb'thatfailedin1983onChannelMarker#4 located just outside of -the Niantic River (NUSCo 1984) . N,esting
                -material was transferred from the-channel marker to the new platform.

Observations Each year after_the return of the first osprey to MNPS, weekly observations of each nesting site are made using binoculars. 3 i '

1 1 Observations of the Quarry and Fox Island nests are made from the meteorological tower when qualified personnel are available for  ! climbing. Observations continue until all osprey have left the MNPS area. RESULTS During 1984, all five nesting platforms were observed at MNPS from March 22 through mid September (Table 1). Of these, four (Wildlife Area Platform, Quarry Platform, Fox Island Platform and North Bay Point Platform) were active with adult osprey and two of the active nests (Wildlife Area Nest and North Bay Point Nest) produced a total of four young. Wildlife Area Nest March 22 marked the return of the osprey to MNPS when one male was observed in the Wildlife area. Mating and nest rebuilding began upon the arrival of the female which occurred in the first week of April.

 'The Wildlife Area platform has a large, well established nest which requires little rebuilding by the birds. This allows the pair to get an early start with breeding and they are usually the first to hatch young.

On May 31, the female appeared to be feeding her young and the male was observed bringing fish to the nest. Ground observations revealed two young in the nest on June 21. Both young had fledged by'the end of July. Quarry Nest On March 26, four osprey were observed circling above the Quarry nest. Three days later a late winter storm hit the area and for several days osprey were not observed in the vicinity of that nest. On April 6, the four birds returned to the Quarry nest, three of them males actively courting the female. By April 13, a pair seemed established and mating was observed, but nest rebuilding was neglected. Observations made from the 375' foot level of the meteorological tower on June 5, revealed only 4

4 K one egg:in the Quarry nest.- In previous years..this nest would have had young . hatched by this date. . By_ June 15, the nest was abandoned-by'the

         - female and' considered unsuccessful.~ The failure of this nest may have been due tc the loss of a mate, possibly the male of the established pair'during the winter. This was indicated'by'the interaction of numerous: males at the nest early in the season, and the lack of nest
                             ~
         . rebuilding'which is primarily a' male activity.

Table 1. Number of' active nests and number of fledglings produced ^ in Connecticut and Millstone Point. Millstone Point Connecticut Active Nest Fledglings Year' Active Nests Fledglings 0 16 10 1969 1 0 13 8

          *1970                      'l 1            3                12                8.   .

1971 ' 3 10. 9 1972 1 2 10- 4 1973' 1 2 9 7 1974 1 2 9 10 1975 1 3 10- 14 1976 1 1 3 14 20 1977 1 3 15 15

          ~1978 1-          2                15              25 1979 2            5                15              26 1980 2            4                22              36 1981 2            3               29              33 1982~

6 34 40 1983 .2 4 4 38 44-1984 45 309 Total 5-

Fox Island Nest i A pair of osprey were observed around the Fox Island platform on April 19. Initial attempts to construct a nest failed because nesting material was not available for the inexperienced birds. Personnel.et NUEL collected and spread sticks of various sizes below the nesting platform on April 24,-1984. On the following day, the male was seen collecting this material and resumed building the nest. Mating activity of this pair lasted into early June, but no young were produced. North Bay Point Nest This platform became active for the first time on April 24. Most likely the birds observed at this site are the pair that built the nest on the channel marker in 1983. This pair may have occupied the newly erected Connecticut DEP monitored Waterford nest for about a week before abandoning it. They were experienced at nest building and quickly constructed a large nest. Two young were observed in the nest on June 6 and had fledged by mid August. Wildlife Area Marsh Nest No activity at this platform has been observed since it was erected in 1983. l Other Observations The close association that osprey have with man is not without its hazards. On September 29, a juvenile osprey was found dead below the 475' meteorological tower. The bird's death probably resulted from a collision with the tower structure or supporting guy wires. Migration I of the osprey occurs at this time of year. Since the MNPS osprey population had already left the area, the osprey that was found was probably migrating through the area. The bird was donated to a regional science center (Thames Science Center, New London, Ct.). 6

P r DISCUSSION

              -This year in Connecticut, osprey produced-44' young in 38 active nests (Greg-Chasko personal communication) (Fig. 2); fourteen of the active nests did not produce young. This lack of success may be due to
                                ~

an' increased number of first-time. breeders in the Connecticut osprey population. As more first time. breeders return to an area, there are fever experienced birds available as mates. Forced ' to mate with each other, they. build nests but fail to produce or incubate eggs until the following' season. Spitzer et al. 1983 estimated the age of first bree' ding to be between three and five years and noted a steady rise in the number of these birds in the New York City to Boston region from 0-1970; 5-1974; 17-1978; 26-1981. A healthy osprey population should

       - contain 5% to 10% of-these non-laying pairs (Henny and van Velzen 1972).

This year'at MNPS, one of the four nesting pairs was considered non-laying. AVERAGE ~ NUMBER OF FLEDGLINGS PER- ACTIVE NEST CMILLSToNE POINT AND CONNECTICUT) 3.5-

              +             :
            ~o-
                                                                                   \  \

F f 1

                 -2.5-'                        l

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            .G      .l.02   ~

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1968 1970 1972 1974 1976 1978 1980 1982 1984 YEAR HILLSToNE= STAR CONNECTICUT = DIAMOND 1 Figure ~2. Average number of fledglings per active nest for Millstone

                              . Point compared to.all of' Connecticut.

7

The 1984 breedsng season at MNPS produced four young in four active nests. This year's annual production rate of 1.0 per nest.is lower than previous years because of the introduction of new nests and the failure of-the Quarry nest. The number of active nests at MNPS doubled from two to four this season, leaving only one platform inactive. Because of the increasing influx of'first-time breeders to the area, we plan to erect another platform on top'of a utility pole at the tip of Bay Point before the

     - 1985 breeding season begins.

REFERENCES CITED Ames, P.L.. 1966. DDT residues in the eggs of the osprey in the northeastern United States and their relation to nesting success. J. Appl. Ecol. 3 (Suppl.) 87-97. NUSCo (Northeast Utilities Service Company). 1984. Monitoring the marine environment.of Long Island Sound at' Millstone Nuclear Power Station, Waterford, Connecticut. Annual report, 1983. Henny, C.J., and W.T. vanvelzen. 1972. Migration patterns and wintering localities of wintering American osprey. J.. Wild. Manage. 36:1144-1141.

             , and J.Y. Wright. 1969. _ Endangered ~ osprey populations; Estimates of mortality and production. Auk 86:188-198.

Spitzer, P.R. 1979. Dynamics of a discrete coastal breeding population of ospreys (Pandion haliaetus) in the northeastern United States during a period of decline and recovery, 1969-1978. Ph.D. Thesis, Cornell University.

             , A. Poole, and M. Scheibel. 1983. Proceedings, first internati.onal osprey-bald eagle conference. David Bird editor, McGill University Press. Montreal, Canada, f
      -Wiemeyer, S.N., Y.G. Lamont, and L.N. Locke. 1980. Residues of environmental pollutants and necropsy data for eastern United States ospreys,. 1964-1973, Estuaries 3:155-167.

t I 8

N UTIEJTIES General Offices e Selden Street, Berlin, Connecticut

          '7sYvSNIrsIsNco,
          .                                                         P.O. BOX 270 wm aa sa m** m***

HARTFORD. CONNECTICUT 06141-0270 L L J 7,((',"d7N,Cg*' (203) 665-5000 May 10,1985 Docket Nos. 50-245 50-336 50-423 B11539 Director of Nuclear Reactor Regulation Mr. B. 3. Youngblood, Chief Licensing Branch No.1 Mr. 3. R. Miller Operating Reactors Branch #3 Mr. 3. A. Zwolinski, Chief Operating Reactors Branch #5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen: Millstone Nuclear Power Station Annual Report 1984 - Monitoring the Marine Environment of Long Island Sound at Millstone Nuclear Power Station Northeast Utilities Service Company hereby submits for. your information ten (10) copies of its 1984 annual report: Monitoring the Marine Environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut, Annual Report 1984, Northeast Utilities Service Company, April,1985. The report contains a detailed report of on-going biological studies of the potential impact of Millstone Nuclear Power Station on Long Island. The report presents 1984 results and provides comparisons with previous years as a basis for impact assessment. Should you have any questions regarding the information contained herein, please call M r. Paul M. Jacobson, Manager, Northeast Utilities Environmental Laboratory, at (203) 444-4239. Very truly yours, NORTHEAST UTILITIES SERVICE COMPANY E- [ d"

3. F. O nka Senior ice President

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