ML20091C348

Ecological Studies Proposed for 1992 at Millstone Nuclear Power Station,Unit 3

ML20091C348
Person / Time
Site:	Millstone
Issue date:	07/31/1991
From:	NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES SERVICE CO.
To:
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ML20091C347	List: ML20091C344 ML20091C348
References
NUDOCS 9108060245
Download: ML20091C348 (13)

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Enclosure 1 to letter No. D04812 ECOLOGIC AL STUDIES PROPOSED FOR 1992 AT MILLSTONE NUCLEAR POWER STATION NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION NPDES PERMIT No. CT0003263 Northeast Utilities Service Company PO Box 270 11artford, Connecticut 061410270 July 1991 y[0l$$$k $b $3 s

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FISil ECOLOGY STUDIES The objectives of the fish ecology sam pling propram are to monitor the occurrence, relative abundance, and distribution of finfish Ln the victruty of Millstone Point, and assess whether there are any power plant-induced changes in the fish connaunities.

Shore zone Seine Shore mne fish will be collected with a 30-foot seine net of 0.25-inch mesh at three sites (Fig.1):

White Point (WP), Jonian Cove (JC), and Giants Neck (GN). During the year, sampling at all stations will be conducted monthly during January through March and in hovember and December, and biweekly from A ?ril through October. Wree 100-foot hauls at adjacent beach areas will be made approximately para lel to the shoreline at each site. He fish in each haul will be identified, counted, and measured. When a large number of a fish is caught, length measurements will be made on a representative subsample. Every effon will be made to return fish to the water alive.

Trawi Sampling by trawl will be conducted biweekly at six sites (Fig.1): Niantic River (NR), Niantic Bay (NB), Jordan Cove (JC), Tv/otree Island Channel (*lT), Bartlett Reef (BR), and Intake (IN).

Triplicate tows will be made using a 30-foot otter trawl with a 0.25 inch cod-end liner. Under certain rarely occurring conditions, which would include damage to the boat or trawl net or severe weather, the number of tows at a station may be reduced from three to two. If only one tow has been made, the station will be re sampled later in the week. When excessive loading of the trawl occurs by macroa!gae and detritus, tow distances may be reduced, but catches will be standardized to o.69 km. All fish collected will be identified, counted, and a representative number of selected species will be measured in the field. Every effort will be made to retum the fish to the water alive.

Ichthyoplankton Monitoring The objectives of the entrainment and offshore plankton programs are to monitor changes in density or seasonal occurrence of fish eggs and larvac in the vicinity of MNPS and to quantify the nember of these organisms passing through the condenser cooling water system.

Entrained ichthyoplankton will be sampled weekly at the discharge of Unit 1,2, or 3. Samples will be collected with a 1 m,0.333 mm mesh net, and each sample will consist of about 400 m3 of fihered water. Sample volume may be reduced during periods of high plankton or detritus concentrations. The planned monthly sampling frequencies and the early life history stages (eggs and/or larvae) that are identified and enumerated are provided in Table 1. This sampling design is a result of several evaluations that increased the efficiency of the monitoring program by maxinu, zing the number of samples collected during the periods of greatest ichthyoplankton abundance.

Offshore ichthyoplankton sampling will be conducted in mid Niantic Bay (station NB in Fig.1) with a 60-cm bongo sampler Obhque stepwise tows will be made for 6 to 15 minutes using 0.202-(generally February and March) or 0.333 mm mesh nets with equal sampling time at the surface, mid-depth, and near bottom. Tow duration may be reduced to less than L5 minutes during periods 3

of high plankton or detritus concentrations. Each tow represents a sample volume of about 120 m 3

(6-minute tow) to 300 m (15 minute tow). Monthly sampling frequency is provided in Table 1; with this design the sampling effort is greatest during high ichthyoplankton abundance. Larvae frora these samples will be identified and enumerated, but fish eggs will only be enumerated from the NB collections.

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Impingement Monitoring Routine im pingement monitoring at Unit 2 was discontinued in _Decemler 1987 and was replaced by a proced ure to monitor unusual impingement events (more than 300 fish or crustaceans in a 24-hour period). Plant operators check the impingement basket as part of their regular rounds and if large numbers of fish or crustaceans are in the basket they will notify NUSCO staff biologists.

The latter will then identify, count, and measure up to 50 specimens and report results to the DEP as part of the monthly operating report. .

Winter Flounder Studies ne objectives of the winter flounder studies are to investigate the population dynamics of this r

' species r.nd assess vssible MNPS impacts, such as the entrainment of larvae through the cooling-water system. Stuc les of winter flounder in the Millstone Point area of Long Island Sound have been conducted since 1973 and have largely focused on the stock known to spawn in the Niantic River. Studies planned for 1992 are described below.

Adult Population Abundance Index: The population abundance index for the adult (>20 cm) Niantic River stock will be estimated during the spawning season using both a mark recapture model and trawl catch per unit effort (CPUE). The survey of adult winter flounder abundance in the Niantic River will begin after ice-out, which usually occurs in Febmary. Sampling will be conducted on at least two days each week (weather or water conditions pennitting) and will continue until the proportion of gravid females decreases to less than 10% of all f'emales examined during two consecutive weeks (usually in early April). During each week, approximately 30-40 tows will be made using an otter trawl in up to eight areas of the river (1,2,4,6,51,52,53, at d 54 in Fig. 2). The tows will be ailocated to stations based on area and observed abundance of winter flounder. The sex ratio ar.d length distribution of the population will be detennined.

Larval Studies: Larval winter flounder studies will be conducted to estimate natural survival rates, to determine the spatial and temporal distribution oflarvae in Niantic River and Bay, and to estimate the number entrained at MNPS. Sampling in the Niantic River will start in February (ice conditions permitting) with preliminary tows made in the upper portion of the river to detennine when larvae are first present. After larvae are present, routme sampling will be conducted at stations A, B, and C (Fig.1). Weather pennitting, sampling will be conducted one day a week with a @cm bongo sampler. Oblique stepwise tows will be made for 6 minutes with equal sampling time at surface, mid-depth, and near bottom. From the start of routine sampling through the end of March, collections will be made during daylight within I hour of low slack tide using 0.202 mm mesh nets. For the remainder of the season, collections will be made at night with 0.333 mm mesh nets during the second half of a flood tide. Sampling will continue at each station until no larvae are found or they are collected in low densities (<30 per 500 m3 ). This sampling design is based on the results of several years of sam 31ing and is structured to maximize the catch oflarvae. ne sampling schedule may be modified c ue to adverse weather.

Post larval Juvenile Studies in Niantic River and Hay: Post larval winter flounder in the Niantic River will be sampled weekly beginning when most larvae have metamorphosed to demersaljuveniles (usually late May) at two stauons (LR and WA in Fig. 3). These data will be used to monitorjuvenile abundance and to estimate the mortality rate during inis post larval period.

l~ Four tows of a 1-m beam trawl (two replicates with each of two successive mesh sizes) will be

! made during the day within a period extending from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> before to I ho.ir after high tide.

Depending upon weather and wind conditions. similar sampling on the san re date will also be

- conducted in Niantic Bay at stations BP and RM (Fig. 3). The latter two s;ations will be sampled either before or after the stations in the river, de 3ending upon the time of sunrise or sunset in relation to high tide. Collections at a station wil . cease at the end of September or when the mean

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4 density of young winter flounder is less than 1 per 100 m2 for two consecutive weeks.

Specimens Supplied for Research Depending upon his needs NUSCO will continue to supply biweekly as many as 40 adult winter flounder to Dr. Larry Renfro for physiological research at the University of Connecticut. NUSCO may also cooperatively supply limited numbers of fish or invertebrates for researth needs at the Umversities of Connecticut and Rhode Island, Wesleyan University, the National Marine Fisheries Service, and other legitimate scientific or educational institutions.

-BENTHIC STUDIES Subtidal and Intertidal Sand Study The subtidal and intertidal sand programs have been designed to assess the potential impact of construction and operation of hiNPS on the localinfaunal communities. To meet the objectives, samples will be collected four times a year (March, June, September, and December) at four

, subtidal and three intertidal stations (Fig. 4a). Station locations are as follows: Giants Neck L

subtidal and intenidal, Intake subtidal, Effluent subtidal, Jordan Cove subtidal and intertidal, and -

White Point intertidal. Ten replicates will be taken at each station with a 10 cm diameter corer to a i 5 cm depth to describe density and distribution of the dominant forms. The samples will be fixed with buffered fonnalin for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, stained with rose bengal, sieved through a 0.5 mm mesh screen, and stored in 70% ethanol. The organisms retained by the screen wil.. be soned from debris, identified to the lowest practical taxon, and enumerated.

Intertidal Rocky Shore Study The objectives of this program are to characterize the rocky intertidal areas in the vicinity of MNPS in terms of the attached algae and sessile invertebrates, and to determine if differences in abundance or distribution of these intertidal species could be attributed to the operation of MNPS.

The monitoring program will include qualitative algal collections, percentage cover estimates of intertidal organisms, measurement of community recolonization, and ;rowth studies of Fucus vesiculosus and Ascophyllum nodosum. Rocky shore study sites are located as follows: Giants Neck, Bay Point, Millstone Point, Twotree Island, Fox Island Exposed, Fox island - Sheltered, White Pomt,' and Seaside (Fig. 4b).

Quantitative and qualitative collections will be made at least bimonthly at all stations except Twotree Island, where only qualitative collections will be made. Each quantitative collection will consist of sampling pennanently marked undisturbed strip transects (5 per station) that run from mean high to mean low water levels, and are divided into 0.5 x 0.5 m quadrats. The pe centage of all organisms and remaining free space in each quadrat will be estimated. At each of four sites (Giants Neck, Fox Island - Exposed Fox island - Sheltered, and White Point), thrre similar transects (recolonization strips) that were dent;ded by burning and scraping in March 1991 will be sampled until rates and pattems of community recovery under three unit operating conditions have been detennined.- Qualitative algal collections will be made from the transect area and habitats not sampled quantitatively (e.g., tide poo s, crevices, and sublittoral fringe). Inclusion of these micro-habitats will allow us to charactenze 'he rocky shore sites in tenns of the species and developmental stages found at each sempling time.

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At three rocky shore sites (Giants Neck, Fox island, and White Point), populations of Ascophylhun nodoswn (a large perenn?al brown alga) will also be monitored. At each site,5 tagged growing tips on each of 50 tagged plants will be measured from the top of the most recently fomied vesicle to the apex. We increase in length over time will be a measure of growth, and the pattem of loss of tagged tips and plants will be a measure of mortality. Growth of Fucus resiculosus, another perennial brown alga, will be monitored at four rocky shore sites (Giants Neck, Fox Island Exposed, Fox island 7Sheltered, and White Point). At each site,18 permanently marked 20 x 20 cm areas (six each in high, mid, and low intertidal zones) will be sampled bimonthly. Nine of these areas at each site (three in each rene) are protected from grazing and predation by stainless steel mesh exclusion cages. If Fucus thalli are present in caged or control areas, the 20 longest plants will be measured from the holdfast to the tip.

Exposure Panels The objectives of this study are to quantify the abundances of wood boring species in the Millstone area and to relate these abundances to wood loss from exposure panels. Standardized pine panels (25.4 x 9.5 x 2.0 cm) will be placed at five dock sites in the Millstone ana and at three sites of increasing distance from the Millstone Quarry Cuts: White's dock at White Point (WP); the Northeast Utilities Environmental Laboratory dock next to Fox Island (FI); the MNPS Quarry effluent (EF); Fredrick's dock at Black Point (BP); llarcke's dock at Giants Neck (GN); and at 100,500, and 1000 m from the Quarry Cuts (Fig. 4c).

At each dock site, a set of six replicated panels (25.4 X 9.5 cm) will be de aloyed in February, May, and August. Panels will be retrieved after 6 months of exposure anc. processed. The density of Limnoria spp. and Chelura spp. (number per panel) and the percentage of panel surface excavated by their activity will be assessed for each panel. The number of shipwonus per panel will be estimated from the examination of radiographs; the percentage loss of wood will be estimated by companng retrieved panel weights to those obtained before deployment. The identification of shipwomis in each panel will be accomplished by splitting the panels and removing individuals for examination. At the 100,500, and 1000 m sites, panels will be deployed in May and in October for exposure periods of five and seven months, respectively. These par els will be processed only for the identification and enumeration of shipworms.

This proposed program incorporates a single change. This year it is proposed to delete the sections of this program that deal with the identification, enumeration, and detennination of the percentage of substratum covered by fouling organisms such as barnacles, mussels, bryozoans, and algae.

Justification for this change is presented in Attachment 1.

Lobster Population Dynamics The lobster study is designed to assess the potential effect of MNPS on the lobster population in the Millstone Point area. The study area will include the nearshore coastal region surrounding Millstone Point, Three stations (Intake, Jordan Cove, and Twotree Island) have been established near rocky outcrops (Fig. 4d). Lobsters will be collected from May through October using 20 wire lobster traps at each station. Tra ps will be hauled on Monday, Wednesday and Friday, weather pemiitting. On v eeks with holic ays, pots will be checked on the first and last working days of the week. Imbsters will be tagged with serially numbered sphyrion tags. Carapace length, sex, crusher claw position, missing claws, and molt stage will be recorded for each lobster. Recaptured lobsters will be released after recording the tag number and the above infonnation.

Lobster larvae will be sampled during their period of occurrence (usually from May through July) at the discharge of Unit 1,2, or 3 (station EN in Fig.1). Samgles will be taken using a 1.0 x 6.0-m conical plankton net (1-mm mesh) that filters about 4,00() m of water during a typical l

4 collection. De sample volume may be reduced when plankton or detritus is abundant or when the number of circulating water pumps has been reduced. Four day and four night samples (total of i

- eight) will be collected each week.

Eelgrass Study he objective of this study is to estimate the above ground standing stock of eclgrass in Jordan Cove and the Niantic River. %ese data will augment results of previous studies, indicate any increase or decrear.c in the size of the beds, and allow evaluation of potential impacts due to MNPS operation. Two study sites (JC, WP) are located in Jordan Cove and one (NR) un the Niantic River (Fig. 4d). Average blade length, biomass, and plant density estimates will be made in June, July, August, and September. These months were selected because they represent periods of peak l biomass. In each month, sixteen replicates (25 x 25 cm quadrats) will be tacen at the three study l sites.

MISSING SAMPLES  ;

On rare occasions, a sample may not be available for laboratory processing (e.g., sample container

- was broken or sample was spilled) or sampling gear deployed in the field (e.g., lobster pots or exposure ?anels) was lost or damaged. Such incidents, however, represent an insignificant fraction of the overall sampling effon for any program and the loss of data has not and will not '

affect the conclusions made as a result of any pamcular study.

REPORT SC11EDULE  ;

- Nonheast Utilities Service Company, acting as agent for Nonheast Nuclear Energy Company, will submit annually on April 30 a detailed report of ongoing biological studies. This trpon will include summaries of data from the monitoring programs and comprehensive analyses of temporal

- and spatial variation of marine communities.

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Table 1, Planned distribution of sampling effort for monitoring entrained and offshore ichthyoplankton. l l

l Number of sample 4 per week for entrainment ichthyoplankton J F M A M J J A S O N D l

collected: ID,1N ID,1N 4D,4N 4D,4N 4D,4N 3D,3N 3D,3N 3D,3N 3D,3N ID,1N ID,1N ID,1N iutsd forlanw: all all all all all ID,1N all all all all all all for eggs: none none none 3D,3N 3D,3N all all all all none none none Numter of offshore ichthyoplankton samples collected per week and processed for lanz only J F M A M J J A S O N D le ID,1N biweekly >l< 2D,2N weekly >l< ID,1N biweekly >l l

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Attachment 1 It is proposed to delete the sectiors of the Exposure Panel Program that deal with identification, enumeration, and determination of percentage of substratum covered by fouling organisms (e.g., barnacles, mussels, bryozoans, algae).

Reasons for chance Present sampling methodology ir.corporates three,6-month exposure periods: Feb-Aug, May-Nov, and Aug Feb. %cse exposure periods encompass the entire year, and overlap during the period of petk annual settlement and growth of shipworms. Based on 7 years of sampling prior to 1989, when the methodology included a Nov May exposure period, it was determined that the highest coverage by surface foulers typically ocrurred Nov-May and Feb Aug, mrresponding to the peak settlement periods of mussels and several species of barnacles and al;ac. It was also determined that littic or no correlation could be found between identity or abundance of surface foulers and the density of woodborcrs.

The lack of a relationship between surface foulers and we,.'dborers in our study is largely explained by the sampling design; e.g., a fouling species that settles primarily around March or April can have no effect on a panel that is exposed from May-Nov or Aug Feb. Species with different settlement periods (e.g.,

Semibalanus balanoides and Teredo navalis) do not compete with each other on our panels.

Examples of the relationships, or lack thereof, between surface foulers and woodborer abundance or actMty, are illustrated in Figure 1. Figure la shows the average percentage of cover for sessile fouling organisms on exposure panels collected between 1979 and 1990 at the ambient water dock sites, Figure Ib shows the average numerical abundance of Teredo navalis in the same pancis, and Figure le shows the resulting wood-loss. Not surprisingly, Figures Ib and Ic are very similar, excepting the Feb-Aug exposure period when the woodborers are recently settled juveniles, and do not acmunt for much wood-loss.

Similar comparisons with Figure la are inconsistent; for example,in May Nov of 1979 at Giants Neck, more than 60% of the panel surfaces were mvered by fouling organisms, yet these pancis npported high densities of Teredo (almost 300 indMduals/ panel). However, during the same exposure period at White Point, pancis with virtually identical degrees of surface fouling supported an unusually low number of shipworms (less than 50 indMduals/pancl).

Here is an apparent inverse relationship between total fouling (high at Fox island and Black Point, lower at White Point and Giants Neck) and woodborer attack (Iow at F1 and BP, higher at WP and GN).

However, this correlation does net imply causality; rathct, trends in woodborer abundance are attlibuted to the building materials used in nearby docks. Teredo densities are high at WP and GN (where docks are supported by untreated oak piles), and lower at F1 and BP (where piles are treated with copper chcomated arsenate (CCA) preservative). Throughout the study, variability in woodborer abundance has been attributed more to physical (e.g., severe winters, availability of wood) and intrinsic biological (e.g.,

fecundity, resistance to disease, larval mortality) factors than to settlement inhibition caused by interactions with foaling organisms.

He 6-month exposure periods used by the Exposure Panel Program do not typically permit development of mature fouling communities; characterization of such communitics is not an objective of the Program.

The process of colonization by marine plants and animals is assessed by another facet of the monitoring program, i.e., the reco!onization studies in the Rocky Intertidal prograta.

The data acquired from analyses of superficial fouling species on exposure panels are not needed to fulfill the objectives of the Exposure Panel Program, f.e., to quantify the abundances '.,f wood. boring species in the Millstone area, and to relate thse abundances to wood. loss from exposure panels. Based on abo e information we request approval of our proposal to delete the analyses of surface foulers on panel surfaces from the Exposure Panel Program.

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