BECO-88-028, Marine Ecology Studies Related to Operation of Pilgrim Station Semiannual Rept 31,Jan-Dec 1987
| ML20153B699 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/31/1987 |
| From: | Richard Anderson, Bird R BOSTON EDISON CO. |
| To: | MASSACHUSETTS, COMMONWEALTH OF |
| References | |
| BECO-88-028, BECO-88-28, NUDOCS 8805060062 | |
| Download: ML20153B699 (378) | |
Text
l marine ~ ecology /tudw Reloted to Operet. ion ofPilgrim./totion SEMI ANNUAL REPORT NUMBER 31 i JANUARY 1987 DECEMBER 1987 i_
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I MARINEEC0LOGYSTUDIES RELATEDTOOPERATIONOFPILGRIMSTATION SEMI-ANNUALREPORTN0.31 REPORTPERIOD: JANUARY 1987 THROUGH DECEMBER 1987 DATEOFISSUE: APRIL 30,1988 Compiled and Reviewed by: , #~
n ar ne heries Biologist ton d ,p 25 Braintree Hill Office Park Braintree, Massachusetts 02184
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TABLE OF CONTENTS .l SECTION : . . , .
I
SUMMARY
(7 5?
II INTRODUCTION MQ..J 4 %, - ;.
III MARINE BIOTA STUDIES PCN p ::% J IIIA Marine Fisheries Monitoring and Impact Ti-l.'
~-
IIIA.1 Annual Report on Monitoring to Assess Impact of the Pilgrim M-Nuclear Power Station on the Marine Fisheries Resources of W "? f-Western Cape Cod Bay, January - Decemoer 1987 (Characteriza- [<fki tion of Fisheries Resources) - (Mass. Dept. of Fisheries, V ,:" . '
Wildlife and Environmental Law Enforcement; Division of dg))
Marine Fisheries) fTy
?.bh.4 IIIA.2 Annual Report on Monitoring to Assess Impact of the Pilgrim ::ge;gl Nuclear Power Station on the Marine Fisheries Resources of j%r/
Western Cape Cod Bay, January - December 1987 (Impact on A 9'S Fisheries Resources) - (Mass. Dept. of Fisherles, Hildlife p i, f and Environmental Law Enforcement; Division of Marine Sc , 3 Fisheries) S? Q u .-Q IIIB Benthic Monitorinc and Imoact q'k i
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IIIB.1 Benthic Algal and Faunal Monitoring at the Pilgrim Nuclear E Pcwer Station, January - December 1937 (Characterization of 'a M Benthic Communities) - (Battelle New Englano Research Lab) 4. ,8C c w IIIB.2 Benthic Algal and Faunal Monitoring at the Pilgrim Nuclear ' . iM
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Power Station, January - Decemoer 1987 (Impact on Benthic -
Communities) - (Battelle New England Research Lab) 4 Cj
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IIIC Plankton Monitoring and Impact IIIC.1 Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station, January - December 1937 (Results) - (Marine Research, Inc.)
IIIC.2 Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station, January - December 1987 (Imca.t Perspective)
- (Marine Research, Inc.)
IIID Imcingement Monitorinc and Imcact Inc!ngennt ;f Organisms at Pilgrim Nuclear Power Station: January -
Decemaer 1937. (Bostoa Edison C xca y)
IV FISH SURVEILLANCE IVA Oserfliants S u r.ru ry R e c e r t - Fish Scotting Overflights in Western Cape Cod Bay in IF (Sci:On Edis: 1 C:r,c a y ,'
V Minutes of Meeting 68 of the Acministrative-Technical Committee, Pilgrim Nuclear Power Station ii
SUMMARY
Highlights of the Environmental Surveillance and Monitoring Program re-suits obtained ovcr this reporting period (January - December 1987) are presented below. (Note: Pilgrim Station was in an outage from early l
April 1986 through December 1987, so data reflects a control situation for 1987, with no thermal influence on aquatic resources. For the period liarch - August 1987 no circulating seawater pumps were operating).
Marine Fisheries Monitoring:
- 1. In the April-November 1987 shorefront sportfish survey at Pil-grim Station, an estimated 1,250 angler visits accounted for 300 fishes caught. Cunner (56%), winter flounder (22%) and bluefish (11%) dominated the sportfish catch. The lack of a thermal component during the 1987 Pilgrim outage resulted in a much reduced sportfishery success rate, as occurred in 1986 and other outage years covering the shorefront angling season.
- 2. Pelagic fish mean CPUE (Catch Per Unit Effort) for 1987 at the gill net station (189.6 fishes / set) increased 90% from 1986 when 99.6 fishes / set were taken. Northern sea robin (35%),
pollock (20%) and Atlantic herring (17%) were 72% of the total catch. Pollock catch rate was similar from 1986 to 1987 while northern sea robin and Atlantic herring increased substan-tially. A significant positive correlation was found for cun-ner catch and Pilgrim Station operational output (thermal loading to the e nv i ronr.<n t ) for 1973-1983, 1985. A general attraction to the thermal discharge appears to exist for tautog.
1-1
- 3. Shrimp trawl catch for 1987 recorded 30 benthic fish species with winter flounder (34%), little skate (30%) and windowpane (16%) composing 80% of the total. Mean CPUE for all species was 25.3 at the discharge surveillance station, 28.2 (highest) at the intake surveillance station and 22.9 (six less than in 1986) for all stations pooled in 1987. The presence of sub-stantially larger numbers of small winter flounder caught in the intake embayment, compared to the other stations each year, suggests its attraction as a possible nursery area. Winter flounder abundance in spring, summer and fall, at the intake surveillance station, was much greater than at the discharge and reference stations. Young-of-the-year Atlantic cod were unusually abundant, being caught in greatest numbers in the PNPS intake embayment, also.
- 4. Adult lobster mean monthly catch rate per pot haul, in May -
October 1987, was 0.33 lobsters which is 57% less than the 1986 rate (0.77) . The surveillance area (thermal plume) catch rate was 0.34 while the reference area (control) was 0.20. The sea-sonal, legal lobster catch rate since 1970 has not been signi-ficantly lower in the thermal plume area than in control areas. A significant negative correlation was noted between legal lobster catch for thermal plume areas and mean annual Pilgrim Station output for the period from 1973 - 1983, 1985.
The lobster research study, which commenced in 1986, identified two parameters to assess PNPS impact when the Station resumes operation - comparative areas for legal catch rate and size frequency comparisons.
I-2
- 5. In May -
November 1987 fish observational dive surveys, 7 species were observed in the thermal plume area. Cunner (79%), pollock (14%) and tautog (2%) were the most numerous species seen, pollock being most abundant in the direct path of the Pilgrim discharge current. Total number of fishes observed decreased 65% from 1986 to the lowest point of the study. Most fishes were in greatest concentrations at stations in the dis-charge zone (45%), followed by the control zone (36%) and the stunted zone (19%). These results are similar to 1984 (also an outage year with a minimal discharge current) when most fish were observed relatively evenly divided between discharge and control zones, but unlike normal discharge current years when fish seem 6.0 greatly favor being in the path of the effluent.
- 6. Atlantic silverside accounted for 78% of the 1987 haul seine (shore zone) fish catch with a total of 29 species collected.
The PNPS intake showed the greatest species diversity, and seine catches were highest overall in August and September.
Fish captured in the PNPS intake embayment (second in CPUE to long Point) were dominated by blueback herring and sand lance spp., and included Atlantic silverside and alewife among the more numerous species. A deeper seine net (10' compared to 6'), to more effectively sample the intake, was utilized beginning in 1984 and results have indicated this area is more similar in fish f auna attraction to an estyary than exposed coastal areas.
1-3
Impingement Monitoring:
- 1. The mean January - December 1987 impingement collection rate was 0.28 fish /hr. The rate ranged from 0 fish /hr (April) to 1.96 fish /hr (December) with rainbow smelt comprising 27.7% of the catch, followed by Atlantic silverside 18.2%, cunner 9.%,
lumpfish 6.8% and winter flounder 6.8%. Fish impingement rates in 1985 and 1986 were several times higher than in 1984 and 1987 when Pilgrim Station outages had both circulating water pumps off for considerable periods of time.
(
- 2. In January and December 1987, rainbow smelt impingement ac-counted for 85.4% of this species collected. They have been one of the most abundant species impinged on an annual basis at Pilgrim Station, predominating in 1978 and 1987.
- 3. The mean January - December 1987 invertebrate collection rate was 1.61/hr with the blue mussel, sand shrimp and polychaete worms accounting for 71.8%, 7.9% and 4.5% of the enumerated catch, respectively. No American lobsters were sampled, and the invertebrate impingement rates in 1985 and 1986 were similar to that recorded at Pilgrim Station during the 1987 outage year, despite lower circulating water pump availability.
- 4. Impinged fish, initial survival at the end of the Pilgrim Sta-tion intake sluiceway was approximately 29% during static screen washes and 43% during continuous washes. Five of the dominant species shcwed greater than 50% survival, overall.
I-4 L. _
tEith Surveillance:
Fish overflights in 1987 spotted four of five major species categories: -herring, Atlantic menhaden, Atlantic mackerel and baltfish. Two sightings of fish -in the nearfield Pilgrim vicinity were made. On June 21, 18,000. pounds of menhaden and on October 19, 105,000 pounds of Atlantic herring were observed near Pilgrim Station, but these occurrences were not reported to -regulatory authorities as the Station was in an outage condition with no thermal plume present. From 1985 - 1987 there have been no observations of pollock.
Benthic Monitoring:
- 1. One new species of invertebrate was added to the list of biota for PNPS benthic surveys as a result of analysis of the 1987 samples. This was a bivalve, Hiatella striata.
- 2. A significant difference in species richness existed between the Effluent and Reference stations based on results of the fall 1987 sampling. The reference stations, which have charac-teristically ranked ahead of the Effluent station in species numbers, appeared more similar to each other than to discharge area.
- 3. Review of overall faunal community structure, via cluster an-alysis, showed that the Effluent Station has a low degree of similarity compared with the reference stations. Faunal clus-terings and algal community overlap values, although somewhat I-5
consistent with past observations, are beginning to show gener-al recovery of community structure at the Effluent site when compared with reference sites.
- 4. The warm-water species, Gracilaria tikvahtae, decreased in the area of the Effluent station during 1986 and was completely e
absent in 1987, after it had normally colonized in 1985. It was also rare in 1984, indicating a direct relationship to the lack of thermal effluent in 1984, 1986 and 1987. Additional evidence of PNPS impacts in the Effluent discharge zone was the prevalent appearance of the cold-water alga, Laminaria, in the Effluent area during 1984 and 1987 transect mappings.
.5 . Four observations of the near-shore acute impact zones were performed during this reporting period. Some changes in the size and shape of the denuded and stunted zones were detected as a result of the 1987 surveys as a result of the PNPS shut-down. These surveys noted a greatly decreased near-field im-pact area in June, possibly due to a virtual stoppage in cir-culating water pump operation for the period March - June, re-sulting in negligible discharge current flow. Evidence of a lagged return to PNPS-induced scouring impacts was realized in the fall when circulating pump operation resumed in September 1987. Approx 1rrately six to nine months is the observed time frame of response to the thermal effects of PNPS operation by Chondrus in the immediate discharge vicinity (within 95 meters of the discharge canal).
I-6
Entrainment Monitoring:
- 1. A total of 36 species of fish eggs and/or larvae were found in the January - December 1987 entrainment collections (20-eggs, 33-larvae).
- 2. Seasonal egg collections for 1987 were dominated by Atlan- ,
tic cod and winter flounder (winter - early spring); mack-erel, rock 1tng, labrids and searobins (late spring - early summer); hake, reckling, labrids, windowpane and cod (late summer - autumn).
- 3. Seasonal larval collections for 1987 were dominated by rock gunnel and sculpin (winter - early spring); winter floun-der, seasnall, menhaden, tautog, reckling and silversides (late spring - early summer); hakes, windowpar,e, reckling and tautog (late summer - autumn).
- 4. No lobster larvae were collected in the entraintrent samples for 1987, and only nine have been sampled from 1974-1987.
- 5. In 1987 an estimated 3.440 x 109 fish eggs and 4.787 x 10 7 fish larvae were entrained at Pilgrim Station, assuming full flow capacity of all seawater pumps. On an annual basis, eggs were dominated by the labrid - Limanda group and Atlantic mackerel, and larvae by seasnall, sculpin and rockling.
I-7
- 6. Total numbers of fish larvae collected for similar volumes of water sampled, in spring and summer 1984 and 1987, were lower than for the same periods in all other years. These results were shown to be significant wtth the fact that both Pilgrim Station circulating water pumps were offline during most of the spring / summer period 1984/1987, but at least one circulating water pump was operating during this period in other years. l
-i i
i I-8
INTRODUCTION
.A Scope and Objective This is the thirty-first semi-annual report on the status and results of the Environmental Surveillance and Monitoring Program related to the op--
eration of Pilgrim Nuclear Power Station (PNPS). The monitoring programs di.scussed in this ~ report relate specifically to the Cape Cod Bay ecosystem with particular emphasis' on the Rocky Point area. This is the nineteenth semi-annual report in - accordance with the environmental monitoring and reporting requirements of the PNPS Unit 1 NPOES Permit from the U.S.
Environmental Protection Agency (#MA0003557) and Massachusetts Division of Water ' Pollution Control (#359). A multi-year (1969-1977) report in-corporating marine fisheries, benthic, plankton /entrainment and im-pingement studies was submitted to the NRC in July 1978, as required by the PNPS Appendix B, Tech. Specs. Programs in these areas have been con-tinued under the PNPS NPDES permit. Amendment #67 (1983) to the PNPS
. Tech. Specs. deleted Appendix 8 non-radiological water quality require-ments, as the NRC felt they are covered in the NPDES Permit.
l l The objectives of the Ervironmental Surveillance and Monitoring Program are to determine whether the operation of PNPS results in measurable ef-l fects on the marine ecology and to eva'uate the significance of any ob-l l served effects. If an effect of significance is detected, Boston Edison l
C0mpany has committed to take steos to correct or mitigate any adverse tituation.
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These studies are guided by the Pilgrim Administrative-Technical Committee (PATC) which was: chaired by a member of the Mass. Division of Water Pollution Control in 1987, and whose membership includes representatives from the University of Massachusetts, the Mass. Division .of Water.
Pollution Control, the Mass. Division of Marine Fisheries, the National Marine Fisheries Service (NOAA), 'the U.S. Bureau of Sport Fisheries and Wildlife, the U.S Environmental Protection Agency and Boston Edison Company. : Copies of the minutes of the Pilgrim Administrative-Technical Committee meetings held during this reporting period are included in Section V.
B. Marine Biota Studies
- 1. Marine Fisheries Studies i
A modified version of the marine fisheries monitoring, initiated in 1981, is being conducted by the Commonwealth of Massachusetts, Division of Marine Fisneries (DMF).
The occurrence and distribution of fish around Pilgrim Station and at sites outside the area of water temperature increase are being mon-itored. Pelagic species were sampled using gill net (1 station) col-lectictns (Figure 1) made at monthly intervals. In 1981, shrimp trawling and haul seining were initiated to provide PNPS impact-related samoling of centhic fish and shore :'one fish, respectively.
5hrimo trawling was done twice/ month at 1 stations (Figure 2) and Saul seining twice/ month during June - November at 5 stations (Figure 1).
II-2
a- ,
Monitoring'is. conducted of ~ local lobster stock catch statistics for ,
areas off Rocky:and Manomet Points (Figure 4). Catch statistics are collected approximate'< y weekly: throughout' the fishing- . season L -(April-October).
A finfish observational dive program was i ni t_l ated in ' June 1978.
~ SCUBA gear is utilized : on- biweekly dives from May-October ' (weekly mid-August to mid-September) at 6 stations (Figure 2) in the- PNPS thermal plume a'rea.
In 1986, an experimental, lobster pGt trawl monitoring effort was initiated to eliminate any biases associated with the collection of lobster stock catch statistics in determining PNPS effects. Ten 5-pot lobster trawls 'were fished in the thermal plume and control-areas around PNPS during 1987 (Figure 3 ).
Resuits of the marine fisheries monitoring and impact analysis during the reporting period are presented in Sections IIIA.1 and IIIA.2.
- 2. Benthic Studies The benthic monitoring described in this report was conducted by l Battelle New England Marine Labs, Duxbury, Massachusetts.
The benthic flora and fauna were samoled at tnree locations at depths I of 10 feet (MLH) (Figure 1). Quantitative (rock substratum) samples I were collected, and the dominant flora and fauna in each plot were recorded. Sampling was conducted two times per year (March and II-3 i
? :
, LJ Septemb'er) : to determine biotic changes, if -any. . Transect sampling -
~1 o off the discharge canal to ' determine 'the extent of .the' denuded and- l
~
stunted zones was conducted four times a year (March, June, Setpember ;
l and December). Results_ of the benthic surveys and impact analysis during this period are discussed in Sections IIIB.1 and IIIB.2.
- 3. Plankton Studies Since August 1973, Marine Research, Inc. (MRI) of Falmouth,-
> Massachusetts, has been monitoring entrainment in Pilgrim Station-cooling water of fish eggs and la vae, and lobster -larvae (from
' 1973-1975 phytoplankton and zooplankton were -also studied). Figure 5-shows the entrainment contingency sampling station locations to be sampled should 'the numbers of eggs / larvae entrained greatly exceed recorded historical averages. Information generated through this monitoring has been utilized to make periodic modifications in the sampilng program to more efficiently address the question 'of the ef-fects of entrainment. These modifications have been developed by the contractor, and reviewed and approved by the Pilgrim A-T Committee on the basis of program results. Plankton monitoring in 1987 emphasized consideration of ichthyoplankton entrainment. Results of the ichthy-oplankton entrainment moni toring and impact analysis for this re- i porting period are discussed in Sections I!IC.1 and IIIC.2.
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4 Ampingement Studies-
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The Pilgrim I impingement monitoring and- survival program speciates, quantifies and determines viability of the organisms carried onto the four' intake traveling screens. Since January 1979, Marine Research, m
Inc. has been conducting impingement sampling with results being re-ported on by Boston Edison Company.
A new screen wash sluiceway system was installed at Pilgrim in 1979 at a total cost of approximately $150,000. This new sluiceway system was required by the U.S. Environmental Protection . Agency and the
-Mass. Division of Water Pollution Control as a part of NPDES Permit
- MA0003557. Special fish survival studies conducted from 1980-1983 to detercine its effectiveness in protecting marine life were - ter-minated in 1984, and a final report on them appears in Marine Ecology -
Semi-Annual Report #23.
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l Results of the impingement monitoring 3nd survival program, as well as impact analysis, for this reporting period are discussed in Section IIID.
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- C. Fis:1 Surveillance Studies l
March - November, weekly fish spotting overflights were conducted as part of a con:inuirg effort to monitor the times when large concentrations of i,
l fisn mignt be excected in the Pilgrim vicinity. Regularly from May-October since 1978, dive inspections have been conducted of the Pilgrim II-5 l
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. discharge canal in order to evaluate fish barrier net durabili ty, .and L
. effectiveness in excluding fishes from the discharge canal. .
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I The annual summary report on fish overflights for 1987 is presented in j l s Section IVA'. Barrier net inspections were not performed in 1987 as
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Pilgrim Station was in an outage the whole year, and the net has been #
I removed from the discharge canal since August, l986.
l h D. Station Ooeration History i l -- <
l The daily average, reactor thermal power levels from January through December, 1983-1987 are shown in Figure 6. As can be seen, PNPS was in an outage during the 1987 reporting period; however, environmental mon-ltoring programs were performed to obtain control data for impact com-parison with past and future high operational years.
I E. 1988 Environmental Programh '
A planning schedule bar chart for 1988 environmental monitoring programs i
related to the operation of Pilgrim Station, showing task activities and I
milestones from December 1987 - June 1989, is included as Figure 7.
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ANNUAL REPORT ON MONITORING TO ASSESS IMPACT OF PILGRIM NUCLEAR POWER STATION ON MARINE FISHERIES RESOURCES OF WESTERN CAPE COD BAY (CHARACTERIZATION OF THE FISHERIES RESOURCES) Project Report No. 44 (January-December, 1987) l (Volume 1 of 2) By Brian C. Kelly, Vincent J. Malhoski, l Robert P. Lawton and Mando Borgatti i April 1, 1987 Massachusetts Department of Fisheries, Wildlife, and Environmental Law Enforcement Division of Marine Fisheries 100 Cambridge Street l Boston, Massachusetts 02202 l l l l
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-TABLE OF. CONTENTS
( u, LSection Page I; , EXECUTIVE
SUMMARY
- 1
'I I . INTRODUCTION 2 I-II. METHODS AND MATERIALS 3 JIV . . RESULTS AND: DISCUSSION 14:
A. Hydrography 14
- 1. Water Temperature 14
- 2. Salinity 16 B. Fisheries 17-
- 1. Commercial Lobster Pot-Catch Fishery 17
- 2. Research Lobster Trap Sampling Program 19 l 3. Nearshore Benthic Finfish 22
- 4. Pelagic and Benthi-Pelagic Fishes 33
- 5. Shorezone Fishes 40 l -
l 6. Underwater Finfish Observations 46 l
- 7. Sportfishing 48 V. CONCLUSIONS 50 VI. ACKNOWLEDGEMENTS 54 l
- VII. LITERATURE CITED 55 l
l t 11 l
LIST OF TABLES Table Page i
- 1. Expanded catch and percent composition of 23 groundfish captured by bottom trawling at four stations in the vicinity of Pilgrim Station, January-December, 1987.
- 2. Checklist of finfish species (following 24 classification of Robin et al. 1980) collected or observed in the adjacent waters of Pilgrim Station, 1987.
- 3. Bottom trawl catch data for dominant groundfish 28 in the vicinity of Pilgrim Station, January-December, 1987.
- 4. Number and percentage composition of celected 33 i finfish species captured by gillnet (7 panels of 3.8-15.2 cm mesh) in the vicinity of Pilgrim Nuclear Power Station, January-December, 1987.
- 5. Shore-zone fishes captured by haul seine at 41 four stations in the vicinity of Pilgrim Nuclear Power Station, June-November, 1987.
- 6. Shoro-zone fiches captured by foot-seine at six 45 stations in the environs of Pilgrim Nuclear Power Station, June-November, 1987.
1
- 7. Abundance and distribution of all species observed 46 during underwater observations at Pilgrim Nuclear Power Station, May-November, 1987.
I l l iii ) l I
LIST OF FIGURES [ .Fisture Eage
- 1. Lobster pot sampling grid for marine fisheries 4 studies.
- 2. Location of experimental lobster gear (5-pot 6 trawls) for Marine Fisheries studies.
- 3. Location of shrimp trawl and dive sampling 8-stations for' Marine-Fisheries studies.
- 4. Location of beach seine and gill net sampling' 10 stations for Marine Fisheries studies.
- 5. Bottom- water temperatures (ambient) recorded 15 in the environs of Pilgrim Station during spring, 1983-1987.
- 6. Monthly lobster catch per trap-haul and percent 18 ovigerous females in the Pilgrim area, 1987.
- 7. Size distribution of lobster captured in the 21 research trap fishery in the Pilgrim Station area, 1987.
- 8. Seasonal mean trawl catch ratec for winter 29 flounder by station in Pilgrim area, 1987.
t I 9. Seasonal mean trawl catch rates for little 31 l skate by station in Pilgrim area, 1987. i 10. Seasonal mean trawl catch rates for windowpane 32 by station in Pilgrim area, 1987.
- 11. Indices of relative abundance (catch-per-unit- 34 effort) for pooled finfish species captured in wastern Cape Cod Bay near Pilgrim Station based on standardized gi]l net gear.
L 12. Indices of relative abundance (catch-per-unit- 36 ! effort) for pollock captured in western Cape Cod Bay near Pilgrim Station based on standardized gill net gear (5 panels of 3.8-89 cm mesh) and procedures, 1971-1987. l l '13. Indices of relative abundance (catch-per-unit- 38 l effort) for Atlantic herring captured in j western Cape Cod Bay near Pilgrim Station based I on standardized gill net gear (5 panels of 3.8-89 cm mesh) and procedures, 1971-1987. ! iv i
- 14. Indices of relative abundance (catch-per-unit- 39 effort) for cunner captured in western Cape Cod Bay near Pilgrim Station based on standardized gill net gear (5 panels of 3.8-89 cm mech) and procedures, 1971-1987.
V
f I. EXECUTIVE
SUMMARY
A modified version of marine fisheries monitoring, initiated in 1981, was conducted by the Massachusetts Division of Marine f Ficheries. Data on the occurrence, distribution, and relative cbundance of finfish and lobster were collected according to a ottndardized sampling scheme to identify trendo and relationships in the study area over time. We directed our efforts to conmercially and recreationally important fisherico resources. Palagic finfish were sampled using gill net collections. Near-l shore bottom trawling and haul seining sampled benthic and shore zone fish, respectively. Monitoring of the local commercial lobster stock catch statistics for areas off Rocky Point was conducted during the inshore lobster season. Experimental lobster pot trawling, also conducted, eliminated any biases l associated with the collection of lobster stock catch statistics. l A finfish observational dive program and a sportfishing creel l survey rounded out the investigations. Catch rates in the Pilgrim area declined from 1986 to 1987 for the top three groundfish (winter flounder, little skate, and I windowpane) The gill net catch of cunner was at its trawled. lowest level of the entire survey, while pollock catch has been quite similar for the last four years. By contrast, the seine catch rates of Atlantic silverside, juvenile river herring (blueback herring and alewife), and sand lance were up from last year. Overall, fish sighted in the diving study was at its l lowest point of the study. Sportfish catches were extremely low l relative to past records. ," l l
l INTRODUCTION II. Environmental monitoring was conducted in 1987 by the
]
Massachusetts Division of Marine Fisherica in an ongoing effort to assess plant-related impact of the Pilgrim Nuclear Power Station on marine resources in western Cape Cod Bay, under Purchase Order No. 63644 to Boston Edison Company. Data on the occurrence, distribution, and relative abundance of finfish and lobster were collected throughout the year following a standardized sampling scheme. Analysea included measuremento, counts, percentages, and indices which were used to identify i trends and relationships in the data throughout the study area over time. Volume 1 is a characterization of fisheries' resources in the Pilgrim area. This report highlights reaults of pertinent findings and discernmenta in a reduced overview of sorts, departing from the former format. Detailed analyses including statistical information and supportive data with complete reaulta are available from the Division of Marine Fisherica and will be supplied upon request. Only essential information la presented in order that the volume of material be substantially reduced. The reporting of environmental studies has evolved in a series of steps from a progress report which included much raw data to an exhaustive scientific report, to the present condensed format. Our intent was to condense subject matter but maintain clarity and precision of data reporting and interpretation. We have endeavored to convey technical information in a more readable report. _2_
III. METHODS AHH MATERIALS Commercial Lobster Pot Catch Many lobstermen trap lobster (Homarus americanus) in the waters off Pilgrim Nuclear Power Station, and there are numerous lcnding sites along the coast. Consequently, it was impractical to monitor the entire local lobster fishery; instead, prior to 1987, we opted to sample the trap-catch of two commercial lobstermen of the area to obtain an index of harvest. However, in 1987, we terminated campling with one fisherman, as he had progressively moved his gear offshore and out of the immediate vicinity of the power plant. Instead, we devoted more time to fishing our own trapa at prescribed locations. We campled the entire day's commercial catch of our accond lobsterman biweekly from May-October, which la the height of the innhore lobster season. To facilitate data collection, the study area was partitioned into a grid (0.8 km2) quadrata), and catch recorded by quadrat (Figure 1), with quadrata later grouped to identify reference and surveillance areas. Catch data included: catch (number) of lobster per pot-haul; pot location (quadrat); and for each lobster - carapace length (CL) in mm, sex, presence / absence of eggs on females, and molt condition. Research Lobater Tran Fishing ( In June 1987, we began the second year of an experimental l
- lobster study which was implemented to measure the impact of the
( i thermal discharge from Pilgrim Power Station on the local lobster population. We conducted research trap fishing from June-September in the discharge area (curveillance) and at two comparable reference (control) locationa using a uniform I l t
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e- , Figure 1 Lobster Pot Sampling Grid for Marine Fisheries Studies. f cxperimental technique to reduce sampling variability as natural populations are rarely ever uniform over space. Ten stations ware monitored: four (E-H) at the surveillance location and six (A-D; I-J) at the two controla (Figure 2). Because of the extended power plant outage, the discharge was monitored for a second year without the influence of waste hest. However, this year, current was reduced further to a cinimal flow of water out of the discharge canal. This allowed us to collect two seasons of base line data under eccentially prestress conditions to compare temporally the potentially inpacted/ treatment stations with the non-impacted / control stations before the plant resumes operation. 1 Our campling design included standardized gear and methoda j to caximize data preclaion and accuracy. Fifty (10 more than in 1 1986) vinyl coated wire lobator traps (91 x 51 x 30 cm) were l fished in trawla. Randomization was applied in our celection of stations from within an area. Ten trawla each having five trapa per trawl with traps spaced about 30 m apart and buoyed at each i enda were employed, one trawl at each of the 10 stations. A station location was permanently marked with an anchor-buoy errangement and was sampled methodically to standardize the distribution of effort. Pota were hauled every other day in the morning, weather peraitting, with coak-timo (duration of a set) recorded. Water touperatures (bottom and surface) were measured approximately weekly. At each campling, traps were emptied of their contents, l rebaited, and relocated on station. Flounder racks were used l L
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.- Point Figure 2 Location of experimental lobster gear (5 pot trawls) for Marine Fisheries Studies.
oxclusively as bait to standardize any effect of bait on catchability. For each pot-haul, lobster were counted, measured, cOxed, and examined for missing claws, presence of eggs, shell hordness, and disease. We released all lobster in the area of c:pture except for a sub-sample retained for radiological cnnlysis. To address the recapture rate of sublegal lobster (<81 mm CL) we tagged a percentage of the sublegala each sampling trip rotating between the three sampling areas. We tagged legala (1 81 mm CL) last year and found very few were recaptured in our l pots; none were tagged this year. We used a coded yellow cinch tag placed proximal to the dactyl portion of the lobster's left clew. Bottom Trawling To monitor the nearchore groundfish community in the Pilgrim 1 area, we continued small vessel (5 m) bottom trawling. Four permanent stations were sampled biweekly during the daytime (Figure 3). Trawling in the impact areas was conducted at i surveillance stations T-3 (Diacharge) and T-6 (Intake). The i primary reference atation was T-1 in Warren Cove, while the other reference site was T-4, northwest of Priscilla Beach. Station selection was based on availability of suitable substrate for trawling, depth, sediment type, and known patterna of the thermal plume. We opted for duplicate 15-minute town at each station to l obtain fish catch / effort data on groundfloh using a 9.8 m Wilcox l trawl (9.8 m sweep; 7.0 m headrope; wings of 11.4 cm stretch conh; fitted with a 6.4 mm stretch mesh cod-end liner). Catch l (number) of fish per standard 15-minute tow was our sampling unit 1 1 Gumer Pt. l CAPE COD l BA Y h 0 1/2 1 N e >iiim SCALE IN MILES l long gous PL YMOUTH BA Y l PL YUQUTit MAR 80M Rock y 1 T=1 Ponnt D*
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SHRIMP TRAWL STATIONS (T) {
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Figure 3. Location of Shrimp Trawl and Dive Sampling Stations , for Marine Fisheries Studies. l 1 1 I 1 i
L or catch-per-unit-effort (CPOE), which was used as the index of ralative abundance. When uncontrollable factora prevented co pletion of a standard tow, catch valuca were extrapolated by u ing a weight e.g function. I In processing the catch, standard survey techt41gues and trcwl log sheets were employed. All fish were identified, enumerated, measured, and then returned to tha water. Invertebrates were identified and counted; lobatar were gauged as to being legal or sublegal .in aise. Surface and bottom water temperatures were taken during sampling operationa at each ctation. Gill Not Sampling l Gill net sampling for pelagic and benthi-pelagic fish was conducted at a site located parallel to ahore at a depth of 3 m L (MLW) near a ledge extending north from the mouth of the ! discharge canal (Figure 4). The site is located partisily within the discharge impact area. An overnight set was made cpproximately once a month throughout the year. The not was set l ct aunact and retrieved the next day at nunriae to take advantage of the greater campling efficiency at night. ! A ainking monofilament gill not, Pt3.4 m long and 3.0 dnap, was anchored and fished the entire water column at low tido. To counter dear selectivity, we fished an experimental net l consisting of a single "gang" of seven 30.5 m panels of the l following mesh nizes: 3.8, S.1, 6.4, 7.6, 8.9 11.4, and 15.2 cm l atretch measure. To further reduce campling blaa, the end of the act positioned to the diocharge canal was reverned on i ____ - ____ ___
1 i i i f 9 Gurnet Pt, CAPE C00 BA Y S-5 g o ut ' N --L4 i SCALE IN MILE Long Beach PLYMOUTH 8AY 9:YMOUTH g,
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& BEACH SEINE STATIONS (S) @ j g*)# sa 7[J" d BENTHIC STATIONS (G) ' '"'.
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j Figure t. Location of Beach Seine and Gill Net Sampling Stations for Marine Fisheries Studies e ,
citernate sets. Surface and bottom water temperaturen were taken th:n the not was set and hauled. I Our objectives were to provide collections of fish for radiation analysis and to obtain recorda of relative abundance for correlation analynia with plant operation. Ecul Seining To countervall tha selectivity of bottom trawling and gill notting, we sampled shallow water habitata, i.e., the intertidal end shallow aubtidal zones, by haul seining. Fishea occurring along the ahoreline included forage specien and the juveniles of acny important sport and commercial specien. Six stations were coined during the daytime on a weekly schedule from June-November (Figure 4). Winter /early spring sampling wca nmitted because cold water temperatures reduce fish diatribution in shcal watera. ( , We adopted a standardized quantitative seining technique, codified after Conover and Ross (1982). The net used at Stations f 2, 4, and 5 was a 45.7 x 1.8 m haul aeine with a 1.8 x 1.0 x 1.8 i o bag of 0.48 cm square mesh (twine #63). Duplicate haula were usually made at each site. Sampling was conducted within i 2 hours of low tide. Surface water temperature and salinity were esaaured at the time of compling. l At the surveillance site (Station 3 - Intake), campling wan l constrained by the limited sampling area and by depth. To alleviate this problem, we are campling thin location with a deeper seine cet from a small outboard-powered skiff; the not escoures 45.7 x 3.0 m with a 3.0 x 3.0 x 3.0 m pocket of 0.48 cm square mesh (twine #631 Sampling was carried out within i 2 hours of low tide.
I Using a smaller seine (6.1 x 1.8 m with no bag of 0.48 cm square mesh), we sampled Stations 1-6 at both high and low tides. I The larger seinea are effective campling pelagic fish, while the l smaller seine with a double lead weighted line was designed to capture demersal fish. At the beginning of each net, area (m2) and volume (m3) of water seined was estimated from the depth and linear distance of the net from shore. Fish were enumerated and measured; length data were obtained by measuring up to 50 individuals of each species caught. Unusually large catches were subcampled to reduce mortality. An estimate of the total number of individuale caught was made by multiplying the subsample ratio (individuale per unit volume) by the total number of volume-units in the catch. Mean catchea were calculated for numerically dominant species at each station. Observational Diving The underwater finfish observational program included standardized inspection of six permanent stations undertaken by biologiat-divera using SCUBA (Figure 3). Two stationa were in the area denoted aa ' denuded', two in the ' stunted' zone, and two were control sitea as defined by Boston Edison Company (1980). Dives were made at 2-week intervals from May through mid-August, weekly from then until mid-September, and then biweekly through October. During each dive, two divora descended to the bottom and occupied each station consecutively, recording viaual observationa of marine biota, with major emphasia on finh identification, numbers, and approximate sizen. Bottom water t:2peratures were taken with a hand-held thermometer, and r vicibility estimates were made with a Secchi disk. This study \ provided _ direct visual observations of fish numbers, location, behavior, and condition just outside the discharge canal. Creel Survev
.Sportfish catch at Pilgrim Station's Shorefront recreational arca in 1987 was monitored by security personnel at the waterfront in a cooperative effort with us to maintain a database on the recreational fishery of the area. A questionnaire was ceployed daily to record data on number of anglers, location of fishing, weather conditions, and catch by species.
i l l l l l t l l t_
l. s IV. RESULTS &HD DISCUSSION l A. HYDROGRAPHY 1 J
- 1. WATER TEMPERATURE In the inshore area of western Cape Cod Bay, we have )
recorded ambient water temperaturas ranging from -1 C in February to 23 C in August at the surface and -1 C in February to 21 C in September on the bottom. Surface waters begin warming in March or April, and a thermocline forms at between 5 and 10 m in June. Surface to bottom temperature differentials have ranged from 0.5 C to 4.7 C. The highest monthly average water temperature (ambient) for western Cape Cod Bay between 1970 and 1987 was 18.8 C, obtained in September 1974. The maximum surface temperature was recorded in August of both 1973 and 1984 at 23 C. Ambient water temperatures for spring and summer were higher in the nearby estuary - Plymouth, Kingston, Duxbury Bay - reaching 25 C in the shallows during summer. Temperatures in Pilgrim Station's . thermal plume, with the plant fully operational, have peaked at 32 C (surface and bottom). During the last five yeara (1983-1987), surface water temperatures, overall, were highest in 1983 and 1985; on the whole, temperatures were somewhat lower in 1986. Most noteworthy was the markedly lower temperatures found during all seasona of 1984 in the Pilgrim area. A plot of bottom water temperaturen for the spring is especially insightful (Figure 5), Cooler apringa are indicated for 1984 and 1987. It in likely that lower commercial lobater catch raten in western Cape Cr,d Bay in 1984 and 1987 were related to reduced molt probability und resultant lower recruitment caused by these cooler abring temperatures. n - , ,. , , -, - -
TEMPER ATURE C 15
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=
1983 l 1984 + 1985 -0 1986 X 1987 Figure 5. Bottom water temperatures (ambient) recorded in the environs of Pilgrim Station during spring, 1983-1987.
- 2. SALINITY Surface salinities in the Pilgrim area range 6 from 29 to 32 L indicating minimal influence of freshwater drainage from watersheds. There was little variation among stations sampled with the average salinity being 31%.. Efficient tidal flushing in Cape Cod Bay accounts for the small salinity variation within the Bay as is true with the waters of Massachusetts Bay and the Gulf of Maine (Davis 1984).
B. FISHERIJE ,
- 1. COMMERCIAL LOBSTER POT-CATCH FISHRR1 Monitoring the commercial American lobster (Homarun americanus) fishery in the Pilgrim study area began 15 May and concluded 27 October, 1987. Lobster catch statistics and biological data (i.e., length, sex, shell hardneas) were collected for the 6-month investigation during 11 sampling trips aboard a commercial lobster boat. Data were recorded for 2,658 lobster taken from 1,818 lobster pot-hauls.
Overall catch per pot for all lobster (legal, sublegal, and ovicerous females 181 mm) for the Pilgrim area was 1.5, down from lost year's CPUE of 2.2. This decrease in catch rate was due in part to our change in sampling strategy in 1987. We no longer tonitor the catch of a second lobsterman, who fished deeper wotors in the Pilgrim area and traditionally has caught more 1 lobater than the individual whose catch we are still sampling. l Twenty-three percent (609) of the total catch were legal lobater for an annual legal catch rate of 0.33 1cbeter/ trap-haul. The lowest monthly legal catch rate occurred in May (0.26), and i the highest of 0.42 in July (Figure 6). This atypical trend in conthly legal CPOE is attributed to the unusually cold bottom water temperatures in the spring of 1987 (Figure 5), which I potentially effects inshore lobster abundance. The monthly catch l reto of sublegal looster paralleled that of the overall lobster CPUE, while monthly legal CPDE appeared independent of total
- catch.
Females comprised 54% of the annual catch (1.2 female to 1.0 talo) and dominated in every month of the study. There were 65
-17 t
MONTHLY LOBSTER CPUE CATOi PER TRAP HAUL t.0 - C w
/ .
oa. -c
- n. h MAY JUN JUL AUG SEP OCT MONTH
- TOTN. LOBSTER E LEGALS C SUBLEGALS MONTHLY PERCENT OVIGEROUS FEMALES 1987 CAPE COD BAY 5 OVEROUS FEMALES 14-
~
12 - ! 10-4- n- - MAY JUN JUL AUG SEP OCT MONTH Figure 6. Monthly lobster catch per trap haul and percent ovigorous females in the Pilgrim area,1987. i
f cvicerous (egg-carrying) females compled (2.4% of the entire entch), of which 30 (2,1% of all females) were lose than 81 mm in c2r: pace length. The overall percentage of ovigorous females was cr;; test in June (7.9%) and October (11.9%) and lowest in nummer (1.4% in July and August) (Figure 6). The seasonality of ovicerous females is typical of the two-year reproductive cycle of the American lobater (Aiken and Waddy 1982). Female lobster C;norally breed after the summer molt, but do not extrude fortilized eggs until fall of the following year. The eggs are then carried throughout the winter and hatch out in the spring.
- 2. RESEARCH LOBSTER TRAP FISHING During the period 20 June through 29 September, 1987, we l
conducted controlled research lobater fishing in the environa of Pilgrim Station (Figure 2). Forty-six nampling days were I co pleted, during which 5449 lobster were sampled from 2282 trap I htuls. The samples were predominantly composed (86.9%) of cublegala (< al mm carapace length - CL). Of the total catch, only 712 lobater were legal-sized (1 81 mm CL), with a ratio of cublegal to legal of 6.7:1. The number caught per trap-haul rcnged from 0 to 15, with legala ranging from 0 to 4 and l l aublegala, O to 8;in 19% of the trap-haulo no lobater were ccusht. In 1986, we tagged legal-aized lobaters in order to datermine their recapture rate in our pots; recaptures could then bo discounted and an unbiased estimate of catch obtained. In 1987, we tagged sublegal lobaters to ascean the magnitude of recapture. A total of 488 oublegala (10% of the aublegal catch) were tagged and released over the course of the summer. Only four (0.8%) of the sublegals tagged were recaptured in our gear, j Although, we did not solicit returns from other lobstermen, a few tags were returned, all from the immediate area of the study. As a result of the two years of tagging data, we feel that catch rate need not be adjusted for recapture. The overall mean CTH (catch-per-trap-haul) for lobater of all sizes and both sexes in 1987 was 2.1, somewhat higher than last year's 1.2. The mean catch rate for sublegal lobater (1.9) was also up from 1986 (0.2);CTH of legal lobster was 0.3 in 1987 and 1.0 in 1986. Males comprised 52.3% of the r search catch with an overall sex ratio of 1.1:1 (males to females). In the commercial catch for western Cape Cod Bay , conducted primarily in deeper watera further from shore, females (60.5%) dominated (Bruce Estrella, personal communication)1 at a ratio of 1.5:1 (females to males). Our finding of a higher percentage of males in the innhore experimental program parallels research in Long Island Sound (Briggs and Muscnacke 1979), where males were found to predominate in shoal waters. We captured 20 ogg-bearing (ovigerous) females, only 0.4% of the total catch of females; of these, 8 (40%) were sublegal. The percent females ovigorous in the commercial catches of the area was 2.4%, with 46% sublegal. Carapace lengtha of the lobater campled in the experimental study ranged from 22 -123 mm. Mean carapace length was 72.9 mm, nearly identical to the 1986 value of 72.7. Further, comparison of length-frequency histograms from 1986 and 1987 (Figure 7) reveals that size composition of the catch for both years also Relative Frequency (%)
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%om / / m d C X f,' / / / / / M O i i i i i i i i i i iiiiiiiiiiiiiiiiiii 39 45 51 57 63 69 75 81 87 93 99 105 111 117 12 3 Carapace Length (mm) in 3 mm inciements I I1986 -!'" ~ 1987 Figure 7. Size distribution of lobster captured in the research trap fishery of f Pilgrim Station l In 1986 and 1987.
L
4 was nearly identical. Kelly et al. (1987) reported that some of the characteristica that may influence size composition were pot design, finhing pressure, and habitat characteristics. With i these factors held constant between 1986 and 1987, the closely matched size compositions suggest good precision in our sampling program. The percentage of culla (this category includes lobster with both missing and regenerating clawa) sampled in research fishing was 20%, which is representative of region in that the cull rate in the commercial catchen was 21.4%. Both of these estimates are identical to 1986 values (Kelly et al. 1987), auggesting a leveling off of the trend for increasing numbers of culla reported for coastal Massachusetta by Estrella and McKeirnan in 1986.
- 3. NEARSHORE BENTHIC FINFISH We completed 107 bottom trawls in the study area in 1987. No camplea were collected in February and April due to adverse weather conditions. A total of 2,450 fiah, representing 30 species, was collected in 1987 (Table 1). A specien check list (Robina et al. 1980) with scientific names is found in Table 2, which includen all fish observed or collected by all gear types in the study area in 1987. Four groundfish - winter flounder, little skate, windowpane, and northern scarobin - compriced 86%
of the 1987 trawl catch. The average catch per tow (CPUE) tor all specica and stations pooled was 22.9. The surveillance stations - I B. Entrolla, Senior Marine Flaheries Biologist, Coastal Lobster Investigations. Massachusetta Division of Marino Fisheries, Sandwich, MA.
Tcblei . Expanded catch and percsnt co: position of groundfish captured by bottom trevling at four stations in the vicinity of Pilgria Station, January-Dees:bar, 1987. Station 1 3 4 6 Warren Pilgrim Priscilla Pilgrim Sp cies Cove Discharce Beach Intake Totals 7. catch ( Winter flounder 159.9 *l12[5$ -184.6 266i7j 823.9 33.6 Little skate 165.6 273.62 210.1 :100?3M 749.7 30.5 Windtwpane 123.7 i 106i8) 102.5 160.3) 393.5 16.0 N:rthern searobin 8.0 [3017j 114.0 .j2j0j 154.7 6.3 Yellevtail flounder 1.0 140;5; 16.0 l!10.32 67.9 2.7 Atlantic cod 18.0 214s04i 12.0 721s01 65.0 2.6 Winter skate 9.0 J1672.1 6.5 :l!10i91 42.6 1.7 Buttcrfish 17.5 1125$. 2.0 %i'll.j 25.1 1.0 Aticntic silverside 4.0 !:5 l47 10.1 ?2.64 22.2 0.9 Lenghorn sculpin 1.0 .J 8.2:i 3.0 :': 3.0 f 15.2 0.6 Othcr spp.2 23.1 127@.! 14.2 726.19 90.5 4.1 Numbsr of species 19 120l 19 $181 30 Numbcr of tous 29 h291 31 j181 107 Tstc1 fish 530.8 73655$ 675.0 507i9I 2450.3 18.3 (25/3' 21.7 08 ;2 -- 22.9 Cctch/ tov Pcreent catch 21.6 130.0! 27.5 ;20.7; 1 Catch rates were expanded for tous less than the standard 15-einute duration. Rcpresents pcoled totals fres 20 species of low catch. Shcded colu ns are data ecliected at surveillance stations. Table 2. Checklist of finfish'soecies (following classification of Robins et al. 1980) collected or observed in the acjacent waters of Ailgrim Station, 1987. Class: Chondrichthyes Order: Squaliformes Farn i l y : Carenarinidae - reculem sharks dM31glug genig (Mitchill) - smooth cogfinn Family Ocontasoididae - sand tigers DE20102213 189C22 (Rafinescue) - sand tape-Family Squalicae - dogfish sharks EGMelMS EESO10 igg (Linnaeus) - sainy cogfish C.rder Rapiformes camily: Rajidae - skates Bela grinagge (ritchill) - little skate Seaa Osellela (Mitenill) - winter s ate Class: Osteichthyes Orcer Cluee1 formes Farn i l y : Clupeidae - horrings 91230 SCS$iYelil (Mitemill) - clunewed rerrirq G1233 322idi25103 (Wilion) - A'o a r i c a n ' ~ ;c G12Da 252Md23SCSO203 (Wilson) - AIGwife BCEM22CliS iMCSDou3 (Latrotei - At' ant 2c mon acen ClM228 bdC202US USCCCGUS (Lino **US) - Atlantic 'e*'#2n9 ramily: Engraulicae - anenovies 609D28 T11Gb1111 (Valenc2ennos) - Say anenovy Order: Sa irnoni f orme s Family: Salmonidae - trouts DDG2CbYDEbuS hiSM1E2 (Waloaum) - como salm e Familys Osmericae - smelts Ggegryg rjorg33 (vitemill) - ra:nton a rm '. t Creert Gaciformes Family: Gacicae - coefashes Qggg3 r39tt33 (Linnaeus) - at1 ant c cor 1ElS0220STSUS S2012f1099 ( innaous) - ,accoca dECl2GG123 2111CESC12 (Mitchill) - Silver 5^We l d1GC990cu5 193G2d ( 4 a '. D a u m ) - at'a6eie tom _oc ' E211dGbluS M1CCO3 ( 2n m aun) - coiloc < Ut222Y2iS G2052 (b^ ' mm) - rec ^ ^ *
- Ur220M212 120D15 (Y1tc31'l) - *"Tto "Ade ramily Zoarcicae - es'couts 10GCQ?2?tc9s averLGPCM9 (Elec' arc Oc"r*1ter' s ocean cou:
Creer Gasterosteiformos Family: Gasterosteid.ae - sticklebacks 2821eC911291 RGyleglyg (Linnaeus) - 2-spine stickleback
~amily: Syngnathidae - Dipefishes and seanorses 3%DED21DM3 fM5 EMS (Storer) - r.ortaern pioefish Orders :it h er i n i f orreo s Family: A:horinidae -
silversicas [gnidig genigig ( L i rm o e us ) - At lant ic silvar% ice Family: Scoreceresocidae - sauries EGOT2Dr2393 Scyry3 (Walbaum) - Atlantic 4aury
.Tamily: Cy pr inoco nt i dae - killifis,ee
~
;MCEMIM2 0222112 (Walbaum) - strinec Willifish Crder Perciformes
~amily Dercichthyadae - teMoerate casses T2EQC2 SSEdliliS (Walbaum) - striaec cass Family: 5erranidae - sea b a s v> a s CED1E22E12103 5)r131s 4 innaeus) - blac< sea tass Family: Pomatomicae - clue #;anas 320E19092 2fli31C1E ( innaGd*) ~
Iu# 1*' Family: Secmbricas - wacWareis anc t u r a 's 6G2T2BC SG2Z2CM9 ( inracus) - Atlar, tic m a c < e - e :. Family: 5paricao - corries 6120212 CMS E2CY2225 ( innaeus) - souc Family: Eciaonicae - crumw E2011GirrOUS 3d5011112 (Bloc' ^^C G C ' < S i c e ) northern Ring # is, Camilys aerscae - wrasses
- 139tgg3 9n1213 ( tenaeus) - tau;o; 2221229182r23 3Gi2TC593 (Wal
- aum) - e n er l
Family: Smolicas - gunnels 339113 EMDCEllM1 ( annaeus) - roc < gunrel i j ramily: Stromateidae - sutt er # ismes j 322C11M2 1CicGOCEDMS ( O e M - butter";s, Fami.y: ~ + tgiicao - searoesna, bC19091ME GOCC11LM2 5 sermeus) -
- 0 +' C ' a r ' f searom:n Family: Cotticae - sculotno Sgrai1C1912 CMS eT2C1GeDgg (3melin) - sua raven dM9E9GR9helSS 990 eggs (Mitc7i11) - gruosy d%959222belM2 9919$2EeTM2iD9223 ("itcNill) - i longhorn sculoin
[Y2M22220elMa SE9C2iMa (Linnaeus) - shortnoen sculoin i Family: Cyclopteridae - lumpfisneo anc snailfssnes GYE19212 CMS IMUDMS ('innaeus) - l u ni o r i s m 612ecia elleD11gga (Jordan and Everreann) - seasnail camily: Ammodytidae - sanc lances 95T9EM123 22c Ceder Pleuronectiformes Far>111y Botnicae - lofteye flouncers 2fral1GDibMS d2 Die 1MS ('innaeus) - summer flounder (fluke) eereliebibYa 2k190EMa (Mitchill) - foursoot flouncer SG99hibel'd g3 agg2393 (Mitemill) - windowoane Family: Dieuronecticae - righteye flouncers biTfDde f9CCMDiDge (Storer) - yellowtail flounder 2HDMd2212MC9DDC10A 202C1G9023 (Walbaum) - winter flouncer Order Looniiformes Family: Lochiidae - goosefisnes 692biM9 002CiGeDME (Valenciennes) - EcoS9Fis' Cecer: Tetraodontiformes Family: Tetraodonticae - ou*fers 59 2 the Intake embayment (Station S) and by the power plant discharge i cnnal (Station 3) - yielded the highest CPUE's of 28.2 and 25.3 (pooled species), respectively. Winter flounder Winter flounder- ranked first in catch (34%, all stations pooled) for the study area, but was second to little skate at three of the four stations. The mean CPUE for all stations co3bined declined slightly from last year's value of 9.0 to 7.7. Station 6 ranked first in winter flounder catch abundance with an ennual mean CPUE of 14.8; Station 1 (reference) was last with an cnnual mean CPUE of 5.5 (Table 3). Winter flounder seasonal trawl catch rates at each station (Figure 8) followed a similar pattern of lowest catches in winter, peak catches in spring, fairly high summer catches, followed by reduced catches in the fall (with the exception of Station 1, when the nadir occurred in fall). Station 6 was highest in CPUE for every season except winter. a . Little skate ! Little skate ranked second, comprising 30% of the overall total catch. Mean annual catch per tow of little skate for all ! ototions pooled was 7.0, as compared with 9.6 in 1986. As in 1986, this species was the dominant finfish trawled at all stations except in the Intake embayment. The highest annual otation catch rate of 9.4 occurred at the Discharge site , while the Intake had the lowest annual CPUE of 5.5 (Table 3). Catch rates for little skate exhibited a similar overall censonal pattern at each station: very low values in winter, peak catches in spring, the beginning of a decline in summer, followed Tcble a . Bottom trcwl catch dets for doninint groundfish in ths vicinity of Pilgrim Station, Jcnucry-Dieseber, 1987, t t Winter Little flounder skate Windowpane STATION.1. Mean catch / tow
- 5.5 5.7 4.2 Mean size (cm) 28.7 39.9 25.7 Size range (cm) 11-40 14-51 15-31
' ' ' ' "' ' " ' ' ' '~ ' '
67 ![ STAT 10NJ3';' ' ?" ' Hein;:' catch /kow/* N'3)) .$9% b3 1
~Meani::sime{(cm); .. ji 728473 Lj3542i . f22.0?
Sizelrangai(ca)l.i , , , ,, 18-40.i s 112s54( .m s J13-31; STATION 4 Mean catch / tow
- 5.9 6.7 3.3 Mean size (cm) 30.1 37.9 21.5 Size range (cm) 11-44 19-55 11-31
- i' STATION?67 ' ' ", "' ' "' ' ' ' ' ' ' ' ' '
; i Nehnicatih/dow*L lid;81 '
[5i5i Ndli-Mean;siaaN(ca)1 127160. i;;'37;91 . , i21.'41.' size (rangh(cm)j s , j4445;;- , !18-54[ , ,,
!11-35j,
- Catch rates were expanded for tows less than the standard 15-minute duration.
Shaded rova are data collected at surveillance stations. I
Winter flounder seasonal catch / tow l NUMBER OF FISH / TOW 28 26-24 - i 22-l 20- ! 18-16-14 - a 12- _ E . WINTER SPRING SUMMER FALL SEASON , E STATION 1-REFERENCE E STATION 3-DISCHARGE U STATION 4-REFERENCE E STATION 6-INTAKE Figure 8. Seasonal mean trawl catch rates for winter flounder by station in Pilgrim aren,1987. i 1
by a marked decline in fall (Figure 9). In the spring, little skate were most abundant in the Intake (18.5), but in the summer relative abundance was highest in the Discharge area (14.5). f Windowoane Windowpane was third overall in annual traal catch (16%) for the fifth consecutive year. The mean annual CPDE for all stations ; combined was 3.7, down from 4.6 in 1986. The highest annual CPUE for windowpane (4.2) was recorded at Station 1 in Warren Cove for the fifth consecutive year. The indices at the other statione ranged from 3.3 - 3.6 (Table 3). Seasonally, windowpane were generally absent from winter groundfish catches (Figure 10). Catches were by far the highest in spring, followed by reduced abundances in summer / fall. Northern sea robin Northern sea robin was fourth in trawl catch, with an overall CPUE of 1.4. However, 86% of the total harvent was captured during one day in May. The occurrence of this species was extremely aporadic. Yellowtail flounder Yellowtail flounder ranked fifth in annual relative abundance for the fourth consecutive year. The annual mean CPUE (0.6) for all stations pooled was similar to laat year's rate. This flatfish was slightly more abundant at Station 3 than at the other sitec campled. Atlantic cod Young-of-the-year Atlantic cod (Gadus morhua) of 3-6 cm length wero unusually abundant in this year's catch, comprising 2.6% of the annual trawl total. These small cod were captured in Little skate seasonal catch / tow NUMBER OF FISH / TOW 20 16 - [ 16 - h 4 14 - , 12-10- 0' h 8- ,
~
6- - 4- : , 2-f g4 ~' 0- - - - WINTER SPR ING SUMMER FALL SEASON STATION 1-REFERENCE
- STATION 3-DISCHARGE I I STATION 4-REFERENCE E'i3 STATION 6-INTAKE Figure 9. Seasonal mean trawl catch rates for little skate by statforn in Pligrim area,1987.
i Windowpane seasonal catch / tow NUMBER OF FISH / TOW ' 12 10-8- 1
- 6-h ;
4-2- t
- - .j A7 O I
' ~
K WINTER SPRING SUMMER FALL SEASON E STATION 1-REFERENCE STATION 3-DISCHARGE L__J STATION 4-REFERENCE E STATION 6-IN FAKE 1 Figue 10. Seasonal mean trawl catch rates for windowpane by station in Pilgrim area,1987.
i September and October at all stationa.
- 4. PELAGIC AND BENTHI-PELAGIC FISHES <
A total of 2578 fish, compris!.ng 32 species was gill-netted during 12 sets made in 1987 (Table 4). No sampling was conducted during, January and February due to inclement weather. A audden otorm in December caused the destruction of the net with cubeequent loss of data. Annual mean CPUR for pooled species was 189.6 fish / set (Figure 11), a notable increase over laat year'a 99.6 fich/ net. This high rate may be partially the result of the obsence of data from January, February, and December, months when colder water temperatures generally result in smaller catchen. Whtn averaged into annual catch statistics, the low CPUE'a (cntch-per-unit-effort) of these months usually cause a lowering of the overall estimate. The unusually large pulse of northern con robin in May and June undoubtedly also contributed to the hicher overall catch rate. Table 4. Number and percentage composition of colected finfish specica captured by gill not (7 panela of 3.8-15.2 cm caeh) in the vicinity of Pilgrim Nuclear Power Station, January-Deccaber, 1987. Percent of
- Species Number total catch Northern aca robin 904 35.1 Pollock 521 20.2 Atlantic herring 456 17.1 Cunner 166 6.4 Alcwife 84 3.3 Tcutog 80 3.1 Bluofiah 66 2.6 l Othor* 301 12.2 l Tntal 32_apecien 2 J78_.._.
C The remaining specien were not found in abundance. t Pooled Species l Mean Catch per glit-net set 250-l 200-t hh Ih
'71 '72 '73 '74 '75 '76 '77 '78 '79'80 '81'82'83 '84'85'86'87 Year Figure 11. Indices of relative abundance (catch-per-unit-ef fort) for pooled finfish species captured in l Western Cape Cod Bay near Pilgrim Station based on standardized gill not gear. t i
l l A new species was added to the project check-list - a sand ticer shark neasuring 101 cm, was captured on 16 September. C:stro (1983) reports that this species in a common summer violtor to the inshore waters of southern New England, j The dominant species was northern sea robin, comprising 35% of the total catch. Pollock, Atlantic herring, and cunner were tha next most abundant species (Table 4), with 20%, 17% and 6% of tho total catch, recpectively. Northern __sen robin Although a common component of project gill-net and trawl catchen, the extremely large numbers taken by both gear types, cill net in particular, during May (428 fish) and June (391 fish) of this year are best viewed as being an anomaly. During the apring and aummer, northern sea robin are commonly taken in the gill-not, but generally in much smaller numbers than in 1987. i j Bigelow and Schroeder (1953) report that northern sea robin are cormon visitora to innhore watera during the warmer montha. i However, beyond basic life history, little appearn to be known about their stock size or trends in abundance over time, i i Pollock Comprising 20% of the total catch, pollock was the second j coat abundant specien captured by gill net. Seasonal estimaten of abundance using the index of CPUE, were 45.3 and 41.8 fich/ set ' l in the spring and nummer and 57.7 fish /aet in the fall,
- ouggesting a stable, if seasonal, local population during 1987.
l Coaparison of annual trendo in CPUE over time (Figure 12), reveal that the 1987 value, 39.6, representa a slight decrease l 1 I
i 1
! Pollock l !
l Mean Catch per gill-net set i 160 5 ) 140-l 120- ,
, 100- l 80-i '71 '72 '73 '74 '75 *76 *77 '78 '79 '80 '81 '82 '83 '84 '85 '86 '87 Year l Figure 12. Indices of relative abundance (catch-per-unit- !
i effort for pollock captured in Western Cape Cod f Bay near Plfgrim Station based on standardized l' gill net gear (5 panels of 3.8-8.9 cm mesh) and procedures. 1971-1987. ; i
y - __ _ _ _ _ _ _ _ _ _ L from previous years' levels. As can be clearly seen, however, ( fluctuations in local abundance are common and given the I aigratory nature of this species (Bigelow and Schroeder 1953) are probably reflective of year-claan strength (Lawton et al. 1985). Atlantic Herring Atlantic herring was third in the dominance hierarchy, conprising nearly 18% of the total catch. With pollock and cunner, herring are a traditional dominant in project gill not recordc. Like pollock, Atlantic horring are highly migratory (Bigelow and Schroeder 1953) and undergo wide variation in local abundance (Figure 13). Conner Ranked fourth (6.4% of the total), relative abundance of cunner as measured by CPDE was at its lowest point (13.5 fish /aet) of the entire study (Figure 14). This level la a continuation of a downward trend noted by Lawton et al. in 1986. An decreased local abundance in the Pilgrim Station area was also noted by project divera, it seems apparent that this trend represents a decline in the local population, perhaps the result of a shift in distribution. Other noecien The remaining specien captured by gill not in 1987 were taken in relatively low numbern, with no ningle specica compricing more than 4% of the total catch. Some, auch as tautog, are regular visitors to the Pilgrim Station area but have experiencrd a recent decline in local abundance. Othera, auch as atriped beca and bluefish, have a known affinity for the thermal i effluent (Lawton et al. 1978) and generally are more scarce when l
Atlantic Herring Mean Catch per gill-net set 100 l 80-
- i j y 60-t 40-TY . . -r
! '71 '72 '73 '74 '75 '76 '77 '78 '79 '80 '81 '82 '83 '84 '85 '86 '87 l Year ! Figure 13. Indices of relative abundance (catch-per-unit-l ef fort) for Atlantic herring captured in Western i Cepe Cod Bay near Pilgrim Station based on I standardized gill net gear (5 panels of 3.8-8.9 cm mesh) and procedures, 1971-1987. i i
l ) l l Cunner l Mean Catch per gill-net set ! '1 4 - ! d
? eo- ,
illi lldl
'71 '72 '73 '74 '75 '76 '77 '78 '79 '80 '81 '82 '83 '84 '85 '86 '87 Figure 14. Indices of relative abundance (catch-per-unit-Year
. hn B near i grim Stat n based on standar zed pr cedures 1 71 198
the plant is not operational. Moat are captured only I dominance sporadically and have never occupied positions of in gill-net records.
- 5. SMORE-ZONE FISHES A total of 30,146 finfish representing 29 apecies was captured in the 45.7 meter haul seines from June-November, 1987 (Table 5). The mean catch of finfish per standard seine set for all stations and species pooled increased by a magnitude of 2.4 from 1986. An increase in catch rates (pooled stations) of Atlantic silverside, blueback herring, alewife, and sand lance contributed greatly to the overall incr0ase. Station catch rates pooled by specica increased at all sitea from last year, with the largest gains at Warren Cove (3.2 fold) and Manomet Point (4.6 fold).
Seine catchea were highest overall at Long Point where over 60% of the total was obtained (Table 5). This was primarily a result of the abundance of silversidea there. Overall, catches again were relatively low at Manomet Point and Warren Cove. In terms of total fish caught, the Intake station was for the second consecutive year more similar to Long Point, an estuarine location, than to the exposed coastal beach stations at Warrea Cove and Manomet Point. Atlantic nilve,rs ida Five taxa - Atlantic silverside. blueback herring, sand lance opp., alewife, and winter flounder - comprised 98% of the overall catch. The Atlantic silverside doninsted the catchen l again ao it haa every year since the study's inception in 1981, l
\
~ TablIf. Shora-sons fishes captured by haul seine at four stations in ths vicinity of Pilgri= Nuclear Power Station, Juno-November, 1987. (Shaded column is data from surveillance station).
Species Abundance _ Station Warren Pilgrim Long Manonet Total Percent of oncies Cove Intakel Point Point Nu=ber total catch R s.l .ld! Slantic silverside 2602 18433 1117 .23568 78.2 luebeck herrin; had Itnen app. 25 2
$l$14'13).l)jl 12515? t 705Mj!
2 0 8 4 2550 2062 8.5 6.8 kwife 1 J055);i$ 22 1 1079 3.6 intsr flounder , 13 180ji! 25 53 271 0.9 c'lantic herring 5 2 0 clantic to= cod 12)Ug 149 0.5 20 45 orchern pipefish $64%ip! 0 129 0.4 17 :51!iiij!! 37 3 108 0.4 )1taticmenhaden 0 $ 0 0 53 0.2 ' devpans g 15 flyM!j$ $$53f!!f3 20 3 43 0.1 annnr 14 4J19.Mij 10 Lher spp.2 0 43 0.1 14 h$18jll 44 15 91 0.3 1 hk +. % pealnu=beroffish 2728 18640 1204 30146 S75714;&idl
- .'. : u . >.. .s!!!? d.!
s Ebtr of sets 21 V20;f 5 22 19 82 (C2 tech / sat 129.9 f!l:!3533 847.3 63.4 367.A f C
~.s ,' f.:.. s. :i.
tal nu=ber of species 16 ' j20!1
, 19 16 29 i
1 sp - L resnt of total catch 9.0 ? '!)S$f!! 61.8 4.0 M}~e : ' 1 l l Species percent frequency of oc urrence, Station l Warren Pilgri Long Mano=et All Stations l Sozeies Cove Intake 1 Point Point Poole'd Atlantic silverside 38.1 [650i 68.2 52.6 56.1 - l Blusback herring 23.8 !.!!15';0; 9.1 21.1 17.1 l Sand lance spp. 4.8 Q35.~0.] 0.0 10.5 12.2 l Alcwife 4.8 ll.15.01 13.6 5.3 9.8 ! Winter ficunder 23.8 $750 54.5 57.9 52.4 Atlantic herring 9.5 $10';0j 9.1 0.0 7.3 l Atlantic to: cod 19.0 ll10:0!! 31.8 0.0 15.9 Northern pipefish 14.3 !!:45j0!! 40.9 10.5 28.0 Atlantic nenhaden 0.0 g5!O'; 0.0 0.0 1.2 Windowpane 38.1 215IOJl 45.5 15.8 29.3 Cunnar 9.5 i!2%0l 31.8 0.0 17.1 l l 1 45.7 m x 3.0 seine; other sites sanpled with 45.7 m x 1.5 m seine 2 Rspresents pooled total for 18 species of infrequent occurrence in haul seine.
# accounting for 78% of the fish caught. Of the total' sil~erside catch, 78% came from the Intake. This species dominated in both catch-per-unit-effort and percent frequency of occurrence (Table
- 5) at all sites except Manomat Po2nt, where it ranked second to winter flounder in the latter category. Catch rates for Atlantic silverside were up from 1986 throughout the study area, with the 4
greatest increases at Long Point and the Intake embayment at Pilgrim Station. Blueback herrina Blueback herring comprised 8% of the total and were captured at all stations. Ninety-eight percent were caught, however, on two sampling days (August 14 and September 15) in the Intake embayment. Although this schooling fish ranked second in numerical abundance, it was fifth in frequency of occurrence; this species' aggregated distribution affecta its availability to capture in any year. Sand lance npo. Hanked third, sand lance spp. were caught almost exclusively (> 99%) in the Intake, with 94% of the total study catch captured on one June day. Sand lance spend a substantial portion of their time burrowed in sand bottoma, and may undertake seasonal migrations to deeper waters in Cape Cod Bay in winter and aummer (Bicolow and Schroeder 1953). Thu mean catch rate of sand lance at the Intake increased 42% from 1986. Alewife and winter flounder Alewife and winter flounder ranked fourth and fifth, ! respectively, in catch abundance. Alewiven were infrequently caught, with the largest catch made in August in the Intake, l
~ . _ . _
nstting 93% of the year's tally. Winter flounder was accond ovsrall in frequency of occurrence, which reflects a relatively ubiquitous distribution. Catch rate for this flatfish was highest at Pilgrim Intake, where it ranked first in percent frequency of occurrence. Seine catches were highest in August and September, concomitant with the highest water temperatures of the year. This relationship has occurred every year of our seine study. In November, moderate catches were made at the Intake and Long Point stations, with silversides, winter flounder and windowpane still inhabiting the cooler shallow waters of late fall. Annual species diversity was highest at Pilgrim Intake (20 species) and Long Point (19 opecies). In terms of percent fcequency of occurrence of dominant species, Pilgrim Intake waa cost like Long Point. Of the 29 species seined in this study, 7 were taken at all stations; by contrast, 12 species were taken only at one station. In summation, Pilgrim Intake was similar to Long Point in total catch and finfish diversity. Both stations chare two characteristics which may account for theco similarities in abundance and diversity: they are in semi-enclosed embayments which offer protection from heavy surf, and both possess come degree of vegetation which provides suitable habitat for small fishes. This contrants with the exposed coastal stations, Warren Cove and Manomet Point, wh3ch have little cover and are periodically subject to heavy surf and where species diversity and abundance were lower.
v l Additional Small Seine Samuline Using a smaller foot-seine (6 m), and sampling mostly the I high tide, a total of 5,317 fish representing 15 taxonomic groups was captured in the shore zone from June-November (Table 6). With little salinity variation (range 29-32% ) amongst stations, temperature was a more important factor governing the seasonal occurrence and abundance of fish along the shoreline. Overall, catches with the small seine were highest at Long Point (Station 5), including total fish, number of species, and catch per effort. For the entire study area, four taxa contributed over 97% of the catch: Atlantic silverside, sand lance app., Atlantic menhaden, and blueback herring which each contributed at least three percent to the total percent species composition. The first three taxa were reported as dominants in the shore zone of Long Island Sound at Millstone Point, Connecticut (Birely 1984). The Atlantic silverside was by far the dominant fish of the shore zone in the Pilgrim area; over three-quarters of the fish captured by all seining operations were silversides. Collected at all seining stations, this species comprised 96% or more of the catch at four of the six sites. Catch per standard seine haul (index of relative abundance) was highest at Long Point (Station 5) at 69 silversides/ haul, followed by Long Beach (Scation 1) at 39 per haul. The relative abundance of i silversides was similnr at Harren Cove (Station 2 - 27.3 and the 1 Pilgrim Station intake ramp (Station 6) - 29.2. !
)
All menhaden and most of the blueback herring were captured at the head of the intake embayment (Station 3). The majority of
e Table (, . Shore-zona fiches ceptured by foot-eains at six stations In the environs of Pilgrim Nuclear Power Station, June-November, 1987. Station 1 2 3 4 5 6 Long Warren Pilgrim Manomet Long Pilgrim Total Percent of Species Beach Cove Intake Beach Point Point Intake Ramp Number Total Catch
? . . . ~. >
Atlantic silverside 1012 656 11$6? , 324 1793 [175l 4116 77.4 Sand lance spp. 0 0 t . j 2; f 553 0 [0 i cy_ 555 10.4 Atlantic menhaden 0 0 357; o o 201 357 6.7 nlueback herring 0 2 (jil50j - 0 0 i;11 153 2.9 Winter flounder 6 2; UIndowpone 1 18 15 l0: 42 0.8 7 4 : 0- 3 21 :0: , 35 0.7 IIorthern pipefluh 0 0 :0 2 25 0 27 0.5
. Othersl 0 1 :22 3 23 '3- 32 0.6 Total no. of fish 1020 669 l[6% ' 903 1877 j(179) 5317
- 4o of sets 26 24 126. 26 26 '61 134 Catch / set 39.2 125,7
. .. O 27.9 3 34.7 72.2 ,29.8j 39.7 4
- Jo. of species 3 6 p. ' 8 :: .
7 11 55 : s 15 vercent total catch 19.2 12.6 il25 17.0 35.3 ~ 3 [4-3 1 Represents pooled totals for eight species of low catch abundance, including mummichog, alewife Atlantic to:acod, grubby, cunner, longhorn sculpin, seasnail, and tautog. Shaded column is data from surveillance station.
sand lance, however, were taken at Manomet Point (Station 4), while winter flounder catches were highest at the latter location and at Long Point.
- 6. DNDERWATER FINFISH OBSERVATIONS Observational diving began in early May, with a total of 13 dives made throv.gh mid-November. Over 500 fish, comprising 7 species (Table 7) were observed in the study area (Figure 3).
Invertebrates noted included blue mussels (Mytilus edulis), lobster, starfish (Asterias spp.), and rock and Jonah crabs (Cancer borealis and C irroratus). As in 1986, we continued qualitative observation of Irish mosa (Chondrus crisnaa) growth and distribution along a transect used by Battelle resea chers in . the discharge area. Table 7. Abundance and distribution of all species observed during underwater observations, May
-November, 1987.
Number Station observed % of where most Species by divers total abundant Cunner 422 78.7 Di+C2 Pollock 93 17.4 Di Tautog 10 1.9 D2+C1 Rock gunnel 8 1.5 D1 Other* 3 0.6
- Longhorn sculpin, Striped bass, winter flounder Estimates of visibility in the water column (obtained laterally with a diver-held secchi disk and metered line) ranged from 2.5 - 10 m (average 6.3 m), depending on sea condition and
incident light. Average visibility in 1985 and 1986 (outage year) was 2.5 and 7 m, respectively, further evidence of enhanced water clarity during p tods of outage as noted by Kelly et al.
-(1987) in 1986.
Overall abundance (536 fish) was at its 'owest point since the inception of the diving study, due primarily to greatly reduced numbers of cunner and tautog. The majority of fish (45%) were observed in the discharge area (D), with 36% sighted in the control area (C), and 19% in the stunted area (S). Cunner remained the finfish species most often seen by j project divers, comprising 78.7% of all sightings (Table 7). Cunner were found at all stations, but were most commonly found j in the control area and at Station D.r The total number observed, 422, is the lowest of the study, an apparent l continuation of the downward trend noted in 1986 by Kelly et al. (1987). i Found primarily in the discharge zone (83% of all sightings), pollock was the second most abundant species observed 1 (Table 7). The 1987 total, 93, represents a decrease from the 1986 total of 130. However, as this species in highly active, occurrence in diver observations is more a matter of chance than 1 a true representation of local pollock abundance. Tautog ranked third in number of fish sighted (Table 7). Their abundance, like that of cunner, was at its lowest level of the dive program. Occurrence was evenly spread throughout the discharge and control areas. Rock gunnel, found primarily under and around the large erratic at Station D 1, w a fourth in abundanco. This small i i benthic species is a common inhabitant of the subtidal area (Bigelow and Schroeder 1953) and is most often sighted under l rocks or beneath clumps of algae. Because of its small size (generally around 15 cm), the rock gunnel is easily over-looked unless specifically sought. Though commonly found by divers and in the trawl, relative abundance of this species in the Pilgrim Station area is largely unknown. The remaining species comprised less than 1% of the total sightings, each represented by a single individual (Table 7).
- 7. SPORTFISHING During the 1987 informal creel survey, conducted from April November, reportedly only 1,250 angler trips were made to the Shorefront, and seven species of fish were caught. Of the sportfish catch (approximately 300 fish), cunner - 56%, winter flounder - 22%, and bluefish - 11%, comprised 89% of the total, while tautog, pollock, skate, and striped bass accounted for the remainder. This is the same ranx order of abundance as reflected in last year's sportfish catch at Pilgrim Shorefront.
Fishing occurred from the two discharge jetties, the outer intake breakwater, and the head of the intake embayment. Still-fishing with natural bait was by far the most popular method from the breakwater. Casting artificial lures was the predominant technique from the discharge jetties. Fishing pressure increased over the spring and was highest ! in July and August, when over 50% of the fishing trips took , place, declining thereafter. Over 50 percent of the angling i tripa in 1986 also occurred in the nummer period - June and July. l This ocanonal distribution of fishing activity has been l 1 .. _. - -.
consistent over the years (Lawton et al. 1984). Favorable weather conditions and the traditional summer vacation period are obvious contributing factors to this pattern of fishing effort. Highest sportfish catchen in number of species and total fish were recorded in July, followed by August. Cunner was nunerically dominant, being angled June-August; peak fishing occurred in July, when 88% of the cunner were taken. Winter flounder ranked second in sportfish catch and were caught May-l November. Highest catches of winter flounder were made in June, July, and August. Taken August-October, bluefish were most l l frequently caught in August. Overall, catches were extremely low relative to recorda from past years. l l l l i l l l l l l l l
V. CONCLUSIONS Lobster - Commercial Fisherv Catch statistics and biological data for the commercial lobster fishery in the Pilgrim area were collected from over 2,600 lobster taken from mid-May through October 1987. Catch per unit effort (CPUE) of total lobster decreased from 1986. Legal catch rate was also down, averaging 0.33 for the study period; the range was from 0.26 in May to 0.42 in July. This decline was partly a function of the change in our sampling regimen (we now sample the commercial catch of only one lobsterman). Unusually cold bottom water temperatures in the spring liekly depressed the commercial catch. Females oatnumbered males in monthly catches. The seasonality of percent ovigerous females has been similar the last three years. Lobster - Research Study Catches from controlled trap fishing (late June-September) were predominantly sublegal lobster (87%). Catch rates (mean catch per trap haul) of legals and sublegals were higher in 1987 than in 1986. The legal catch rate (0.3) for our research study matched up well with that from the commercial lobsterman sampled in the area (0.33). Mean carapace lengths and size compositions of catches were nearly identical in 1986 and 1987. Males slightly outnumbered females (1.1:1) in research trapping, which contrasts slightly with commercial trap data (1 male:1.5 females). Only 0.4% of the research catch of females were ovigerous females as compared to 2.4% of the commercial catch. The percentage of culls in the research catch (20%) approached that of the commercial catch (21.4%) and was identical to the
1986 level. Only 0.8% of the sublegal lobster we tagged were recovered in our gear, obviating the need to adjust our sublegal catch rates. Groundfinh Thirty fish species were collected by bottom trawling in the noarshore area in the environs of Pilgrim Station. Four species comprised 86% of the catch. The average catch per standard trawl (CPUE) for all species and stations combined was 22.9, with the two surveillance stations yielding the highest overall CPUE's. Winter flounder ranked first in total catch (34%) due to ist obundance in the Intake embayment. Although little skate dominated trawl catches at the other sampling stations, it ranked second in total catch (30%). Little skate were most abundant in the Discharge area. Over the last 4-5 years, windowpane and yellowtail flounder have ranked third and fifth, respectively, in trawl catch. Catch rates in the Pilgrim area declined from 1986 to 1987 for the top three species but remained at a similar level for yellowtail flounder. Young-of-the-year Atlantic cod captured in September and October were unusually abundant at all sampling i sites, pelaric and Benthi-celagic Fighes Thirty- cwo fish species were netted in monthly gill net sampling. Annual mean CPUE of pooled species was up from last year. Northern searobin led all species in catch for the first time, comprising 35% of the total. Although this species is common to our inshore waters in warmer months, the reason for the 1 large catches in 1987 is unknown. Pollock ranked second (20%), l ! I
with- their numbers being quite similar to the last four years. Atlantic herring was third (18%), and cunner, fourth (6%) in catch abundance. The latter was at its lowest relative abundance of the entire survey, suggesting a decline in the local - population. The remaining species were taken in relatively low numbers. A sand tiger shark was captured for the first time in the Pilgrim area since studies' began in 1969. Shora Zone Fish Twenty-nine fish species were captured in the 45.7 m haul seine study from June-November 1987. An increase in the catch rates, of Atlantic silverside, blueback herring, alewife, and sand lance greatly contributed to increase the overall 1987 mean catch per seine haul in the study area for all species combined. Station catch rates for pooled species also increased from 1986 to 1987. Five species comprised 98% of the total catch. The Atlantic silverside continued to dominate catches, as it has since the beginning of the study in 1981, comprising 78% of the total catch and ranking first in both overall CPUE and overall percent frequency of occurrence. Blueback herring were second in numerical abundance (8.5%) but fifth in frequency of occurrence. Sand lance numerically ranked third (6.8%). They were, however, caught almost exclusively at the Intake Station, with 94% of their total catch occurring in June. A)ewives ranked fourth in relative abundance (3.6%), with 93% of their total catch occuring in Auguet. Winter flounder were fifth in catch abundance (0.9%) but second in overall frequency of occurrence. Highest seine catches continued te occur in August and September when area water temperatures peak. Annual species diversity was highest at
tho Pilgrim Intake Station (20' species) followed by the Long Point Station (19 species). Relative abundance, due primarily to the large number of silversides, was highest at Long Point. In conjunction with the larger haul seines, a.6 m seine was
-uncd .to sample-finfish in the study area June-November 1987.
Fifteen species were collected. Four species (Atlantic silverside, sand lance, Atlantic menhaden, and blueback herring) comprised 97% of the catch with Atlantic silversides again dominating. Total number of fish, CPUE, and diversity were l highest at Long Point. All the menhaden and most of the blueback l horring were captured in the Intake. l Underwater Finfish Observatione Seven finfish species were observed by divers in the study area from early May to mid-November. The overall number of fish i l recorded was at its lowest point since the inception of diving observations, primarily due to the decline in sightings of cunner and tautog. The majority of fish (45%) were observed in ( the discharge area followed closely by the ccntrol area (36%). ! Although apparently continuing a decline noted in 1986, cunner l l remained the predominant species seen (79% of the sightings), Pollock ranked second (14%) but declined in numbers from 1986. This decline, however, may be more a result of fish activity than a decrease in population abundance. Tautog was third in I numerical abundance (2%) and, like cunner, was at its lowest level of the study. Rock gunnel was fourth in abundance (1.5%). l The remaining fish species comprised less than 1% of the total sightings. Periods of plant outage generally increased visibility as noted in 1986. l
T Soortfishina . An informal creel survey was again conducted at Pilgrim Shorefront from April-November. An estimated 1,250 angler trips were made to the area and an estimated 300 fish caught representing seven species. Cunner (56%), winter flounder (22%) and bluefish (11%) comprised almost 90% of the landings. Fishing activity was greatest in June and July. Highest catches were garnered in July and August; with cunner predominating in July and bluefish in August. Overall catches were extremely low relative to past records. i l i
1 l VI. ACKNOWLEDGMENTS l We acknowledge the contributions of numerous staff members of the Division of Marine Fisheries, who assisted in various phases of field sampling and data analysis, especially Karen Bugley, Neil Churchill, Steven Correia, Kevin Creighton, Robert De anche, Virginia Fay, Dan McKiernan, and Carl Sylvia. We thenk Chris Kyranos for allowing us to sample his lobster catches, and W.C. Sibley and Richard Schneider for overseeing the collection of creel data at the Shorefront area. Also greatly eppreciated is the work of Carleen Loper and Marie Callahan for typing this report. Finally, we thank Robert D. Anderson, W. Lsigh Bridges, and the Pilgrim Administrative-Technical Committec l for overseeing the entire study program. i VII. LITERATURE CITED Aiken, D. E., and S. L. Waddy. 1982. Cement gland development, ovary maturation, and reproductive cycles in the American lobster, Homarus americanus. Journal of Crustacean Biology 2(3):315-327. Bigelow, H. B., and W. C. Schroeder. 1953. Fishes of the Gulf of Maine. U.S. Fish and Wildlife Service Fishery Bulletin 53:577 p. Birely. L. E. 1984. Multivariate analysis of species composition of shore-zone fish assemblages found in Long Island Sound. Estuaries 7(3):242-247. Boston Edison Company. 1980. Benthic map overlays and assessment of benthic monitoring programs, Vol. 2. Nuclear Engineering Dept., Environmental Sciences Group. Boston Edison Company, Boston, MA, USA. 25 p. Briggs, P. T., and F. M. Muschacke. 1979. The American lobster in western Long Island Sound. New York Fish and Game Journal 26(1):59-86. Castro, J. I. 1983. The Sharks of North American Waters. Texas A. and M. University Press, College Station, Texas. 180 p. Conover, D. O., and M. R. Ross. 1982. Patterns in seasonal abundance, growth, and biomass of the Atlantic silverside, Menidia menidia, in a New England estuary. Estuaries 5(4): 275-286. l ! Davis, J. D. 1984. Western Cape Cod Bay: hydrographic, I i geological, ecological, and meteorological backgrounds for environmental studies, p. 1-18. In: J. D. Davis and l D. Merriman (editors), Observations of the Ecology and L
~
Biology of Western-Cape Cod Bay, Massachusetts. Springer-Verlag, Berlin, FRG. 289 p. Estrella, B. T., and D. J. McKiernan. 1986. Massachusetts coastal commercial lobster trap sampling program, May-Nov. 1985. Mass. Div. Marine Fish. 74 p. Kolly, B. C., V. J. Malkoski, S. J. Correia, R. P. Lawton, M. Borgatti, and B. Hollister. 1987. Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay (Vol. 1). Project Report No. 42. In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report No. 29. BECo, Braintree, MA. Lawton, R. P., W. T. Sides, E. A. Kouloheras, R. B. Fairbanks, M. Borgatti, and W. S. Collings. 1978. Final report on the ! assessment of possible effects of Pilgrim Nuclear Power Station on the marine environment. Project Report No. 24 (1970-1977). Massachusetts Division of Marine Fisheries. In: Marine ecology studies related to operation of Pilgrim Station. Final Report, July 1969-December 1977. Vol. 1, l sect. III.9. 19 p. Nuclear Engineering Dept., Boston Edison Company, 800 Boylston Street, Boston, MA. Lawton, R. P., R. D. Anderson, P. Brady, C. Sheehan, W. Sides, l E. Kouloheras, M. Borgatti, and V. Malkoski. 1984. Fishes of western Cape Cod Bay: studies in the vicinity of the Rocky Point Shoreline, p. 191-230. In: J. D. Davis and D. Merriman (editors), Observations on the Ecology and
Biology of Western Cape Cod' Bay, Massachusetts. Springer-Verlag, Berlin, FRG. 289 p. l Lawton, R. P., C. Sheehan, V. Malkoski, S. Correia, and M. :Borgatti. 1985. Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fishery resources of western Cape Cod Bay. Project Report No. 38 . (Jan.-Dec. 1984). In: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-Annual Report No. 25. Boston Edison Company, Braintree, MA, USA. Lawton R. P., V. J. Malkoski, S. J. Correia, J. B. O'Gorman and M. R. Borgatti. 1986. Annual report on monitoring to assesa impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay. Project Report No. 40 (Jan.-Dec. 1985). In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report j No. 27. Boston Edison Company, Braintree, MA. Robins, C. R., R. M. Bailey, C. E. Bond, J. R. Brooker, E. A. Lachner, R. N. Lea, and W. B. Scott. 1980. A L i si. .r? Common and Scientific Names of Fishes from the United States and Canada. 4th Edition. Special Publication No. 14. American Fisheries Society. 174 p.
, - , . _ , y --
o ANNUAL REPORT ON MONITORING TO ASSESS IMPACT OF PILGRIM NUCLEAR POWER STATION ON MARINE FISHERIES RESOURCES OF WESTERN CAPE COD BAY (IMPACT ON FISHERIES RESOURCES) Project Report No. 44 (January-December, 1987) (Volume 2 of 2) By Robert P. Lawton, Brian C. Kelly, VJncent J. Malkoski, and Mando Borgatti April 1, 1985 Massachusetta Department of Fisherica, Wildlife, and Environmental Law Enforcement Division of Marine Fisheries 100 Cambridge Street Boston, Massachusetto 02202
TABLE OF CONTENTS Section Page I. EXECUTIVE
SUMMARY
1 II. INTRODUCTION 2 III. RESULTS AND MATERIALS 3 A. Physical (Abiotic) Factors 3
- 1. Power Output and Thermal Capacity - 3 Impact Analysis
- 2. Discharge Current 3
- 3. Water Temperature 4 B. Impact of Pilgrim Station on Fisheries Resources 8
- 1. Commercial Lobster Pot-Catch Fishery 8
- 2. Research Lobster Trap Fishing 12
- 3. Nearshore Benthic Finfish 15
, 4. Pelagic and Benthi-Polagic Fisheu 22
- 5. Fishes of the Shore Zone 34
- 6. Underwater Finfish Observations 39
- 7. Sportfishing 46 IV. IMPACT PERSPECTIVE 49 V. CONCLUSIONS 53 VI. ACKNOWLEDGEMENTS 58 VII. LITERATURE CITED 59 l
\ 11 1
c LIST OF TABLES Table Page
- 1. Catch per unit effort from experimental fishing 13 for American lobster in the Pilgrim area for 1987. CTH represents catch per trap haul; CTHSOD indicates catch per trap haul per set-over-day.
Catch data are presented in numbers of lobster caught. Mean 12 standard errors is an estimate of precision.
- 2. Mean catch per standard gill net set (5 panels 26 of 3.8-8.9 cm mesh) for various time periods and the percent differences for selected species caught in the vicinity of Pilgrim Station, 1971-1987.
- 3. Mean catch per standard haul seine set for 37 selected species collected along the Plymouth shoreline, western Cape Cod Bay, 1983-1987.
- 4. A summary of impact assessment by study of 50 Pilgrim Nuclear Power Station (PNPS) on marine fisheries resources in western Cape Cod Bay during the operational history of the power plant.
i l 111 l l
LIST OF FIGURES Firure Page
- 1. Annual mean cumulative Pilgrim Station Unit I 4 Capacity Factor (MDC Net %) for 1972-1987 and circulating water pump operation at the plant for 1983-1987.
- 2. Surface water temperatures in the vicinity of 7 Pilgrim Station averaged by season and area for the year of highest plant operational status (1985) and lowest (1987).
- 3. Lobster pot sampling grid for the commercial 9 lobsterman monitored in the Pilgrim Power Plant area [ surveillance (H-11, H-12, I-11, and I-12) and reference (E-13, E-14, and F-13) quadrats are shaded]
and distribution of his traps sampled in 1987.
- 4. Mean annual catch per standard tow of three dominant 17 groundfish by bottom trawl at reference Station 1, and surveillance Station 3, 1982-1987.
- 5. Seasonal mean trawl catch rates with vertical error 19 bars for winter flounder by station in the Pilgrim area, 1987. Note changen in Y-axis scale with season,
- 6. Seasonal mean trawl catch rates with vertical error 20 bars for little skate by station in the Pilgrim area, 1987. Noto changen in Y-axis scale with season.
- 7. Seasonal mean trawl catch rates with vertical error 21 bara for windowpane by station in the Pilgrim area, 1987. Note changes in Y-axis scale with season.
- 8. Cumulative length frequency distributions by station 23 for winter flounder trawled in spring and summer 1987, near Pilgrim Station.
- 9. Mean annual gill not catch per unit effort for 25 pollock in the Pilgrim Station area and annual Unit I Capacity Factor (MDC Net %) at Pilgrim Station, 1971-1987.
- 10. Mean gill not catch per unit effort for cunner 28 in the Pilgrim Station area and seasonal Unit I Capacity Factor (MDC Net %) at Pilgrim Station, 1971-1987.
- 11. The average gill not catch / effort for Atlantic 31 horring in the Pilgrim Station area and yearly Unit I Capacity Factor (MDC Not %) at Pilgrim Station, 1971-1987.
iv
l
- 12. Mean gill net catch rate of tautog in the Pilgrim 33 {
Station area and seasonal Unit I Capacity Factor (MDC Net %) at Pilgrin Station, 1971-1987. ,
- 13. Catch rate of alewife captured by gill net in the 35 Pilgrim Station area and seasonal Unit I Capacity Factor (MDC Net %) at Pilgrim Station, 1971-1987.
i
- 14. Distribution of finfish observed by divers in each 40 j zone (S-stunted; D-denuded; C-control) off Pilgrim '
Station discharge canal, 1983-1987.
- 15. Index of relative abundance (fish / dive) for cunner 42 observed by divers at Pilgrim Station, 1981-1987.
- 16. Distribution of cunner observed by divers in each 43 zone (S: stunted; D= denuded; C control) off the Pilgrim Station discharge canal, 1983-1987.
- 17. Annual mean circulating water pump operation at 43 Pilgrim Station, 1981-1987.
- 18. Index of relative abundance (fish / dive) for tautog 45 observed by divers off Pilgrim Station, 1981-1987.
- 19. Distribution of tautog observed by divers in each 47 zone (S= stunted; D= denuded; C= control) off the Pilgrim Station discharge canal, 1983-1987.
l V
( f t LIST OF PLATES { Plate 1. Biologist collecting length-frequency data from the catch of a commercial lobsterman in the proximity of Pilgrim Station. Lobsters constitute the area's most valuable fishery resource. Plate 2. Operations aboard a fishing vessel used during the 1986 experimental lobster study. This investigation is designed to better assess the impact on lobsters of the thermal effluent at Pilgrim Station. Plate 3. Retrieval of the experimental gill net after a standardized overnight set in the thermal plume area. Caught in the net is a smooth dogfish, a common summer migrant in the Pilgrim area. Plate 4. Fishes caught by gill-nat in the area of the thermal plume at Pilgrim Station. Gill-net catches include commercially important species, e.g., Atlantic cod, pollock, Atlantic mackerel, striped bass, and winter flounder. Plate 5. Bottom trawl being set to sample groundfish in the inshore waters of western Cape Cod Bay. Catches are used to measure potential impacts of Pilgric Station on the benthic fish community. Plate 6. Typical trawl catch is processed which includes identifying, enumerating, and measuring the different species for environmental assessment. Catches of winter flounder have been consistently larger at the Pilgrim Station intake trawl station. Plate 7. Haul seining in the intake embayment at Pilgrim Station: the net is being set from a powered-skiff to enclose a rectangular area. Seine catches can be integrated with impingement data for a more comprehensive evaluation of potential impact on shorezone fishes. Plate 8. Haul seine catch processed or. the beach near the Pilgrim Station intake (fish are enumerated and measured). Among the shoresone fishes are important forage fish such as the Atlantia silverside and sand lance, and the jusenile stages of several commercial i species such as the winter flounder and Atlantic I menhaden. Plate 9. Biologist-diver deploying a transect line between observational stations. Diving observations have recorded the greatest number of fishes in the "denuded" cone directly off the discharge canal. vi
l Plate 10. A tautog foraging at the mouth of the discharge canal (Station D) at Pilgrim Station. A popular catch of recreational fishermen, tautog are in the Pilgrim area from spring through autumn and have been used as an "indicator" organism to assess strese mposed by the i release of the heated effluent. Plate 11. Pictured is the thermal effluent discharging into Cape Cod Bay and anglers fishing off the discharge jetties and from boats in the plume which is visible in the
. background by the calm water. Striped baus and bluefish, which are attracted to and concentrate in the thermal current, are the dominant species sought by sport fishermen at this location.
Plate 12. Anglers seeking sportfish at the mouth of the discharge
- canal. Casting artificial lures is the most popular
- method of fishing che discharge current which attracts a variety of species.
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I. RYRCUTIVE
SUMMARY
In accordance with the operational monitoring and reporting requirements of the U.S. Environmental Protection Agency and the Massachusetts Division of Water Pollution Control, marine coological studies were continued at Pilgrim Nuclear Power Station in 1987. Marine Fisheries studies were recommended and Epproved by the Pilgrim Administrative-Technical Committee, an oversight committee established to insure that Pilgrim Station carine studies havo the benefit of qualified scientific input and era responsive to regulatory agency concerns. Fisheries' crapling data were collected from reference and surveillance otntions to assess plant impact. Emphasis was placed on conparing data from from 1983 and 1985, years of high power plant thormal output (>80% capacity), with 1984 (outage), 1986 (low output), and 1987 (outage).. Results this year confirmed that the power plant outage has resulted in localized environmental differences from when the plant waa operating. Sportfish catches of striped base and bluofish were markedly reduced without the thermal discharge, It was more evident that cunner area attracted to the current , corponent of the Station discharge. Lika cunner, tautog data support some attraction for thin species to the discharge current. There appears to be nn inverse relaticnahip between the
, concercial legal lobster catch rate in the discharge area and the PNPS cooling water discharge. ~, . . - -
l: II. INTRODUCTION Monitoring studies were conducted by the Massachusetts ' Division of Marine Fisheries to assess environmental impact induced by Pilgrim Nuclear Power Station. Ecological investigations of fisheries resources in the surrounding waters of Western Cape Cod Bay-for 1987 were funded by Boston Edison Company under Furchase Order No. 63644. Sampling date were collected from refarence and surveillance stations during January-December, 1987; analysis included a summarization of the data and a discussion in relation to past findings. It is noted that the plant did not operate the entire year of 1987. This outage negated waste heat discharge, and current flow was reduced or nil. Measurements, counts, percentages, and indices of abundance are used in this report to identify trends and/or relationships in the data both spatially and temporally. Volume ) 2 is an assessment of power plant impact on the marine i environment. Emphasis was placed an comparing data from 1983 and 1985, years of high power plant thermal output (> 80% capacity), with 1984 (outage year), 1986 (low output year: 17.5% capacity) , and 1987 (outage year). Plates 1-12 (found on the next several pages) depict sampling program operations to assess power plant impact on fisheries resources in the western inshore region of Cape Cod , Bay. 4 4
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III. RESULTS AND DISCUSSION A. PHYSICAL (ABIOTIC) FACTORS
- 1. POWER OUTPUT AND THERMAL CAPACITY - IMPACT ANALYSJH To assess power plant impact on marine fisheries' resources in the surrounding waters of Cape Cod Bay, we compared assessment dcta with the Pilgrim Nuclear Power Station Unit I Maximum C:pacity Factor (MDC Net %). The latter is an index of operational output which roughly approximates thermal loading (colefaction) to the marine environment (100% MDC - 15.1 C above ccbient water temperature, referred to as21T). Since inception of plcnt operation in July 1972, the annual MDC factor at Pilgrim l
Stntion han ranged from 0.0% this year (1987), an outage year, to l l c high of 84.4% in 1985 (Figure 1). The power level capacity was , alco extremely low (0.1%) in 1984 (ecaentially an outage year), while it exceeded 80% during two other years besides 1985, viz. j 1979 and 1983. In thic report, we streno data comparisons for 1984, 1986 (17.5% sanual MDC),and 1987 with the two recent yeara l ! (1983 and 1985) of high operational output Pilgrim Station han j oparated over the years at a cumulative capacity factor of just under 50% (~ 7 C d T above ambient) or at just about half its po2sible output. With thin operational history, we probably have not fully realized to date potential plant impact on aquatic rocources. 1
- 2. DISCHARGIL CURRENT-At the Pilgrim Scation site, localized currenta are induced by the plant's circulating water intake and discharge. This once-through cooling nyatem, besiden removing waste heat from the plcnt's condeneer tuben, releases a current of water which han
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...i J F M J ASCNOJ FMAMJ J ASCNDJ F MAMJ J ASCNDJ F WMJ J ASC.OJ F MAMJ J ASCND f 1983 1984 1985 1986 1987 Figure 1 . Annual mean cumulative Pilgrim Station Unit I Capacity Factor (MDC Net %) for 1972-1987 and c at ng s'ater pump operation at the p ant
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tha physical effect of a accuring or abrasive action on the benthic environment. Furthermore, the interaction of tt perature, salinity, and currents is important in influencing tho occurrence, distribution, and abundance of marine life. During the plant outage of 1984, one or both circulating cc water pumps were off (Figure 1), thus minimizing or at least cubstantially reducing the offshore discharge current. In 1986, both pumps were operated from the beginning of January to early March; thereafter during the outage only one pump was utilized. With the outage continuing in 1987, the plant's two circulating l purps were off from approximately March-August, while one circulating pump was run during the majority of the other six l conthn. During the remainder of the time from 1933-1987 both circulating acavater pumps were operating, i 3.WlLTER TEtiEERATURES. Taking a closer look at water temperaturo in the Pilgrim 1 crea for the laat five years, we found, an expected, in 1983 and 1985 (>80% power plant capacity) ceasonal water temperatures were generally highest in the discharge area because of the addition of waate heat to the watera contiguous to the power plant (Figure 2). Wheroaa the extent of the near-field region delimited by the diacharge flow included a 1,100 m 2 to 1,400 m 2 ' denuded' zone (primarily a result of accuring), a peripheral area of ' stunted" l algal growth of about 1,900 m 2 to 2,900 m 2 resulted from the thermal component of the discharge (Bridges and Anderson 1984). In summer with the power plant at 100% operating load, we have tenaured a temperature differential (6 T) up to about 15 C between discharge Ond ambient waters. Conversely, in 1984 (outage yea.-), 1986 (plant outage April-December), and 1987 (outage year), water temperatures.in the discharge area mirrored aubient levels (Figure 2).
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l f I } l 1985 Temperaturo C 80 20-10 -- - l T-I 5 - - 0 - r- vvri . 4 i r- r i . i v v r- . . 1 234 5 1 234 5 12345 1234 6 Winter String Summer Fall D 1 ceste s.= a 6 % p. m 1+ M*a Cave 6
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of Pilgris Station averaged by season and area for the year of hig!.est plant oper-ational status (1985) and lowest (1987). 7-l . \ _ _ _ _ . _. __- .
B. IMPACT OF PIIGRIM STATION ON FISHERIES RESOURCES
- 1. CONMERCIAL LOBSTER POT-CATCH FISHRRY Pooled lobster catch statistics from the surveillance (discharge) quadrats (H-11, H-12, I-11, and I-12) were compared with data from the following reference quadrats (E-13, E-14, and F-13) located in Warren Cove (Figure 3) to assess the impact of Pilgrim Station on the local lobster population and fishery. We can compare data collected in 1987 with past years because the same lobsterman has supplied most, if not all, of the impact / control data.
Females outnumbered males in the catch for the entire study i area in 1987. Of all the lobster sampled, 54% were females. In the surveillance area, females comprised 53% of the sampled catch; while at the reference quadrats, females comprised 67% of the catch. As in 1986, the percentage of culls in the surveillance area in 1987 was markedly lower (12.3%) than in the referenco area (21.4%). A chi-square test (Sokal and Rohlf i969) showed this difference to be significant (P 1 0.05) in 1987. Lobster cull rate is enhanced by lobster fishing and bottom trawl activity (Keser et al. 1983; Estrella and McKiernan 1986). In Warren Cove (reference area), commercial trawling is seasonally (November-March) conducted for groundfish; this may account for the higher cull rate there. The 1987 mean catch rate (catch in number of lobsters per trap haul) for legal-sized lobsters (1 81 mm carapace length - CL) in the surveillance area was 0.34 legals / trap-haul, while the reference area's legal catch rate was markedly lower at 0.20 e
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F4cere 3 Lobster pot say11ng grid fut t he i . +ae r s t il let*tersen evnttered in tte Pilgrit P.r Plant trea[surve tt l eNe (H-II . k-l!. t-il, and 1-ll) and re f erence g F .1 3 . E l., tw . f-l)) quadrats are snadgil anJ distributto-s of his t r ips sample;f in 146?, i I
k The catch rate at the control area dropped over 50% from last year. Mean legal catch rates in the discharge area have declined l alightly over the last five years, ranging from 0.47 in 1983 to 0.34 in 1987. The legal catch rate there was 0.40 in 1985 and 1986 and 0.42 in 1984. This contrasts with the trend for the Pilgrim area and for coastal waters overall. With the cooler ambient temperature regime in 1984 (Estrella 1985), the early season molt apparently was depressed or at least delayed; this, in turn, would have affected recruitment to legal size and impeded lobster activity I (Campbell 1983; Estre'.la 1985). The mean catch rate of legal-sized lobster in western Cape Cod Bay was lower by about 50% or more in 1984 (0.32 legals / trap haul) compared to 1983 (0.61), 1985 (0.66), and 1986 (0.77). The catch rate in 1987 was 0.51. According to Estrella (1985) and Er,trella and McKiernan (1986), the coastwide commercial catch rate (catch per trap haul) of marketable lobster in 1984 was lower than in 1983 and 1985 by 19% and 20%, respectively. Record lobster landings were documented for Massachusetts in 1985 and 1986 (Estrella and McKiernan 1986). Cape Cod Bay lobstermen had to contend with colder spring i temperatures again in 1987 which delayed the lobster molt, resulting in a 34% reduction in commercial catch rate from 1986. We tested catch data using several nonparametric statistical tests, which are not dependent on a given distribution but usually work for a wide range of distributions (Sokal and Rohlf 1969). Annual legal catch rates were compared for the discharge and reference areas for block periods of time. The K ruskal- 1
Wallis test revealed no statistical differences (P > 0.05) between areas over the entire survey, for the pr: operational / outage years, or for the operational years. With tho Wilcoxon's signed-ranks test of legal catch rates by year l (operational) arranged as paired observations (surveillance varaus reference), we found no significant differences in CPUE (P
> 0.05) between control and test areas.
Catch sampling data and plant thermal output were examined for a relationship using correlational analysis (Sokal and Rohlf 1969) of Unit I Pilgrim Station Capacity Factor (MDC Net %) i versus mean legal catch rates by year for prescribed areas. Sublegala were not examined in this way because of the sampling I l bica of commercial pots. We found a significant negative l correlation (r : -0.57; P 1 0.05) between legal lobster catch l rate for thermal quadrats pooled (surveillance area) and mean cnnual Pilgrim Station MDC Not % Capacity Factor for operational l yocra. We then ran a correlation analysis on the mean Unit I I I thermal output for the period of May-December, which approximates ! the inshore lobster fishing season, versua legal catch rates for tha surveillance area and also obtained a correlation coefficient of -0.57 which is significant at the 95% level Conversely, when l power output and legal lobster catch rates for reference quadrats wars tested for annociation, no correlations were statistically ! varifiable. When two variables are correlated, cause and effect l 10 not necessarily validated; however, there la the possibility of cn inverse relationship between the catch rate of legal-sir.ed lobstern in the impacted area (quadrats H-11, H-12, I-11, and I-
- 12) and the opers-ting level of Pilgrim Station.
As to the effect of current flow on catch rate, Auster - (1985) reported that a water current above a critical velocity f will retard the foraging behavior of lobster by inhibiting mobility. It is reasonable to conclude this might translate into reduced trap catches in the immediate discharge area where current velocity may reach several feet /second. In fact, our diving observations have revealed few lobster in the immediate arca of the discharge canal.
- 2. RESEARCH LOBSTER TRAP FISHING An experimental pot-catch sampling program was completed for a second consecutive summer (mid-June through the end of September 1987), with the intent of further determining, in addition to commercial catch monitoring, whether Pilgrim Station operation measurably affects the local lobster population and 1 fishery. Data on lobster sizn frequencies, sex ratios, culls, berried femalen, and catch rates were examined.
From 2,282 trap hauls, 5,449 lobster were captured. Catch por unit effort (CPOE) of sublegal lobster (181 mm carapace length - CL), as measured by catch per trap haul (CTH), averaged 2.076 overall (Table 1), an increase of 110% from 1988. CTH weighted by immersion time of the pota (CTHSOD), which was the most appropriate measure of CPUE for legala (181 mm CL), averaged 0.151 in the study area in 1987, up 72% from last year. Catch raten were up in both reference areas (Rocky Point and White Horae /Priscilla Beach) and in the surveillance area. The reason for the increase in not known at thin time. i Table 1. Catch per unit ef fort from experimental fishing for American lobster in the Pilgrim area for 1987. CTH represents catch per trap haul; CTHSOD indicates catch per trap haul per set-over-day. Catch data are presented in numbers of lobster caught. Mean 22 standard errors is an estimate of precision. Legal-sized Lobster Sublegal Lobster ( > 81 mm CL) (< 81 cm CL) Mean 22 Mean 22 Ar a CTESOD Standard Errors CTH Standard Errors Entire Study Area 0.151 0.139 - 0.163 2.076 1.997 - 2.155 Surva111snee Area 0.146 0.127 - 0.165 1.882 1.758 - 2.006 Entire Reference Area 0.154 0.139 - 0.169 2.204 2.102 - 2.306 Rocky Point (Control) 0.138 0.120 - 0.156 2.244 2.114 - 2.374 White Horse (Control) 0.186 0.157 - 0.215 2.127 1.967 - 2.287 l l l l l l l l l l l The overall sex ratio of males to females in the study area - was- 1.1:1 jn 1987 and approximately 1:1 last year. Within the
. respective surveillance and reference zones, males slightly outnumbered females, except in 1988 at White Horse /Priscilla Beach (more females caught). The percentage of females captured that were bearing eggs (ovigerous) was 0.8% in 1987 and 2.9% in 1S88. No clear pattern emerged within the sampling zones. Last year, over 80% of the berried females were taken at White Horse /Priscilla Beach; whereas, this year only 10% were captured there. Over half of the egg-carrying females were captured in the surveillance area in 1987.
In 1986 and 1987, the percentage of cull lobster (missing or regenerating claw (s)) captured in the study was about 20%. The density of culla (CTH) was lowest in the discharge area and highest at White Horse /Priscilla Beach each year. The field research lobster trap study conducted for the last two years has been in effect a trial experiment under essentially control conditions (i.e. plant' outage, with no waste heat discharge and reduced or minimal current flow). The data will be compared with data from future high operational years. This was l fortuitous giving un the opportunity to refine the field sampling design. The work became a uniformity trial where we fished standard traps in a standardized manner over the proposed < experimental area. The proper pairing of potentially impacted /aurveillance sites with non-impacted / reference siten was of prime importance, for it was assumed that lobster at both locations will respond in a nimilar way to changen in abiotic variablea. The invalidity of thin assumption would negate the 4 l cccessment of stress at the surveillance location when the power i plcnt resumes operation. Based on two sampling seasons of trapping data, two parameters were identified that offer promise for detecting lobster population impact at Pilgrim Station - catch rate (ralative abundance) and size composition of lobster. Using the cample mean and estimates of precision, and the approximate test of equality of means of two samples whose variances were unequal (F-max test) (Sokal and Rohlf 1969), catch rates of legals and cublegals were tested between areas. It was found that Rocky Point (reference) and the discharge (surveillance) areas are an cpproximate station pair to assess power plant effect on catch rate of legal lobster. The Kolmogorov-Smirnov procedure (Sokal ( and Rohlf 1969) was used to test size distributions of lobster ccught in the different areas. As for size composition, it was found that size frequency data of legala at both reference areas r could be pooled to increase sample size and then tested against cice distribution of legals in the discharge for potential power Plcnt imptot.
- 3. NRARSHORE BENTHIC FINFISH Pilgrim Station discharged no waste heat and little water current in 1987. For comparative purposes, trawl data from the outage years - 1984, 1986, 1987 - are compared with those recent hich operation years when the plant operated greater than 80% of its capacity (1983 and 1985). During the low /off operational years, the amount of current coming from the discharge canal varied, depending on the number of circulating seawater pumps in l
l use. Station 1 (Warren Cove) was considered the primary reference site and was compared with the surveillance site, Station 3 1 (Discharge), for impact analysis. Mean annual catch rates for the three dominant groundfish - winter flounder (Pseudooleuronectna americanus), windowpane (Scophthalmun aquosus), and little skate (Raia erinacea) - were examined for differences between reference and surveillance sites (Figure 4). Mean annual CPOE of winter flounder for 1987 at Station 3 exceeded that of Station 1 for the second consecutive year. In 1984 (another outage year), the Station 1 winter flounder catch index was nearly double that of Station 3. Since - 1983, however, CPUE of winter flounder at Station I has generally declined, while at Station 3, the catch rate has been fairly constant. Thus, the apparent change in relative distribution at these Stations noted in 1986 and 1987 does not appear to be related to reduction in output of heated effluent. From 1984-1986, the annual catch rate of little skate at Station 1 steadily rose; concurrently, it declined at Station 3. In 1987, those trends were reversed. The annual relative abundance of windowpane increased slightly at both stations in 1988, but declined in 1987 at Station 1. If differences in relative abundance (indexed by CPOE) resulted from plant operation, one would expect to see differences in 1986 and 1987 data at Stations 1 and 3 relative to previous years, with the exception of the outage year in 1984. This was not apparent, an abundance indices for 1988 and 1987 were independent of each other, indicating no measurable impact of plant operational status on the distribution of the three l ,I
,nuseta or riswTow r
e - - s - - - - - WINTER FLOUNDER
- - - - ~
s - - - - - - - - -
- NUMBER OF FISH / TOW 8 - -- - - - - '
30 30 l , . .. _ _ _ _ 25 - 25 "g" " " ' M sTesoes i EZIsTaeon s ; j 20 - - 20 , ! L l 7 15 - 15 l 10 - - 10 5 pd
/ -- -
5 13TTLE SKATE M # # nuemen or resserow 1982 1983 1984 1985 198 198 : l YEAR io - -- - - - M STATION 1 Eh3 SIATION 3 e - - - - - --- j . _ _ g -. _ .- . 1982 1983 1964 1986 1988 198F YEAR j M sT4 son i EE3stason s Figure 4 Mean annual catch per standard tow of three dominant groundfish by bottom trawl at reference Station 1. and surveillance Station 3.1982-1987.
)
groundfish species evaluated. A similar conclusion was reached ' from trawl data for the outage year of 1984 (Lawton et al. 1985). We have used annual mean trawl CPUE of selected finfish species to measure changes in relative abundance over time. Within the annual CPUE for each species are marked seasonal patterns of abundance. The variances of a species' seasonal mean CPUE are less than that of the corresponding annual catch rate; hence, seasonal CPOR's are a more precise statistic to analyze trawl data. To investigate seasonal variation in trawl catch rates for 1987 at each station, we partitioned catch data for winter flounder, little skate, and windowpane by season: winter (January-March), spring ((April-June), summer (July-September), and fall (October-December). Choice of seasonal demarcations was J based on bottom trawl catch rates and sea water temperature data collected at sampling stations in the Pilgrim area over the last decade (Lawton et al. 1983). Comparisons between stations within
- a seanon of the overlap of the CPUE standard error bars gives an approximation of any significant differences in catch rates.
Trawl data are inherently highly variable; hence the large standard error bars for catch data (Figures 5-7). Winter CPUE's for the species selected were extremely low and will not be considered further. In summer, little skate (Figure 6) at Station 6 (intake) and at primary reference Station 1 were significantly less abundant . l than at reference Station 4 and primary surveillance Station 3 (discharge). There is no indication that winter flounder or
WDITER 8Pf4NG unmEn w rieevvow w o, ,,wo , 12 go I ! to -:
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tam STATION STATION Figure 5. Seasonal mean trawl catch rates with vertical error bars for winter flounder by station In Pilgrini area,1987. Note changes in Y-axis scale with season.
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.as asowsm moree.ca o. ma l STADON STATION I F!gu:'s 6, Seasonal mean trawl catch rates with vertical error bare for little skate by station in PI' grim area,1967. Note changes in Y-axis scale with season.
l WDITER sppgge ansmeER & FiswTO* NumeER OF FISwTOw tt
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PJ e-* a N FAl1. NL.eER OF FiSwTOW NUMBER OF FiswTOist F 4 e - - - - - 4 - s a -- - - _ _ . ._ --, s s-- ; 2 - -- -. - - -- 1 i . -
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bTATION STATION Figure 7. Seasonal mean trawl catch rates with wertical error bars for windowpane by station in Pilgrim ares,1987. Note changes in Y-axis scale
'sith season.
windowpane relative abundance differed significant1, amongst any of the stations during the seasons of 1987. Previous analyses of trawl data indicated the Intake (Station 6) to be a haven for small winter flounder <22 cm total length, presumably due to the algal cover and sheltered , environment (Lawton et al. 1985, 1986). To test this seasonally, we subjected this year's spring and summer data for winter l flounder to the nonparametric Kolmogorov-Smirnov test for differences in length-frequency distributions between Station 6 and the other stations. In apring, there was a significant difference in the size distribution of winter flounder between Station 6 and reference Station 4 (P 1 .05); the comparison , between Station 6 and Station 1 generated a probability level of P =0.07. In summer, none of the compared length frequency distributions were significantly different. Plots of the spring and summer percent cumulative frequencies of winter flounder lengthe (Figure 8) illustrate that the significant difference in length frequency distributions in spring is due to a pulse of r small fish residing in the Intake which exposes them to potential impingement and\or thermal backwash effects.
- 4. pRLAGIC AND BENTHI-PELAGIC FISHES Our gill net survey abundance index (overnight gill not catch) was influenced by sampling error (variance) and bias (gill neta in general are size selective). Some species were susceptible to a wide range of mesh sizes, and some were entrapped by opinea or mouth parta regardlena of size. We assumed gear efficiency did not change over time, and fishing effort of the not was uniform for all mesh aizes. Vulnerability
SPRING 1987 SUMMER 1987 CUMULATIVE PERCENT CUMULATIVE PERCENT 300_ joo_ - . ~ . .
/ r
/
75 - --
/ -- 75-E3- l 50-i/
-yO
' '/
25- . . . 25-
." l l O _.... ...... .... .. ...... ,
.... .... O I.__.
7 10 13 16 19 22 25 28 31 34 37 40 43 4 7 10 13 16 19 22 25 28 31 34 37 TOTAL LENGTH (CM) TOTAL LENGTH (CM)
- - STATION 1 - STATION 3 - STATION 1 - STATION 3
--- STATION 4 - STATION 0 - STATION 4 - STATION 6 Figure 8. Cumulatlwe length frequency distributions by station for winter flounder trawled in spring and summer 1987, near Pilgrim Station.
of each species was assumed constant, and we assumed that the number of fish already caught did not influence the capture of additional fish, pollock This benthi-pelagic species ranked second, comprising 20% of the 1987 gill-net catch. Relative abundance estimates, generated from catch-per-unit-effort (CPUE) data, reflect local population fluctuatir.as over the survey years (Figure 9). An increase in relative abundance occurred from 1971-1972 (preoperational years), followed by a substantial reduction from 1974-1976. Stock index rebounded in 1977 to exceed past levels and remained relatively high through 1981; CPUE declined in 1982 and has subsequently fluctuated at a reduced level through 1987. Comparing means of CPUE for the preoperational and operational (1973-1983,1985) study years; and between 1983/1985 when Pilgrim Station operational output exceeded 80% and 1984/1086/1987 (outage periods), revealed, respectively, that relative abundance was 13% lower overall during the operational years and 23% lower in 1984/1986/1987 pooled than in 1983/1985 (Table 2). There is no apparent relationship between the annual index for Pilgrim Station operational output and annual CPUE (relative l abundance) data for pollock (Figure 9). When statistically tested, these variables were not significantly correlated (r = 0.231; P > 0.05). Changes in relative abundance apparently reflect natural variability. i
Pollock Mean Caten per gill-net set MDC Net Annual Mean % 160 100 140- - 120- - - - - -
-80 100- X (j -
J -60 80- - - - -- - 60- -- -- - - - - - -- _.
-40 40- -
/
20- - - - g _ -20 - 0 i i i i i i i i i . i i i i . . . 0
'71 '72 '73 '74 '75 '76'77'78 '79'80 '81'82'83'84'85'86'87 Year Mean CPUE I IMDC Net %
Figure 9. Mean annual gill-not catch per Unit ef fort for pollock in the Pilgrim Station area and annusi Unit I Capacity Factor (MDC Not %) at Pilgrim Station, 1971-1987.
' A t
s f
- Table 2 Mean catch per standard 3111 net set (5 panels of 3.8 -
8.9 cm mesh) for various time periods'and the percent differences for selected species caught'in the vicinity
>f Pilgrim Station. 1971-1987.
Species Atlantic Year Pollock Cunner herring Alewife Tautos 1971-1972 93.8 18.8 7.8 25.6- 0.6
.973-1983. 1985 81.3 32.9 32.2 9.2 2.2 Preoperational -
operational - 13% + 75% + 313% -- 67% + 267% percent diffe:ence -l 1983 and 1985 ( > 80% capacity) 62.4 25.9 9.1 5.8 5.4 1984, 1986 an.1987 47.8 19.2 19.3 4.1 4.5 (outage years) 1983/1985 - 1984/198a - 23% - 26% + 112% - 29% - 17% i- 1987 percent difference i } i t
,,,-.m...--. ~,-,-m-,--
Cunnnr Cunner ranked fourth in overall gill-net catch (6%). Annual cbundance estimates peaked in the operational years of 1978 and 1980 (Figure 10). The benthic cunner exhibited population consistency in the Pilgrim area from 1971-1976, with a grand mean CPUE for these 6 years of 22 fish per gill-net set. From 1977-1983 annual catch rates were about double (grand mean CPOR of 41 c anner por set) that obtained the first six years of the survey, indicating a marked change in distribution and/or abundance of tha local population. Subsequently, beginning in 1984, relative cbundance has declined with the 4-year catch rate for 1984-1987 cvoraging 18 fiah per set. CPOE in 1987 was the lowest of the su rvey . Pooled CPUE for cunner captured during operational study i j yoaca increased 75% from the average for the pre-operational atudy years. Catch ratea were down again in 1984, an outage year; in 1985, a year of high thermal output; and again in i 1986 and 1987 (outage perioda).
- The plot of plant operational output for spring and aummer, ,
- when cunner occur in the area, versus CPDE auggesta a possible relationship between the two variables (Figure 10). We statistically tested data on CPDE and plant operation power level l for survey years through 1987 and found a significant positive correlation (r =0.581; P 1 0.05). Regression analyala of catch ,
rato on t:e seasonal (apring-summer) plant capacity factor for curvey yearn yloided a significant F ratio (F a : 7.13; P 1 0.018). It la evident from the observed value of F that the variance of CPDE of cunner can be explained partially by the
- - -. _. - ._ ~ - - - . --
Cunner Mean Catch per glli-net seMDC Net Seasonal Mean % (spring-summer) 50, 100 40- - G 80 30- -
=_ -
-60 g ^ w---
i 20- s _
--40 10- _
_ --20 0 i i i i i i i i i > > i i i i i i O
'71 '72'73 '74 '75 '76 '77 '78 '79'80 '81'82'83'84 '85'86'87 Year Mean CPUE I IMDC Net %
Figure 10. Mean gill-not catch per unit effort for cunner in the Pilgrim Station area and seasonal Unit I Capacity Factor (MDC Not %) at Pilgrim Station, 1971-1987.
regression on plant load. Specifically, almost 34% of the { variability in cunner CPUE can be explained by variation in plant operational level (MDC). Supporting evidence for a positive relationship between ralative cunner abundance in the Pilgrim Station discharge crea and the power plant thermal outflow into Cape Cod Bay comes from our observational diving program. Substantially more cunner were cichted in the discharge zone than in surrounding areas from 1981-1983, when Pilgrim Station was operating and releasing a earm discharge current. In 1985, cunner were most abundant at Station D i in the diacharge area. Conversely, in 1984, an outage ycor, divers sighted relatively more cunner at reference stations then in the surveillance area, which suggesta a localized shift in distribution. Waste heat was released from Pilgrim Station on only one day in 1984, and no water current was generated from April-August of that year, when both circulatlng water pumps were off. In 1966, no waste heat was released from Pilgrim Station into the discharge area during the cunner's stay innhore; however, one circulating seawater pump was operated, releasing an offshore flowing current. During the d3ving study in 1986, cunner were nighted in greater numbera in the discharge zone. In 1987 (ottage year), with no heat releaned from the plant and no cppreciable current discharged from March-August, cunner were egain, an in 1984, less abundant in the diacharge than in the > , control area. In conclusion, it is evident that cunner are cttracted to the cooling water diachar ge at Pilgrim Station. On
- 1.
the negative side, this subjects cunner to potential nearfield plant effects of heat or cold shock. gas bubble disease, and I exposure ',o chemicals (e.g., chlorine). Atlantic herrina Comprising 18% of the gill-net collection in 1987, Atlantic herring ranked third in catch. Over the survey years, annual relative abundance has fluctuated extensively, with an overall decline indicated subsequent to 1976 (Figure 11). Until 1985, CPUE for sea herring was lowest in 1972 (preoperational study year); by far, the highest annual catch rate was obtained in 1976 (operational study year). Catch statistica for Massachusetts ' -generally corroborated our findings; statewide landings declined in 1973 but increased steadily the next few years, peaking in 1976 (National Marine Fisheries Service 1976). After the decline in the Pilgrim area in 1972, CPUE generally increased during the operational years, but again dropped markedly in 1978. This was followed by a fluctuating CPUE that nevertheless declined overall to an all-time low in 1985; a slight upswing was suggested for 1986 and 1987. The grand mean catch rate for the operational study years was much greater than the average for the preoperational period i (Table 2). Catch rate was 112% higher for the average of 1984/1987 (outage) and 1986 (low plant output) than the average for 1983 and 1985 (> 80% plant capacity). However, no power plant effect has been detected to date. No relationship is discernible in the plot of annual Pilgrim Station operational
Atlantic Herring Mean Catch per gill-net set MCC Net Annual Mean % 100 - -- 100 80--
-80 60-- - --
-_ 60
~
e y 40--
/ I k-
-40
/ \ /
20- - - - - - r - (; , -20 0 N-L / i .
. i i . . . . . . . .
T N./ i 7,r i i O
'71'72'73'74 '75'76'77'78'79'80 '81'82'83'84'85'86'87 Year Mean CPUE I IMDC Net %
Figure 11. The average glli-not catch /ef fort for Atlantic herring in the Pilgrim Station area and yearly Unit I Capacity Factor (MDC Not %) at Pilgrim Station, 1971-1987.
output and annual catch data (Figure 11). Catch rate of herring and plant ' load' were not statistically correlated (r =0.027; P
>0.05).
Tautog Tautog comprised 3.1% of the gill-net catch in 1987. Relative abundance fluctuated at low levels from 1971-1981, but from 1982-1986, a high level of abundance was noted (Figure 12). Annual mean catch per set was especially low in 1975 (operational year of low thermal capacity) and high in 1985 (operational year of highest thermal capacity). Creel survey data from Pilgrim Shorefront corroborate this finding; sportfish catches of tautog were relatively low in 1974 and 1975, but peaked in 1985. A comparison of mean CPUE for preoperational and operational study years revealed an increase in numbers during the latter period (Table 2). The mean of catch rates for 1984, 1987 (outage) and 1986 (low thermal capacity) was 17% lower than the average for 1983 and 1985 ( high operational output). For the operational period, excluding the outage years, we found a significant positive correlation (r = 0.590; P 1 0.05) between CPUE and Pilgrim Station MDC (Net %) mean Capacity Factor for spring and summer (Figure 12), when tautog are most abundant inshore (Bigelow and Schroeder 1953). The relationship is somewhat questionable, however, for when we included the three outage years in the correlation analysis, no significant relationship was found (r : -0.012) at the 95% probability level. McWifn The pelagic alewife comprised 3.3% of the annual gill-not total for 1987. Over the curvey years, seasonal catch abundance Tautog Mean Catch per gill-net set MDC Not % Seasonal Mean(spring-summer) 6- ---
=100 5- -
-80 4_. . . _ _
_ -60 d, 3- - - ^ - - m.
/\
-l- \ -40 2- - --- - --- -- -- - - -
( -- -' 3_ _. . _gg _ . . . _.j_ . _ ._ _ ._ __ -20
~s N, s -
0 i i i i i i i . . . . i i i i i i 0 71 '72 '73 '74 '75 '76 '77 '78 '79 '80 '81 '82 '83'84 '85 '86 '87 Year Mean CPUE I IMDC Net % Figure 12. Mean gill-not catch rate of tautog in the Pilgrian Station area and seasonal Unit I Capacity Factor (MDC Net %) at Pilgrim Station, 1971-1987.
has been routinely highest in spring when this anadromous species migrates inshore to spawn in natal rivers. The annual mean CPUE markedly declined in 1972 and then has fluctuated at reduced levels during the operational study period (Figure 13). Catch rates were highest in 1971, followed by 1974. The difference between the overall CPUE for the preoperational and operational study years represents a downward trend of 67% (Table 2). Between 1983 and 1984, catch rate declined 68%, with low catches continuing into 1985 and 1986. There has been a general declining trend in relative abundance during the survey that began prior to operation of Pilgrim Station; the nadir in the catch occurred in 1981, with a slight upswing noted in 1983 and 1987 (Figure 13). It is believed that decreased catches are related to natural variability. No statistical correlation (r = -0.071; P > 0.05) was found between catch index and the mean Unit I Capacity Factor (index of power station operational output) for spring and summer, when most alewives were found in the study area. Diver herring have been subjected to intensive exploitation for years along the Atlantic coast, and the trend for commercial catches has been generally downward in the 70's and 80's (Resource Assessment Division, Northeast Fisheries Center 1983). Thus, the decline indicated in the gill-net records appears to be wide-spread and not limited to the Plymouth area.
- 5. EISiiES OF THE SHORE ZONE Fishes along the local beaches can potentially be impacted by Pilgrim Station via thermal stress, gas supersaturation, Alewife Mean Catch per gill-net setMDC Net Seasonal Mean % (spring-summer) 50--- 100 40- -
-80 30- - -- - -
-60 i
Y - 20- - -- - - - - - -
-40 10- _-- j bj 6 \
A _ 20 Y % -
/ (- , /
s - _ 0 . . 1 i . . . . . , . . . . . . . O
'71'72 '73 '74 '75 '76 '77 '78 '79 '80 '81'82 '83'84 '85'86 '87 Year Mean CPUE IMDC Net %
I Figure 13. Catch rate of the alewife captured by gill-not in the Pilgrim Station area and seasonal Unit I Capacity Factor (MDC Not %) at Pilgrim Station, 1971-1987.
discharge flow, impingement, entrainment, and heated backwashes. The shore-zone seine program has generated a species list and estimates of the numbers of finfish residing in the intertidal and shallow subtidal zones in the Pilgrim area. As to sampling surveillance sites, the rocky shoreline and breakwater in the area of the discharge precludes seining; however, suitable topography occurs in the Intake (Stations 3 and 6). Reference stations include habitats ranging from open coastal beaches to the mouth of an estuarine embayment. The seine, as a sampling tool, provides information on the occ.urrence, distribution, relative abundance, and size range of fish in the shore zone. Abundance data (catch per standard seine haul) of selected species were examined as a means of assessing power plant impact (Table 3). The surveys reveal some rather large natural variations in relative abundance which complicate the measuring of other than large ecosystem level effects of power generation. Using correlation analysis, relationships between monthly mean densities of the study area's dominant species, Atlantic silverside, in the Intake at Pilgrim Station and monthly Pilgrim Station thermal capacity (MDC net %); and between the former and monthly plant pump capacity were tested. No correlations were found (P > 0,05). Haul acining in the Intake embayment can identify potential sourcea of impinged fish. Of the 20 finfish species seined form i June-November, 1987 in the Intake, 9 were impinged at the power plant during the name time period. Because of the station outage and related decrease in pumping capacity, impingement for the aforementioned six montha was extremely low (19 apecies l l
Table 3 Mean catch per standard haul seine set for selected species collected along the Plymouth shoreline, vestern Cape Cod Bay, 1983-1987. Stations Warren Cove Long Point PNPS Intake *Manomet Point Pooled Ye r Mean Catch per Haul Seine Set Atlar. tic 119eididh4i 1983 103.7 197.7 :' $1670E ' i " 119.1 3984 51.2 220.9 44124] 101.7 3985 413.5 165.4 ; !!!2.92 Si 201.5 8986 21.5 107.0 g J2s9M 'l 46.9 F E70!8lt 1987 109.6 837.9 58.8 287.4** WinterflhuhM4r? Y 1983 1.0 4.9 [0l3tl , ; 2.4 l1984 1.1 2.9 62f0) 1.8 1985 1.0 7.4 ' 14~.~ 85 4.5 1986 0.4 4.3 , f9231 4.3 1987 0.6 1.1 ( 9. 0 t- 2.8 3.3** BluebackLherrins' 1983 1.0 13.1 10.0 5.6 ,1984 0.1 0.2 13.7? 1.1 1985 352.0 4.9 1144.7: , 178.2 1986 1.8 14.3 495.91 . 32.9 1987 1.2 0.1 1125.8- 0.4 31.1** Sand lance 'spp. - 1983 0.4 0.0 10.6' O.3 : 1984 0.5 0.2 140.6 10.7 1 1985 0.0 0.0 1449.5 140.5 1986 0.0 2.0 .-72.3l 21.2 1987 0.1 0.0 102.8 0.2 25.2** Pooled species 1983 188.1 253.7 24.7- 176.8 l 1984 54.3 233.8 92.0 120.1 i 1985 854.5 186.9 688.6- 569.0 ! 1986 30.9 150.5 -225.9: 129.0 l987 130.0 847.5 380.4 63.4 368.1** bFirst full season of data collected at this site. l
)01nclud3s data from Mancmet Point in the calculations.
Shidsd column is data from surveillance station. [ I t y _ .- - . , ,e.-r , y
totaling only 69 fish). Cunner comprised 20% of the collection; lumpfish, 14%; and winter flounder, 10%. Seine catches in the intake consisted predominantly of blueback herring (32%), sand lance (24%), and Atlantic silverside (21%). Highest seine catches were made in August, while the peak impingement month was September. The Pilgrim Station Intake with its man-made breakwaters and dredged channel is an artificially created embayment that is a haven for shore-zone fish in an otherwise open coastal region. In terms of total fish seined, catch rates, and numbers of species collected, the Intake most resembled the estuarine sampling site off the Long Point barrier beach; catches at the exposed coastal beaches were magnitudes lower. Fish concentrating in the Intake, especially in proximity to the Intake screen wall, are subject to mechanical and backwash thermal effects of the power plant. I Comparing abundance indices over the last five years (two on-line years of high operational output - 1983 and 1985; three , nonthermal-stress years - 1984,1986, and 1987), no relationships between catch and plant operation are suggestod (Table 3). However, some patterns emerged. Catches in 1987 were gcnerally comparable to those in 1986, with the exception of the large increase in Atlantic silversides at all stations. Catch rates of , winter flounder and blueback herring have been highest in the Intake the last two years. Sand lance have consistently been more abundant in the Intake. To date, however, no correlation to plant operation has been detected for these patterns. i l
}
) } 8. UNDERWATER FINFISH OBSERVATIONS With the continuation of the 1986 plant outage through 1987, [
no waste heat was released and no pumps were in operation from M:rch through August. Through the summer a very dense bed of { blue mussels (Mytilus adulia) flourished along the entire length ! of the discharge canal,and extended out beyond the mouth. In f. come areas of the canal, shell stock and clumps of living mussels ! care piled as deep as 15 cm, inducing mortality due to over- ! l crowding. With the resumption of pump operation in September 1987, much of the stock and some of the smaller clumps were ! corried out of the discharge and deposited in the denuded area as f for out as the large erratic at Station D t. l t Qualitative evaluation of the standing crop of Irish mosa (Chondrum crispus) in the dive area over the course of the summer , i ! revealed enhanced growth (distribution and density) even to the ( i i point of initial recolonization of the denuded area. By summer's had differentiating ' j cnd, the project divers difficulty in i
- distinct lines between the denuded, stunted, and control areas. j i Other flora such as kelp (Laminaria app.) and the filamentous t i !
j brown and green algae noted in 1986 (Kelly et al. 1987) were I
- also commonly observed.
l r Overall finfish di stribution (Figure 14) was somewhat i ! eicilar to 1986 in that the majority of fish (45%) were found in [ tha discharge area. However, relatively more fish were found in j ! the control and stunted areas in 1987 (36% and 19%, respectively) ! l l then in 1986 (31% and 4.6%, respectively). Total number of fish i in 1987 (536) wan the lowest recorded, primarily the result of . I
- dapreseed cunner sightings. Species diversity (7 species) and i l
{ l _
Pooled Finfish Percent of Finfish 70 60- . . . . ..... ............ 50-L
? 40-30- F l 0 i i . .
ai i e i i i i i
- i .
a s i i e i i l S D C S D C S D C S D C S D C 1983 1984 1985 1986 1987 Annual Finfish Distribution by Zone Figure 14. Distribution of finfish observed by divers In each mone (8-Stunted;D-Denuded;C-Control) off the Pilgrien Station discharge canal, 1983-1987.
- l
composition were essentially the same as previous years. Cunner Cunner remained the most frequently observed species with 79% of the total sightings. Howcver, a total number of 422 cunner cichted in 1987 represents the lowest relative abundance of the cntire study. Comparison of the number of cunner per dive, as an index of relative abundance for the years 1981 ( the year the dive stations were located at their present sites) to 1987 (Figure 15), revealed marked variation between years with a otrong pulse in 1984 and the sharp decline of 1987. During pravious outatto periods (1984 and 1986), higher densities of cunner were observed by divers than in the immediately proceeding (1983 and 1985) years of high output (annual mean MDC 1 80%).
- A major component of these higher abundance years was large
- nu bers of juveniles, especially in 1984. In 1986 we hypothesized that increased eightinga of juveniles during periods of outage were due to the absence of the high velocity thormal effluent. As few juveniles were seen in 1987, however, i
tha large numbera sighted in 1984 and 1986 may have reflected
- yaor class atrength, rather than a response to the activity of the plant, recreased occurrence in 1987, particularly that of juv
- niles, could also result from a shift in diatribution.
Further, when comparing numbers between years it should be remembered that diving observations are qualitative and can be lioited by visibility. Cunner were found at all stations in 1987, though most often in the control area (Figure 16). Comparinon with the outage {
- I
l l k I Cunner / Dive 200 150 -- l ! l l
, 100 -
s~ \ j 1981 1982 1983 1984 1985 1986 1987 ] Year Total Area / Discharge Figure 15. Index of relative abundance (fish / dive) for cunner observed by dlwers at Pilgrim Station 1981-1987. ,i t i _ . _ _ . _ - . _ _ _ . _ . . - _ _ . - , _ _ _ _ _ _ . - _ _ _ _
l l l Cunnor
,, . .. o..,,....
l 00- s eo- \; lg do-30 ys
'l s
t f; 20- r - l'; i bkh
* ,d.6' E ,d. 6 '
- d. 6 '
- d. 6 '
- d, 6 d h ',
-.i o,.,,,wii. ~ m.
,..,.....ri.......-,...,....
s.a. (. 9t v.t.e,D 0.end et,C C..t r.0 .t, t h. Pile, e tiet to. 4 L..h rg. .a.at, 1941 194 F. I a of Purns operating , R l s .m { ss l l l1 :1 5f r! I l 0= . t hHH s
+H+Hh::
b( N J Fl44AJ J AScr4DJ F WMJ J AScrCJ F WMJ J ASCtOJ F WMJ J ASCPcJ F huh 4J J ASot40 1883 1984 1888 1988 1887
... 47. A ; g ,.., . g i.i, g ,7 ,.. .... ..... . . .t
I years of 1984 and 1986, revealed a similar trend in 1984, but greatest abundance in the denuded area in 1986. Although thermal component was essentionally zero (some waste heat was released in early 1986) all three years, there was at least one pump in operation throughout 1986 (Figure 17). In 1984 and 1987, however, there were no pumps in operation during the spring and early summer months. Kelly et al. (1987) theorized a relationship between cunner distribution and pump operation, believing adult cunner to be attracted to the current as a source of food. The absence of current in the early spring and summer, a time when increasing water temperatures cause renewed foraging activity (Creen and Farwell 1971), may have induced a shift toward the l more fertile control area and away from the sparae denuded zone. Increased occurrence in the stunted area in 1987, as opposed to j previous outage years, may have resulted from an attraction to the abundant flora and fauna growing in the absence of the , thermal effluent. pollock Second in observed abundance, pollock was sighted primarily in the denuded area. Relative abundance (93 finh) was down comewhat from 1986 (130), but eatinatea of pollock abundance l baned solely on vlaual obaervation are generally tenuous because of their active behavior. An always, obaervation of thin specien ] I la rather sporadic and local abundance and dintribution I l more dependent on natural variation than any effect of the plant, j l Tautoc l Tautog alghtings were infrequent (10 fish) in 1987 (Figure 18), reflective of an apparent decline in the local population. J
l Teutog/ Dive 20 t i 15 - - - - - - - - - - - - - -
\
10 t,; - l 5 - -- - l 0 1981 1982 1983 1984 1985 1986 1987 l , Year l M Total Area ?M Disctlarge , ! Figure 18. Index of relative abundance (fish / dive) for l tautog observed by divers off Pilgrim Station, l 1981-1987. 1 i 1 _ --
l i ! l l Depressed abundance was also noted in the project gill-net study. l Distribution was evenly apportioned between the denuded and control areas (Figure 19), a shift from past years when tautog ; were found almost exclusively in the denuded area. As no relationship has been found, to date, between tautog occurrence and plant output (mean seasonal MDC), decreased local abundance seems to be t'+ c38 ult of natural variation.
- 7. SPORTFIS! .aq Overall, angling activity and sportfish catches at Pilgrim Shorefront in 1987 were the lowr.st recorded at the area since its opening in April, 1973. We attrit o' this, at least in part, to restricted access at the Shorefron, 'ing April and May and to the extended station outage.
- Angling activity was curtailed as the footbridge that apans the the discharge channel was closed in April and May becauno of a storm-induced break in its cement construction. The bridge allown pedestrian passage to the right discharge jetty (facing l.
meaward), the outer intake breakwater, and the beach at the head t-of the intake embayment. Anglers were limited to fishing from the left discharge jetty, thus effectively removing most cf the ! l fishing accean. The bridge was repaired, and all fishing locations were accessible again in June. Throughout all of the fishing season, Pilgrim Station releaned no waste heat into Cape Cod Bay. From April through i August, bo15 circulating water pumpa were inoperative, and only a minimal flow of water inaued from the d!.acharge canal an a renult ! of the operation of one or more of the five nervice water pumps. ;
l l iC 7 iD 98 1 h iS c a eh e i n t if . f 7
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r o8 e) vl d r o-1 9 iO 98 o n t 83 1 yn9 Z b o1 C _iS o n y d - eCa v ;n l i o r d a it e sd ec iC u bonu ge b 5 ir g e ar iD 98 ist uDh t - c LD s 1 D t
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t 3 n iD 98 e 1 c r e iS P - - - - 0 0 0 0 0 0 0 0 0 0 0 0 9 8 7 6 5 4 3 2 1 1
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In early September, one of the circulating pumps resumed operation. It is conclusive that outages at Pilgrim Station markedly reduce sportfish catches at the Shorefront, especially striped bass and bluefish. Creel data reveal that in 1983 (high plant operational year) an estimated 1,000 bluefish and 150+ striped bass were caught by anglers at the Shorefront. Likewise, in 1985 (high output capacity) an estimated 2,200 bluefish and almost 400 bass were landed there. Conversely, with the absence of a heated discharge current during the three fishing seasons of 1984, 1986, and 1987 (outage periods), the catches of bass and bluefish declined drastically to under 150 fish total for both species and all 3 years combined. Thus, the operation of Pilgrim Station has a positive connotation for sport fishermen off Rocky Point by concentrating popular game fish at a point source within casting distance from shore. However, this attraction to the discharge elevates the potential for fish kills caused by gas supersaturation and thermal stress and can substantially increase the exploitation rate of a species.
IV. IMPACT PERSFECTIVE The following summary is provided of the major findings of icpact on fisheries' resources in the inshore sector of western Ccpe Cod Bay, centering on the area around the Pilgrim Nuclear Power Station (Table 4). As the summary only highlights salient points, the reader is encouraged to refer to individual sections of this report for more detailed discussion of investigative craas. Western Cape Cod Bay supports commercially important lobster cnd groundfish fisheries as well as intensive seasonal l racreational lobster and hook-and-line fisheries. The population dynamics of an individual species are influenced by a complex interaction of biotic interrelationships, including intra- and interspecific coactions with abiotic factors (e.g., water tsaperature and currents). The assessment of ecological impact of Pilgrim Station operation on the area's fisheries' resources involves measuring many of the parameters that influence distribution, abundance, and size composition of target species. Based on monitoring data collected to date off the power station, l there have been local biotic changes and environmental I disruptions documented; these have been site specific, however. t Although no major perturbations have been detected in the ecology of western Cape Cod Bay as a result of plant operation, the potential for future impact by the plant, either overtly or 1 indirectly by altering community structure, exists. As Pilgrim Station has operated at an average of slightly less than 50% of its operational capacity, we probably have not yet realized the plant's full potential for impacting marine resources. Impact Tab 13 y . A summary of irpact asassament by study of Pilgria Nuclear Pcwer Station (PNPS) on marine fisheries' resources in western Cape Cod Bay during the operational history of the power plant. Investigation tmpact of PNPS 1983/1984/1985/1986/1987 Comme n t s Gill-net study Cunner evidently attracted to Relative abundance of cunner The imp!! cations of the thermal effluent. In the area of the thermal attraction are twofoldt' discharge down in 1984 to sport fishermen this (outage year) and down is beneficial but con-further in 1985 (high output versely this concentrates capacity). suggesting a fish in a high-risk area recent decline in local with the potential for stock aise. CPUE in 1986 was overfishing, thermal stattar to that in 1985. In stress, gas bubble disease. 1987. CPUE declined further. and exposure to chemicals. There is a (?) relationship between Relative abundance-n r Saee as above. CPUE for tautog and PNPS eperational tautog was not crpree tably - output, dif ferent over these year s. SCUBA observations Supporting data that cunner are Increased cunner sfr.htings in With no thernal ef fluent (1984, attracted to the plant discharge the control tone in 1984/1987; 1987) there was an apparent current. in the discharge in 196h shift in distribution of 1985, and 1986 (reduced cunner away from the die-current). charge (denuded) sone and toward the control zone. Concentrations of striped bass in Por the first time slace 1979. As bass exhibit a pref er-the vicinity of PNPS linked to the bluefish and bass were not ence for moving water, cooling water discharge. sighted by divers in the such as PNPS affluent, environs of PNPS in 1984 l'ut their absence / scarcity in the were again sighted in 1985 diving area during outages la in small schools frequenting apparently related to the the discharge area. Cnly a lack of discharge flow. few bass were seen in 1986-87. Creel survey With the plant operating, the over 1.000 bluefish and > 150 Power Plant has had a outf all at PNPS has proven to be en striped bass were caught by positive effect on the attracttve feedict ground concen- anglera at PN78 in 19833 and sport fishing of f Pecky trating sportfish for an entended 2.200 bluefish and almost 400 Point however, the attrac-period of time in a location close bass in 1985: no bass and only tion of game fish to the to shore , a small number of bluefish discharge increases the were caught in 1984. Catches potential for overfishing were once again low in 1986-87 a local stock and for floh during the extended outage. kills via high temperature and gas supersaturation. 81uefishing was prolonged into November 1985 by the presence of the hot-water discharge. Haul-seine study Int.ke embarment with it s break- Seine catches in the intake Shoreto3e finfish residing watec and dredged channel appears increased in 1984 and 1985. In the Intake, especially to to be a haven for fishes in an were down in 1986. but back the vicinity of the intake otherw'se open coastal region, up in 1987. screen wall, are subject to plant entrapeent. trpingeeent and thereal backwash effects. Trawl study Winter flou $ der may only avoid the A bisodal distribution of Autumn trends (plots) of iteediate aras of the dis- flounder relative abundance relative abundance for winter charge canal. Catch abun- was found at the surve!!!ance flounder were dif f erent dance of winter flounder, yellow- station in 1984 that was not at reference versus surve11-tail flounder, and windowpang was found for 1981-1983,1985- lance sites from 1981-1983 found to be ctrrelated (positive) 1987. In 1986-87,CPUE in the (crerational years) but to PNPS M.D.C. fcetor (output), discharte area exceeded that were sistlar in 1984 (outage when the plant is operating, at the reference location. year). In 1985, we found CPUE to be correlated (+) at reference and discharge areas. Concentrating in the hannel of Catch per-effort for winter Seasonal bottom trawl catch the intake eebayment are winter flounder dropped rarkcily in rates for winter flounder flounder. 1994 and 1985 at both the were coasJaeJ7 higher in reference and discharge the intake embarrent in stations. CPUE stabilized somewhat, in 1985 and 1987*. the sprirt. summer, fall. l This is a boon to recree-tional fisherren at PNPS Shorefront.
I Table y . Trawl study (cont.). The intake at FNPS an altered A coeparlann of 1983 to 1984 This situation has the environment, has characteristics is not applicable because potential for negative (relatteely sheltered habitat with routine trawling was not con- impact for it increases rock and algal cover) which appar- ducted in the inrake in 1983. susceptibility to ently attract juvenile fish. However, coeparing the ispingement and back-catches in the intake with wash effists. the other sites sampled from 1984-1986, we found that sub-stantially iarger numbers of smaller winter flounder were in the intake channel in spring or surwer. 1,obster pot-cas.ch study There may be a connection between Catch rate of legal lobsters A significant negative PNPS cooling water discharge and declined overs!! in the study correlation (P < 0.05) legal lobster catch rate in the area in 1984 from the 1983 exists for annual thermally-affected area. level and was the lowest value thereal capacity and for the l$. year study: legal lobster catch rate increasing again in 198$ by in the impacted area about 1001. In 1986. CPUE and a correlation (nega-was the highest of the entire tive) (P < 0.10) between survey but in 1987 dropped seasonal thermal to a level identical to 1984. capacity and catch. Dissolted gas analysis in August 1985. PNPS was operating No GBD incidents observed in Cas supersaturation and gas bubble disease at or rear 1002 capacity: water 1983. In 1986 rNPS had no resulted in several (CBD) incidents at temperatures in the discharge were thermal coeponent to induce noteworthy incidente of FNFS. as high as 30.5 C and dissolved CBD. This was also the CBD in fish at PNPS. gases were supersaturated (Nitrogen case in 1986 and 1987. ilortalitter. of 43.000
+ argon saturation .'evels ranged and 3,000 adult een-from 112-: 691). An esticated 600 haden occurred in the silversides and 300 j.ivenile men- discharge in 1973 and haden were afflicted with C80 in 197$. respectively.
the discharge canals fish were Striped sullet schooling stressed,but mortality, which was in the discharge were likely, was not evidencec. afflicted in late 1975. CSD can severely stress or kill (outright or through increased susceptibility to dis-ease or predation) fish residing in the discharge. assessment at the past level of plant output may not be valid for a long-term, higher operational status in the future. 1
)
f
)
-S2- l
\
j
V. CONCLUSIONS Lobster - Commercial Fisherv Sampled commercial lobster trap-catch data from surveillance cnd reference areas were examined over time. The commercial catch rate of legal lobster (181 mm CL) in the discharge area in 1987 was 0.34/ trap-haul, while legal catch rate in the control area we.n 0.20. These figures represent declines of 15% and over 50%, respectively, from 1986. Catch rates in the discharge area, which have declined slightly over the last five years (from 0.47 in 1983 to 0.34 in 1987), have not mirrored commercial catch rates ( in western Cape Cod Bay which have fluctuated. Legal catch data from discharge and reference areas were l conpared statistically and no significant (P > 0.05) differences ware found over time. However, we found a significant (P 1 0.05) negative correlation between catch rate of legal-sized lobster in the impacted area and the operating level of Pilgrim Station in contrast to no significant correlation for reference areas. Lobster - Research Study l The field research lobster trap study has been conducted for l the last two years under essentially control conditions (no waste i heat and reduced or no current during the extended plant outage). This unique situation enabled us to conduct a uniformity trial, where we fished standard traps in a standardized manner in one surveillance and two reference areas. The proper pairing of potentially impacted / treatment sites with non-impacted / reference sites is imperative to assess stress when the plant resumes operation. l l
We identified two parameters that can be used to assess impact of Pilgrim Station on the local lobster population. Rocky Point (reference) and the discharge area are an appropriate station pair to assess power plant effect on catch rate of legal lobster. As for size composition, size frequency data of legals at the two reference areas can be pooled and tested against size distribution data in the discharge when the plant resumes operation. Inshore Groundfish Trawl annual catch / effort data of the three dominant groundfish - winter flounder, little skate, and windowpane - were compared over the years 1983 through 1987, which included three outage years, between Stations 1 (reference location in Warren Cove) and 3 (Discharge area) to assess plant impact. There was no indication of a plant effect on the distribution of these species. Seasonal mean catch rates with estimates of precision were examined spatially. No significant differences are indicated between stations for winter flounder and windowpane. However, in summer, little skate were significantly more abundant in the discharge area (Station 3) and off White Horse Beach (Station 4 - reference) than in the Intake (Station 6) and at the primary reference location (Station 1 - Warren Cove). There is additional confirmation that the Intake is a haven for small winter flounder (< 22 cm), at least seasonally. Pelacic and Benthi-Pelagic Fish No relationship was found between plant operation and relative abundance of pollock, Atlantic herring, and alewives off Pilgrim Station. There is a possible attraction impact on tautog
abundance in the general discharge area. With cunner, we also found a significant positive correlation between CPUE and plant operational power level (r=0.581; P 1 0.05). Almost 34% of the variability in relative abundance of cunner can be explained by vcriation in plant operational output. Shore-Zone Fishes The haul seine provides data on the occurrence, distribution, size composition, and relative abundance of shore-zone fishes in the Pilgrim area. Our surveys have revealed rather large natural variations in relative abundance. The Pilgrim l intake embayment most resembled the estuarine sampling site off I Long Point in terms of total fish seined, catch rates, and species diversity. Catches at the open coastal beaches, which
. lack cover, were magnitudes lower. Fish concentrating in the intake channel are subject to impingement and heated backwashes.
Ws tested monthly mean densities of the Atlantic silverside, the doainant fish seined overall, against monthly Pilgrim Station thermal capacity and monthly pamp capacity. No significant i correlations (P > 0.05) were found. To date, plant impact on chore-zone fishes has not been detected from seine data. l l ,Divina Observations l The 1986 plant out age continued through 1987, essentially l creating pre-operational conditions for the biota in the l discharge area from March-August because both circulating water i punps were not operating during those months. The blue mussel population throughout the entire discharge canal and surrounding the canal mouth rapidly itscreased in numbers through the summer.
-SS-
Irish moss in the study area also experienced enhanced growth and began recolonizing the denuded zone; zone demarcations thus became difficult to distinguish. Kelp and filamentous brown and green algae were also commonly observed. l The majority of finfish observed (45%) was found in the discharge area, followed by the control area (36%). The total number of fish observed wae the lowest recorded since study inception, primarily due to a decline in cunner sightings. I Species diversity and composition were essentially the same as in previous years. Cunner, although at its lowest relative abundance in the study, remained the predominant species observed (79%). The decline in cunner may reflect changes in juvenile abundance and distribution. Cunner numbers increased in the control and stunted areas over previous years, possibly in response to the floral recolonization at these sites. There has been observational evidence of attraction of cunner to the current component of the station discharge. Pollock ranked second in sightings, observed primarily in the denuded area. Relative abundance of pollock decreased from 1986 (130 fish) to 1987 (93 fish); however, this observed decline may be a sampling artifact related to their mobility. The number I of tautog observed was very low in 1987 (10 fish) reflecting a possible decline in the local population. Distribution was evenly apportioned between the denuded and control areas, in contrast to past years when tautog were found almost exclusively in the denuded area. Tautog data support the contention of some attraction for this species to the discharge current.
Soortfishina Overall angling activity and sportfish catches at the Pilgrim Shorefront were the lowest recorded since the area opened to the public in 1973. Two factors contributing to the low cctivity and catches were: restricted access to the right diccharge jetty, outer intake breakwater, and the beach at the head of the Intake embayment in April and May; and the power outage that lasted throughout the fishing season. Power outages tarkedly reduce sportfish catches of striped bass and bluefish at the Shorefront as historical data show. The release of a heated I diccharge concentrates popular gamefish in an area within casting distance from shore. The concentration of fish in the heated l offluent, however, increases the potential for fish kills caused by gas supernaturation, thermal stress, and cold shock. Imoact Persoective Based on monitoring data collected to date off the power station, there have been local biotic changes and environmental disruptions documented; these have been site specific, however. Although no major perturbations have been detected in the ecology of western Cape Cod Bay as a result of plant operation, the potential for future plant impact, either overtly or indirectly by altering community structure, exists. As Pilgrim Station has operated at an average of slightly less than 50% capacity over its operational history, we probably have not yet realized the plant's full potential for impacting marine resources. Impact assessment at the past level of plant output say not be valid for a long-term higher operational status. l
l VI. ACKNOWLEDGMENTS We acknowledge the contributions of numerous staff members l of the Division of Marine Fisheries, who assisted in various phases of field sampling and data analysis, especially Karen Bugley, Neil Churchill, Steven Correia, Kevin Creighton, Robert Demanche, Virginia Fay, Dan McKiernan, and Carl Sylvja. We thank Chris Kyranos for allowing us to sample his lobster catches, and W.C. Sibley and Richard Schneider for overseeing the l collection of creel. data at the Shorefront area. Also greatly 1 appreciated is the work of Carleen Loper and Marie Callahan for typing this report. Finally, we thank Robert D. Anderson, W.
)
Leigh Bridges, and the Pilgrim Administrative-Technical Committee 1 for overseeing the entire study program.
l ! VII. LITERATURE CITED Aucter, P. J. 1985. Factors affecting catch of American lobster, Homarus americanus in baited traps. NOAA National Undersea Research; University of Connecticut, Groton, CT. 46 pp. Bridges, W. L. and R. D. Anderson. 1984. A brief survey of Pilgrim Nuclear Powe- Plant effects upon the marine aquatic l environment, p. 263-271. In. J. D. Davis and D. Merriman (editors), Observations on the Ecology and Biology of western Cape Cod Bay, Massachusetts. Springer-Verlag, Berlin, FRG. 289 pp. Canpbell, A. 1983. Growth of tagged lobsters (Romarus americanus) off Port Martland, Nova Scotia, 1948-80. Canadian Technical Report of Fisheries and Aquatic Sciences, No. 1232. 10 pp. l Entrella, B. T. 1985. Massachusetts coastal commercial trap sampling program May-November 1984. Mass. Div. Marine l Fish., Boston, MA. 58 p. i Estrella, B. T. and D. J. McKiernan. 1986. Massachusetts coastal commercial lobster trap sampling program, May-November, 1985. Commonwealth of Massachusetts Dept. of Fisheries, Wildlife, and Environmental Law Enforcement, Division of Marine Fisheries. 74 pp. l Green, J. M. and M. Farwell. 1971. Winter habits of the cunner, 1 l Tautocolabrus adsoerana (Walbaum 1792),. in Newfoundland. Canadian Journal of Zoology 49:1497-1499. l Kelly, B. C., V. J. Malkoski, S. J. Correia, R. P. Lawton, M. Borgatti, and B. Hollister. 1987. Annual report on l
monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay (Vol. 1). Project Report No. 42. In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report No. 29. BECO, Braintree, MA. Keser, M., D. F. Landers, Jr., and J. D. Morris. 1983. Population characteristics of the American lobster, Romarus americanus, in Eastern Long Island Sound, Connecticut. NOAA Technical Report, NMFS SSRF-710. 7 pp. I Lawton, R. P., P. Brady, C. Sheehan, M. Borgatti, and V. Malko-ski, 1983. A comparison of Power Plant Impingement with other types of sampling gear to survey finfish off Pilgrim Nuclear Power Station. In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report No. 21. Boston Edison Company, Boston, MA. 9 pp. Lawton, R. P., C. Sheehan, V. Malkoski, S. Correia, and M. Borgatti. 1985. Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fishery resources of western Cape Cod Bay. Project Report No. 38 (Jan.-Dec. 1984). In: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-Annual Report No. 25. Boston Edison Company, Braintree, MA. Lawton, R. P., V. J. Malkoski, S. J. Correia, J. B. O'Gorman, and M. R. Borgatti. 1986. Annual Report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay. Project Report No. 40 (Jan.-Dec. 1985). In: Marine Ecology Studies
I 1 l l Related to Operation of Pilgrim Station. Semi-Annual Report l No. 27. Boston Edison Company, Braintree, MA. National Marine Fisheries Service. 1976. Current fisheries l l statistics (No. 7179), Massachusetts Landings, Dec. 1976. National Oceanic and Atmospheric Administration. Resource Assessment Division, Northeast Fisheries Center. 1983. Status of the fishery resources of the Northeastern United { States for 1982. NOAA Technical Memorandum. NMFS-F/NEC-22. 128 pp. I I l l l l l l l 1 I l l FINAL l SEMI-ANNUAL REPORT l Number 31 (Volume 1 of 2) f to BOSTON EDISON COMPANY i on l BENTHIC ALGAL AND FAUNAL MONITORING AT THE PILGRIM NUCLEAR POWER STATION (CHARACTERIZATION OF BENTHIC COMMUNITIES) January - December 1987 l l 4 l \ 7 April 1988 i I BATTELLE Ocean Sciences 397 Washington Street Duxbury, Massachusetts 02332
I l l l l l Battelle does not engage in research for advertising, sales promotion, or endcLeament of our clients' interests including raising investment capital or recommending investment decisions, or other publicity purposes, or for any use in litigation. Battelle endeavors at all times to produce work of the highest l quality, consistent with our contract commitments. However, because of the research and/or experimental nature of this work the client undertakes tha sole responsibility for the , consequences of any use, misuse, or inability to use, any
- information, apparatus, process or result obtained from
! Battelle, and Battelle, its employees, officers, or Trustees have no legal liability for the accuracy, adequacy, or efficacy l thereof. l l l 1 l l
l 1 1 l l l I TABLE OF CONTENTS i PAGE ! 1 EXECUTIVE
SUMMARY
....................................... 1 ' 1 INTRODUCTION............................................ 2 METHODS................................................. 3 RESULTS................................................. 7 i FAUNAL STUDIES..................................... 7 Systematics................................... 7 Species Richness............................... 7 , raunal Density................................ 9 1 Species Dominance............................. 11 Species Diversity............................. 14 Measures of Similarity........................ 16 ALGAL STUDIES...................................... 28 Systematics................................... 28 Algal Community Description................... 28 l Algal Community Overlap....................... 29 Algal Biomass................................. 33 Chondrus/Phyllophora Colonization Index Study. 38 QUALITATIVE TRANSECT SURVEY........................ 38 March 1987 Transect survey.................... 40 i June 1987 Transect Survey..................... 42 September 1987 Transect Survey................ 44 l December 1987 Transect Survey................. 46 5 CONCLUSIONS............................................. 48 i FAUNAL STUDIES..................................... 48 l ALGAL STUDIES...................................... 48 QUALITATIVE TRANSECT SURVEY........................ 49 LITERATURE CITED........................................ 50 l l i i
l LIST OF TABLES l TABLE PAGE
- 1. Faunal Species Richness for the Months of March and September 1987..................................... 8
- 2. Faunal Densities at the Effluent, Manomet Point, and Rocky Point Stations in March and September 1987............................................... 10
- 3. Rank Order of Abundance for the 15 Dominant Taxa in Samples Collected in March and September 1987...... 12 i
- 4. Diversity Values (Shannon-Wiener) For Each Station Sampled in March and September 1987................ 15
- 5. The 37 Algal Indicator Species Used in the Quantitative Ccamunity Analyses.................... 30 ,
- 6. Average Dry Weight Biomass per Replicate (g/m ) of Macroalgae at Effluent, Manomet Point, and Rocky Point Subtidal (3 m MLW) Stations in March and September 1987. Numbers in Parentheses Represent Contribution to Total Algal Biomass................ 34
- 7. Colonization Index Values for Chondrus crispus and Phyllophora spp. at the Manomet Point, Rocky Point, and Effluent Subtidal (3 m MLW) Stations in March and September 1987.................................. 39 l I
l t I I if l
LIST OF FIGURES FIGURE PAGE
- 1. Location of the Rocky Point, Effluent, and Manomet Point Subtidal (3 m MLW) Stations.................. 4
- 2. Dendrogram Showing Results of Cluster Analysis of ,
March 1987 Data Using Bray-Curtis and Average Sorting............................................ 18
- 3. Denurogram Showing Results of Cluster Analysis of Septesoer 1987 Data Using Bray-Curtis and Group Average Sorting.................................... 19
- 4. Dendrogram Showing Results of Cluster Analysis of March and September 1987 Data Using Bray-curtis and Group Average Sorting ......................... 20
- 5. Dendrogram Showing Results of Inverse Cluster Analysis of March and September 1987 Data Using Bray-Curtis and Group Average Sorting.............. 22 f 6. Constancy Diagram for Species Groups and Replicate Groups in 1987. Clustering Is with Bray-Curtis similarity and Group Average Sorting............... 24
- 7. Fidelity Diagram for Species Groups and Replicate Groups in 1987. Clustering Is with Bray-Curtis Similarity and Group Average Sorting............... 25
- 8. Algal Community Overlap (Jaccard's Coefficient of Community) and Number of Species Shared Between Replicate Pairs at the Manomet Point, Rochy Point, and Effluent Subtidal Stations (3 m MLW), March 1987.............................................. 31
- 9. Algal Community Overlap (Jaccard's Coefficient of Community) and Number of Species Shared Between Replicate Pairs at the Manomet Point, Rocky Point, and Effluent Subtidal Stations (3 m MLW),
i September 1987..................................... 32 i l 10. Configuration of Denuded and stunted Zones at Pilgrim Nuclear Power Station for 25 March 1987.... 41 l l 11. Configuration of Denuded and Stunted Zones at Pilgrim Nuclear Power Station for 9 June 1987...... 43 1 iii [
LIST OF FIGURES (Continued)
- 12. Configuration of Denuded and Stunted Zones at Pilgrim Nuclear Power Station for 29 September 1987............................................... 45
- 13. Configuration of Denuded and Stunted Zones at Pilgrim Nuclear Power Station for 22 December 1987............................................... 47 t
LIST OF PLATES PLATE PAGE
- 1. Aerial view of the Rocky Point and Effluent Quantitative Sampling Stations. The Rocky Point Station Is Located Approximately 0.25 Nautical Miles Northwest of the Effluent Station and I Serves as a Reference Station...................... 5
- 2. Aerial View of the Manomet Point Quantitative Sampling Station. The Manomet Point Station Is Located Approximately 2 Nautical Miles Southeast of the Effluent Station and Serves as a Reference Station............................................ 5 t
I l l l l iv l
1 i l l EXECUTIVE
SUMMARY
j This report presents the results of the most recent benthic monitoring surveys at the Pilgrim Nuclear Power Station (PNPS). The surveys are part of a long-term monitoring effort by Boston Edison Company (BECO) to assess the impact of the thermal effluent on the inshore benthic community. Volume 1 of this report characterizes t.se benthic l environment and its seasonal changes it. 1987. Methods and procedures follow guidelines established by the Pilgrim Administrative Technical Committee (PATC) and adopted by BECO as modified in 1981 (Boston Edison Co., 1987a). The habitats and their algal and faunal communities found at the Manomet Point, Rocky Point, and Effluent subtidal stations are typical of shallow, exposed areas in western Cape Cod Bay (Grocki, 1984; Davis and McGrath, 1984). The rocky substrata characteristic of all three stations are covered with dense macroalgal communities typically dominated by Chondru2 crispus and _Phyllophora spp. This algal turf has created a habitat suitable for diverse faunal communities. Faunal species at all three sampling stations have numbered from 50 to more than 100 species, and total faunal densities have ranged from 10 4 to 10 6 individuals per square meter. 1 The faunal communities are dominated by arthropods, particularly of the order Amphipoda. The results of this study indicate that faunal species richness, faunal diversity, and total algal biomass in western Cape Cod Bay exhibit seasonal cycles, with low values in spring followed by high values in fall, raunal densities do not reflect such a cycle and may depend more on the topography of the stations than on seasonality. I
l
)
INTRODUCTION i This report presents, in a condensed format, the results of the most recent series _ of benthic monitoring surveys performed at the Pilgrim Nuclear Power Station (PNPS). Detailed technical information is available from Battelle Ocean Sciences upon request. The report is presented in two volumes. Volume 1 contains a characterization of the benthic environment and its seasonal changes in 1987; Volume 2 discusses the impact of the PNPS operations on the benthic communities based on the observations described in Volume 1 , and in comparison to earlier observations (1983 to 1986). It l is hoped that this format will make the results more readers who are not necessarily interested in ; accessible to technical details. PNFS is located on the northwest shore of Cape Cod Bay, . 8 km (5 miles) southeast of Plymouth Harbor, Massachusetts.
- The quantitative algal and faunal data presented and analyzed in this report were derived from field collections conducted in March and Septr .oer 1987. Qualitative transect data were I collected on March 25, June 9, September 29, and December 22, l 1987.
I L l L 2
METHODS The specifications for methods and procedures follow guidelines established by the Pilgrim Administrative Technical Committee (PATC) and adopted by BECO as modified in 1981 (Boston Edison Co., 1987a). A detailed description of the field, laboratory, and analytical processes that pertain to the current report can be found in Semi-Annual Report No. 29, Volumt 1 (Boston Edison Co., 1987a). As in previous 2 samplings, five replicate 0.1089-m benthic samples were , collected with SCUBA at the Effluent station and the two reference stations at Manomet Point and Rocky Point (Figure 1, Plate 1, Plate 2). Quantitative samples were preserved in the field and returned to the laboratory, where faunal and algal fractions were separated and analyzed. Qualitative transect data were collected using a fixed line stretched offshore along the discharge canal centerline and a movable line placed perpendicular to the fixed line. The transect was traversed by divers who noted the boundaries of the stunted and denuded Chondrus (Irish moss) zones that extend offshore from the effluent canal. Quantitative data were l analyzed on the Battelle VAX system using software that had previously been used to analyze PNPS benthic data. The continuing outage at PNPS that began in April 1986 was of particular interest during this reporting period. No thermal loading took place during 1987. One circulating pump was operating for most of January, February, and September through December (during six days in December, two pumps were i operating); from March through August, there was no or very little current generated. Battelle's Project Manager for the PNPS algal and faunal investigations was Ms. Tracy Stenner. Algal taxonomy was performed by Ms. Brenda Cavicchi and Ms. Maureen Nolan, raunal taxonomy was conducted by Ms. Nancy Padell and Mr. Russell Winchell. Field logistics and collections were 3 l
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I i Plate 1. Aerial view of the Rocky Point and Effluent quantitative sampling stations. The Rocky Point station is located approximately 0.25 l nautical miles northwest of the Effluent station and serves as a reference station, 1 v., 4 A . ? r .y ,g's., 4. , ayal *
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1 l J supervised by Mr. John Williams. Additional personnel 1 participating in this project included Dr. Brigitte Hilbig, ; Dr. James A. Blake, Mr. Phillip Nimeskern, Mr. Robert , Williams, Mr. Steven Mellenthien, Mr. Carlos Fragata, Mr. f Mark Curran, Mr. Tom Angell, Mr. Brian Dwyer, Mr. Eugene { Ruff, MG. Ellen Baptiste, Ms. Barbara Greene, and Ms. Elisabeth Haase. I i i 4 4 6
, RESULTS FAUNAL STUDIES Systematics During 1987, a new species was added to the taxonomic list of benthic invertebrate fauna at PNPS. This species is the bivalve Hiatella striata, which was collected at all three station. This species co-occurs with its congener H.
arctica and is distinguishable from the latter only as a juvenile when the characteristic spines on the shell are still visible. H. striata has been found to be quite common in Massachusetts Bay (Blake et al., 1987; Sebens et al., 1987). The taxonomic list now consists of 466 invertebrate species that have been observed at the three monitoring stations sampled during this program. l l Species Richness Species richness value'; (number of species) for all three stations in March and September 1987 are presented in Table 1. The values for spring 1987 were recalculated excluding the indeterminate and juvenile individuals that were not identified to species. Both in spring and fall, the lowest number of species (S) was found at the Effluent station (36 and 41 species, respectively). The numbers of i species at the two reference stations were quite similar. At the Manomet Point station, 48 species were found in March, l and 62 species in September. At the Rocky Point station, 42 I species were found in March, and 60 species were found in { September.
- 7 I
\
TABLE 1. FAUNAL SPECIES RICHNESS FOR THE MONTHS OF MARCH AND SEPTEMBER 1987. ) Nur.ber of Species Richness Variance Station / Month Species (S) ($)(:t95% ct) ($) Effluent March 36 43.2 7.37 7.04 September 41 48.2 i 6.47 5.44 Manomet Point March 48 57.6 7.53 7.36 September 62 72.4 t 7.33 7.36 Rocky Point March 42 49.2 4.15 2.24 September 60 67.2 12.36 19.84 l CI - confidence interval. , 1 l l l 8
In order to assess rare species that might be present i but not found in the samples because of the relatively small area sampled (five replicates equals 0.5445 m2), a jackknifed estimate was calculated following procedures ot Heltshe and f Forrester (1983). The estimated species richness (S) was lowest at the Effluent station both in March and September, followed by the Rocky Point station and the Manomet Point station. The variance of the estimated species richness (var
$) is a measure of the spatial distribution of speciec that occurred only in one replicate sample from a station
("unique" species). High values for var ($) indicate that all unique species at the station are concentrated in a small space; low values for var ($) indicate that the unique species are randomly distributed over the area a community inhabits. High var (3) was found only in September at Rocky Point; for all other samples, var (3) was low. At all three stations, species richness increased from spring to fall. Speciee richness was not significantly l different among stations in spring, as indicated by i overlapping 95 percent confidence intervals. In the fall, l the Effluent station had significantly lower species richness than the reference stations, indicated by a lower 95 percent I confidence interval that does not overlap with those of the reference stations. Species richness calculated from samples of previous years and a comparison of these earlier values with ones from 1987 will be discussed in relation to PNPS operations in volume 2 of this report, l Faunal Density Benthic macrofaunal densities per replicate sample and per square meter were calcu3ated for both March and September 1987 (Table 2). In March, mean densities at the Effluent 9
)
TABLE 2. FAUNAL DENSITIES AT THE EFFLUENT, MANOMET POINT, AND ROCKY POINT STATIONS IN MARCH AND SEPTEMBER J 1987. Mean Number of Number of Individuals per Individyals Replicate per a Mar Sep Mar Sep Effluent 3346 3106 30,725 28,518 Manomet Point 6086 5744 55,873 52,746 Rocky Point 3282 4133 30,125 38,009 r i 10
i station were intermediate between densities at the Manomet l Point and Rocky Point stations. In September, mean densities , at the Effluent- were lower than those at the reference stations. The highest mean densities per replicate among the fall samples were again found at Manomet Point. Densities increased from spring to fall at Rocky Point by 26 percent, but decreased at the other stations by 6 to 7 percent. i species Dominance The 15 numerically dominant species present in replicate samples from each station in March and september 1987 are presented in Table 3 as mean number of individuals per l replicate. The species composition of the March samples is , detailed in Semi-Annual Report No. 30 (Boston Edison Co., ; 1987b) and can be summarized as follows: the Effluent station shared all of the top 5 and 10 of the top 15 species with the Manomet Point station; with the Rocky Point station, the Effluent station shared 3 of the top 5 and 12 cf the top l 15 species. The two reference stations shared 3 of the top 5 and 11 of the top 15 species. The top 15 species contributed l 97.24 percent of the total fauna at the Effluent, followed by 95.09 percent at Manomet Point and 93.02 percent at Rocky Point.
- In September, the Effluent station and the Manomet Point station shared 2 of the top 5 species and 9 of the top 15 species. The shared two species of the top five dominants, the arthropods calliopus laevisculus and Ischyrocerus l
anguipes, ranked first and third, respectively, at the Effluent and third and fifth, respectively, at Manomet Point. l } The remaining top five species at the Effluent ranked much I lower at Manomet Point; the top two species at Manomet Point (Margarites helicinus and Pleusymtes glaber) did not occur f among the dominants of the Effluent station. 11 l
TABLE 3. RANK ORDER OF ABUNDANCE FOR THE 15 DOMINANT TAXA IN SAMPLES COLLECTED IN MARCH AND SEPTEMBER 1987. mars 1987 september 1947 mean naam masber per member per statiesVspecies maplicate station / species soplicate Efflumet affluent Jassa falcata 1642.4 calliopius laevisculus 149.6
!schyrocerua anguipes 443.2 Jassa falcata 566.4 Acarina 378.4 !schyrocerus anguipee 312.0 Dennaine thea 191.2 Pontogeneia inermis 296.8 Mytilus eEITs 106.4 taeuna incta 212.4 corophium acutum 96.8 Acarina 198.4 Idotes phosphorea 92.0 capre11a penantis 185.6 calliopius laevisculus 76.0 texamine thea 102.4 Lacuna vtneta 61.6 Idotea ph Tphorea 65.6 Pontogeneia inerais 52.8 corophium acutum 43.2 Capre11a penantie 39.2 Maliclystus salpina 36.8 corophium insidiosus 37.6 corophtum insidiosum 24.0 corophium bonelli 13.6 capre11a linearis 28.0 corophium spp. 12.0 Motopella anqueta 21.6 Paqurus acadianus 11.2 Mytilus edults 20.8 Total of 15 species 3254.4 Total of 15 species 2908.4 Remaining Fauna-27 spp. 92.0 Remaining Fauna-46 spp. 196.8 Total Fauna-42 spp. 3346.4 Total Fauna-61 spp. 3105.6 Mmmomet Point Mamomet Point Jassa falcata 2479.2 Margarites he31cinus 635.2 1schyrocerus angulpes 1081.6 Plousyntes k g 615.2 corophium acutum 449.6 Acarina 460.0 Acarina 347.2 calliopius laevinculus 313.6 Mytilua edulis 276.0 onoba seules 284.4 Desamine thea 215.2 1schyrocerus anguipe. 284.0 caprella Enantis~
210.4 MYtilus edulis 257.6 Lingula aculous 176.4 Demanine thea 252.0 14cuna vincta 172.8 corophium E idiosum 250.4
'nargarites helleinus 81.6 Pentogeneta inerais 248.8 Idotea phospherea 72.0 Jassa falcata 225.6 Protoloides holmest 72.0 taeune vineta 165.6 Pleusyntes glabor 41.6 capre11a linearis 145.6 Pontogeneia inerais 40.0 corophium bonelli 142.4 corophtum bonelli 32.0 Mitre 11a lunata 121.6 Total of 15 species $144.0 Total of 15 species 4403.2 Remaining Faune-to spp. 298.4 Romaining Fauna-76 spp. 1340.4 Total Fauna-55 sp. 6046.4 Total Fauna-91 spp. 5744.0 Rocky Point Rocky Point Ischyrocerus anguipes 659.2 Jassa falcata 404.8 Jassa falcata 500.0 Acarina 349.6 Demanine thea 426.4 !sehyrocerus anguipes 307.2 Acertna ~ 281.6 Pleusyntes glabor 247.2 taeune vineta 265.6 Pontogeneia inermis 238.4 Pontogeneta inermis 254.4 tenantne then 219.2 cinquia seulous 131.2 A1vania o f 204.8 calliopius laevisculus 117.6 capre11e penantis 161.6 corophium acutum 108.0 Margarites helseinus 154.4 caprella penantis 95.2 corophium bonelli 136.0 Mytilus edulis 56.8 onoba acules 134.4 corophfum bonelli 53.6 Nicolea sostericola 126.4 Idotea phosphorea 37.6 Corophium insidiosum 124.8 Phomocephalus holbo111 31.2 calltepius laevisculus 114.4 coropha a insidiosum 30.4 capre11a linearis 95.2 Total of 15 species 3052.8 Total of 15 species 3054.4 Remaining Fauna-33 spp. 228.8 Remaining Fauna-70 spp. 1080.8 Total Fauna-48 spp. 3281.6 Total Fauna-45 spp. 4139.2 12
s-f The Effluent and Rocky Point stations shared 3 of the top 5 and 8 of the top 15 species. The shared top five species included the two species also shared by the Effluent and Manomet Point stations and in addition the amphipod Pontogeneia inermis. Calliopus laevisculus, which ranked first at the Effluent, occurred at a much lower rank at Rocky Point; Lacuna vincta, ranking fifth at the Effluent, was not among the dominants at Rocky Point. The two reference stations shared 2 of the top 5 and 11 of the top 15 species in September 1987; three of these
, species, Margarites helicinus, Pleusymtes glaber, and Onoba aculea, were not among the top 15 species at the Effluent station. Margarites helicinus, which ranked first at Manomet Point, ranked much lower at Rocky Point; similarly, Jassa I
falcata, which ranked first at Rocky Point, ranked much lower at Manomet Point. Seven of the top 15 species were present at all three stations. Mytilus edulis ranked 15th at the Effluent, sixth at Manomet Point, and was not among the top i 15 species at Rocky Point. The comparison of the dominant species in spring and { fall samples revealed that seasonal changes were the least noticeable at the Effluent station. Two of the top five dominants in spring (Jassa falcata and Ischyrocerus anguipes) were also among the top five dominants in fall, outranked by Calliopus laevisculus that increased about 10-fold in number between spring and fall and moved into first rank. In addition, 11 of the 15 top spring dominants were present among the 15 top fall dominar's. Slight changes took place in the species rankings; changes in species composition were minor and occurred among relatively rare species. At Manomet Point, changes were evident both in ranking of the dominants and species composition. Only one of the I top five spring dominants was also among the top five fall and only 8 of the spring top 15 dominants were dominants, also among the fall top 15 dominants. The two species l ranking first and second in the fall samples (Margarites 13 i l 1 l l
helicinus and Pleusymtes glaber) increased about 10-fold in number between March and September and therefore outranked the top two species of the spring samples, onoba aculea was . among the top five species in the fall but was not among the dominant species at any station in the spring, cerophium . acutum, which ranked third in the spring samples, was not among the dominants in the fall at Manomet Point. Seasonal changes at Rocky Point were somewhat intermediate. Four of the five top spring dominants were also among the fall top five dominants, and 8 of the top 15 spring dominants were also among the top 15 fall dominants. Many of the rankings changed slightly; changes in species composition were noted mostly among the relatively rare species. Lacuna vincta, ranking fourth in the spring samples, was not among the top 15 dominants in the fall samples. Mytilus edulis, which was present in low numbers in the spring samples from Rocky Point, was no longer among the dominants in fall. Species Diversity Species diversity is a measure of the number of species present (species richness) in combination with the distribution of population size of the respective species (evenness). In general, low evenness values indicate that a community is dominated by one or a few species (Levinton, 1982). Communities with high diversity are normally not stressed. Shannon-Wiener diversity (H') and evenness (J') values (Levinton, 1982) were calculated for samples collected in March and September 1987 (Table 4). The data were calculated excluding juvenile and indeterminate individuals that were not identified to species. The practice of calculating diversity with and without Mytilus has been continued for consistency with past reports. 14
_ 1 ( l TABLE 4. DIVERSITY VALUES (SHANNON-VIENER) FOR EACH STATION SAMPLED IN MARCH AND SEPTEMBER 1987. March 1987 September 1987 Vith Vithout With Vithout Mytilus Mytilus Mytilus Mytilus Station H' J' B' J' H' J' H' JI~ Effluent 2.47 0.48 2.33 0.46 3.33 0.62 3.29 0.62 Manomet Point 2.88 0.52 2.74 0.49 4.50 0.76 4.43 0.75 R:cky Point 3.60 0.67 3.53 0.66 4.48 0.76 4.42 0.75 H' Shannon-Viener diversity. J' - evenness. i I I i 15
j i
)
Both in spring and f all, the lowest diversity (H') was 3 found at the Effluent. The highest diversity was found at / Rocky Point in March and at Manomet Point in September. Excluding Mytilus from the data decreased the diversity index slightly at all stations during both seasons, reflecting the essentially small contribution cf Mytilus to the total fauna. Species diversity increased from March to september at all stations. The evenness values (J') show the same general pattern as tha diversity index. In spring, evenness was highest at Rocky Point, followed by Manomet Point and the Effluent. In fall, evenness was equally high at both reference stations and livest again at the Effluent station. Elimination of Mytilus, from the Effluent station data decreased evenness in March and had no effect in september; at the reference ! stationL, the elimination of Mytilus decreased evenness. At all stations, evenness was highest in the fall. , Measures of similarity similarity analysis followed by cluster analysis (Boesch, 1977) was used to answer the following questions , concerning the structure of the benthic communities present at the three stations sampled in 1987: O e Does the benthic community at the Effluent station differ from the ; community at the reference stations? e Do seasonal changes of the benthic l community at the Effluent station differ from those at the reference stations? e If there are differences in species composition and/or seasonality: which i sr,ecies cause these differunces? l 16 i e
~ , e----- , - ,-
..-------p.--, ----n. w-,--c-m,e- ,-,_,.n-.,_g_,,_,---c - , , , - , ,, - , - -- , n,, - - - , - - , -
To- answer these quostions, similarity analyses were performed for replicates (normal analysis) and species (inverse analysis). By the normal cluster analysis, all 30 replicates sampled in 1987 were compared for the species present in each replicate; by the inverse cluster analysis, the co-occurrence of the top 50 numerically dominant species identified in the 1987 samples was compared. Normal Analysis Normal cluster analyses were performed using the Bray-Curtis similarity measure follcwed by group average sorting (Boesch, 1977). A second similarity measure, the Normalized Expected Species Shared (NESS) (Grassle and Smith, 1976), was also used, but the results are omitted from this report because both Bray-Curtis and NESS showed the same pattern. The results of the similarity analysis for the spring samples are shown in rigure 2. The dendrogram shows that the Effluent station is almost as similar to the reference stations as the reference stations are to each other; this is indicated by the levels of similarity marked on the horizontal lines connecting the Effluent station with both reference station 6 (0.69) and the reference stations to each other (0.72). The difference between these two values is l minor. The cluster analysis of the fall samples resulted in a l dendrogram with two main groups, one comprising all replicates of the Effluent station and the other including both reference stations (rigure 3). The most dissimilar group within the reference station cluster contains two replicates of the Rocky Point station (outer right edge of l the dendrogram). In comparison to spring, the reference stations were more similar to each other in fall, whereas the Effluent station was less similar to the reference stations. A normal cluster analysis of the combined spring and fall data was performed to show seasonal patterns, rigure 4 17 r t
d t n
.6 0 -
, x j
. e T ! g .70 - .69 2 .72
- to l 1
M R .76 l .75 l .76 I a- .77 .78 3 .80 - O i i
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l I l REPLICATE 1 5 3 2 4 1 4 3 2 5 1 4 3 5 2
+ Manomet Point--*~ Rocky Point == Effluent :
I i FIGURE 2. DENDROGRAM SHOWING RESULTS OF CLUSTER ANALYSIS OF MARCH 1987 DATA USING BRAY-CURTIS AND GROUP AVERAGE SORTING.
40 -
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HEPLICATE 1 3 2 4 5 1 5 3 4 2 2 5 1 3 4
= Elfluent == Manomet Point =c Rocky Point :
FIGURE 3. DENDROGRAM SHOWING RESULTS OF CLUSTER ANALYSIS OF SEPTEMBER 1987 DATA USING BRAY-CURTIS AND GROUP AVERAGE SORTING.
?
..o-g .so-a j
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o _L _[ 1" 1 AfPtaCATE taps saps eaP3 adP2 W. RPS RP4 RP3 RP2 RPS Eft EF4 EF3 EFs EF2 eft EF3 EF2 EF4 EFS tePS ASPS asp 3 edP4 te2 ' AP2 APS Art NP3 AP4
,a .r = = si r FIGURE 4. DENDROGRAN SHONING RESULTS OF CLUSTER ANALYSIS OF MARCH AND SEPTEMBER 1987 DATA USING BRAY-CURTIS AND GROUP AVERAGE SORTING.
l shows the Bray-Curtis similarity measure for all 30 samples collected in 1987. The two main clusters of replicates seen in this dendrogram are the spring samples on the left side and the fall samples on the right side, clearly indicating seasonal differences in species composition at all three stations. All clusters were *dentical to those produced when spring and fall data were analyzed separately; i.e., the March cluster in rigure 4 is the same as the dendrogram shown in rigure 2, and the september cluster in rigure 4 is the same as the dendrogram shown in rigure 3. The absence of seasonal differences would have resulted in clusters that contained a mixture of spring and fall replicates. Inverse Analysis The top 50 numerically dominant species were used in an inverse analysis of the spring and fall 1987 data. This analysis indicated the fauna responsible for the seasonal pattern shown in rigure 4. The dendrogram resulting from this analysis is presented in rigure 5. Eight species groups were identified in this analysis. Group 1 contains 16 species, including 11 arthropods, four molluscs, and one polychaete. Except for the latter, all species of Group 1 were among the top 15 dominants of at least one station in 1987. Group 2 contains 13 species that include arthropods (four species), molluses (four species), echinoderms (two species), polychaetes (two species), and coelenterates (one species). Some of these species occurred among the top 15 dominants of at least one station in 1987. Group 3 is formed by nine species that are mostly polychaetes (five species); the remaining species are two molluscs, one echinoderm, and one arthropod. Group 4 includes two arthropod species; one of them, the hermit crab Pagurus acadianus, was among the top 15 dominants at the Effluent station in spring. Group 5 is composed of two arthropods and two polychaetes; only the amphipod Phoxocephalus holbolli was 21
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# 5 5 3 5131 F h8 S d !!I! 3 IEL 3) 53 I i s al 11 65533 i
FIGURE 5. DENDROGRAM SHOWING RESULTS OF INVERSE CLUSTER ANALYSIS OF MARCH AND SEPTEMBER 1987 DATA USING BRAY-CURTIS AND GROUP AVERAGE SORTING.
~ .
found among the top 15 dominants in 1987. Group 6 contains two molluscs; one of them, Cingula aculeus, occurred among the top 15 dominants. Group 7 comprises the sea star Asterias forbesi and the polychaste Dodecaceria sp. A. Group 8 is composed of an amphipod, Capre111dae sp. A, and a polychaete Fabricia sabella. The members of each of these eight groups were found to co-occur and rank similarly; the higher the level of similarity, the more often this co-occurrence was. observed. Nodal Anal'ysis Nodal analysis is a method to relate the groupings resulting from the normal cluster analysis (by replicate) and inverse analysis (by species)and allows interpretation of the patterns observed in the similarity analyues of stations (Boesch, 1977). Two different measures are used: constancy and fidelity. Constancy is a measure of the frequency of a species group in one replicate group (in this instance, a ! station) compared to its -frequency in all replicates 1 j combined; fidelity is the degree of restriction of a species l group to a replicate group. The highest possible constancy i value is 1.0, indicating that all species of a species group occurred in all replicates of a replicate group. The lowest l l possible constancy value is 0, indicating that no species of l a species group occurred in any of the replicates comprising a replicate group, ridelity values are between 0 (all j species of a species group are evenly distributed over all replicates) and >3 (all species of a species group occurred in only one replicate). Results of the nodal analysis are presented in Figures 6 and 7. Both figures show an abbreviated version of the dendrograms used for this analysis and a matrix. The top dendrogram in Figures 6 and 7 is the same as shown in rigure 5 (species groups 1 through 8); the dendrogram on the left side is the one shown in rigure 4 (replicate groups 1 through 23
.10 - SPECIES GROUPS
.2 0 - .15 x
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=
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3 '34 .32 g .40 - [-- .36 'r G .41 ; y .50 - 1 5
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BRAY-CURTIS SIAflLARITY E E E R E E i [ [ i i i i 2 3 4 5 78 l D;;J.y.w:\.p;MW. : { o uanonwt. Roewy mnt ] y $f yij g U i g -
. . . . . . ~ . .... ,
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U e = 1 I bb 1 nomet. Accry %nt I l CONSTANCY k 0.7-1.0 4" " 0.5-0.7 E 0.3-0.5 .:- 0.1-0.3 < 0.1 Very High I* E l ' Hgh Moderate Low Very Low I I FIGURE 6. CONSTANCY DIAGRAM FOR SPECIES GROUPS AND i REPLICATE GROUPS IN 1987. CLUSTERING IS WITH j BRAY-CURTIS SIMILARITY AND GROUP AVERAGE SORTING. , l 24
( .10 SPECIES GROUPS
.20 - .15 D
E x
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.34 40 - l .36 e 41 9
b o
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BRAY-CURTIS SIMILARITY O E E R E E i i [ [ ,' [ 1 2 4 5 678 lW $ fly, s.. O < Manomet. Rocky Point 4 [ 3xa. [
.q Septoneer 19sdn. .x e,( n[ it df..f,;
[!,2 m . m I '
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a March 1987 k o L s, % M
< Manomet. Rocwy Point 1
IA?.itgh,cg jy' " "@ .)
$ .$hfi b FIDELITY
>3 4'
- 2-3 3 1-2 <1 Hgh s- Moderate b'f Low Very Low 1
l FIGURE 7. FIDELITY DIAGRAM FOR SPECIES GROUPS AND REPLICATE GROUPS IN 1987. CLUSTERING IS WITH BRAY-CURTIS SIMILARITY AND GROUP AVERAGE SORTING. I 25 l l l
1 4). The central part of rigures 6 and 7 is the matrix l showing- the intersections of each species group with each replicate group. The width of each field of the matrix f depends on the number of species that form each species i group. For example, the fields in column 1 are widest } because species group 1 contains 16 species; columns 4 and 6 I thecugh 8 are narrowest because the species groups 4, 6, 7, and 8 each contain only two species. The length of each field depends on the number of replicates that form each replicate group. That is, the fields in the upper and lower rows of the matrix are twice as wide as the ones inbetween, because replicate group 1 contains 10 replicates, whereas replicate group 2 contains only five replicates, species group 1 showed very high constancy at all stations during both spring and fall (rigure 6); this was to be expected because species group 1 includes species that were among the top 15 dominants of all three stations during both seasons. The fidelity of species group 1 was low to very low (rigure 7), i.e., none or only very few species of this. group were restricted to a particular station. Seasonal differences as shown in rigure 4 were mainly a result of changes in the species groups 2, 3, and 6. For example, species group 2 showed a seasonal pattern both in constancy (rigure 6) and fidelity (rigure 7). In spring, constancy was low at the reference stations and moderate at the Effluent station; i.e., members of species group 2 were found in some of the spring replicates of each station, ridelity was very low at all stations; i.e., the species occurred scattered in replicates of all stations. In fall, constancy was high at the reference stations and very high at the Effluent station; i.e., most or all species of this group occurred regularly in all replicates of each station. Tidelity in the fall was low. Species group 3 showed seasonal patterns at the reference statione. Constancy was moderate in March and high 26
in September (rigure 6); fidelity was very low in March and i l moderate in September (rigure 7). Species group 6 exhibited a clear seasonal pattern at f all stations. Constancy was high (Effluent station) to very high (reference stations) in spring but very low (Effluent station) to moderate (reference stations) in fall (rigure 6), ridelity was low (Effluent station) to mocerate (reference stations) in spring but very low in fall at all stations (rigure 7). In summary, the nodal analysis revealed that species groups 2 and 3 were characteristic for fall samples, whereas species group 6 was characteristic for spring samples. Sp6tial differences (among stations) were mostly caused by species groups 3, 4, 6, and 8. rer example, species group 3 showed very low constancy (rigure 6) and fidelity (rigure
- 7) at the Effluent station in both seasons, wh;c9as constancy at the reference stations was moderate (spring) to high (fall) and fidelity was very low (spring) to moderate (fall).
Species group 4 showed a pattern opposite to that of group 3: constency was low and fidelity was very low at the reference stations during both seasons, whereas constancy at the Effluent station was high (spring) to very high (fall) and fidelity was low (both spring and fall). Species group 6 showed a spatial pattern in the constancy values. Constancy was very low (September) to high (March) at the Effluent station, whereas constancy at the reference stations ranged from moderate (September) to very high (March). Species group 8 showed a strong restriction to the reference stations, indicated by moderate constancy and very high f,idelity in September. At the Effluent station, both constancy and fidelity were very low during both seasons. The very low constancy and fidelity values at the reference stations in March indicate that this species group also exhibits a seasonal pattern. 27
l 1
)
In summary, the nodal analysis showed that species
]
groups 3, 6, and 8 had their strongest affinities with the > reference stations, whereas group 4 had its strongest affinity with the Effluent station. ALGAL STUDIES l Systematics ( The list of species identified in the 1987 samples was identical to the cumulative algal species list presented in Semi-Annual Report No. 16 (Boston Edison Co., 1980). No additional species have been found. Algal Community Description l The rock and cobble substrata found at the Manomet Point, Rocky Point, and Effluent stations were heavily colonized by red macroalgae (Rhodophyta) during 1987. Biomass of Chondrus crispus was highest at the Effluent station; biomass of Phyllophora spp. was highest at the Effluent in fall, whereas in spring the highest values were found at Manomet Point. The highest biomass of benthic flora other than Chondrus and Phyllophora occurred at Rocky Point; the highest biomass of epiphytic algae was found at Manomet Point, whereas the lowest values were from the Effluent station. The primary hosts for epiphytes were Chondrus and Phyllophora, but other benthic species, such as Polyides rotundus and Ahnfeltia plicata, also served as host plants. Red algae), including Spermothamnion repens, Polysiphonia elongata, Phycodrys rubens, and ceramium rubrum were the most 28 _ _ _ _ _ _ _ _ _ _ i
{ commonly observed epiphytes. The warm-water indicator Gracilaria foliifera was neither seen in the replicate samples of March and September, nor observed within the stunted and denuded zones during the transect surveys of 1987. Algal Community Overlap community overlap was calculated for the March and September 1987 data; Jaccard's coefficient of community (Grieg-Smith, 1964) was used to measure the similarity in algal species composition between stations. This coefficient provides a mathematical evaluation of the similarity between two replicates or stations using only species occurrence, without referring to any differences in the abundance of the species observed. Species occurrence records of the 37 indicator species listed in Table 5 were used for all community overlap calculations. Results of community overlap comparisons between replicate samples for each station for the March and September 1987 collecting perdeds are presented in matrix form in rigures 8 and 9. The co:amunity overlap was generally higher between the two reference stations (77.2 percent in March, 80.0 percent in September) than between either of the reference stations and the Effluent station (66.7 to 70.8 percent in March, 70.8 to 76.0 percent in September), indicating more of a difference between the Effluent Station and the reference stations. This difference was less distinct in September. The everlap values for September were identical at 80.0 percent between the two reference stations and between the Effluent and Manomet Point stations. Overall, the similarity of all three stations was high (>65 percent in March, >75 percent in September). All replicate overlap ranges were narrower in September thart in March; 29
l TABLE 5. THE 37 ALGAL INDICATOR SPECIES USED IN THE QUANTITATIVE . COKMUNITY ANALYSES. ! CHLOROPHYTA (green algae) Bryopsis plumosa Enteromorpha flexuosa Chaetomorpha linum Rhizoelonium tortuosum C. malagonium Ulva lactuca PEAEOPHYTA (brown algae) Chordaria flagelliformis Laminaria digitata Desmarestia aculeata L. saccharina D. viridis sphacelaria cirrosa RHODOPHYTA (red algae) Ahnfeltia plicata Phyllophora truncata Antithamnion americanum P. pseudoceranoides Bonnemaisonia hamifera P. traillii l Calophyllis cristata Plumaria elegans ceramium rubrum Polyides rotundus Chondrus crispus Polysiphonia elongata l Corallina officinalis P. fibrillosa Cystoclonium purpureum P. harveyi l Gracilaria foliifera P. nigrescens
! Gymnogongrus crenulatus P. urceolata j Membranoptera alata Rhodomela confervoides Palmaria palmata Spermothamnion repens Phycodrys rubens 30 i
1 2 3 4 3 I 2 3 4 3 1 \ II 10 10 10 1 13 13 12 12 2 73.3 11 10 11 Nurnber of 2 76.3 13 12 13 Number of Specses 3 77.0 63.3 10 Species
!! Shared 3 31.3 72.2 13 13 Shared 4 66J 32.6 62.3 10 4 73.0 66J 31.3 13 3 77.0 63.3 34.6 62.3 3 73.0 76.5 31.3 36J Percent Overlap Percent Overlap A. MANOMET POINT STATION B. ROCKY POINT STATION OVERLAP BETWEEN STATIONS Number of C-r .c_ _2ty 2 Shared Srh Overlap Station Pair 1 2 3 4 3 Manomet Point-Rocky Pt. 17 77.2 1 7 12 9 12 Manomet Point-Elliuent 16 66J 2 30.0 3 7 3 Number of Rocky Point-Efiluent 17 70.3 Species 3 30.0 30.0 11 14 Shared 4 36.3 46J 64J 11 3 66J 42.1 73J 33.0 Percent Overlap C. EFFLUENT STATION FIGURE 8.
ALCAL COMMUNITY OVERLAP (JACCARD'S COEFFICIENT OF COMMUNITY) AND NUMBER OF SPECIES SHARED BETWEEN REPLICATE PAIRS AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT SUBTIDAL STATIONS (3 m MLW), MARCH 1987.
1 2 3 4 5 1 2 3 4 3 1 16 16 17 14 1 14 14 13 14 2 69.6 16 13 16 N* of 2 70.0 17 14 13 Monber of Species Species 3 30.0 76.2 13 14 Shared 3 66.7 33.0 13 16 Shared 4 77.3 31.3 63.2 16 4 63.4 70.0 75.0 14 3 66.7 30.0 73.7 30.0 3 70.0 71.4 76.2 70.0 Percent Overlap Percent Overlap A. MANOMET POINT STATION B. ROCKY POINT STATION OVERLAP BETWEEN STATIONS Number of Comunwdty Shared Species Overlap u u Station Pair 1 2 3 4 3 Manoneet Pohn-Rodcy Pt. 20 30.0 1 13 13 hl 13 Manosnet Point-Effluent 20 30.0 2 63.0 14 11 11 Number of Redcy Point-Effluent 19 76.0 Speces 3 63.2 70.0 14 13 Shared 4 73.9 33.0 66.7 14 5 63.4 61.1 63.0 37.3 Percent Overlap C. EFFLUENT STATICN FIGURE 9. ALGAL COMMUNITY OVERLAP (JACCARD'S COEFFICIENT OF COMMUNITY) AND NUMBER OF SPECIES SHARED BETWEEN REPLICATE PAIRS AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT SUBTIDAL STATIONS (3 m MLW), SEPTEMBER 1987.
----w - - . - -- ---e _ - , - w . w - . ,, w
l l i.e., the similarity among the September replicates was greatet than among the March replicates. Algal Biomass Algal biomass usually shows a very regular seasonal pattern at all three stations, with biomass values being low in spring and high in fall (Boston Edison Co., 1987). This typical pattern, however, has been reversed in the previous year to high biomass values in spring and considerably lower values in fall. In 1987, this atypical pattern was somewhat evident, but the more typical pattern seemed to dominate. Chondrus crispus Biomass chondrus crispus biomass values by station for March and September 1987 are presented in Table 6. In March, the mean r9plicate value for Chondrus biomass was highest at the Effluent (ca. 172 g/n ) and lowest at the Rocky Point station (ca. 33 g/m 2 ). The mean at the Effluent was 38 percent higher than at Manomet Point and mote than 5 times higher then at Rocky Point. The range of replicate biomass was greatest at the Effluent (ca. 10 to 315 g/m ) 2and smallest at Rocky Point (ca. 1 to 110 g/m2). Chondrus comprised 52 percent of the algal biomass at the Effluent station, followed by 34 and 22 percent at the reference stations at Manomet Point and Rocky Point, respectively. In September, the highest mean ,Chondrus biomass values per replicate were again observed at the Effluent (ca. 180 2 g/m 2 ), but were lowest at Manomet Point (ca. 95 g/m ). The mean Chondrus biomass at the Effluent was 3 percent higher than at Rocky Point and 90 percent higher than at Manomet Point. The greatest range of replicate biomass was again 2 found at the Effluent station (ca. 1 to 454 g/m ), and the 33 s
TABLE 6. AVERAGE DRY VEIGHT BIOMASS PER REPLICATE (g/m ) 0F MACROAff.AR AT EFFIRENT, MANOMET POINT,' Alm ROCKY FOINT SUBTIDAL (3 a MLU) STATIONS IN MAltCE Als SEPTEMBER 1987. NUMBERS IN PARC";ES REPRESENT COPTRIBUTION TO TOTAL AIEAL BIOMASS. Effluent Maaomet Point Rocky Potat March September March September March September Chondrus crispu 172.35 (52%) 180.09 (36%) 124.79 (34%) 94.81 (27%) 32.92 (22%) 174.02 (32%) Phy11ophora spp. 132.78 (40%) 245.70 (49%) 218.89 (59%) 167.76 (47%) 76.10 (51%) 157.77 (29%) Remaining Benthic Species 17.04 (5%) 24.04 (5%) 3.23 (1%) 20.14 (6%) 23.83 (16%) 156.23 (28%) y Epiphytic Species 9.79 (3%) 47.16 (9%) 25.58 (7%) 73.35 (21%) 17.50 (12%) 63.48 (12%) Total 331.95 4 % .99 372.49 356.05 150.35 551.49 l l L.._________._ _. -_ __ . . . . _ . _ _. _. _ _.
{ lowest at Manomet Point (ca. 24 to 127 g/m 2). Chondrus made up 36 percent of the total algal biomass at the Effluent station, followed by 32 and 27 percent at the reference stations at Rocky Point and Manomet Point, respectively. Overall, chondrus biomass increased from March to September at the Effluent and at Rocky Point, but decreased at Manomet Point. This atypical pattern was observed at this station in 1986. The fact that the decline from spring to fall was more drastic in 1986 than in 1987 may indicate a return to the more typical seasonal pattern (increase from March to September) of the algal biomass. Phyllophora spp. Biomass Mean values of Phyllophora biomass measured in March and September 1987 are shown in Table 6. In March, the mean Phyllophora biomass per replicate was highest at Manomet Point (ca. 219 g/m ) and lowest at Rocky Point (ca. 76 g/m ). Mean biomass at the Effluent station was intermediate (ca. 2 133 g/m ); this value is 39 percent lower than that at Manomet Point and 74 percent higher than that at Rocky Point. The range of replicate biomass was greatest at Manomet Point (ca. 107 to 372 g/m 2 ) and smallest at the Effluent (ca. 80 to 204 g/m ). 2 Phyllophora spp. comprised 40 percent of the total algal biomass at the Effluent, 51 percent at Rocky Point, and 59 percent at Manomet Point. In September, the highest mean Phyllophora biomass per replicate was found at the Effluent (ca. 246 g/m2) and the lowest at Rocky Point (ca. 158 g/m ). Biomass at the Effluent was 46 percent higher than at Manomet Point and 56 percent higher than at Rocky Point. The greatest range of replicate biomass was observed at the Effluent (ca. 62 to 372 2 2 g/m ), and the smallest at Rocky Point (ca, 111 to 209 g/m ), l Phyllophora spp. comprised 49 percent of the total algal ! biomass at the Effluent station, followed by 47 and 29 percent at Manomet Point and Rocky Point, respectively. 35 i
/
A typical seasonal increase of Phyllophora biomass from spring to fall occurred at the Effluent and Rocky Point, / whereas a decline was noted at Manomet Point. The seasonal variations of Phyllophora were similar to those observed for l Chondrus. Biomass of Remaining Benthic Species (RBS) The algal biomass category designated remaining benthic species (RBS) is composed of all benthic algae excluding Chondrus crispus, Phyllophora spp., Laminaria spp., and algal epiphytes. Abundant species were Chaetomorpha spp. at all stations, Phycodrys rubens at the reference stations, and Polyides rotundus at the Effluent. l Mean replicate biomass values for the RBS are presented in Table 6. In both March and September 1987, the-highest mean RBS biomi.3 was found at Rocky Point (ca. 24 and 156 2 g/m , respectively). The lowest mean RBS biomass was noted 2 in both months at Manomet Point (ca. 3 g/m in March and 20 2 g/m in September). The mean RBS biomass at the Effluent was 2 2 intermediate (ca. 17 g/m in March and 24 g/m in September). The range of replicate biomass was greatest at the Effluent in March (ca. 1 to 70 g/m2) and at Rocky Point in September 2 (ca. 1 to 749 g/m ); the smallest range of replicate biomass 2 was observed at Manomet Point in March (ca. 1 to 8 g/m ) and at the Effluent in September (less than 1 to ca. 18 g/m2), The RBS comprised 5 percent of the total algal biomass both in March and September at the Effluent, 0.9 percent in March and 6 percent in September at Manomet Point, and 16 percent , in March and 28 percent in September at Rocky Point. ! Epiphytic Algal Species 1 Mean replicate biomass values of epiphytic algae are l presented in Table 6. As during most of the previous studies, Phyllophora spp. exhibitr e a higher degree of l 36
epiphytic colonization than Chondrus crispus. It has been hypothesized that the higher biomass of epiphytes associated with Phyllophora spp. was due to the sturdier morphology of this species (Boston Edison Co., 1986a). In both March and September 1987, mean biomass was highest at Manomet Point 2 (ca. 26 and 73 g/m , respectively) and lowest at the Effluent 2 (ca. 10 and 47 g/m , respectively). In March, epiphytic f algal biomass at the Effluent was 62 percent lower than at i Manomet Point and 44 percent lower than at Rocky Point; in Septecber, epiphytic algal biomass at the Effluent station was 36 percent lower than at Manomet Point and 26 percent lower than at Rocky Point. Epiphytic algae at the Effluent station made up 3 percent of the total algal biomass in March and 9 percent in September; at the Manomet Point and Rocky Point stations, the contribution of epiphytic algae to the total algal biomass was 7 and 12 percent, respectively, in March, and 21 and 12 percent, respectively, in September. At all three stations, the biomass of epiphytes increased from spring to fall. I Total Algal Blomass Mean values for total algal biomass in March and September 1987 are shown in Table 6. In both months, the values at the Effluent were intermediate between the values measured at the reference stations, but the average biomass for the entire year was greatest at the Effluent. In March, total algal biomass at the Effluent station was 11 percent lower than at Manomet Point and more than twice as high as at Rocky Point; in September, total alga' biomass at the f Effluent was 10 percent lower than at Rocky Point and 40 percent higher than at Manomet Point. Biomass increased from ! spring to fall at the Effluent and at Rocky Point, whereas it decreased at Manomet Point. In comparison to 1986, the l atypical seasonal decline of biomass reversed to the normal 37
pattern at the former two stations and was still present only at the latter station. Chondrus/Phyllophora colonization Index Study Colonization and colonization index values for Chondrus crispus and Phyllophora spp. are presented in Table 7 for March and September 1987. Colonization values are determined for the primary host species (Chondrus and Phyllophora) and are a qualitative measure of the degree of algal epiphytes and invertebrate species present on the host species. Colonization index values are the summations of colonization values for algal and faunal colonizers. Details of the procedure are the same as presented in the Semi-Annual report No. 30 (Boston Edison Co., 1987b). Data from 1987 continue to indicate that Phyllophora app. was more heavily colonized by epiphytes than was Chondrus. This observation has been typical during most of I the past samplings and, as was noted earlier, is probably due to the denser frond development of Phy11ophora spp. compared i with Chondrus. Generally, colonization was lowest at the ! Effluent and highest at Manomet Point; it increased from spring to fall.
)
QUALITATIVE TRANSECT SURVEY l Qualitative transect surveys of nearfield impact zones were initiated in January 1980 and have been conducted quarterly since 1982. Four surveys of the area were performed during 1987 (March 25, June 9, September 29, and December 22), bringing the total number of surveys conducted to 28. Results of surveys conducted from 1980 through 1983 38
TABLE 7. COLONIZATION INDEX VALUES FOR.CHONDRUS CRISPUS AND PHYLLOPHORA SPP. AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT SUBTIDAL (3 m MLW) STATIONS IN MARCH AND SEPTEMBER 1987. Manomet Point Rocky Poirt Rffliwrt Mat Mat Mar Sep Sep Sep f Chondrus c:iscus Algal Colonization 5 12 6 11 5 8 Faunal Colonization 1 13 5 M 5 l_4 Total 10 25 11 23 10 22
. Phy11ophora spp.
Algal Colonization 12 20 12 20 7 17 Faunal Colonization M 20 8 16 9 M Tctal 24 40 20 36 16 34 l l l l 39
were summarized in Semi-Annual Report No. 22 to Boston Edison Company (Boston Edison Co., 1983). A detailed discussion of the March and June 1987 surveys can be found in Semi-Annual Report No. 30 (Boston Edison Co., 1987b). These results will be summarized here, along with new data from the September and December 1987 surveys. The denuded zone has been defined as being essentially , devoid of Chondrus crispus, whereas the stunted zone was defined as having Chondrus of decreased size and density j compared with conditions considered normal for this species. However, because of the increasing recolonization of the ) denuded and stunted zones caused by the continuing outage of PNPS, it became difficult in 1987 to define these zones. The border between the stunted and denuded zones was no longer clearly defined; the denuded zone had areas of patchy or scattered chondrus growth and other areas that were either partly denuded or partly overgrown by new Chondruc plants. These zones were thus ill-defined, but nevertheless still visible, because recolonization had not advanced far enough to give the area a completely normal appearance. The zones were, therefore, still marked in the drawings (Figures 10-13), but the size (m 2) of the stunted and denuded zones was not calculated after June 1987. March 1987 Transect Survey The extent of the denuded and stunted areas immediately ; offshore from PNPS, as measured on March 25, 1987, is shown in Figure 10. The denuded zone extended approximately 78 m ; offshore along the centerline of the effluent discharge canal. As in previous years, the denuded zone was wider on the northwest (left) side of the centerline than on the i southeast (right) side, ranging in lateral extent from 5 to 18 m on the northwest side. One prominent peak at 30 m was 40
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Effluent Canal I & I I I I 30 20 10 0 10 20 30 Chondrus Chondrus Denuded Stunted Zone Zone FIGURE 10. CONFIGURATION OF DENUDED AND STUNTED ZONES AT PILGRIM NUCLEAR POWER STATION FOR 25 MARCH 1987. 41
1 observed on the northwest side. The southeast portion, to the right of the centerline, was of relatively uniform width (except for a reduced area at 30 m), averaging about 5 m out from the transect line. Ulva lactuca and Polysiphonia spp. were present in the denuded zone during the quantitative survey. The boulder plotted in rigures 10-13 serves as a visual fix for the proper placement of the transect line; it 7 is used as a landmark by the Battelle and Division of Marine Fisheries dive teams. The stunted zone in March extended 80 m offshore along the centerline and like the denuded zone was much broader on ; the northwest side of the transect line, ranging from 10 to 18 m. The southeast portion of the stunted zone was narrow, averaging about 6 m out from the transect line. 2 The area encompassed by the denuded zone was 676 m , representing a 10 percent reduction since December 1986 (753 2 m 2). The stunted zone equaled 176 m , representing a 58 2 percent reduction since December (421 m ). The total 2 nearfield impact area in March equaled 852 m , which was 27 percent less than in December. June 1987 Transect survey 1 The transect map for June 9, 1987, is presented in Figure 11. The denuded zone extended approximately 60 m l along the transect line. The southeast extent of this zone l ranged from 0 to 10 m, and the northwest extent from 0 to 9 m. The prominent peak noted on the northwest portion of the denuded zone in March was not present in June. The stunted zone observed in June 1987 extended approximately 70 m offshore along the discharge centerline. The stunted zone ranged in width from 1 m on the southeast side to 5 m on the northwest side. As mentioned earlier, the zonal boundaries were less distinct, as the zones themselves were being 42
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Inl bl 1 0 I Effluent Canal i e i 0 10 20 30 3O 20 10 Chond rus Chondrus Denuded 's' Stunted Zone Zone FIGURE 11. CONFIGURATION OF DENUDED AND STUNTED ZONES AT PILGRIM NUCLEAR POWER STATION FOR 9 JUNE 1987. 43
recolonized. As in March 1987, the warm-water indicator--Gracilaria spp.--was absent, whereas the cold-water Laminaria spp. was observed within the acute impact zone. This change in species composition is directly caused by the absence of thermal effluent. The area contained within the denuded or partially 2 denuded zone was 179 m, a 74 percent decrease from March 1987. The stunted zone equaled 284 m 2 , a 61 percent increase since March 1987. This increase is di'rectly related to the ( decrease of the denuded zone. The total nearfield impact 2 area equaled 463 m, representing a 46 percent reduction since March 1987. ( September 1987 Transect Survey { The extent of the denuded and stunted zones as measured on September 29, 1987, is shown in rigure 12. The stunted and denuded zones observed in September extended offshore I approximately 82 m along the transect line. Up to 50 m offshore, it was impossible to define a denuded zone; the zonal boundaries were indistinct, but a stunted zone could be seen starting at the ends of the submerged jetties. The denuded zone was again wider northwest of the transect line (5 to 8 m) than on the southeast side (3 to 5 m). A prominent peak of the stunted zone was noted 50 m offshore on the northwest side. Except for this peak, the stunted zone extended about 4 to 10 m out on the northwest side and 6 to 8 m out from the transect line on the southeast side. Fucus spp. and Laminaria spp. were present, the latter being a cold-water indicator; the warm-water species codium spp. was also seen. This species seems to be more temperature resistant than Gracilaria, a typical warm-water organism that was completely absent from the denuded zone in 1987. 44
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l 45
l December 1987 Transect Survey The extent of the denuded and stunted zones as measured 1 on December 22, 1987, is presented in Figure 13. It was again extremely dif fictilt to define zones. The denuded zone was relatively well-defined only between about 60 and 80 m offshore; it extended about 8 m out from the transect line on j i the northwest side and 2 to 3 m out from the transect line on the southeast side. The stunted zone was identifiable ; between 60 and 80 m offshore on the northwest side and at 70 m offshore on the southeast side. The remaining former denuded zone was partially denuded on the northeast side; i.e., some of the rocks were denuded, whereas others were colonized by Chondrus and Laminaria. This partially denuded zone extended 5 to 11 m out from the centerline. The remaining former stunted zone on the northeast side of the transect line showed patchy Chondrus growth; it extended 10 to 15 m out from the centerline. The entire acute impact i zone on the southwest side of the centerline (except for the small areas with defined denuded and stunted zones) showed patchy Chondrus extending 2 to 8 m out from the centerline. Laminaria and Fucus were frequently observed in the acute impact area; no typical warm-water algae were seen. i
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i s a a # # 30 20 10 0 10 20 30 Chondrus Chondrus .* W Potchy Denuded Stunted 3,3r? di Denuded Partially . i. i. Chondrus Zone Zone ' Chondrus Zone C]" Growth FIGURE 13. CONFIGURATION Of DENUDED AND STUNTED ZONES AT PILGRIM NUCLEAR POWER STATION FOR 22 DECEMBER 1987. 47
l I CONCLUSIONS FAUNAL STUDIES e Species richness was lowest at the Effluent station both in March and September. At all three stations, species _ richness increased from March to September. 1 e Faunal densities were intermediate at the Effluent in March and lowest in September. At Rocky Point, densities increased by 26 percent from March to September. At the other stations, densities decreased by six to seven percent. , e Dominant species were similar among stations both in March and September. Seasonal changes were least noticeable at the Effluent. l l e Species diversity was lowest at the Effluent both in March and September. Mytilus edulis contributed only very I little to the total fauna. Diversity increased from March to September at all stations. i e Similarity among all stations was high both in March and September. The Effluent station was as similar to the i reference stations as the reference stations were to each other. Seasonality was evident at all stations. l l ALGAL STUDIES I e Algal communities were dominated by Chondrus crispus and Phyllophora spp. The warm-water indicator Gracilaria foliifera was not found, l 48
- .~. - , ,,.,_w . . , __ ,....,,..,.v.--..._-._.-__ - . , . - ~ . _ . , - - . _ _ . - . . ,
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l e Algal community overlap among stations was generally greatest in September. The values for the two reference stations were somewhat higher than for the Effluent and i reference stations. l e Chondrus biomass was highest at the Effluent both in March and September. Phyllophora biomass was intermediate at the Effluent in March and highest in September. Total algal biomass was intermediate at the Effluent during both months; however, the average biomass for both months combined was highest at the Effluent, , e Colonization was lowest at the Effluent and highest at Manomet Point during both months. Phyllophora was most l heavily colonized. l QUALITATIVE TRANSECT SURVEY l e The acute impact zone decreased considerably between March and ' June because of chutdown of the circulating water pumps. By September recolonization advanced so far that zonal boundaries were obscured. The impact area increased again between June and September because of current scouring caused by circulating water pumps. i l I 49 1 L
LITERATURE CITED , i l Blake, J.A., E.M. Baptiste, R.E. Ruff, B. Hilbig, B. Brown, R. Etter, and P. Nimeskern. 1987. Marine ecology and water quality field studies for outfall siting. Deer Island Secondary Treatment Facilities Plan. Soft-bottom benthos of Massachusetts Bay. Draft report to Camp Dresser and McKee, Inc., Boston, MA. Bold, H.C. and M.J. Wynne. 1978. Introduction to the Algal ! Structure and Reproduction. Prentice-Hall, Englewood Cliffs, NJ. 706 pp. Boesch, D.F. 1977. Application of numerical classification in ecological investigations of water pollution. U.S. Department of Commerce, NTIS PB-269 604. EPA-60013 033, 114 pp. Boston Edison Co. 1980. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 16. Boston, MA. Boston Edison Co. 1983. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 22. Boston, MA. Boston Edison Co. 1985. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 26. Boston, MA. I Boston Edison Co. 1986. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report ] No. 27. Boston, MA. ) Boston Edison Co. 1987a. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report j No. 29. Boston, MA. Boston Edison Co. 1987b. Marine ecology studies related to I operation of Pilgrim Station. Semi-Annual Report No. 30. Boston, MA. , 1 Davis, J.D. and R.A. McGrath. 1984. Some aspects of nearshore I benthic macrofauna in western Cape Cod Bay. In: John D. Davis and Daniel Merriman (Ed.) Observations on the Ecology and Biology of Western Cape Cod Bay, Massachusetts. Lecture Notes on Coastal and Estuarine Studies. 228 pp. Springer-Verlag, NY. Grassle, J.F. and W.L. Smith. 1976. A similarity measure i sensitive to the contribution of rare species and its
- use in investigation of variation in marine benthic .
communities. oecologia 25:13-22. ' l 50
Grieg-Smith, P. 1964. Quantitative Plant Ecology. 2nd Ed. Butterworths, Washington. 256 pp. Grocki, W. 1984. Algal investigations in the vicinity of Plymouth, Massachusetts. In: John D. Davis and Daniel Merriman (Ed.) Observations on the ecology and biology of western Cape Cod Bay, Massachusetts. Lecture Notes on Coastal and Estuarine Studies. 228 pp. Springer Verlag, NY Heltshe, J.F. and N.E. Forrester. 1983. Estimating species richness using the jackknife procedure. Biometrics, 39:1-11. Levinton, J.S. 1982. Marine Ecology. 525 pp. Prentice-Hall
- Inc. N.J.
Sebens, K.P., J.D. Witman, N. Maciolek, and B. Brown. 1987. Marine ecology and water quality field studies for outfall siting. Deer Island Secondary Treatment Facilities Plan. Rocky Subtidal Ecology. Draft report to Camp Dresser and McKee, Inc., Boston, MA. I s 51
FINAL SEMI-ANNUAL REPORT Number 31 (Volume 2 of 2) to BOSTON EDISON COMPANY I on f BENTHIC ALGAL AND FAUNAL MONITORING AT THE PILGRIM NUCLEAR POWER STATION (IMPACT ON BENTHIC COMMUNITIES) January - December 1987 L l 7 April 1988 BATTELLE Ocean Sciences 397 Washington Street Duxbury, Massachusetts 02332 l
)
Battelle does not engage in research for advertising, sales promotion, or endorsement of our clients' interests including raising investment capital or recommending investment decisions, or other publicity purposes, or for any use in litigation. Battelle endeavors at all times to produce work of the highest quality, consistent with our contract commitments. However, 4 because of the research and/or experimental nature of this work the client undertakes the sole responsibility for the i consequences of any use, misuse, or inability to use, any information, apparatus, process or result obtained from Battelle, and Battelle, its employees, officers, or Trustees have no legal liability for the accuracy, adequacy, or efficacy thereof. l i l i i
T TABLE OF CONTENTS PAGE EXECUTIVE SUK A,Y...................................... 1 INTRODUCTION........................................... 2 METHODS................................................ 7 QUANTITATIVE FAUNAL COMMUNITY STUDIES.................. 10
)
SPECIES RICHMESS.................................. 10 j FAUNAL DENSITY.................................... 12 SPECIES DOMINANCE................................. 14 SPECIES DIVERSITY................................. 14 SIMILARITY AMONG STATIONS......................... 16 DISCUSSION--FAUNAL STUDIES........................ 18 QUANTITATIVE ALGAL COMMUNITY STUDIES................... 21 ALGAL COMMUNITY DESCRIPTIONS...................... 21 ALGAL COMMUNITY OVERLAP........................... 22 ALGAL BIOMASS..................................... 22 DISCUSSION--ALGAL STUDIES......................... 24 QUALITATIVE TRANSECT SURVEYS........................... 29 CONCLUSIONS............................................ 33 i i FAUNAL STUDIES.................................... 33 i QUANTITATIVE ALGAL COMMUNITY STUDIES.............. 36 i QEALITATIVE TRANSECT SURVEYS...................... 36 LITERATURE CITED....................................... 38 I
LIST OF TABLES TABLE PAGE
- 1. Algal Community Overlap in Percent Between Stations for the Period 1983-1987................. 23
- 2. Summary of Impacts of PNPS on Benthic Communities. 34 LIST OF FIGURES FIGURE
- 1. Monthly PNPS Capacity Factor (Bars) and Circulating Pump Activity (Dotted Line) Plotted for the Period 1983 Through 1987.................. 4
- 2. Location of Rocky Point, dffluent, and Manomet Point Subtidal (3 m MLW) Stations................. 8
- 3. Species Richness for the Period April 1983 Through September 1987 Plotted with the Monthly PNPS Capacity Factor (MDC). Values of April 1983 ,
Include Juvenile and Indeterminate Individuals.... 11
- 4. Faunal Densities (m ) for the Period April 1983 Through September 1987 Plotted with the Monthly PNPS Capacity Factor. A: Total Fauna, B: Mytilus edulis............................................ 13
- 5. Shannon-Wiener Diversity (H') for Data Excluding Mytilus edulis Plotted with the Monthly PNPS Capacity Factor (MDC)............................. 15
- 6. Dandrogram Showing Results of Cluster Analysis of March 1987 Data Using Bray-Curtis and Group Average sorting................................... 17
- 7. Seasonal Fluctuatior.s in Total Mean Chondrus Bionsss at the Manomet Point, Rocky Point, and Effluent Stations During Spring and Fall Sampling Periods for the Collections Between April 1983 and September 1987 Plotted with the Monthly PNPS Capacity Factor (MDC)............................. 25
- 8. Seasonal Fluctuations in Total Mean Phyllophora Biomass at the Manomet Point, Rocky Point, and Effluent Stations During Spring and Fall Sampling Periods for the Collections Between April 1983 and September 1987 Plotted with the Monthly PNPS Capacity Factor (MDC)............................. 26 ii
l i f , l : LIST OF FIGURES (Continued)
- 9. Seasonal Fluctuations in Total Mean Algal Biomass at the Manomet Point, Rocky Point, and Effluent Stations During Spring and Fall Sampling Periods for the Collections Between April 1983 and September 1987 Plotted with the Monthly PNPS Capacity Factor (MDC)............................. 27
- 10. Area of Denuded and Stunted Zones in the vicinity of the PNPS Effluent Canal Plotted with the Monthly PNPS Capacity Factor (MDC). No Area Measurements were Made in September and December
. 1987 Because of Lack of Definitive Demarcations of Denuded and Stunted Zones......................... 30
- 11. Results of 1987 Qualitative Transect Surveys of the PNPS Acute Impact Zone off the Discharge Canal............................................. 31 l
l l l l ( l l iii
LIST OF PLATES 1 PLATE PAGE
- 1. Effluent Plume Exiting the PNPS Cooling Water Discharge Canal. The Effluent Plume Presents Two Sources of Potential Impact on Benthic Communities: Increased Ambient Temperatures and Increased Current Velocities Resulting in Benthic Scouring.......................................... 3
- 2. Diver with Underwater Writing Tablet Preparing to Enter Water. Diver Transect Surveys Are Conducted Quarterly to Map the Acute Impact Zone Associated with the PNPS Effluent Canal...................... 3 l
i i
)
iv
EXECUTIVE
SUMMARY
This volume of Semi-Annual Report No. 31 summarizes impact findings for the benthic monitoring program from 1983 through 1987. Methods and procedures follow guidelines established by the Pilgrim Administrative Technical Committee j (PATC) and adopted by Boston Edison Company (BECO) as modified in 1981 (Boston Edison Co., 1987b).
} The cooling system at Pilgrim Nuclear Power Station (PNPS) could potentially affect the benthic communities at the mouth of the discharge canal by warming ambient waters and by increasing current velocit-les enough to cause benthic scouring. In 1987 the benthic communities near the effluent canal of PNPS went through a stage of recovery because of the continuing power outage at PNPS. The response of the algal community was directly related to the outage. The former acute impact zone was almost completely obscured, and warm-water species were replaced by typical cold-water species. The response of the faunal community at the Effluent we.s not as evident, because the fauna depends on the
) algal cover for habitat. Even subtle differences in density j or height of the algal cover may result in insufficient conditions for the settlement of many invertebrates. Such l conditions were present in 1987, resulting in lower species richness, diversity, and density of the faunal communities at the Effluent. However, some recover; of the faunal community was reflected by the increased levels of similarity between the Effluent and reference stations. If the outage is l prolonged in 1988, fauna at the Effluent station will 1 probably closely approach normal. ! 1 r
1 l INTRODUCTION The benthic monitoring program being conducted near the Pilgrim Nuclear Power Station (PNPS) began in 1972 and has continued at varying levels to the present time. The objectives of this program are to identify and assess the significance of impacts associated with operations of PNPS on the nearshore benthic communities. Introduction of an ' environmental perturbation has the potential to affect members of these communities because their ability to migrate ; away from disturbances is limited. Significant changes in i benthic community parameters may, therefore, be entrelated , with the source of the perturbation. PNPS is a base-loaded, nuclear-powered electrical , generating unit designed to produce 655 megawatts of energy under full operational conditions. The station is cooled by water withdrawn from Cape Cod Bay; the water is used to , remove heat from the station condensers. The cooling water is then returned to the Bay via a discharge canal designed to . I dissipate heat from the water through rapid mixing and dilution. The two circulating water pumps produce a combined flow of approximately 20 m 3 per second at full operational capacity. Plate 1 shows the plume created as the effluent leaves the discharge canal. The cooling system at PNPS presents two sources of potential impact on the benthic ( communities at the mouth of the discharge canal: warming of ambient waters and increased current velocities resulting in benthic scouring. 1 Operational conditions at PNPS over recent years have provided an opportunity to assess the degree of impact ; experienced by the benthic communities and the time frame over which *r.ese communities could be expected to recover if the effect of PNPS were removed. Figure 1 presents the annual maximum dependable capacity factor (MDC) and circulating water pump operation for PNPS from 1983 to 1987. 2 l
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l Plate 2. Diver with underwater writing tablet preparing I to enter water. Diver transect surveys are conducted quarterly to map the extent of the acute impact zone associated with the DNPS effluent canal, 3 l
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_ . . ~
I \ The MDC is a measure of reactor output that roughly approximates thermal loading to the marine environment. A maximum value of 100 percent for the MDC represents the highest allowable change in ambient temperature (32'r oT). The cumulative capacity factor from 1983 to 1987 has been approximately 36 percent. During this time, there have l been dramatic swings in porar output. In 1983, PNPS sxperienced a productive year, with an annual MDC of 80.3 percent. The following year (1984), PNPS was off-line for a full 12 months, resulting in an annual MDC of only 0.1 percent. The outage in 1984 also resulted in reduced scouring off the effluent discharge canal, with partial circulating weter flow during most of the year and no flow from April to mid-August 1984. The extremely low MDC in 1984 was followed by a record high in 1985 (84.4 percent). The recent up and down trend in PNPS output was continued in 1986, with an annual MDC of 17.5 percent. outages of some duration began on March 7, 1986, and since mid-April 1986, , the station has been completely off-line until the publication of this report. Two circulating water pumps operated through February 1986; only one pump was on line from March 1986 through February 1987. Except for a few days, no ,. ps were operating from April through August 1987. From September through December 1987 one pump was again on line; during six days in December, both pumps were operating. The situation at PNPS from 1983 through 1987 has, therefore, presented a valuable opportunity to compare the results from two peak operational yec.rs (1983, 1985) r ith results from i three years of high potential environmental recovery (1984, , i 1986/87). Because the outage that began in April 1986 lasted throughout 1987, it was expected that responses of the benthic communities to the lack of thermal effluent and reduced current from PNPS would be more pronounced in 1987 I than in 1986, and that these responses would be similar to those noted during 1984 when PNPS experienced a negligable 5
power output. These 1984 responses were summarized in , Semi-Annual Report No. 27 (Boston Edison Co., 1986) and included the following: e A change in the relative rankings of the Effluent and reference stations in terms of species richness; the Effluent station typically ranked third prior to the 1984 outage, but ranked second in March 1985. e Species diversity values at the Effluent station were more similar to diversity at the reference stations than would be typical if PNPS were~ operating. o A lagged recovery at the effluent acute impact zone resulting in macroalgal growth within the ' previously denuded chondrus zones. e Prosence and absence of several species of algae (most notably Gracilaria foliifera and Laminaria spp.), considered indicators of warm-water (G. foliifera) and cold-water (Laminaria spp.) habitats, in response to the presence and absence of thermal effluent from PNPS. This volume of the Semi-Annual Report summarizes impact findings in relation to the benthic monitoring program. It discusses overall trends in the data presented in Volume 1 and in previous reports in an effort to summarize the effects associated with PNPS operations on benthic communities. Volume 2 places particular emphasis on the period from 1983 to 1987 for reasons discussed above. ) i I 6 _ . . . . . , - , - - - - - - , - - - - -.---- --..- -----~.---- -. - - . . -
METHOD 5 The present design of the benthic monitoring program includes quantitative and qualitative approaches for determining the presence and extent of impacts associated L with PNPS. Specifications for methods and procedures follow guidelines- established- by the Pilgrim Administrative x Technical Committee (PATC) and adopted by BECO as modified in 1981 (Boston Edison. Co., 1987b). The quantitative studies measure and compare benthic community parameters at three stations (rigure 2): a surveillance station located
- . approximately 120 m offshore from the mouth of the discharge canal' (Effluent station), and two reference stations located
, 0.25 nautical miles northwest (Rocky Point station) and 2 nautical miles southeast (Manomet Point station) of the Effluent station. Algal and faunal community analyses performed on data collected from these stations are compared
- for spatial (reference vs. surveillance) and temporal I (differences in seasonal trends) variability. Differences
! between the Effluent and reference stations are then examined for indications of an impact from PNPS at the Effluent f. f station. Because of its distance from the source of perturbation, f the quantitative Effluent station was chosen as a site likely l to experience a less severe effect from PNPS than that ! experienced by communities located closer to the effluent discharge canal. The acutely impacted areas immediately I offshore of the canal (0 to 90 m from the submerged ends of ! the canal) are monitored through qualitative methods. The techniques for these areas include diver surveys (Plate 2) to measure the offshore and lateral extent of algal stunting and denudation caused by the effluent discharge. The focus of these observations is the red macroalga chondrus crispus, a species prevalent throughout western Cape Cod Bay. Divers ! swin along a measured transect line, noting the boundaries of l 7 i i
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i the denuded, stunted, and normal Chondrus zones typical of the acute impact area associated with the PNPS discharge effluent. Variations in the size of these zones over time l are recorded as a means of determining the area most severely affected by PNPS operations. Detailed descriptions of all sampling and analysis techniques can be found in Semi-Annual Report No. 29, volume 1 (Boston Edison Co., 1987a). { l 0 9
1 QUANTITATIVE FAUNAL COMMUNITY STUDIES ; r SPECIES RICHNESS Until 1985, speci6s richness values, at all three stations sampled during this study had varied according to a seasonal pattern of low species richness in spring followed by high species richness in fall (rigure 3). Additionally, the Effluent station had exhibited depressed species richness in comparison with the reference stations. The consistent pattern of reduced species richness at the Effluent station was assumed to be directly related to an effect associated with PNPS operations. As discussed in Semi-Annual Report No. 27 (Boston Edison Co., 1986), data from 1985 indicated a lagged response at the Effluent station to the refueling outage of 1984. In 1986, species richness values at the Effluent station were again affected by the lack of heated effluent being discharged from , PNPS. The response to the outage of 1986 was similar to that in 1984-1985, in that a high output year (1985) followed by a low output year (1986) appears to have disrupted the typical, PNPS-induced pattern of spen ~ 's recruitment at the Effluent station. In March 1986 (immediately after the first brief outages in 1986), the Effluent station ranked second among the stations for pooled species richness and by September 1986, the Effluent station ranked first (rigure 3). In 1987, the number of species was lowest at the Effluent station both in spring and fall, and at all three stations the species richness increased from March to September (rigure 3). These conditions, observed during the continuing power outage of PNPS, resemble the observations made until 1985, i.e., during years when PNPS was operating more or less continuously. It seems, thus, that in 1987 the benthic community at the Effluent station still had not fully 10
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FIGURE 3. SPECIES RICHNESS FOR THE PERIOD APRIL 1983 THROUGH SEPTEMBER 1987 PLOTTED -l WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC). VALUES OF APRIL 1983 INCLUDE JUVENILE AND INDETERMINATE INDIVIDUALS.
i l recovered from the effects of the thermal effluent discharged until early spring 1986. The results of the 1986 analysis seemed to indicate a more complete recovery of the fauna than do the results of the 1987 analysis. The lack of flow from circulating water pumps in spring and summer 1987 may have accounted for the low species richness in the fall of that year and in 1984. FAUNAL DENSITY Figure 4A presents total faunal densities at the Effluent and the reference stations during 1983 through 1987. As was reported in previous years, there seems to be no seasonal pattern at any of the three stations. There is also no consistent relationship between the densities at any two stations. Generally, densities are lower at the Effluent than at the reference stations, and the reference stations change in their ranking relative to each other. However, faunal densities at the Effluent station are occasionally higher than at one or even both reference stations. The contribution of the blue mussel Mytilus edulis (rigure 48) to the total faunal density changed dramatically at all three stations, with extremely high densities occurring in fall 1984 at all stations and a second peak at the Effluent station in spring 1986. Except for this peak, Mytilus densities have been very low since the fall of 1985. The MDC values shown in rigures 4 and 5 reveal that changes in faunal densities are not directly related to PNPS operations. Total faunal densities at the Effluent station during the two high-capacity years (1983 and 1985) differ in value as well as in the way they change from spring to fall (sharp increase in 1983, slight decrease in 1985); total densities during the two long outage periods in 1984 and 1986/87 differ dramatically in value. Since 1985, densities 12
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84 : 85 - 86 87 Sampling Period M Effluent M Manomet Point E Rocky Point ~~ C pacity actor (%) l FIGURE 4. FAUNAL DENSITIES (m ) FOR THE PERIOD APRIL 1983 l THROUGH SEPTEMBER 1987 PLOTTED WITH THE MONTilLY PNPS CAPACITY FACTOR. A: TOTAL FAUNA, B: MYTILUS EDULIS 13
followed roughly the same pattern at all three stations. Changes in faunal- densities at the Effluent station can therefore not be relatad to the degree of operation of PNPS, but must be interpreted as part of naturally occurring processes in Cape Cod say. The absence of environmental stress including high water temperatures and scouring by strong currents during the power outages at PNPS may influence the composition of rare species; these changes, however, are not detectable when the total fauna is analyzed. SPECIES DOMINANCE t composition of the 15 numerically dominant species at all three stations has remained relatively similar throughout this study. The same species made up the largest portion (generally >80 percent) of the faunal communities from season to season and year to year. Rankings of the top 15 dominants may vary, but the species composition has been fairly consistent at all three stations. Faunal species dominance has not been noticeably affected by PNPS operations. . SPECIES DIVERSITY ( l A seasonal pattern of low faunal diversity in spring followed by high diversity in fall has been observed at all three stations over the course of this study. This pattern l is shown for the 1983 to 1987 period in Figure S. For ) consistency with previous reports, Mytilus counts have been excluded from the calculations for the 1987 data, rigure 5 also shows that, in general, the Effluent station exhibits lower diversity values than do the reference stations. 14
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l Deviations from this last trend, as observed in spring 1983, 1986, and 1987, do not appear to be related to PNPS operations. These deviations appear to reflect isolated incidents of reduced diversity at the reference stations, r rather than increased diversity at the Effluent station. SIMILARITY AMONG STATIONS
.e The results of cluster analyses discussed in Volume 1 show that the faunal community at the Effluent station is somewhat different from the communities at the reference i stations. Prior to 1987, this difference was much more distinct; the increasing similarity between the Effluent and '
reference stations indicates the recovery of the benthic community at the Effluent station because of the continuing ' outage at PNPS. Figure 6 presents the results of the March 1987 analysis, where the reference station samples show only a slightly higher level of similarity with one another th'n with samples taken from the Effluent station. A similarity analysis of the combined spring and fall data resulted in clear patterns of seasonal changes in the benthic communities at all etations. The results of additional analyses indicated that differences among stations and seasonal fluctuations can be related to certain groups of species, j Generally, the major differences between the faunal communities at the Effluent and reference stations were in the composition and density of subdominant species. These species play a significant role in influencing overall community structure and the effect that PNPS has on it. 4 1 16 y -
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FIGURE 6. DENDROGRAM SHOWING RESULTS OF CLUSTER ANALYSIS OF MARCH 1987 DATA USING BRAY-CURTIS AND GROUP AVERAGE SORTING.
DISCUSSION--FAUNAL STUDIES The results of faunal community analyses conducted during 1987 indic:ste only a minor difference between the Effluent station and the reference stations. Although species richness is still lower at the Effluent station than at the reference stations, the similarity analysis shows that the similarity between the Effluent and reference stations has increased considerably. Species richness declined greatly at the Effluent station compared to previous years; however, a similar decline was also observed at the reference stations. Differences in faunal densities among the stations are not correlated with PNPS operations and the species that contribute the majority of the individuals (typically greater than 80 percent) to the total fauna at the three stations differ only in relative rank. Seasonal trends in faunal diversity covary at the three stations and usually indicate depressed diversity at the Effluent station compared with the reference stations. Logan and Maurer (1975) have hypothesized that faunal : communities in the mouths of thermal effluent canals are in a "noninteractive, pioneer state." This state is reflected in high diversity, low species numbers, and low population densities caused by intermittently severe environments (i.e., temperature variations, as well as changes in turbidity). The results of the current study indicate that the faunal communities at the Effluent station exhibit characteristics somewhat different from those described by Logan and Maurer. Although species richness is typically depressed at the Effluent station, diversity is also depressed and faunal densities are not always lowest at the Effluent station. The
- community found at the Effluent station is one that is more commonly believed to be characteristic of a stressed environment. l t
18
Logan and Maurer state that the occurrence of high diversity in the path of a thermal effluent is probably caused by recolonisation following periods of severe, intermittent environmental change. An example of such a change would be decreased ambient temperatures caused by storms, extreme tides, or plant shutdown. Data from the present study, therefore, seem to indicate that although there is an effect at the Effluent station, conditions at the c station have been relatively stable for prolonged periods of time, resulting in sustained low diversity compared with the reference stations. This stability was maintained at least until 1984, when PNPS experienced a long shutdown. Under "normal" PMPS operating conditions, the faunal communities at the Effluent station experience different temperature variations annually than are experienced at the reference stations (i.e., greater ambient temperatures in the summer and winter due to thermal loading); temperature variations result in differences in the community parameters discussed earlier. These annual variations were compounded by the extreme maxima and minima of operation experienced by PNPS from 1983 through 1987, creating Onvironmental variability at the Effluent station on a different scale than is usually experienced. As has been noted, the impact of PNPS at the Effluent station is on the rarer, more transitional species rather than on the dominant species. Although the effect of PNPS at the Effluent station is not extreme under normal conditions, erratic PNPS operation during recent years created prolonged perturbations at the Effluent station in the form of high power output (maximum impact) followed by no power output (maximum recovery), including variations in discharge current flow from full flow (maximum impact) to no flow (minimum impact). These fluctuations by PNPS have resulted in environmental impacts at the Effluent station that are less consistent than those seen prior to 1984, a fact which accounts for the changes in 19 i
e-
-l relative . ranking of the three stations for severalLof.the parameters measured in this study.
{ I I 20 1
._ __ _ _ J
QUANTITATIVE ALGAL COMMUNITY STUDIES ALGAL COMMUNITY DESCRIPTIONS Like the faunal communities, the algal communities at the Effluent station are dominate by species that also dominate the reference stations. However, one indication of the effect of PNPS on algal communities at the Effluent station has been the presence of several less abundant species that do not occur at the reference stations. The most significant of these species is Gracilaria foliifera. G. foliifera, considered an important indicator of warm-water habitats (Boston Edison Co.,1982), was not found in any of the samples taken in 1987. This species had occurred regularly at the Effluent station during normal operational years. In 1986, a drastic decrease of G. foliifera was observed, the species being present in only two replicate samples out of ten, and the disappearance of this species in 1987 is clearly related to the continuing outage of PNPS. A similar decrease in G. foliifera abundance at the Effluent j station was also noted in response to the outage of 1984 (Boston Edison Co., 1986). l Divers conducting qualitative transect surveys at the , effluent discharge canal in 1987 reported G. foliifera as being completely absent; a significant decrease in abundance had been observed from March to December 1986. According to these qualitative and quantitative findings, the occurrence of G. foliifera is apparently related to the impact of the PNPS thermal effluent, i 21 L
T ALGAL COMMUNITY OVERLAP Table 1 presents algal community overlap values between stations (i.e., the number of species shared by a given pair of stations) for the last five years. The general tendency of the two reference stations to be more similar to each other (higher overlap values) than to the Effluent station has again been confirmed by the values calculated for 1987. However, as in previous years, the overlap values for the various station pairs (Manomet Point vs. Rocky Point, Manomet Point vs. Effluent, and Rocky Point vs. Effluent) were not significantly different, indicating a relatively homogeneous distribution of algae among all stations. In September 1987, the overlap between the Manomet Point and Effluent stations was identical with the overlap between the two reference stations, thus approaching the unusual conditions reported in April 1983 and September 1985. It was suggested earlier (Bosten Edison Co., 1987b) that thesu variations in species overlap are not directly caused by effects related to PNPS operations, but rather are part of naturally occurring, long-term variations in Cape Cod Bay, overall, the continuation of the outage to almost two years did not cause any significant changes in the algal species composition, again indicating that effects of PNPS operations on the algal species composition are minimal. 1 ALGAL BIOMASS The 1987 biomass data generally showed the same pattern ! observed in previous years except for 1986 (Boston Edison Co., 1987a). That is, biomass was low in spring and high in fall at all stations. The only exception to this pattern in 1987 was the Manomet Point station, which showed a decrease 22
. _ _ _ _ - _ .- ._ _ =
'l TABLE 1. ALGAL COMMUNITY OVERLAP IN PERCENT BETWEEN STATIONS FOR THE PERIOD 1983-1987.
1983 1984 1985 1986 1987 Apr On Mar Sep Mar Sep Mar Sep Mar Sep M P vs. RP 81.0 77.8 76.0 84.0 88.0 65.5 90.9 84.0 77.2 80.0 M P vs. EF 85.2 67.9 68.0 73.1 77.0 73.1 76.9 70.4 66.7 80.0 0 RP vs. EF 81.0 73.0 70.4 71.0 75.0 88.9 80.8 77.8 70.8 76.0 Ma = Manomet Poirt R1' = Rocky Poirt EE = Effluert
3 4 4 f l in algal biomass from spring to fall; in 1986, both reference stations had high algal biomass values in spring and considerably lower values in fall (rigures 7 to 9). The fact that the biomass values at the Rocky Point station followed the regular pattern in 1987 after showing irregularities in 1986 makes it very unlikely that the conditions noted in 1986 i were a response to the outage. The changes are apparently part of natural processes occurring in Cape Cod Bay; this conclusion was suggested earlier (Boston Edison Co., 1987b) after statistical investigations of the 1986 data did not show any evidence of a correlation between the PNPS j operations and biomass values at any station. DISCUSSION--ALGAL STUDIES i The results of algal community studies presented for 1987 support the conclusions drawn earlier for the faunal studies. Measures of similarity between station pairs (in - this case, Jaccard's coefficient of community) indicate a f slightly higher degree of similarity between the reference stations compared with the Effluent station. This observation is typical for the study, and is caused by the variation of species considered rare in terms of their contribution to the i total algal biomass at each station. One example of this type of species is Gracilaria foliifera, which occurred only near f the effluent canal during the years when PNPS was normally f operating. The continuing outage accounted for the disappearance of G. foliifera in 1987. However, biomass values for the major algal categories fail to show any patterns, either among stations or over time, that would indicate a significant effect of PNPS at the Effluent station. These observations are analogous to those noted earlier in this report for faunal species richness and faunal i densities. 24 i
- 10 0 600 - L g...........==== Rock y Point 4 3 A g
- Manomet Point O 2
g e.............. Etfluont
$ MDC 3_
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*er .l if Chondrus a o a i a o o o 1 I I I ' I I I I I I 4/83 10/8 3 3/84 9/84 3/85 9/85 3/86 9/86 3/87 9/87 Sampling Period FIGURE 7. SEASONAL FLUCTUATIONS IN TOTAL MEAN CHONDRUS BIOMASS AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT STATIONS DURING SPRING AND FALL SAMPLING PERIODS FOR THE COLLECTIONS BETWEEN APRIL 1983 AND SEPTEMBER 1987 PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC).
- 10 0 500 -
g............... Rocky Polnt a - Manomet Point O O ;. g.............. Effluent :s e : 7 O MDC .< 400 - 4 ! . p ;
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d PhyllOphOra A A A A A A *. A I I I I ~ I I I ' I I I 4/83 10/8 3 3/84 9/84 3/85 9/85 3/86 9/86 3/87 9/87 Sampling Period FIGURE 8. SEASONAL FLUCTUATIONS IN TOTAL NEAN PHYLLCPHORA BIONASS AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT STATIONS DURING SPRING AND FALL SAMPLING PERIODS FOR THE COLLECTIONS BETWEEN APRIL 1983 AND SEPTEMBER 1987 PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC).
. _ _ . -=- --
- 10 0 1,000 -
3.....*********- Rock y Poi nt 900 - 0 I- Manomst Point Elfluent E I e.............. o
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4/83 10/8 3 3/84 9/84 3/85 9/85 3/86 9/86 3/87 9/87 Sampling Period FIGURE 9. SEASONAL FLUCTUATIONS IN TOTAL MEAN ALGAL BIOMASS AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT STATIONS DURING SPRING AND FALL SAMPLING PERIODS FOR THE COLLECTIONS BETdEEN APRIL 1983 AND SEPTEMBER 1987 PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC).
1 Like the faunal communities found at the Effluent station, the algal communities have experienced perturbations ; over time that have affected species composition rather than l overall abundance (biomass). More specifically, the impact ; of PNPS on the algal communities at the Effluent station is f reflected in the presence or absence of several less dominant ; species. This impact seems to imply an effect on the ; opportunities available for new species to colonize the . Effluent station rather than the reference sites and is considered less severe than what might be expected if the ! Effluent station were located closer to the areas of acute impact (i.e., closer to the mouth of the discharge canal). , l L I [ r I s l l l l 28
5 l l QUALITATIVE TRAN8ECT SURVEYS ' A lagged recovery response within the acute impact ! sono to the 12-month outage at PNPs during 1984 was reported ! in Semi-Annual Report No. 27 (Boston Edison Co., 1986). ! Evidence of this response included a downward trend in the ' extent of the total impact area that began in mid-1984 and l continued through mid-1985. Figure 10 presents results for [ all qualitative transect surveys from 1983-1987. The total acute impact area is plotted along with the extent of the ( i denuded zone and the monthly PNPS maximum dependable capacity I factor. The stunted zone is represented by the difference t L between the denuded and total acute impact nones. Between i December 1984 and December 1985 the total impacted area f (denuded and stunted zones combined) was the smallest ever recorded, indicating a period of lagged recovery within this area -in response to the lack of thermal effluent from FNPS. [ The downswing in areal extent reversed itself between i september and December 1985, showing a legged increase in l size of the acute impact zone due to the continuation of { normal operating conditions. I These results confirmed the lagged period of approximately six to nine months between the causal factor (cessation or resumption of effluent discharge) and ; associated response (decrease or increase in size of the { acute impact zone). In 1987, the recolonization of the denuded and stunted zones by Chondrus advanced to far that it ! was difficult to distinguish the zone boundaries (rigure 11). f The size (in square meters) was therefore not calculated. The considerable decrease of the acute impact zone in June ' 1987 was mostly the result of the shutdown of the circulating ! water pumps from March to August. Water current scouring is l apparently a greater stress to algal colonization than an ! increase of the water temperature. The increase of the acute impact zone in September and December confirms this 29
100 3000- g i 4 O Denuded and Stunted
* ' g
. D. nod.d Z
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4 3 % 3 4 % 3 4 % 4 1 a %% 1 3 % i 3 i i l' i i 1983 8984 1985 5986 1987 FIGURE 10. AREA OF DENUDED AND STUNTED ZONES IN THE VICINITY OF THE PNPS EFFLUENT CANAL PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC). NO AREA MEASUREMENTS WERE NADE IN SEPTEMBER AND DECEMBER 1987 BECAUSE OF LACK OF DEFINITIVE DEMARCATIONS OF DENUDED AND STUNTED ZONES. i I sm - - ---tu - _ _ .-w - ' - - - w -
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Clf'- D?? C5' f 'tLD :l2 Cdhh ??- September 1987 December 1987 i l i FIGURE 11. RESULTS OF 1987 QUALITATIVE TRANSECT SURVEYS OF THE j PNPS ACUTE IMPACT ZONE OFF THE DISCHARGE CANAL. l 31 L.
assumption because it can be related to the resumption of circulating water pump operation in september. 32
I r l i e CONCLUSIONS The responses of the benthic communities to PNPS . operations between 1983 and 1987 are presented in Table 2. , The long power- outage of 1986/87 resulted in a lagged recovery of the communities during 1987. This recovery was ! most obvious and most directly related to PNPS operations in the algal community of the acute impact zone. Overall, the ! full potential of FNPS has not been observed yet, because the a cumulative operating rate of the plant has been only 50 f percent to-date. The normal rate is about 75 percent. i i FAUNAL STUDIES : r Species e richness was lowest at the Effluent during both March and September 1987, indicating that the power outage had no effect on the number of species. However, depressed species richness may be the result of lacking flow from the l circulating water pumps. t i e raunal densities were generally lowest at the Effluent j in 1987, but results from 1983 through 1987 indicate that there is no direct relationship between PNPS operations and , j densities. ! 1 i l e species composition of the top 15 dominants has been relatively similar among all stations and fairly consistent f over time since 1983. Dominant species were not affected by ; PNPS and thus showed no response to the outage in 1987.
! e species diversity was generally lowest at the Effluent ;
1983. The continuation of this trend in 1987 may be since f indicative of the extended period of time required for full recovery of faunal communities to the outage at PNPS. [ F I 33 [
TABLE 2.
SUMMARY
OF IMPACTS OF PMPS ON BENTHIC COMMUNITIES. Impact Steady of Component Parameter FWPS 1963-1987 C-tm Species Effluent station ranks last relative Effisent staties ranked second im Outages eering 1964 and 1986 resulted Ric9 mess to reference stations indicating Arch 1905 and narch 1946 and first in in:reases is species richness impact from PNPS operations. in September 1946. Species richness values at the Effisant staties. declined from spring to fall 1985. Flesctinating posser outpist destabilised Effisent staties ranker. Raat in conditions and prolonged pioneer 1987. state, introencing new myocios at 1:2f1 ment. Species richness in 1987 was law, apparently becaisse of circulating water passy activity. 1 Density me detectable pattern everall. We change in response to minimsm pelative ranks and degree of difference (1964, 1986/s 4 er annimum (1983, between the reference and serveillance 1985) autpist. stations have boem * - istemt ever the years of this stendr, ladicating Las absence of a detectable effect at the Effluent staties en faumal densities. Quantitative species Dominant species relatively constant Cowntion of domanant species at Dissimilarity betiseen serveillance and Paumal Dominance in occiatrence at all thsee stations, all statisms innaf fected from 1983 to reference statiens ene to effect en Standies oahibiting me impact from FWPS 1947. species that centribute little to total 1 eperations. fausa (by percent compositiemi. i species Reference stations exhibit hsgher No significant changes in ranks of Belat1wely stable diversity values at Diversity species diversity than the Effisent diversity among stations as a result the Effluent staties indicate stable station indicating impact from FWPS of fluctinating psesor from 1983 to conditions (i.e., sustained inquect) with opesations. 1987 regard to this parameter. Meamistes of Deference statieses more similar to meterence stations centimmed to Classter analyssa reinforce centention similarity one another them to the Effluent eshibit higher similarity with one that. impact of FuPS le en =hment statiam indicating impact free PNPS another them with Efflemet staties, species at the Effluent. Eagged recovery epocations. even enring perish of high potential of faumm1 commmities evidmet in 1987. recovery at the Efflamat statism amatil 1966. In 1987, similarity between reference stations esos egenal to that betuosa Effloset and both reference stations.
TKILE 2. (Ccntinund). Impact Study of Component Parameter PNPS 1983-1987 Co===ats community Several species indicative of warm Outages of 1984 and 1986/87 uphold Effluent algal communities, like the Descriptions habitats have become established at indicator species hypothesis. faunal c-mities, are distinguishable the Effluent station indicating Gracilaria follifera and f aminaria from reference stations by subd minant impact from PNPS operations. spp. both respond to maximum and members of the communities. minimum output of PNPS. Quantitative community Greater community overlap between No significant change in typical e-mity overlap indicates a relatively Algal Overlap reference stations than between response to PNPS noted from 1983 to stable impact at the Effluent requiring Studies Effluent and reference stations 1986. In the fall 1987 overlay periods greater than 12 months for indicating impact from PNPS between Effluent and reference recovery. Overlap increase in September operations. stations increased. 1987 may indicate beginning recovery. W Algal No pattern evident in terms of
- Algal biomass unaffected by 1984 and Algal biomass categories, representing Biomass relative algal biomass among all 1986/87 outates. dominant algal components, do not three stations. exhibit a Jetectable impact from PNPS.
Qualitative Acute Denuded and stunted algal zones tagged recovery at the effluent A lagged response is logical given the Transact Impact Zone created by effluent discharge. impact zones in response to outages destructive nature of the impact in survey in 1984 and 1986/87. Zones ill- these zones. Scouring caused by defined after June 1987. circulating water pumps has greater effect than elevated water temperatures.
1 l e similarity between the Effluent and the reference stations increased considerably during 1987 and was as high as the similarity between the reference stations. From 1983 through 1986, similarity between the reference stations was much higher than between the Effluent and reference stations. The partial recovery of the fauna indicated by the similarity measure in 1987 is a lagged response to the outage at PNPS. QUANTITATIVE ALGAL COMMUNITY STUDIES 4 e Algal communities at all stations were similar in 1987. No warm-water algae were found at the Effluent. During normal operational years, Gracilaria foliifera was regularly observed, but the species declined in 1986 because of lacking thermal effluent from PNPS. e Algal community overlap among stations was not affected by PNPS operations. The number of species shared between the reference stations was generally higher than between the Effluent and reference stations since 1983, but the differences were not significant. e Algal biomass was lowest at the Effluent station. However, it was not influenced by PNPS operations and since 1983 showed no response to maximum or minimum output. QUALITATIVE TRANSECT SURVEYS e The size of the acute impact zone was mainly influenced by the circulating water pump operation. A lagged recovery of the algal community occurred in 1987. Extensive recolonization resulted in a considerable decrease of the stunted and denuded zones in June. By September, the zones 36
increased again in size because of resumption of circulating pump operation, but the boondaries were ill-defined. i l l l l l 1 1 1 1 l l 37
LITERATURE CITED Boston Edison Co. 1982. Marins ecology studies related to } operation of Pilgrim Station. Semi-Annual Report 1 No. 19. Boston, MA. Boston Edison Co. 1986. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 27. Boston, MA. Boston Edison Co. 1987a. Marine ecology studies related to I operation of Pilgrim Station. Semi-Annual Report No. 29. Boston, MA. Boston Edison Co. 1987b. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 30. Boston, MA. Logan, D.T. and D. Maurer. 1975. Diversity of marine invertebrates in a thermal effluent. J. Water Poll. Con. Fed. 47(3):515-523. 38
1 7 , f.: . L Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station
. January -LDecember'1987 Volume 1 of 2' (Results)
Submitted to Boston-Edison Company-Boston, Massachusetts. i o 1. by Marine Research, Inc. Falmouth, Massachusetts l? l March 11, 1988 revised April 6, 1988 l l l I, . . , - , , , . ....;-,...-...,.,.,..,, . , , - , - , - - - , _ _
4
-TABLE OF CONTENTS SECTION PAGE
'/
- I-
SUMMARY
' 1
.II' INTRODUCTION 3 III METHODS AND MATERIALS - 4 IV RESULTS AND DISCUSSION A. Ichthyoplankton Entrained -'1987 13 B. Multi year Ichthyoplankton Comparisons 20 C.. Lobster Larvae Entrained 34 V LITERATURE CITED 36-
! APPENDICES A and B (available upon request) J' 4 ( l l l i k 2
LIST OF FIGURES FIGURE PAGE 1 Entrainment sampling station in PNPS discharge canal. 5 2 Location of entrainment contingency plant sampling stations, C-1 through C-13. 12 3 Mean monthly densities per 100 m 3 of water in the PNPS . discharge canal for the eight numerically dominant egg species and-total eggs, 1987 (dashed line). Solid lines show high and low values over the 1975-1986 period. 26 4 Mean monthly densities per 100 m 2 of water in the PNPS discharge canal for the ten numerically dominant larval species and total larvae, 1987 (dashed line). solid lines show high and icv values over the 1975-1s.o period. 30 LIST OF TABLES TABLE PAGE 1 Species of fish eggs _(E) and larvae (L) obtained in ichthyoplankton collections from the Pilgrim Nuclear Power Station discharge canal, January-December 1987. 14 2 Species of fish eggs (E) and larvae (L) collected in the PNPS discharge canal, 1975-1987, 21 LIST OF APPENDICES APPENDIX A* Densities of fish eggs and larvae, per 100 m 8 of water, recorded in the PNPS discharge canal by species, date, and replicate, January-December 1987. B* Mean monthly densities and range per 100 m 2 of water for the dominant species of fish eggs and larvac entrained at PNPS, January-December, 1975-1987.
*Available upon request.
l l l l l 1 li )
SECTION I
SUMMARY
Ichthyoplankton samples were collected from the Pilgrim Nuclear Power Station discharge canal in triplicate twice per month in January, c'ebruary, October-December, and weekly from March through September. No sampling occurred in April due to circulating water system pump shutdown, and sampling during May through August occurred primarily with only one Salt Service Water I
. System pump running.
Numerical Dominants - 1987: A total of 36 species were represented in the 1987 samples; 20 were represented by eggs, 33 by larvae. During the winter-early spring spawning season (December-April), egg collections con- , tained small numbers of Atlantic cod and winter flounder. Rock gunnel and sculpin dominated among the larvae. The late spring-early summer ichthyo-plankton season (May-July) was represented primarily by labrids, mackerel, rockling, and searobins among the eggs plus seasnails, winter ficunder, rockling, menhaden, tautog, and silversides among the larvae. Late summer-autumn (August-November) collections produced primarily labrid, Enchelyopus-Urophycis-Peptilus, windowpane, and cod eggs as well as small numbers of tautog, hakes, windowpane, and fourbeard rockling larvae. Multi-year Comparisons: Comparisons between 1987 monthly mean densities, l per 100 m of water, and those recorded over the 1975-1986 period suggest 8 that searobin eggs were abundant in June 1987 as were Atlantic herring , I larvae in December. Eggs and larvae which appeared to be relatively uncommon l l in 1987 entrainment samples included among the eggs the Enchelyopus-Urophycis-I 1 L .
~ i Peprilus group 'and fourbeard rockling.during July;and August, the labrids during July and August, mackerei during' July,.the Paralichthys-Scophthalmus. group during July and August, and the hakes during August and September; , among.the uncommon larvae were sand lance during January through May, rock gunnel and sculpin-in March, radiated shanny during May through June, mackerel during June and July, vinter flounder during June, and rockling during July-and August. The large number of low values during May-August appeared to be due to the operation of only one SSWS pump during that period. Lobster Larvae: Lobster larvae were absent from the 1987 collections. The last time one was taken was in 1982 which represented the ninth since sampling began in 1974. l t I i 2 4
,,-v- -, .,m, , - ,_,,.,_e , , - . _ _ _ _ , , _ . , , -~___7.-
e-- - ~ . - y+. , n. -e n .-
y a f SECTION II INTRODUCTION This. report summarizes results of ichthoplankton entrainment sampling.
- conducted at the Pilgrim Nuclear Power Station.(PNPS) discharge canal on a 1
regular basis from January-through December 1987. Work was carried out by Marine Research, Inc. (MRI) for. Boston Edison Company (BECo) under Purchase
~
Order No. 63653 in compliance with environmental monitoring and reporting requirements of' NPDES Permit No. 0003557 (U.S. EPA and Massachusetts DWPC). In an effort to condense the volume of material presented in these reports,
-details of interest to some readers may have been omitted. Any questivns or requests for additional information may be directed to Marine Research, Inc., Falmouth, Massachusetts.
,, a-- J
.,1 4
SECTION III METHODS AND MATERIALS I s The entrainment sampling protocol at PNPS specified that samples will ? be collected in triplicate twice monthly in January, February, October, November, December, and weekly March through September. All samples were collected with a 0.333-mm mesh, 60-cm diameter plankton net streamed in the discharge canal at low tide during daylight for 6 to 12 minutes depending on the abundance of plankton and detritus. In each case a minimum of 100 m3 of water was sampled. Generally sampling at PNPS is completed from rigging mounted approximately 30 meters from the headwall of the discharge canal
.(Figure 1). However, in late March 1987 the single circulating water system (CWS) pump in operation since an extended plant outage began April 1986 was shut down for all but brief periods usually occurring at night; because of this no sampling was conducted in April. Beginning in May and continuing through August collections were made while one or two Salt Service Water System (SSWS) pumps were in operation. By sampling for 30-40 minutes per replicate upstream of the usual location nearer the headwall, 100 m 8 of water continued to be filtered for most samples. On three occasions (May 30, June 25, August 19) sampling was conducted while one CWS pump was in operation for brief periods. In September one CWS pump was put back in service and remained in regular use through December. Filtration volumes for each sample were obtained using General Oceanics Model 2030R digital flowmeters mounted in the mouth of the net. When only SSWS pumps were operating, a Model 2030R2 meter was used since it is more sensitive to low flow.
4
s ( CAPE COD BAY p ..
.b.
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UNIT I INTAKE .. PNPS 7 ' '- U-O ICHTHYOPLANKTON UnlT t STATION t 1 100 METERS 1 l Figure 1. Entrainment sampling station in PNPS discharge canal. 5
i
'lJ All samples were preserved in 10% Formalin and returned to the laboratory for~ microscopic analysis. Fish eggs and larvae were identified to the lowest distinguishable taxonomic category and counted. Common and scientific names followed' Robins et al. (1980). In most cases,-species were identifiable. In certain cases, however, eggs--particularly in the early stages of development--
could not be identified at the species level in the preserved samples. In such cases, species were grouped. A brief description of each of these egg groupings is given below.
- Cadidae-Clyptocephalus group (Atlantic cod, ,Gajpls morhua; haddock Melanogrammus aeglefinus; pollock, Pollachius virens; and witch flounder, I
Glyptocephalus cynoglossus): egg diameters overlap, no oil globule present. Stage III eggs (those containing embryos whose tails have grown free of the yolk; Ahlstrom and Counts 1955) are separated based i on relative size and pigmentation combinations. Haddock eggs are diffi-I cult to identify until shortly before hatching (late stage III). Because of this, some early stage III haddock eggs may have been identified as cod eggs. This error should be Taite small judging from the relatively low numbers of late stage III haddock eggs and haddock larvac collected at PNPS. The gadidae-Glyptocephalus grouping was not considered necessary in January, February, and December because it is unlikely that witch flounder spawn during these months (Fahay 1983) and haddock spawning is not likely to occur in December nor in peak numbers during January and February (Hardy 1978). All eggs of the gadidae-Clyptocephalus type were therefore classified as either cod or pollock based on differing egg diameters during those three months. 1
h.
. Enchelyopus-Urophycis-Peprilus group (fourbeard rockling, Enchelyopus cimbrius; hake, Urophycis spp.; and butterfish,'Peprilus triacanthus):
egg and oil globule diameters overlap. Stage III eggs are separated based on differences in embryonic pigmentation.
- Merluccius-Stenotomus-Cynoscion group (silver hake, Merluccius bilinearis; scup, Stenotomus chrysops; and weakfish, Cynoscion regalis):
egg and oil globule diameters overlap. Stage III eggs are separated based on differences in embryonic pigmentation.
. Labridae-Limanda group (tautog, Tautoga onitis; cunner, Tauto2olabrus adspersus; and yellowtail flounder, Limanda ferruginea): no oil globule present, egg diameters overlap. Stage III eggs are separated into labridae and yellowtail flounder based on differences in embryonic pigmentation. A high percentage of the two species of labrid eggs are distinguishable but only with individual, time-consuming measurement r (Marine Research 1977a). Labrid eggs are therefore grouped in all three stages of development in PNPS samples, i
- Paralichthys-Scophthalmus group (fourspot flounder, Paralichthys i
l oblongus, and windowpane, Scophthalmus aquosus): oil globule and egg diameters as well as pigmentttion are quite similar. Separation of these two species, even at stage III, remains uncertain. They are therefore grouped in all cases. Eggs of the 'sy anchovy (Anchoa mitchilli) and striped anchovy (Anchoa 1 hopsetus) are essi distinguishable, but their larvae are not. Eggs of i L these fishes are tht ! ore listed by species while the larvae are listed ! simply as Anchoa spp. l l 1 ! 7
)
1 i Several other groups of eggs and -larvae were 'not identified to species because adequate descriptions of each species are not available at this time. These groupings are as follova:
- Urophycis spp. - cor.sists of the red hake (U. chuss), the spotted hake (U. regia), and the white hake (jl. tenuis). Most larvae (and eggs) in this genus collected at PNPS are'probably red hake (see summary in Hardy 1978).
- Menidia spp. - consists of the inland silverside (ji. beryllina) and Atlantic silverside (ji. menidia). Atlantic silverside larvae are i probably more likely to. occur as far north as Plymouth based on their '
more northern distribution.
- Ammodytes sp. - No species designation was given the sand lance because considerable taxonomic confusion exists in the literature (see for example Richards et al. 1963; Scott 1968, 1972; Winters 197C; Fahay .
1983; Dalley and Winters 1987). 'Meyer et al. (1979) examined adults collected on Ste11wagen Bank and classified them as A,. americanus (= A,. hexapterus). This population is probably the source of larvao entrained at PNPS. i e Prionotus spp. - consists of the northern searobin (P. carolinus) and the striped searobin (P. evolans). Larval rainbow smelt (Osmerus mordax), cunner (Tautogolabrus adspersus), and vinter flounder (Pseudopleuronectes americanus) were classified into , three or four arbitrary developmental stages because these species have been of particular interest in studies c*. PNPS. These developmental stages and corresponding length ranges are given below. x
Rainbow smelt Stage ~I - from hatching until the yolk sac is fully absorbed (5-7 mm TL). Stage II - from the end of. stage I until dorsal fin rays become visible 6-12 mm TL). Stage III - from the end of stage II onward (11.5-20 mm TL) . Cunner Definitions of. developmental stages are the same as for smelt larvae. Observed size ranges for each -s tage are: stage I, 1.6-2.6 mm TL; stage II, 1.8-6.0 mm TL: stage III, 6.5-14 mm TL. Winter flounder Stage I - from hatching until the yolk sac is fully absorbed (2.3-2.8 mm TL). Stage II - from the end of stage I until a loop or coil forms in the gut (2.6-4 mm TL). Stage III - from the end of stage II until the lef t eye migrates past the midline of the head during transformation (3.5-8 mm TL). , Sta'ge IV - from the end of stage III onward (7.3-8.2 mm TL). r l Generally entire samples were examined for fish larvae and all but the ,, i most abundant types of fish eggs. When a species was especially abundant, subsamples were obtained with a plankton splitter modified from Matoda (1959; t i see also Van Guelpen et al. 1982). Pure sampic counts of eggs and larvae I were used to establish a subsampling regime where the minimum number of specimens considered acceptable increased as the size of an aliquot decreased. (For example,100 larvae were required for a one-half split; 200 were necessary ! l for a one-quarter split.) . In each case all aliquots were held separately in labeled beakers, the smallest split having been established based on visual ; e l 9
lJ observation and preceding samples. Sorting proceeded from the smallest ali-quot with the most abundant species being dropped ~at the end of a particular split if the minimum number requirement was met. Based on the pure sample counts, mean error associated with this regime was 9.7% for eggs, 11.1% for larvae. Coefficients of variation, following 10 to 20 replicates each of 1/4 and 1/8 splits with three types of eggs and two types of larvae, ranged from 6.6 to 18.7% (mean = 12.9%). All final counts were converted to numbers per 100 m3 of water. i-l In addition to fish eggs and larvae, all samples taken from May through October were examined for larval lobsters (Homarus americanus). Because they have been found to be uncommon at PNPS, no subsampling was done; each sample was examined in its entirety. All entrainment samples were returned to 10% buf fered Formalin-seawater solutions for storage of not less than three years to conform with !C#S Permit requirements. When the Cape Cod Bay ichthyoplankton study was completed in 1976, a contingency sampling plan was added to the entrainment monitoring program. This plan was designed to be implemented if eggs or larvae of any dominant species proved to be "unusually abundant" in the PNPS discharge samples. The goal of this sampling plan was to determine whether circumstances in i l f the vicinity of Rocky Point attributable to PNPS operation were causing an l abnormally large percentage of ichthyoplankton populations there to be entrained or alternatively whether high entrainment levels simply were a reficction of unusually high population levels in Cape Cod Bay. "Unusually 10
h.- abundant" was defined as any mean density, calculated over.three replicates, which was found to be 50% greater than the highest mean density observed during the same month from 1975 through 1986. The contingency sampiing plan consisted of taking additional sets of triplicates fr'om the PNPS discharge on subsequent dates to monitor the temporal extent of the unusual density. An optional offshore sampling regime was also established to study the spatial distribution of the species in question. The of fshore contingency program consisted of single, oblique tows at each of 13 stations (Figure 2) on both rising and falling tides for a total of 26 samples. Any contingency sampling required authori-zation from Boston Edison Company. i I i i i 11 l l
l l i
, .:' *,c- O './
C 13 O O ouxeumv j . c.11 c 12 l l ouseva r as O O c to en== s 's C4 at O.*.* O O C C1 st ruourw nameos
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?
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#; 1 k /k Location of entrainment contingency plan sampling stations, Figure 2.
C-1 through C-13. l l 12
SECTION IV RESULTS AND DISCUSSION A. Ichthyoplankton Entrained - 1987
;.- Population densities per 100 m8 of water for each species listed by date, station, and replicate are presented for 1987 in Appendix A (available upon request). Table 1 lists all species represented in the 1987 collections, indicates the months eggs and/or larvae of each species were found, and for the more common spe'cies the months of peak abundance.
Ichthyoplankton collections are summarized below within the three primary spawning seasons observed in Cape Cod Bay: winter-early spring, late spring-early summer, and late summer-autumn. Winter-early spring spswners (December-April). Although sampling occurs at the end of the calendar year De, @ci represents the beginning of the winter-early spring spawning teason. I Four species were collected in December 1987, two species of eggs and two species of larvae. Atlantic cod represented 88% of the eggs with a monthly mean of 6 per 100 m of water and Atlantic herring (Clupea 8 l harengus harengus) represented 98". of the larvae with a mean of 7 per j 100 m2 . Six species were represented in the January collections followed by seven in February and eight in March (no sampling occurred in April). Samples taken during those three months contained relatively few eggs since species contributing most to entrainment during that period spawn, ! demersal, adhesive eggs which are generally not subject to entrainment. Only Atlantic cod eggs were found in January and February with monthly 13 l
Tchle 1. Species of fish eggs (E) and larvae (L) obtained in ichthyoplankton collections from the Pil'gria Nuclear Power Station discharge canal, January-December 1987. Lines indicate peak periods for the more abundant species. Species Jan Feb Mar Apr* May June July- Aug Sep Oct Nov Dec E E Atlantic menhaden Brevoortia tyrannus Atlantic herring Clupea harengus harengus -L- L L -L L-Anchovy Anchoa spp. L ) Rainbow smelt Osmerus mordax L i Goosefish Lophius americanus E E l
. . . -E E- E E -E E- E Fourbeard rockling Enchelyopus cimbrius ,
7
^
. E E E E E E E -E-l Atlantic cod Gadus morhua E E E Silver hake Merluccius bilinearis I
Atlantic tomcod Microgadus tomcod L L E Pollock Pollachius virens I l
. E -E- E E E E Hake Urophycis spp.
Silversides Menidia spp. L L l Northern pipefish Syngnathus fuscus L Black sea bass Centropristis striata L L 1 I
- - .. _, _a
Tcble 1 (ccatinued). Species Jan Feb Mar Apr* May June July Aug Sep: Oct Nov Dec k*rasses Labridae E -E E- E E Tautog Tautoga onitis L L L. L' Cunner Tautogolabrus adspersus L L L Radiated shanny Ulvaria subbifurcata -L- L Rock gunnel Pholis gunnellus L -L L- L Sand lance Ammodytes sp. L L
~ ~
Atlantic mackerel Scomber scombrus L L _ Butterfish Peprilus triacanthus E E Scarobins Prionotus spp. E -E E-Grubby Myoxocephalus aenaeus L -L L- L Longhorn sculpin M. octodeceaspinosus L L L Shorthorn sculpin M. scorpius L L Lumpfish Cyclopterus lumpus L Seasnail Liparis atlanticus -L- L Gulf seasnail L. coheni L L Smallmouth flounder Etropus microstomus E
lll1jll 1 ll I l' II) Il I I!1 c e 4 D v - o 6 N t 4 c E E 1 O p - 5 S e E E E E 1 - g u E E 7 A - l y u E E 0 1 J e - n E E E E L 8 u 1 J y - a E E E E gL 7 1 H - - r p A r a 8 M - b e 7 F n a s 6 J s u e n s d a u i c s o i s s r o s e s l e m u s g t a t u o a a s n l a s t o y p e e n u c n t e q s i c _ d a s e g e . u d u n h n s s l i r o t w y s u a o r r n o h u g m h s e u o d t l p s f e m t h n a e o l / i t c o h c l a p s h i l t o g d o e s s l a b o h p t p o p n a d u i c p - e r o y p m e e m
)
i c e p P a P S c l G i H i L r P s f p s u p o d S e o t e r d u e n r e n r d e u r e u i e n r c o e b d t d u e i l d m n n o d a f n u g ( 1 o c l f u o l f t o e n a p l f n u o l p n a l i a t l f u o N i l n p m r p w c w r a e e s o h i o e s l t d c r l t b m u n t e l n o _ T a S u o F i W i W c A i Y e i W N
= -
> !I f lllll
E , [ mean densities of 0.1 per 100 m 8 of water in both cases. March samples contained primarily winter flounder eggs which accounted for 97% of the. egg. total with a monthly mean density of 48 per 100 m 2 of water. Atlantic cod eggs continued to.tde taken and, assuming they contributed most to-the gadidae-Glyptocephalus egg grouping, their mean density of 0.9 per 100 m8 accounted for all remaining eggs in March. Since winter flounder eggs are demersal and adhesive, their densities in the PNPS ( discharge canal cannot be considered representative of densities in the waters around Rocky Point. Those which were collected from the discharge canal were probably dislodged from the bottom by currents, rough seas, or perhaps fish. Larval collections during January-March consisted primarily of rock , gunnel (Pholis gunnellus) and sculpin (Myoxocephalus spp.). Larval rock gunnel represented 25% of the January catch, 26% of the February catch, l and 43% of the March catch; monthly mean densities were 0.5, 5, and 3 per 100 m of water, respectively. Sculpin contributed 17% of the larvae 2 in January, 67% in February, and 52% in March. For these species pooled monthly mean densities amounted to 0.3, 12, and 4 per 100 m 3 of water, l
- i. !
respectively. Among the three species of sculpin larvac, grubby P (Myoxocephalus aenaeus) were numerically dominant, accounting for 74%
! r ! of all sculpin taken during the three-month period. Shorthorn sculpin i
(M. scorpius) ranked second at 22% and longhorn sculpin (M. octodecem- [ i l spinosus _) third at 4%. Atlantic herring contributed over half the 1 [ larvae taken in January ($2%), but at that time densities of all species .
- vero very low; the monthly horring mean density was 1 per 100 m' of i ,I l water.
I 1 i . ! 17 i
Late spring-early summer spawnces (May-July). Overall 17 species were represented in May, 18 in June, and 10 in July. Egg collections were dominated by the labrids, mackerel (Scomber scombrus), fourbeard rockling, and searobins (Prionotus spp.). The .labrids, including the labridae-timanda group, accounted for 19". of all eggs taken in May, 94% of those taken in June, and 98" of those taken in July; mean monthly densities were 21, 5277, and 719 per 100 m , re- 8 - 3pectively. Atlantic mackerel represented an additional 32% of the egg catch in May with a mean density of 36 per 100 m of water, an additional 2 2% in June with a mean of 123 per 100 m', declining sharply to 0.01"* in July with a mean of 0.1 per 100 m 2. Including eggs classified as Enchelyopus-Urophycis-Peprilus, fourt-ard rockling contributed 34". of - the May egg total with a mean monthly density of 37 per 100 m8 of water, 0.8" of the June total with a monthly mean of 44, and 0.5% of the July total with a mean of 4 per 100 m . 8 Searobin eggs accounted for 0.1, 1, and 0.9% of the May, June, July egg totals with respective mean monthly i densities per 100 m 3 o f 0.1, 77, and 7. i Numerical dominants among the larvae were seasnails (Liparis l atlanticus) and winter flounder in May followed by fourbeard rockling, ' t Atlantic menhaden (Brevoortia tyrannus), tautog in June, and silversides (Me.'dia spp.) and menhaden in July. Seasnails accounted for 48". of all l larvae taken in May with a monthly mean density of 16 per 100 m 3 of water. ; Winter flounder added 37" of the total with a mean of 10 per 100 m 3 of water. In June rockling accounted for 42". of the month's larvae with a monthly mean density of 6 per 100 m3 ; menhaden followed with a density 18
. _ _ _ . _ _ . _ . _ _ _ _ _ _ _ _ . . _ . . _ . . . - ~ . .
i of 2 per 100 a , accounting for 18% of total. Tautog ranked third in-- 8 June-with a mean density of 2, representing an additional 15% of the catch. Only silversides and menhaden were_taken in July. Silversides were slightly more abundant than menhaden with a mean density of 0.2 per 100 m3 , accounting for 57" of the month's total compared with 0.1 for menhaden which accounted for the remaining 43". Late summer-autumn spawners (August-November). , t The number of species collected generally declines during and par- ; ticularly toward the end of this period; eight species were represented , in August, 15 in September, 14 in October, and 6 in November. Egg f collections were dominated numerically by declining numbers of labrids, the Enchelyopus-Urophycis-Peptilus group, windowpane, and late in the period by Atlantic cod. Combined with the labridae-1.imanda grouping, which they probably dominated, labrid eggs accounted for 36% of all eggs ! taken in August, 8% of those taken in September; they were subsequently absent. Mean monthly densities for these eggs were 5 per 100 m 8 of water in August and 2 per 100 m of water in September. . Rockling and hake eggs 8 I combined with the Enchelyopus-Urophycis-Peprilus grouping represented 33". of the August eggs, 24% of the September eggs, 82", of the October eggs, and 23" of the November eggs. Mean densities were 5, 7, 3, and 0.4 l L during those four respective months. Assuming, based on the larval I 1 co11cetions, that windowpane accounted for most eggs within the Paralichthys-Scophthalmus grouping, they represented 12, 64, 6, and 0" of the August, September, October, November totals, respectively. Atlantic cod eggs appeared in November and, combined with the i
} 'e l
i l l undifferentiated Gadidae-Glyptocephalus group, accounted for 70% of.all eggs at that~ time with a monthly mean density of 1 per 100 m 8 of water.
' Late summer-autumn larval collections were dominated by small numbers of tautog, hakes, windowpane, and fourbeard rockling. Mean monthly tautog ,
t dencities of 0.4 in August, 0.3 in September, 0.3 in October, and 0 per 100 m8 on November represented 74, 6, 8, and 0% of those respective collections. Hake had mean monthly densities per 100 m 8 of 0.1 in ! August, 0.4 in September, 0.2 in October, and 0 in November, which-accounted for 12, 9, 5, and 0% of those respective totals. Windowpane and rockling added 13 and 0% to the August catch with mean densities of 0.1 and 0 per 100 m of water, 16 and 42% to the September catch with 8 mean densities of 0.8 and 2 per 100 m 3, 7 and 47% to the October catch with mean densities of 0.3 and 2 per 100 m , 8and 0 and 13% to the November catch with monthly mean densities of 0 and 0.4 per 100 m . 8 ; B. Multi-year Ichthyoplankton Comparisons Ichthyoplankton densities meeting the "unusually abundant" criterion did-not occur in 1987; therefore no contingency sampling was performed under that ( program. Table 2 presents a master species list for ichthyoplankton collected from , the discharge canal at PNPS and indicates the years each species was taken from 1975 through 1987. The general period of occurrence within the year is also indicated for each species including the peak period for the numerical dominants. A total of 36 species were represented in the 1987 co11cetions which was below the 1975-1986 average of 38. No new species were added to ' the list in 1987. P f i . , ~ _,. - - .. _ m , . _ _ , _ _ _ , _ _ ._. ___ _ ._._._____ _ ,___ ,_ . . _ _ . _ _ , _ _ .
^
-]
Table 2. Species of fish eggs (E) and larvae (L) collected in the PNPS discharge canal. 1975-1987. General periods of occurrence for eggs and larvac combaned are shown along the right sade; f or the doennant species periods of peak abundance are also shown in pasentheJes. Spe:nes 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 Period of Occurrence Aneualla rostrata Ja J J J J Feb - Jun Alasa s;>. L L J L L May - Jul presoortia tyrannus E/L E/L E/L E/L E/L E/L E/L E/L E/L E E/L E/L E/L Apr(Jun)-(Oct)Dec Clupea Sareneus hereneus L L L L L L L L L L L L L Jan - Dec* Anchas spp. L L L L L L L L L L L Jun - Sep A. natchalli E E E E E/L E E lun - Sep Osmerus mo.Jan L L L L L E/L L L L L L Apr - Jun lophaus americanus E/L E E/L E/L E/L L E/L t/L E/L E/L E/L E E May - Oct erasne t osse E/L E/L E/L E/L E/L E E E Apr - Jul tachelsopus cimbraus E/L E/L E/L n E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L Apr (Jun)-( Sep) Dec ca.tu s morava E/L E/L E/L E/L E/L E/L E/L [/L E/L E/L E/L E/L E/L Ja a(Nov)-( Dec) Dec Melen*erammus m e_e. le f i nu s L E/L E/L E/L L L E Apr - Jul Merluccaus bilanearns E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L stay (May)-(Jun)Nov Macrormous e nac od L L L L L L L L L L Jan - May Pollachaus virens ETL E/L E E/L E/L E/L L L E/L L E/L Jan-Jun .Nov. Dec tir oph e c_a s spp. E/L E/L E/L E/L E/L E E/L E/L E/L E E/L E/L E/L Apr - Nov Ophadaadae-Zearcadae L Sep Stronevtura marana L Jul Fundulus spp. E E Jul F. he t e roc li tu s E Jun F. majalis J Oct Meni la a spp. L L L L E/L E/L E E/L L L L L May - Sep M. cenadas E/L E/L E L May - Sep Syneamehus fuscus L L L L L L L L L L L L L Apr - Oct Centreprastas striata L L L L L L 'L Jul - Oct OAbsens August and September; peaks - March-May and November-December. e w wa y-g,w --.~,--,y-- , - , w , , . ,,y .-- , - -- ,
4 Table 2 (continued). Species 1975 1976 1977 19?8 1979 1930 1981 1982 1983 1984 1985 1906 1987 ' Period of Occurrence Cenoscion veralis L L L Ma y - Se p
<t enot c us chrtsops L L Jun - Jul' Menticarrhus sauatitis L L Jul - Aug Labradae E E E E E E E E E E E E E Mar (May)-(Aesg)Sep Tautoes onitis L L L L L L L L L L L L L May(Jun)-(Aug}Oct Tautoenta5rus adspersus L L L L L L L L L L L L L Mr/(Jun)-(Aug)Oct' 4? g Lunpenus luepretaeformis L L L L L Jan - Jun y; t*1varia subbifurcata L L L L L L L L L L L L L Teb(Apr)-(Jun)Oct Phalas runnellus L L L L L L L L L L L L L Jan(Feb)-(Apr)Jun Cryptacanthodes maculatus L L L L L L L L Feb - Apr lj Amnadytes sp. L L L L E/L L L L L L L L L Jan(Mar)-(May)Jun Cobsos. sea p,i n s bu r g i i L L Jul - Aug sc oct.c r scombrus E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L F/L Apr ( May)-(Jul )Sep repratus triacanthus E/L E/L E/L E E E/L E/L L E/L E/ L L E May - Oct Prionotus spp. E/L E E E E/L E/L E 1- './ L E/L E/L E/L May(Jue)-(Aug)Sep a vo=ucephalus spp. L L L L L L L L E/ E/L L L Dec(Mar)-(Apr)Jul
- 3. acnaeus L L L L L o L L L Dec(Mar)-(Apr)Jul
- 3. oc t odecenspinosus L L L L L L L L Jan(Mar)-(Apr)May M. scorpius L L L L L L L Feb - Apr Aspadophoroades monopterygnus L L L Mar - Apr Cyclopterus tumpus L L L L E L L- Apr - Jul Liparis spp. L L L L L L L L L L L L L Jan(Apt)-(Jun)Jul L, . atlanticus L L L L L L L Mar (Apr)-(Jun)Jul L. cohen L L L L L L L. Jan(Feb)-(Mar)Apr Fe s og us encrostomus L L E E/L E Jul - Oct
,~ , _ _ ,
l .s. l Table 2 (continued). Specses 1975 1976 1977 1978 1979 1980' 1981 1982 1983' 1984' 1985 1986 1987 Period of Occurrence Para *schthys dentatus E/L E/L. L E/L Sep '%2r f,. ottoneus E/L E/L L E/L E/L E/L E L L L E/L May - Oct. scophthalmus aquesus E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L Ap t ( May )-( Se p)Oc t Clvprocephalus conoglossus E/L E/L E/l E/L E/L E/L E/L E/L E/L E E/L E/L E/L Mar (May)-(Jun)Nov Hippoglossoides platessoides E/L E/L E/L E/L E/L E/L
~E/L E/L E/L E/L E/L E/L E/L Jan(Mar)-(Jun)Mov-Lamanda ferruginea E/L E/L E/L E/L E/L l E/L E/L E/L E/L E E/L E/L- E/L. Eeb(Apr)-(May)Mov I
laopsetta putnaqt L E/L Mar - Jun Pseudopleuronect e s amer icanus E/L E/L L E/L E/L E/L E/L E/L E/L E/L E/L E/L E/L Jan(Apr)-(Jun)Aug Trinectes mac. status E E E E E
'j Sphaeroides maculatus L May - Sep L Jul - Aug l
l NumNe t of s pecies* 41 36 43 35 37 35 40 38 37 34 42 37' 36
*For comparatave purposes three specses of Myomocephalus were assumed for 1975-1978 and two species of Liparis for.1975-1980.
l t i 1
. . . . , _ _ _ _ . _ _ - - - - . _ . _ - _ _ , . _ . - . .. .__s . - - . . . _ _ . .. . . . . _ .. - . - - _ ._, . , _ , , . ,_ .w. -
n
)
I i Monthly mean densitt.ss per 100 m 8 of water were calt;ulated for each of the numerically dominant fish eggs and larvae entrained at PNPS over ' the years 1975-1987 (Appendix B, available upon request). Based on these values, searobin eggs were abundant in June 1987 relative to past years as were Atlantic herring larvae in December. In both these cases the mean ' density- for the month indicated was the highest observed over the 13 year period from 1975 through 1987. Eggs and larvae which appeared to be rela-tively uncommon in 1987 included among the eggs the Enchelyopus-Urophycis-Peptilus group and fourbeard rockling during July and August, the l'abrids during July and August, Atlantic mackerel during July, the Paralichthys-Scophthalmus grouping during July and August, and the hakes during August and September; among the uncommon larvae, sand lance during January through May, rock gunnel and sculpin in March, radiated shanny (Ulvaria subbifurcata) during May and June, Atlantic mackerel during June and July, winter flounder during June, fourbeard rockling dering July and August. In each of these cases either the 1987 monthly cean densities were the lowest values recorded over the 1975-1987 period or only one other year ranked lover. The large number of low values during the May-August period, when only SSWS pumps l were operational, suggests that entrainment densities were low due to changes > in PNPS pump utilization, a subject discussed further in Volume 11 - Impact [ t i Perspective. f Monthly mean densities per 100 m 8 of water for 1987 are shown in Figure 3 for the eight numerically dominant types of eggs, those accounting for 99% of the 1987 egg total, as well as total eggs (all species combined). Figure 4 shows comparable data for the ten numerically dominant larval , r f 2 i
?
h , k , r species, those accounting for 84% of the catch, as well as total' larvae (all species combined). For each category shown the highest and lowest monthly means obtained from 1975 through 1986 are-joined by solid-lines with 1987 monthly means-joined by dashed lines. Mean densities for Atlantic menhaden, gadidae-Givptocephalus, and Atlantic mackerel eggs, as well as radiated shanny and Atlantic mackerol larvae, remained within the range of densities established over past years. Densities for the remaining species ran below I previous low values for at least one month with the exception of searobin eggs in June, total eggs in March, and Atlantic herring larvae in December and January, which exceeded previous respective high values. The relatively high total egg value for March resulted from the entrainment~of many winter f?ounder eggs which appeared to be due to rough seas on two sampling dates; i ac' mentioned earlier, heavy weather disturbs the bottom near shore and stirs demersal winter flounder eggs up into the water column where they are more ) likely to be entrained. L Ichthyoplankton populations sampled over a long time series typically 1 display density variations of one order of magnitude, and two orders of l l magnitude are not unheard of (see Figures 3 and 4). Variations in spawning l stock size and condition, food availability, predator densities, and physical l 1 l t variables such as water temperature and wind all contribute to the level of observed ichthyoplankton densities. In many cases the 1987 monthly densities ! which extended above or below all previous values at PNPS did so only slightly.
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C. Lobster Larvae Entrained . No larvat lobsters were found in the 1987 entrainment samples. The last time one-vas taken was in June of 1982, making a total of nine over the 1974-1987 period. These collections are tabulated as follows: 1983-1987: none found. 1982: 1 larva - stage I on June 14. 1981: 1 larva - stage IV on June 29. 1980: none found. 1979: 1 larva - stage I on July 14. 1978: none found. 1977: 3 larvae - 1 stage I on June 10; I stage 1 on June 17, 1976: 2 larvae - 1 stage I on July 22; 1 stage IV-V on August 5, 1975: 1 larva - stage I, date unknown. 1974: none found. The lobster larvae collected in 1976 were obtained during a more intensive lobster larvae program which employed a 1-meter net, collecting relatively large sample volumes, in addition to the standard 60-em plankton net (Marine Research 1977b). Both larvae taken in 1976 were collected in the meter net; none were found in the routine ichthyoplankton samples. The scarcity of larval lobsters in PNPS entrainment samples is most interesting considering that, in 1980, 918 tons of legal-sized lobsters were landed in Plymouth County by enmmercial lobstermen with a value of four million dollars (Lawton et al.1983). Among lobstermen working inshore waters, this increased to 1381 tons valued at $6.8 million in 1985 (Hoopes 1986) and 1485 tons values at $7.5 million in 1986 (Hoopes 1987). Neuston 34
sampling conducted in the northwest sector of Cape Cod Bay (Lawton et al. 1983; Matthiessen and Scherer 1983) also indicated that larvae were not particularly abundant there. To support such a strong fishery it would appear young lobsters must arrive in the Plymouth area from other regions. Sampling around Rocky Point from 1974 through 1977 showed considerably more late-stage larvae than young larvae (Lawton et al. 1983). That, coupled with the prevailing counterclockwise Cape Cod Bay currents, suggests that larvae may arrive from the north. Sampling at the mouth of the Cape Cod Canal suggests that large numbers of larvae enter Cape Cod Bay f rom Buzzards Bay and perhaps the Canal itself (Matthiessen and Scherer 1983; Matthiessen 1984). Regardless of source, larval lobsters appear to be especially uncommon in PNPS entrainment samples. This is supported by Lawton et al. { (1983) who caught only eight larvae in twenty neuston tows near shore around Rocky Point in 1975. In addition to their apparent scarcity in near-shore waters, larval lobsters' neustonic habits may reduce the proba-bility of their entrainment since they would contact the intake skimmer wall which might prevent some from passing to the condensers. l l i
)b l
1 S ECT IO_N_ _V. l LITERATURE CITED 4 Ahlstrom, E.H. and R.C. Counts. 1955. Eggs and larvae of the Pacific hake, ; Merluccius productus. U.S. Fish and Wildlife Service, Fishery Bulletin
$6199):295-329.
a Dalley, E.L. and G.H. Winters. 1987. Early life history of sand lance ! ( Ammodvtes) with evidence for spawning A. dubius in Fortune Bay, j Newfoundland. Fishery Bulletin U.S. 85(3):631-641. : i Fahay, M.P. 1983. Guide to the early stages of marine fishes occurring ? in the western northern Atlantic Ocean, Cape Hatteras to the southern i Scotian Shelf. Journal of Northwest Atlantic Fishery Science, Volume 4, 423p. j Hardy, J.D., Jr. 1978. Development of fishes of the mid-Atlantic Bight. An atlas of egg, larval and juvenile stages. Volume II. Anguillidae through syngnathidae. U.S. Fish and Wildlife Service, Biological Services Program. 458p. ; Hoopes, T.B. 1986. 1985 Massachusetts Lobster Fishery Statistics. Tech- j nical Series 20. Massachusetts Department of Fisheries. Wildlife and ; Environmental Law Enforcement. Division of Marine Fisheries. 20p. ,
. 1987. 1986 Massachusetts Lobster Fishery Statistics. Tech- 1 nical Series 21. Massachusetts Department of Fisheries, Wildlife and I Environmental Law Enforcement. Division of Marine Fisheries. 17p.
Lawton, R., E. Kouloheras, P. Brady, W. Sides, and M. Borgatti. 1983. Distri-bution and abundance of larval American lobsters Homarus americanus j Milne-Edwards, in the western inshore region of Cape Cod Bay, Massachu- , setts, p. 47-52. Ijl: M.J. Fogarty (ed.), Distribution and relative j abundance of American lobster, Homarus americanus, larvae: New England j investigations during 1974-1979. NOAA Technical Report NMFS SSRF-775. 64p. [ t Marine Research, Inc. 1977a. Investigations of entrainment of ichthyo- l plankton at the Pilgrim Station and Cape Cod Bay ichthyoplankton studies, March-December 1977; twelve-month summary for 1977, Cape Cod Bay ichthyo-plankton studies. III.C.2-1. In,: Marine Ecology Studies Related to [ Operation of Pilgrim Station, Semi-Annual Report No. 11. Boston Edison f Company. ; i
. 1977b. Entrainment investigations and Cape Cod Bay ichthyo- (
plankton studies, July-September 1976. III.C.1-i-71. In: Marine EcoloEy Studies Related to Operation of Pilgrim Station, Semi-Annual Report No. 9. Boston Edison Company. l
?
i i f r b
Matthiessen, G.C. 1984. The seasonal occurrence and distribution of larval lobsters in Cape Cod Bay, p. 103-117. In J.J. Davis and D. Merriman (eds.), Observations on the Ecology and Biology of Western Cape Cod Bay, Massachusetts. Springer-Verlag. 289p. and M.D. Scherer. 1983. Observations on the seasonal occurrence, abundance, and distribution of larval lobsters (Homarus americanus) in Cape Cod Bay, p. 41-46. Jgt: M.J. Fogarty (ed.), Distribution and relative abundance of American lobster, Homarus americanus, larvae: New England investigations during 1974-79. NOAA Technical Report. NMES SSRF-775. 64p. Meyer, T.L., R.A. Cooper, and R.W. Langton. 1979. Relative abundance, behavior, and food habits of the American sand lance, Ammodytes americanus, from the Gulf of Maine. Fishery Bulletin U.S. 77:243-253. Motoda, S. 1959. Devices of simple plankton apparatus. Memoirs of the Faculty of Fisheries, Hokkaido University 7:73-94. Richards, S.W., A. Perlmutter, and D.C. McAneny. 1963. A taxonomic study of the genus Ammodytes from the east coast of North America (Teleostei: Ammodytes), Copeia 1963(2):358-377. Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A. Lachner, R.N. Lea, and V.B. Scott. 1980. A list of common and scientific names of fishes from the United States and Canada. American Fisheries Society Special Publication 12. 174p. Scott, J.S. 1968. Morphometries, distribution, growth, and maturity of of fshore sand lance ( Ammodytes dubius) on the Nova Scotia banks. Journal of the Fisheries Research Board of Canada 25:1775-1785.
. 1972. Morphological and meristic variation in Northwest Atlantic sand lances ( Ammodytes). Journal of the Fisheries Research Board of Canada 29:1673-1678.
Van Cuelpen, L., D.F. Markle, and D.J. Duggan. 1982. An evaluation of accuracy, precision, and speed of several zooplankton subsampling techniques. International Council for the Exploration of the Sea 40:226-236. Winters, G.ll. 1970. Meristics and morphometrics of sand lance in the Newfoundland area. Journal of the Fisheries Research Board of Canada 27:2104-2108, n
WI \ APPENDIX A* Densities of fish eggs and larvae, per 100 m 8 of water, recorded in the PNPS discharge canal by species, date, and replicate, January-December 1087.
*This Appendix is available upon request.
1
F 1 APPENDIX B* Mean monthly densities and range per 100 m 3 of water for the dominant species of fish eggs and larvae entrained at PNPS, January-December, 1975-1987.
*This Appendix is available upon request.
l Ichthyoplankton Entrainroent Monitoring at Pilgrim Nuclear Power Station January - December 1987 Volume 2 of 2 (Impact Perspective) Submitted to Boston Edisor. Company Boston, Massachusetts by Marine Research, Inc. Falmouth, Massachusetts March 11, 1988 revised April 6, 1988
TABLE OF CONTENTS SECTION PAGE I SUtetARY 1 II INTRODUCTION 2 III IMPACT PERSPECTIVE A. Contingency Sampling Plan 4 B. Ichthyoplankton Entrainment - General 7 C. Ichthyoplankton Entrainment - Specific 10 D. Potential Pump Effects 11 IV LITERATURE CITED 18 l ( mc z - .v . r., .
LIST OF FIGURES FIGURE PAGE 1 Number of eggs estimated to have been entrained by PNPS in 1987 had it operated at 100% capacity by species or species group _(dominsnts only) including all egg species combined. 8 2 Numbers of larvae estimated to have been entrained by PNPS in 1987 had it operated at 100% capacity for each dominant species including all larvae combined. 9 I 3 Mean monthly densities, per 100 m* of water, for total eggs entrained at PNPS, April-August 1983-1987. Pump regime operating during the period is indicated for l each year. 13 J 4 Mean monthly densities, per 100 m 8 of water, for total larvas entrained at PNPS, April-August 1983-1987. j Pump regime operating during the period is indicated for each year. 14 l l l LIST OF TABLES l l TABLE 1 lehthyoplankton densities, per 100 m3 of water, which reached the "unusually large" level in PNPS entrainment l samples, 1980-1987. 5 l l l LIST OF PLATES PLATE 1 Plankton net streaming in the discharge canal at Pilgrim Station for the collection of fish eggs and larvae (lobster larvae are also recorded). A single, six-minute collection can contain several thousand eggs and larvac representing 20 or more species. 3 li
\ SECTION I
SUMMARY
Ichthyoplankton collections were made in the Pilgrim Nuclear Power Station (PNPS) discharge canal in triplicate twice per month in January and February, weekly from March through September, and twice per month from October through December; no sampling occurred in Aprit due to circulating water pump shutdown. Specific results appear in "Ichthyu-plankton Entrainment Monitoring at Pilgrim Nuclear Power Station, January-December 1987:, Volume 1, Results. Volume 2 offers a general discussion of more impact-related issues. Ichthyoplankton densities meeting the "unusually abundant" criterion defined under the contingency sampling program did not occur in 1987. Total numbers of eggs potentially entrained at 1987 vere estimated at 3,440,242,677 and total numbers of larvae at 47,870,538. Data collected in 1987 when only one SSWS pump was operating support results obtained in 1984, suggesting that fish larvae are less susceptible to entrainment by the small SSWS pumps when compared to the main circulating water system pumps. l i l l 1
l
- SECTION 11 INTRODUCTION This report addresses results of PNPS ichthyoplankton entrainment samp-ling with an accent on potent.al impact assessment. Discussions are based i
on results presented in "Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station January-December 1987", Volume 1 - Results. Work was conducted by Maring Research Inc. (MRI) for Boston Edison Company (BEco) under Purchase Order No. 63653 in compliance with environmental monitoring } l and reporting requirements of NPDES Permit No. 0003557 (U.S. EPA and Massa- d chusetts DWPC). In a continuing effort to condense the volume of material presented in this and related reports, details of interest to some readers may have been omitted. Any questions or requests for additional information may be directed to Marine Research, Inc., Falmouth, Massachusetts. Plate I shows the ichthyoplankton sampling net being deployed in the PNPS discharge canal. l 1 I l l l l I l 2
l s l / l L 1 i
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?
s SECTION III ! IMPACT PERSPECTIVE i l i A. ' Contingency Sampling Plan L I Ichthyoplankton densities meeting the "unusually abundant" criterion, , defined as exceeding by 507. the highest mean density over three replicates j recorded during the same month from 1975 through 1986, did not occur in l 1987 or in 1986. This compares with four occurrences in 1985, six in 1984, ;
)
one in 1983, eight in 1982, seven in 1981, and twelve in 1980 (Table 1). No specific events occurred prior to 1980 primarily because "unusuall/ 'f large" was not precisely defined early in the contingency plan. , In past years it was standard practice for BEco, in consultation with $ regulatory personnel, to authorize the collection of an additional set of triplicate entrainment samples following the recording of an "unusually ! i large" density at PNPS. In most cases the additional sets were taken within I two days of the original. In all but three cases when this occurred mean densities dropped back to levels within the range established over previous i years, indicating that the "unusual" density probably reflected the entrain- l ment of a high density ichthyoplankton patch rather than a more widespread [ t phenomenon. In the three cases where high densities persisted (larval rock gunnel, April 1982; larval rock gunnel, February 1985; larval Atlantic menhaden, June 1981) additional entrainment sampling at about two-day { intervals indicated that high densities continued for up to two weeks. { Since no changes in PNPS operation occurred, it appeared in those situations i that productivity was generally high relative to previous years. [ t I i 4 i i
[ Table 1. Ichthyoplankton densities, per 100 m 8 of water, which reached ; I the "unusually largr* 1evel in PNPS entrainment sampics, 1980-1987.
"Unusually large" Previous high f Species Month density (year) density (year)
ECCS Brevoortia tyrannus June 74.2 (1980) 6.2 (1978) September 1961.9 (1982) 1.4 (1979) 1065.8 (1982) October 37.8 (1980) 0.2 (1978) Enchelvopus-Urophicis- gg ) 39, 3 7 ) 979) Pepettus Urophyeis spp. September 152.8 (1980) 22.3 (1978) Labrid-Limanda & labrid July 12917.0 (1981) 8116.8 (1975) Scomber scombrus. May 15261.3 (1985) 572.0 (1980) 1457.6 (1985) LARVAE Brevoortia tyrannus June 7.1 (1981) 4.2 (1980) 495.9 (1981) 34.7 (1981) October 11.7 (1980) 1.8 (1976) November 24.3 (1980) 3.2 (1978) Enchelyopus cimbrius August 204.6 (1983) 36.0 (1980) Urophycis spp. September 105.6 (1984) 22.3 (1981) Tautorolabrus adspersus June 624.5 (1981) 378.8 (1977) July 296.5 (1980) 138.5 (1974) 2162.5 (1981) 296.5 (1980) ; September 20.3 (1980) 1.5 (1975) Tautora onitis August 21.6 (1984) 4.1 (1974) , September 9.2 (1980) 4.8 (1975) Pholis runne11us rebruary 19.6 (1984) 7.4 (1975) 13.8 (1984) 47.5 (1985) 19.6 (1984) , March 70.2 (1980) 36.9 (1975) l 210.5 (1984) 70.2 (1980) 415.2 (1984) ! April 74.0 (1982) 12.1 (1977) 74.7 (1982) 34.0 (1982) 22.4 (1982) L 23.5 (1982) l o l
i5 J 1 l Table 1 (continued). I "Unusually large" Previous high Species Month density (year) density (year) LARVAE (continued) Ammodytes sp. January 31.1 (1980) 13.5 (1975) 104.4 (1965) 31.1 (1960) Scomber scombrus June 2700.0 (1981) 128.0 (1975) Myoxocephalus spp. March 153.6 (1980) 97.0 (1975) April 303.6 (1982) 53.1 (1981)
*"Unusually large" was defined as 50% greater than the previous high density observed during the same month 1975-1987.
6
B. tehthyoplankton Entrainment - General Entrainment of ichthyoplankton at PNPS represents a direct negative environmental impact since fish eggs and larvae pass through the plant in large numbers each day and are subjected to elevated temperatures, mechanical forces, and chlorination. When PNPS is not on line, ichthyoplankton may still be subjected to mechanical forces and chlorination. Although survival hss been demonstrated for some species of fish eggs at PNPS such as the labrids (45%; Marine Research 1978, 1982) and among larvae at other power plants (Ecological Analysts 1981), mortality is assumed to be 100% as a conservative approach to PNPS impact assessment. To place fish egg and larval densities recorded in the PNPS discharte canal, expressed as numbers per 100 m) of water, in some perspective, they were multiplied by plant flow rates over each respective period of occur-tence. This was completed for each of the numerically dcminant species as well as total eggs and larvae. Mean monthly densities were multiplied by 17,461.44, the full load flow capacity of PNPS in 100 m units per 24-hour 8 day, then by the number of days in each respective month. Values for each month in which a species or species group occurred were then summed to arrive at a seasonal entrainment value in each case (Figures 1 and 2). Among the eight numerically dominant groups, numbers of eggs entrained ranged trom 338,403 for Atlantic menhaden (Brevoortia tyrannus) to 3.168,423,687 for the labrid-Limanda group. For all eEgs combined a value of 3,440,242.677 was obtained. Among the ten dominant species of larvae values ranged from 162,391 for sand lance ( Amedytes sp.) to 9,554,900 for seasnail (tiparts spp.) and amounted to 47,870,538 for all larvae combined. These numbers indicate
?
l l 1 l i i I 1 i MILLIONS OF EGGS ENTRAINED - 1987 I o 5 5 8 U 8 $ $ $ 8 l Species and Occurrence Period i { Brevoortia tyrannus l 333,403 i (June-September) ~ r_' ":=JJ l Fnchelyopus-Urophycis-Peprilus L u_ , _138,180.940 C 1 _ ! ( Stay-Novembe r ) l Gadidae-Clyptocephalus Q 195.370 f _] I (January-December) l Labridae-Limanda i ,
~ -
13,168,423,687 C 2 _ za - _ _ _ _ _s- 5 ID l m ( Stay-Sept embe r ) Scomber scombrus i- , _ _ a 83.818,405 L _ ' - .
--._ lid j ( Stay-July)
_ _ 14 4,612,232 Y ~
.i 1 Prionotus spp. ;_ _ _ _ __
j (Stay-July ) _~
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F 143,568,039 0 s Paralichthys-Scophthalmus . (Flay-October) ! liippc.glossoides platessoides 1,218.809 , !, (?tay-June) I t 1 i Total Eggs L J 3.440,242,677 y - _r d i i Figure 1. Number of eggs estimated to have been entrained by PNPS in 1987 had it operated at 100% capacity by species l or species group (dominants only) including all egg species combined. The period of occurrence observed in i 1987 is also indicated. I i I
p. MILLIONS OF LARVAE ENTRAINED -1987
. s 8 0 8 8 8 8 8 Spectes and Occurrence Period 9
Clupea harengus harengus E , -1 5.114.456 (Jan-Feb; Oct-Dec) Enchelyo:-us cimbrius L. _ 'I 6.392,633 (May-November) Tautogolabrus adspersus l 666,503 (June-October) Ulvaria subbifurcata 3 1,187,378 (May-June) o Pholis gunnellus F 7 4,463,144 (January-May) Ammodytes sp. 162,391 (March-May) Scomber scombrus l 263,668 (May-June) Mynxocephalus spp. F :'c _E 6.792,500 (January-May) Liparis spp. [_ 1 9.554,900 (January-June) Pseudopleuronectes americanus [ , .__ .1 5,678,460 (May-June) Total Larvae - _- 3 47,870,538 i : 1 L' - Fir,ure 2. Numbers of larvae estimated to have been entrained by PNPS in 1987 had it operated at 100% capacity for each dominant species including all larvae combined. The period of occurrence observed in 1987 is also indicated.
the tremendous quantities of eggs and larvae which can be entrained by the circulating seawater system at PNPS during a year and are presumed to be lost from the population. C. Ichthyoplankton Entrairment - Specific The effects of entrainment on populations of Atlantic menhaden, vinter flounder (Pseudopleuronectes americanus), pollock (Pollachius virens), cunner (Tautogolabrus adspersus), rainbow smelt (Osmerus mordax), Atlantic silversides (Menidia menidia), and alewives (Alosa pseudoharengus) were assessed by Stone and Webster (1975) using flow rates for two units at Pilgrim Station. Using conservati.ve assumptions and ignoring density-dependent compensation among non-entrained ichthyoplankton, no appreciable adverse impact on indigenous populations was predicted to occur. Modeling studies conducted on five species of larval l fish which appear to be more abundant in western Cape Cod Bay than in the remainder of the Bay (tautog, Tautora onitis; seasnail; radiated shanny, Ulvaria subbifurcata; sculpin, Myoxocephalus spp.; rock gunnel, Pholis gunnellus) suggested that the percentage of original larval production contributing to entrainment by PNPS Unit I was less than 1.0 (Marine Research 1978). For twelve additional categories of eggs and larvae considered to be more widely distributed in Cape Cod Bay, percentages contributing to entrainment were smaller, the highest being 0.12" (labrid-Limanda eggs). If entrainment of ichthyoplankton at PSPS represented a significant cause of mortality in western Cape Cod Bay, the losses might be reflected in finfish collections in the PNPS area. A review of indices of relative abun-dance based on otter trawl and gill net sampling by Massachusetts Division of Marine Fisheries personnel (Lawton et al. 1986) does not indicate any 1 l 10
long-term steady declines among Atlantic herring (Clupea harengus harengus),_ pollock, silver hake-(Merluccius bilinearis), cunner, tautog, Atlantic menhaden, or windowpane (Scophthalmus aquosus). On the other hand winter flounder and yellowtail flounder (Limanda ferruginea) have shown declines in the PNPS area during recent years. In both these cases however, commercial landings and stock assessment research indicate that these declines appear to be videspread, extending all along the Massanhusetts coastline (Foster 1987, Howe et al. 1988). Therefore, these specific declines appear to be the result of natural population variation probably coupled with overfishing. D. Potential Pump Ef fects PNPS has been involved in a long-term outage which began in April 1986 and continued into 1988. During most of this period only one of two main circulating water system (CWS) pumps was operating (flow = 155,000 gpm, or 2 9.78 m2 per second, compared with 310,000 gpm, or 19.56 m per second, when the plant operates with two pumps). As discussed in Volume 1, Methods and Materials, beginning in late March 1987 intermittent use of a single circu-l lating seawater pump made it basically unavailable for entrainmer.t sampling, i leaving only one or occasionally two Salt Service Water System (SSWS) pumps in service, each with a capacity of about 2500 gpm, or 0.16 m per second. 2 t From May through August 1987 sampling continued with only the SSWS pump (s) providing flow for entrainment sampling, as occurred in 1984. To compare the response of ichthyoplankton to dif ferent pump regimes, l densities per 100 m) of water were compared for single SSWS pump periods (1987), two SSWS pump periods (1984), single CWS pump periods (1986), and I two CWS pump periods (1983, 1985). Compar'. sons involving 1987 data were 11
I I restricted primarily to the May through August period when sampling was possible and the stated pump schedules were consistently maintained. When collections were made using only the relatively small SSWS pumpa, an original assumption was made that plankton would continue to be sampled in proportion to their abundance in the Rocky Point area since larval fishes, especially the small ones, show little directional swimming ability and certainly eggs drift passively. Results reported in the 1986 annual entrain-ment report (Marine Research 1987) indicated that April-August 1984 larval collections were so low that local populations did not appear to be impacted in similar proportion by the SSWS pumps as by the CWS pumps. Figures 3 and A taken-from Marine Research (1987) show monthly mean densities, per 100 m 3 of water, April-August, for total eggs and total larvae, 1983-1986. Monthly mean densities for larvae in April, June, and July of 1984 (the first year sampling occurred with only two SSWS pumps operating) were all the lowest on record, 1975-1986, as were May and July mean egg densities. Data for 1987 vere added to Figures 3 and 4 for the same period when only one (or, on 2 of 14 sampling occasions, two) SSWS pumps were operating; data obtained on May 30, June 25, and August 19, 1987, were omitted because these samples were taken during brief periods of single CWS pump operation. Clearly May-August larval densities for 1987 were exceptionally low each month (Figure 4), even when compared with 1984. Egg densities in 1987 ranked lowest over the five year period only for August. These data were examined further using a nonpara-metric, single classification, Kruskal-Wallis test with mean densities, per 100 m8 of water, for each sampling date from May through August, 1983-1987. 4 No significant difference was apparent among years for eggs (p = 0.05) but 12
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W o /' \\ Z l s 4 i U \ 10 - 'g fgg7 (; gggg) l 1-i l i ' i 0 APRIL MAY JUNE JULY AUG Figure 3. Mean monthly densities, per 100 m 3 of water, for total eggs l entrained at PNPS, April-August 1983-1987. Pump regime ! operating during the period is indicated for each year. l l l l I.
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O APRIL MAY JUNE JULY AUG Figure 4. Mean monthly densities, per 100 m of water, for total 2 larvae entrained at PNPS, April-August 1983-1987. Pump regime operating during the period is indicated for each year. I !.
v a very highly significant difference (p < 0.001) was found for larvae. Non- [ parametric multiple comparisons among years for larvae sh' owed no dif ference between 1985 ~ and 1983 values, no dif ference between 1984 and 1986 although thed! years were different from 1985 and 1983; 1987 appeared significantly different from all other years. The summed ranks as.well.as results of the multiple comparisons (indicated by vertical bars) were as follows: h Larvae 1983 - 536 1983 - 689 1985 - 519 1985 - 685 1986 - 505 1986 - 506 1984 - 444 1984 - 422 1987 - 426 1987 - 182 l H = 7.718 n.s. H = 30.408*** The apparent reduced susceptibility of larvae to the SSWS pumps was further indicated by sampling on May 30, 1987 when collections were made while one CWS pump was placed into service for a short period. On May 28 no larvae were obtained while sampling under the influence of one SSWS pump. Two days later on May 30 a mean density of 132 larvae per 100 m was obtained consisting 8 of eight species. On June 4, again with only one SSWS pump operating, two larval species were taken with a combined mean density of 2 per 100 m 3 of water. A comparison of the number of species recorded from May through August over the 1983-1987 period indicated that 1987 was clearly the lowest with 13 overall (23 with inclusion of the 3 dates when one CWS pump was in use); 1984 and 1986 followed with 29 each, 1983 had 32, and 1985 had 34 The low species count in 1987 was due primarily to a scarcity of larvae. Only four species l of larvac were recorded over the May-August period of 1987 compared with 24 l i l t l$
l in 1984, 26 in~1986, 29 in 1983, and 31 in 1985. Numbers of egg species were somewhat more consistent with 9 being taken in 1987 compared with 15 in 1984,- 17 in-1985~and 1986,.and 18 in 1983. Including May 30, June 25, and August 19 when a single CWS pump was #n service brought the 1987 totals up to 15 species of eggs and 16 species of larvae. The low densities of larvae in 1984 and the strikingly low densities in 1987 over the spring and summer period strongly suggest that ichthyoplankton populations near PNPS were not impacted in similar proportion by the SSWS pumps as by the main circulating seawater pumps. A sharp decline in larval densities occurred between 1984 and 1987 values, suggesting that dropping from two to one SSWS pump prevented many larvae from being entrained. The inter-mediate values for 1986, when one CWS pump was in service, ranking between 1984 and 1983,1985 suggests a direct relationship between pump flow and larval entrainment; although 1986 was not shown to be significantly different from 1984, it was very nearly so, q = 2.73 vs 2.77 for p = 0.05. Apparently the relatively low flow of the SSWS pumps has very limited influence on drawing , larvae into the intake embayment area and subsequently through the PNPS condensers. These results could reflect mainly physical flow effects acting upon free-floating larvae or perhaps an active larval swimming ability, per-mitting an increasing number of them to avoid entrainment as pump capacity declines. For example, at some point water entrained by the PNPS intake separates from the prevailing Cape Cod Bay current and enters the intake area. The area over which the flow separation occurs is presumably more widespread and the action more forceful (the velocity higher) when two seawater pumps operate than when only one seawater pump operates or one or two SSWS pumps operate. Passive larvae and eggs should be entrained in proportion to their la
I abundance, but more active larvae may swim, to the extent of their ability, to. remain within the Cape Cod Bay water mass. Also the more widespread the influence of a particular pumping rate, the higher the probability that high-density ichthyoplankton patches will be entrained. .The, role which vertical
' distribution plays may be of great importance as well, as the smaller pumps probably draw water over a more restricted vertical profile, one which may not coincide with the presence of many eggs and larvae.
Although no significant difference was detected.among eggs, it is interesting that years did rank in the same order as the larvae with the two CWS pump years (1983', 1985) showing the highest values followed in decreasing order by the single CWS pump year (1986), the two SSWS pump year (1984), and the single SSWS pump year (1987). It is important to keep in mind that all comparisons based on different pump capacities were made without knowledge of ichthyoplankton population ( levels around Rocky Point. The observed rankings could have been due entirely or in part to differences in production among the five years, although that
- l. would appear to be an extraordinary coincidence given the well-defined i
relationship between ichthyoplankton densities and PNPS flow. I l t I l 17
SECTION IV LITERATURE CITED Ecological Analysts, Inc. 1981. Entrainment survival studies. Research Report EP 9-11, submitted to Empire State Electric Energy Research Corporation, New York. Foster, K.L. 1987. Status of winter flounder (Pseudopleuronectes americanus). stocks in the Gulf of Maine, Southern New England, and Middle Atlantic areas. Woods Hole Lab.'Ref. Doc. 67-06, National Marine Fisheries Service, 60 p. + appendix. Howe, A.B., T.P. Currier, S.L. Sass, and J.B. O'Gorman. 1988. Coastwide fishery resource assessment - coastal Massachusetts. Massachusetts Division of Marine Fisheries. 12 p. + appendix. Lawton, R.P., C. Sheehan, V. Malkoski, S. Correia, and M. Borgatti. 1985. Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay. Project Report No. 38 (January-December 1984). III.A i-80. Irl: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-Annual Report No. 25. Boston Edison Company Marine Research, Inc. 1978. Entrainment investigations and Cape Cod Bay ichthyoplankton studies, March 1970-June 1972 and March 1974-July 1977. Volume 2, V.1 i-44. In,: Marine Ecology Studies Related to Operation of Pilgrim Station. Final Report. July 1969-9ecember 1977. Boston Edison Company.
. 1982. Supplementary winter flounder egg studies conducted l at Pilgrim Nuclear Power Station, March-May 1982. Submitted to l Boston Edison Company. 4p.
1987. Ichthyoplankton entrainment monitoring at Pilgrim l Nuclear Power Station January-December 1986, Volume 2 (Impact perspective), l 17p. In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report No. 29. Boston Edison Company Stone and Webster Engineering Corporation. 1975. Demonstration Pilgrim ! Nuclear Power Station Units 1 and 2, Boston Edison Company, Boston, Massachusetts. l-
IMPINGEMENT OF ORGANISMS AT PILGRIM NUCLEAR POWER STATION ) (January - December 1987) Prepared by: '/ f . Robert D. Anderson Senior Marine Fisheries Biologist Acril 1988 Regulatory A# fairs and Prcgrams Boston Edison Company
f Herring d w gw,_ Smelt l j Cunner I hlOSI Commonly Siherside impinged species
L TABLE OF CONTENTS Section' Title Page t 1
SUMMARY
1 2 INTRODUCTION 2 3 METHODS AND MATERIALS 5 4 RESULTS AND DISCUSSION 7 4 4.1 Fishes 7 f 4.2 Invertebrates 19 4.3 Fish Survival 22 F 5 CONCLUSIONS 25 6 LITERATURE CITED 27 l l t i l-L L
LIST OF FIGURES _ Figure Paye-I Location of Pilgrim Nuclear Power Station 3 2 Cross-Section of Intake Structure of Pilgrim 4 Nuclear Power Station 3 Trends of Intake Water Temperature, and Number 12 of Fish Captured by month from Pilgrim Station Intake Screens for the Five Most Abundant Species Collected, January-December 1987 t 4 Relationship of Pilgrim Station Circulating 15 Hater System (CWS) Pumps' Operation (Pump t Flow) to Fish Impingement Rate for the Period 1983-1987. t i k l l t 4
b LIST OF PLATES
- Plate-1 The 300 foot long' Pilgrim Station, concrete ? screenwash. sluiceway is molded from 18" corrugated metal pipe,.and meanders over !
t breakwater rip rap. i . 2~ Fish survival testing is done at the end of the. sluiceway where.it discharges to ambient. temperature intake waters. l t ? : I : [ i : [ 111
c - - LIST OF TABLES I Table Page 1 Monthly Impingement for All Fishes Collected From , 8 f Pilgri'.n Station Intake Screens, January-December 1987 2 Species, Number, Total Length (mm), Weight (gms) 9 and Percentage for All Fishes Collected From Pilgrim Station Impingement Sampling, January-De: ember 1987 3 Annual Impingement Collections (1978-1987) for 10 the 10 Most Abundant Fishes From Pilgrim Station Intake Screens During January-December 1987 1 4 Approximate Number and Cause for Most Notable Fish 14 Mortalities at Pilgrim Nuclear Power Station, 1973-1987 5 Impingement Rates per Hour, Day and Year for All 17 Fishes Collected From Pilgrim Station Intake Screens During January-December 1987, Assuming 100% Operation of Pilgrim Unit I tv
Table Page i 6 Impingement Rates Per-Hour, Day and Year for 18 All Fishes' Collected from Pilgrim Station Intake Screens During 1973-1987, Assuming 100% Operation of Pilgrim Unit 1 7 Monthly Heans of Intake Temperatures (*F) Recorded 20 During Impingement Collections at Pilgrim Nuclear Power Station, 1978-1987 8 Monthly Impingement for All Invertebrates Collected 21 From Pilgrim Station Intake Screens, January-December 1987 9 Survival Summary for the Fishes Collected During 23 i Pilgrim Station Impingement Sampling, January-December 1987. Initial, One-Hour and latent (56-Hour) Survi"al Numbers are Shown Under Static (8-Hour) and Continuous Wash Cycles i 1 i i i
t. SECTION I SUMRARY Fish impingement rate averaged 0.28 fish / hour during 'the period January-December 1987, which is the second lowest rate in the last several years because of low or no circulating water pump operation during the year. i Rainbow smelt (Osmerus mordax) accounted for 27.7% of the fishes collected. Atlantic silverside (Tautogolabrus (Menidia menidia), cunner adspersus), 10mpfish (Cyclooterus lumpus) and winter flounder (Pseudcoleuronectes , americanus) accounted for 18.2, 9.5, 6.8 and 6.8%, respectively, of the fishes impinged. The peak impingement month was December when rainbow smelt and Atlantic silverside were most represented. Initial impingement survival for all fishes from static screen wash collections was approximately 29%, and from continuous screen washes 43%. Delayed mortality data was not available do to i failure of the screenwash survival pools or samf ling in the screenhouse during [ portions of 1987. At full-load yearly (January-December) operation of Pilgrim Nuclear Power l Station (PNPS) the estimated impingement was 2,460 fishes (187 lbs.). The j PNPS capacity factor was 0.0% during 1987. l l The collection rate (no./hr.) for all invertebrates captured from January- - l l Oecemoer 1987 was 1.51. Blue mussel (Mytilus edul_i_s), sand shrimp (Crangon sectenssinosa) and polychaete worms were most numerous, accounting for l accroximately 71.8, 7.9 and 4.5%, respectively, of the invertebrates imoinged. Mixec species of algae collected on intake s:reens amcunted to 563
- cunds.
l t
SECTION 2 INTRODUCTION , I Pilgrim Nuclear Power Station (lat. 41'56' N, long. 70'34' W) is located on i the northwestern shore of Cape Cod Bay (Figure 1) with a licensed capacity of 655 MWe. The unit has two circulating water pumps with a capacity of ap-proximately 345 cfs each and five service water pumps with a combined capacity of 23 cfs. Water is drawn under a skimmer wall, through vertical bar racks spaced approximately 3 inches on center, and finally through vertical travel-ling water screens of 3/8 inch wire mesh (Figure 2). There are two travelling - water screens for each circulating water pump. This document is a report pursuant to operational environmental monitoring and reporting requirements of NPOES Permit No. 0003557 (USEPA) and No. 359 (Mass. CHPC) for Pilgrim Nuclear Power Station, Unit I. The report describes im-pingement of organisms and survival of fishes carried onto the vertical trav-elling water screens at Unit I. It presents analysis of the relationships [ among impingement, environmental factors, and plant operational variables. The report is based on data collected from screen wash samples during January-December 1987.
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SECTION 3 METH005 AND MATERIALS I L Three screen washings each week were performed from January-December 1987. to provide ~ data for evaluating the magnitude of marine biota impingement. The total weekly collection time. was 24 hours (three separate 8-hour periods: morning, afternoon and night). Two collections represented dark period sam-t pling and one represented light period sampling. At the beginning of each collection period, all four travelling screens were washed. Eight hours later, the screens were again washed (minimum of 30 minutes each) and all or-ganisms collected. When screens were being washed continuously, one hour col-lections were made at the end of the regular sampling periods, and they repre-sented two light periods and one dark period on a weekly basis. Hater nozzles directed at the screens washed impinged organisms and debris into a sluiceway that flowed into a trap. The original trap was made of gal-vanized screen (3/8-inch mesh) attached to a removable steel frame and it col-lected impinged biota shortly af ter being washed off the screens. A second trap was designed and used for sampling, in conjunction with slutceway sur-vival studies, consisting of a section of half 18" corrugated metal pipe with 3/16-inch nylon, delta mesh netting attached. Impinged biota sampled by th.is trap were collected at the end of a 300' sluiceway where initial, one-hour and latent (56-hour) fish survival were determined for static (8-hour) and contin-uous screenwash cycles. Plates I and 2 provide views of the beginning and end
# this :1uiceway structure which was constructed in 1979.
Variables recorded for. organisms were total numbers, .and individual total lengths (mm) and welghts (gms) for up to.20 specimens of each species. A ran-dom sample of 20 fish or invertebrates was taken whenever the total nuinber for a species exceeded 20; if the total collection for a species was less' than 20,
]
all were measured and weighed. Field work was conducted by Marine Research, Inc. Intake seawater temperature, power level output, tidal stage, number of circu-lating water pumps in operation, time ' of ~ day and date were recorded at the time of collections. The collection rate (#! hour) was calculated as number of f organisms impinged per collecting period divided by the -total number of hours l l in that collecting period. All common and scientific names in this report follow the American Fisherles Society (1980) and Smith (1964). I i 1
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SECTION 4 RESULTS AND DISCUSSION 4.1 Fishes In 527 collection hours, 148 fishes of twenty-four species (Table 1) were-collected from Pilgrim Nuclear Power Station intake screens during January-l- December 1987. The collection rate was 0.28 fish / hour. This annual im-pingement rate is the second lowest in several years because of limited or no circulating water pump operation for 1987. Rainbow smelt (Osmerus mordax) was the most abundant species in 1987, accounting for 27.7% of all fishes col-lected (Table 2). Atlantic silverside (Menidia menidia) cunner (Tautocolabrus adspersus), lumpfish (Cvelooterus lumous) and winter flounder (Pseudooleuronectes americanus) accounted for 18.2, 9.5, 6.8 and 6.8% of the total number of fishes collected and identified to lowest taxon. Rainbow smelt occurred predominantly in monthly samples from January and December. Hourly collection rates per month for them ranged from 0 to 0.89. Rainbow smelt impinged in December accounted for 61% of all this species captured in impingement collections from January-December 1987. They averaged 110 mm total length and 8 grams in weight. Their impingement indicated no re-lationship to tidal stage or diel factors. It is unusual for them to be the dominant fish in the annual impingement catch, as happened previously in 1978. A review of historical data shows them to be impinged in greatest numbers during the month of December. Rainbow smelt have been one of the most abundant species impinged at Pilgrim Station as illustrated for the past 10 years in Table 3. _ - _ ~ _ - . l Table 1. Monthly Impingement for All Fishes Collected from Pilgrim Station Intake Screens. Jar.uary-December 1987
'yp'edp_ ~' Jan. feb. March April May June July Aug' Sept Oct Nov -Dec Total- -
l Raintwiw smelt 10 1 2 3 25 41 Atlantic silverside 1 5 2 19 27-t (.unner 3 7 4 14 l Iumpfi h 6 2- 2 10: ' Hinter ilounder 2 1 6 1 10 Atlantic tomcod 1 2 1 .1 5-i i ..bt,y I I 2 1 5 lautog 1 4' S Alewife 4 ~4 tittle state 3 1 4 l tellowtaiI flounder 1 2~ 1 [4 Niathern searobin 1 2 3 billotA 1 1 1 3
'.ilver hake 2 2 in ndowpane 2 2 Attantic herring 1 .' l bl tk sea bass 1 I Blatttpotted stickleback 1 1
- j. Blutbait herring 1 1-l Radiated shanny 1 1
( in,tk qunnel 1 1 Stripe.1 >illifish 1. 1-fla cespine stickleback 1 __ 1 Hinter skate 1 1 tot At S 16 1 6 0 1 5 1 - 26 17 20' '55 148 (c,llection Time (hrs.) 25 9 5 1 2 94 72 0 111 77 103 .28 527 nellet. tlon Rate (#/hr. ) 0.64 0.11 1.20 0.00 0.50 0.05 0.01 - 0.23 0.22 0.19' l.96 0.28
*IL ispir.sementsamplestakenbecausetravelingwaterscreensweretaggedout.
t / Table 2. Species, Number, Total Length (mm), Height (gms) and Percentage For
; All Fishes Collected From Pilgrim Station Impingement Sampling, January-December 1987 Length Mean. Weight Mean Percent of Species Number Range Length Range Weicht Total Fish Rainbow smelt 41 71-220 110 2-44 8 27.7 Atlantic silverside 27 65-143 ;05 2-12 5 18.2 Cunner 14 50-130 84 1-34 11 9.5 Lumpfish 10 18-50 36 0.1-3 2 6.8 Winter flounder 10 58-249 120 1-81 27 6.8 Atlantic tomcod 5 54-195 132 1-80 29 3.4 Grubby 5 63-105 85 3-20 9 3.4 l Tautog 5 56-78 69 3-8 6 3.4 l
Alewife 4 66-130 93 2-18 8 2.7 Little skate 4 430-510 471 576-1,725 913 2.7 Yellowtail flounder 4 44-80 58 1-30 9 2.7 Northern searobin 3 80 80 7 7 2.0 Pollock 3 95-230 145 7-112 44 2.0 Silver hake 2 295 295 152 152 1.4 Windowpane 2 47-72 60 2-4 3 1.4 A%1 antic herring 1 128 128 13 13 0.7 Black sea bass 1 74 74 7 7 0.7 Blackspotted stickleback 1 42 42 1 1 0.7 Blueback herring 1 70 70 4 4 0.7 Radiated shanny 1 58 58 1 1 0.7 Rock gunnel 1 - - - - 0.7 Striped killiftsh 1 83 83 7 7 0.7 Threespine stickleback 1 65 65 1 1 0.7 Winter skate 1 854 854 - - 0.7 l l l l I
wf Table 3. Annual Impingement Collections (1978-1987) for the 10 Most Abundant fishes frone Pilgrim Station '
- Intake Screens During January - December 1987
~~
Number of Impinged fishes Collected from January - December , Species 1978 1979 1980 1981 1982 1983' 1984 1985*- 1986 1987'* Totals 1 Rainbow smelt 3,019 87 95 13 60 57 5 8 1278 41 3,663-Atlantic silverside 722 1,173 14 S,466 133 97 22 174 "44 27 7,872 Conner 61 22 116 SS 63 16 6 27 26 14 406 l lumpfish 1 4 4 0 12 9 13 S. .S_ _10 63' Hinter flounder 34 34 15 15 27 20 5 39 76 10 275- , Attontic tomcod 31 30 4 5 14 17 12 18 ;6 5 '152 1 Grubby 51 14 9 24; 13 38 IS 36 -30 5 '235 8 Tautug 0 2 0 2 2 2 2 2 2. 5 17 g Alewife 131 28 8 11 25 8 12 37 25' 4 2891
, tittle skate 1 3 0 1 1 4 2 2 1 4 .19 Totals 4,051 1,397 265 S 592 350 268 94 348 503 125 12,991 J
Collection Time (hrs) 1,442 494.25 603.75 574.5 687 763 1,042 465 806 527 11.072.5 Collection Rate (#/hr) 2.81 2.83 0.44 9.73 0.51 0.35 0.09 0.75 0.62 0.24 1.17
~
l I 'No Clis pumps were in operation 29 March - August 1984.
No CHS pumps were in operation 18 Fe ruary - 8 September 1987.
1 i l
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' Atlantic silverside was most represented in December impingement collections
.but are generally dominant in the early Spring period. This species has been h.
Typically collected in large numoers, usually dominating other species on an annual basis (Table 3). Cunner dominated the impingement catch in October (7 specimens) and were relatively prevalent in September and November samoles. Historically, cunner-impingement at P11 grim' Station has been greatest in Summer-early Fall . In 1985 they were first in numbers impinged. This species annually is one of the dominant fish collected from the intake screens. i 1.umpfish were greatest in September. They are characteristically Impinged in largest numbers during the early Winter period although their overall impingement in the past has been relatively low. Hinter flounder occurred predominantly in November, possibly reflecting this species offshore wintering movement. It has been one of the abundantly i laipinged fish over the years, primarily during February / March when its inshore j spawning migration is underway. Monthly intake water temperatures, and impingement rates for the five dominant species in 1987 are illustrated in Figure 3. There was one impingement incident (20 fish or greater /hr.) at Pilgrim Station i
- 1. In 1987, wnen one circulating water pump was in operation. The incident invcived 11 rainbow smelt. 10 Atlantic silverside, 1 winter flcunder and 1 tantog on December 16. All lar p fish impingment mortalities (>1,000 fish) have occurred while both circul: ~ q water pumps were operating.
4 1 1987 ) JANUAHY FrfWRJAHY MAIOi AlYllL MAY .CUNE JLAY m) GUST SE PTEunEH OCTOBEH P40VEM3EH DECEMIER WATER u 60- TEMIiluTut;E p # -
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- 50 40 - 40 FMtJiK)W SMELT l
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10 - - 10 g curern E N.14 3 h 5- -5 $ s 5 c u g LUMPF Gi N-10 3 5- -5 e a y WINT E R t FLOUNDE R h 5- -5 3 s 5 0 --- '" O
.AANUARY FEBICARY LMfOi APHE. MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEM3ER DECEMBER Figure 3. Trends Of Intake Water Temperature, and Number of Fish Captured by Month from Pilgrim Station intake Screens for the Five Most Abundant Species Co!!ected. January-December 1987. Only Minimal Sampling was Possible from February- May, and No Sampling in August.
Ten large fish -incidents have been documented since operation commenced and most (6) have involved impingemen; as the causative agent (Table 4). However, at least in two of these the possibility of pathological influence was impil-cated as indirectly contributing to the mortalities. They were the Atlantic herring (Clupea .hlrenaus harenaus) (tubular necrosis) and rainbow smelt (Osmerus _mordax) (piscine, trythocytic necrosis) impingement incidents in 1976 and 1978, respectively. Fish impingement rate at Pilgrim Station has been shown to be significantly related to the number of circulating pumps operating (Lawton, Anderson et al, 1984). Reduced water pumping capacity has lowered total impingement, particularly during the April-mid - August 1984 and portions of the mid-February-August 1987 periods when no circulating water pbmps were operating. The significance of this relationship is supported by the fact that total fish impingement and rate of fish impingement were several times l lower in 1984 than in 1985 and 1986, despite a greater number of collecting < hours in 1984. In 1987, far fewer collecting hours were possible when both circulating pumps were off than in these other years which limits comparisons to them. However, total fish impingement rates in both 1984 and 1987 were several times lower than in 1985 and 1986 when at least one circulating pump was always in operation. Figure 4 illustrates the relatforship between fish impingement rate and number of circulating pumps operating which demonstrates, for the most part, the reduction effect of no pumps vs. 1 or 2 pumps.
4
.l Table 4. Approximate Number and Cause for Most Notable Fish Mortalltles ;
at Pilgrim Nuclear Power Station, 1973-1987 Date Species Number Cause April 9-19, 1973 Atlantic Menhaden 43,000 Gas Bubble Disease August / September, 1973 Clupelds 1,600 Impingement April 2-15, 1975 Atlantic Menhaden 5,000 Gas Bubble 01sease August 2, 1975 Atlantic Menhaden 3,000 Thermal Stress August 5, 1976 Alewife 1,900 Impingement November 23-28, 1976 Atlantic Herring 10,200 Impingement August 21-25, 1978 Clupelds 2,300 Thermal Stress December 11-29, 1978 Rainbow Smelt 6,200 Impingement March / April, 1979 Atlantic Silverside 1,100 Impingement September 23-24, 1981 Atlantic Silverside 6,048 Impingement sa$g 8s a 2 , 0 l 0 l N - l N l O E - 0 l G l h S N l S iS l A F A R A l E E
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Projected fish impingement rates were calculated assuming 100% operation of ) Pilgrim Nuclear Power Station during the period January-December _1987. Table 5 presents hourly, daily and yearly impingement rates for each species cap-tured (rates are rounded to significant figures). For all fishes combined the respective rates are 0.28, 6.74, and 2,460. The yearly rate of 2,460 fishes impinged is 13.1% of the 15-year (1973-1987) me n annual projection of 18,793 fishes (Table 6). This is the second lowest, yearly fish impingement rate since 1975 at Pilgrim Station. It may be attributed to low cir:ulating water pump operation (as in 1984) and/or population variances of the dominant species. Over the 15-year period (1973-1987) it has been operating, Pilgrim Station has had a mean annual impingement rate of 2.15 fishes /hr., ranging from 0.13 (1984) to 10.02 (1981) (Table 6). Anderson et al. (1975) documented higher annual Impi ngerrents at seven other northeast power plants in the early 1970's. Maine Yankee Atomic Power . Company (1978), at their Nuclear Generating Station, had a mean impingement rate of approximately 58 fishes /hr from late 1972 - late 1977. Stupka and Sharma (1977) showed annual impingement rates at numerous power plant locations for dominant species and compared to these, rates at Pilgrim Station are lower than at most other sites. However, in t9rms of the number of fish species impinged, Pilgrim Station displays a far greater variety than other power plants in the Gulf of Maine area (Bridges and i Anderson, 1984), i l i Table 5. Impingement Rates Per Hour, Oay and Year For All Fishes Collected From Pilgrim Station Intake Screens During January - December 1987,- Assuming. 100% Operation of Pilgrim Unit 1* l Dominant Species Rate /Hr. Rate / Day Rate / January- Months December 1987* Of Occurrence [ Rainbow smelt 0.08 1.87 682 December [ ~ Atlantic silverside 0.05 1.23 449 December - Cunner ~ 0.03 0.64 233 October Lumpfish 0.02 0.46 166 September (--_ Winter flounder 0.02 0.46 166 November Atlantic tomcod 0.009 0.23 83 September Grubby 0.009 0.23 83 June Tautog 0.009 0.23 83 December Alewife 0.008 0.18 66 September Little skate 0.008 0.18 66 September
-Yellowtail flounder 0.008 0.18 66 September Northern searobin 0.006 0.14 50 October Pollock 0.006 0.14 50 June-July
. Silver hake 0.004 9.09 33 November Windowpane 0.004 0.09 33 December l
Atlantic herring 0.002 0.05 17 September Black sea bass 0.002 0.05 17 November Blackspotted stickleback 0.002 0.05 17 December Blueback herring 0.002 0.05 17 November Radiated shanny 0.002 0.05 17 January Rock gunnel 0.002 0.05 17 June l Striped killiftsh 0.002 0.05 17 December Threespine stickleback 0.002 0.05 17 May Winter skate 0.002 0.05 17 October Totals 0.28 6.74 2,460 l
- Rates have been rounded to significant figures, i
i l i i
Table 6. Impingem.nt Rates Per Hour, Day and Year For All Fishes Collected From Pilgrim Station Intake Screens During 1973-1987, Assuming 100% Operation of Pilgrim Unit 1* q J Dominant Species 1 Year Rate /Hr. Rate / Day Rate / Year (Rate / Year) - 1973 1,41 33.89 12,371 Clupeids** (7,473) 1974 0.58 13.85 5,056 Clupeids** (4,542) 1975 0.19 4.54 1,659 Atlantic silverside (702) 1976 6.67 160.17 58,461 Atlantic herring (45,065) 1977 1.06 25.44 9,286 Atlantic silverside (2,735) l 1978 4.04 97.03 35,416 Rainbow smelt I (29,357) 1979 3.24 77.69 28.280 Atlantic silverside (20,733) l 1980 0.66 15.78 5,769 Cunner (1,683) 1981 10.02 240.42 87,752 Atlantic silverside (83,346) l 1982 0.93 22.39 8,173 Atlantic silverside (1,696) 1983 0.57 13.65 4,983 Atlantic silverside (1,114) 1984+ 0.13 3.13 1,143 Atlantic silverside (185) 1985 1.14 27.46 10,022 Atlantic silverside (3,278) 1986 1.26 30.34 11,075 Atlantic herring (3,760) + 1987++ 0.28 6.74 2,460 Rainbow smelt (682) Means 2.15 51.49 18,793
- Rates have been rounded to significant figures.
"Herrings (clupeids) identified as a general category in 1973 and 1974 conststed of alewife, blueback herring and Atlantic mennaden.
+No CHS pumps were in operation 29 March - 13 August 1984.
++No CHS pumps were in operation 18 February - 8 September 1987.
i h Monthly intake . water temperatures recorded during impingement collections at Pilgrim Station were generally higher the first half of 1987 and lower the second half than the comparable mean monthly temperatures for the 10-year interval 1978-1987 (Table 7). The January - March water temperatures exceeded [ any previous highs for these months in that 10-year period. In general, 1982/1983/1985/1986 displayed relatively warm water temperatures, 1978/1981/1984/1987 were average years, and 1979/1980 were cold water years. Pilgrim station intake temperatures approximate ambient water temperatures. A fairly even distribution of both cold water species (i.e., lumpfish, rainbow smelt and winter flounder) and warm water species (i.e., tautog, alewife and cunner) was impinged in 1987. 4.2 Invertebrates In 527 collection hours, 848 invertebrates of 17 species (Table 8) were recorded from Pilgrim Station intake screens, from January-December 1987. The annual collection rate was 1.61 invertebrates / hour. Unlike the fishes and the l invertebrates in 1984, the 1987 invertebrate impingement rate was not much less than in 1985 and 1986 despite very low circulating water pump capacity available in 1987. Blue mussel (Mytilus edulis) (71.8%) dominated the catch with the great majority being captured in January when 1 circulating pump was functional. The sand shrimp (Crangon septemscinosa) and polychaete worms accounted for 7,9 and 4.5%, respectively, of the total invertebrates enum-erated. An unusual occurrence has been the collection of so many blue mussels in 1986 and 1987 which from 1982-1985 were impinged in very low numbers. This could be an effect of the Pilgrim Station outage which precludes the use of thermal cackwashes for macrofouling control. Table 7. Monthly Means of of Intake Tempsratere (*f) Recorded During Impingement Collections at Pilgrim Nuclear Power Station, 1978-1987 Year (X) Month 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1978-1987 January 38.42 35.97 35.61 33.55 38.88 31.95 36.75 34.47 35.72 february 38.71 34.98 33.40 36.08 37.05 32.63 30.36 32.88 34.52 March 40.70 37.18 37.84 37.62 40.25 39.04 35.51 34.98 37.89 April 44.98 41.85 43.14 43.60 37.60 41.77 39.92 40.67 42.53 May 48.84 50.55 47.26 49.73 45.99 48.18 49.56 47.22 48.41
- June 56.68 56.11 56.31 57.54 55.10 52.74 49.49 54.39 50.04 54.26 o i July 63.00 61.51 58.96 67.00 59.44 55.98 61.01 52.78 55.56 56.03 59.12 August 63.29 63.44 64.62 61.46 60.23 63.68 58.02 56.73 60.48 61.33 September 58.21 58.26 63.74 60.91 61.06 59.04 f.L 70 55.89 53.75 58.59 59.32 October 52.73 58.58 57.75 55.88 55.38 55.60 54.64 51.94 52.80 55.04 November 47.49 52.23 52.01 45.71 49.64 50.36 46.33 48.75 49.22 49.08 December 41.30 44.00 42.22 42.30 41.43 44.55 39.34 40.86 40.41 41.84 Mean 48.25 l
' Temperatures were incompletely recorded during PNPS outages in these months.
~ -
Table 8. Monthly Impingement for All Invertebrates Collected from PiIgrim Station Intake Screens, January-December 1987 Species Jan. feb. March April May June July Aug' Sept Oct Nov Dec Total _ Ulue mussel 387 87 25 5 65 36 2 2 609 Sand shrimp 6 4 32 25 67 Polys.haete 16 2 9 8 1 2 38 Rotk crab 9 1 1 4 6 3 1 5 30 Green trab 13 5 4 1 1 I 25 tiemer t ean I 10 3 1 1 16 Ilo ,eshoe crab 8 1 1 1 11 Green seaurchin 2 3 2 I I 9 Isopod 1 I 1 5 8 Caneer spp. 7 7 iongiin squid 6 6 fJudibranth 5 1 6 Coenon start ish 2 2 1 S tjereis sp. S S t.ady ci ah I 3 4 1_i i t or_i__n.y s p . I 1 Purple seaurchin 1 I 101 Al.S 433 94 77 6 81 70 14 - 17 3 IS 38 848 Gillet t ion time (hrs.) 25 9 5 1 2 94 72 0 111 77 103 28 527 Gillet tion Rate (#/hr.)17.32 10.44 15.40 6.00 40.50 0.74 0.19 - 0.15 0.04 0.15 1.36 1.61
'rio impingement saaples taken because traveling water screens were tagged out.
_1
1
)
Sand shrimp were the most abundant invertebrates imoinged in March and December. February-April impingement is characteristic of them at Pilgrim ) Station. Polychaete worms were impinged in highest numbers in January, and 1 rock crab (Cancer irroratus) impingement peaked in January, also. The J greatest collections of green crabs (Carcinus maenus), the fifth most impinged ,
)
invertebrate, were in June. 1 l No specimens of the commercially important American lobster (Homarus americanus) were captured in 1987. This is unusual as during most years some lobsters are impinged. I Approximately 563 pounds of mixed algae species were collected during 1987 imoingemer,t sampling for a rate of 1.1 pounds /hr. As expected, this rate (like 1984) is lower than normal because of low circulating pump availability . in 1987. 4.3 Fish survival Fish survival data collected in 1987 while impingement monitoring was conducted are shown in Table 9. Static screen wash collections provided the greatest numbers of fishes and revealed an overall survival rate of 29.1%. Fishes collected during continuous screen washes fared better, as expected, showing a survival rate of 43.5%. Typically fishes have a higher survival rate during continuous screen wasnes because of reduced exposure time to the effects of imoingement. However, reduced intake currents in 1984, associated ditn limited circulating water pump coeration, may have been a factor in
I.a i. 9. a us vival Sumai y f or the fishes Collected During l'ilgric Station [mpingement Sampling. Janu ry-December 19h/. Init .1, One-flour and latent (56-Hour) Survival Numbers Are Shown Under Static (8-ilour) and (i.ntinuous Hash Cycles. Number Collected Number Surviving Static Cont. Initial 1-Hour' 56-ilour
- Total 1.enJth_ (nun)
Speiies Hashes Hashes Static Cont. Static Cont. Static Cont. Mean Range Raintum smelt 16 25 0 3 0 3 0 0 110 71-220 Atlantit silveiside 10 17 0 4 0 2 0 0 105 65-143 Conner 6 8 5 8 5 8 4 8 84 50-130 tumptish 9 1 6 1 - 1 - 1 36 18-50 Hinter i tonnifer 7 3 2 3 - 3 - 1 120 58-249 Atlantic tomtod S 0 1 - - - - - 132 54-195 Grubby 3 2 3 1 - 1 - I 85 63-105 lautog 1 4 0 4 0 - 0 - 69 56-78 Alewife 4 0 0 - 0 - 0 - 93 66-130 Little skate 4 0 1 - I - 1 - 471 430-510 Yellowtail f lonnifer 2 2 1 1 - 1 - 1 58 44-80
'j Northern searobin 2 1 1 1 -
1 - I 80 80
- Pollotk 3 0 0 -
0 - 0 - 145 95-230 Silver hake 2 0 1 - - - - - 295 295 Hindowpane 0 2 - 1 - - - - 60 47-72 Atlantit heiring 1 0 0 - 0 - 0 - 128 128 Bla L sea b ss 1 0 1 - I - 1 - 74 74 Bla Lspotted stiallebark 0 1 - 1 - - - - 42 42 Bluchack herring 1 0 0 - 0 - 0 - 70 70 Radiated sh.uiny 0 1 - 1 - 1 - 0 58 58 Ro46 gunnel 1 0 1 - - - - - - - Striped killirish 0 1 - 1 - 1 - I 83 83 Thi eespine stit tleback 0 1 - 0 - 0 - 0 65 65 Hinter state 1 0 0 - 0 - 0 - 854 854 All Species: Hun.ber 79 69 23 30 - - - - ( 7. ',u r v i v i n g > (29.1) (43.5)
' 1imited <!ala foi some species because survival pool was down in June and part of December 1987, or fishes were sampled in the screenhouse.
l s higher static wasn survival then because of.less stress on impinged individu- E als although this wasn't . apparent from 1987 results. Only initial survival ~ rates' are reported because 1-hour -and 56-hour data were rendered Incomplete
- when survival pools were out of service during all of June' and part - of December, samples were collected in the screenhouse, or fishes were lost, t l
t Among the ten numerically dominant species lapinged in 1987, cunner, lumpfish, i winta.r flounder, grubby and tautog demonstrated initial survival rates 50% or i greater. Rainbow smelt showed 7.3% survival, Atlantic silverside 14.8%, Atlantic tomcod 20%, alewife 0%, and little skate 25%. i I i t l 1 t [ i 1 i i ) ! 1 ! i !
SECTION 5 CONCLUSIONS (
- 1. The average Pilgrim collection rate for the period January-December 1987 was 0.28 fish / hour. The impingement rates for fish in 1984 and 1987 were several times lower than in 1985 and 1986 bec'ause of much reduced circulating water pump capdcity during the former years.
- 2. Twenty-four species of fish were recorded in 527 impingement collection hours during 1987. In 1985 and 1986 several times the number of fishes were sampled as compared to 1984, despite more collection hours in 1984.
This illustrates the importance that the number of circulating pumps operating has on the quantity of impinged organisms. Less collecting hours for portions of 1987 precluded this comparison with other years.
- 3. At full-load (conservative assumption) yearly operation the estimated maximum January-December 1987 impingement rate was 2,460 fishes (187 lbs.). This projected annual fish impingement rate is the second lowest since 1975 at Pilgrim Station.
- 4. The major species collected and their relative percentages of the total collections were rainbow smelt, 27.7%; Atlantic silverside, 18.2%;
cunner, 9.5%; lumpfish, 6.8%; and winter flounder, 6.8%.
- 5. The peak in impingement collections occurred during January and December i
for rainbow smelt. Rainbow smelt hourly impingement rate varied frem 0 l to 0.39 L
- 6. Monthly intake water temperatures, which reflect ambient water temper- )
atures, were generally higher for the first half and lower for the second half; of 1987 than the ten-year monthly averages for the period 1978-1987. January - March mean water temperatures were the highest l recorded for these months in the last ten years.
- 7. The hourly collection rate for invertebrates was 1.61. Blue _ mussel dom-inated the samples.- Sand shrimp and polychaete worms were 7.9 and 4.5%
of the enumerated catch. No American lobsters were collected.
- 8. Impinged fish initial survival was approximately 29% during static screen -
washes and '43% during continuous washes for pooled species. Of the ten fishes impinged in greatest numoers during 1987, five showed initial survival rates 50% or greater. SECTION 6 LITERATURE CITED l ; American Fisheries Society, 1980. A list of Common and Scientific Names of f Fishes From the United States and Canada. Spec Pub. No. 12: 174 pp. I Anderson, C. O., Jr., O. J. Brown, B. A. Ketschke, E. M. Elliott and P. L. Rule. 1975. The Effects of the Addition of a Fourth Generating Unit at the Salem Harbor Electric Generating Station on the Marine Ecosystem of Salem Harbor. Mass. Div. Mar. Fish., Boston 47 pp, f Bridges, H. L. and R. D. Anderson. 1984. A brief survey of Pilgrim Nuclear f Power Plant effects upon the marine aquatic enviroment, p. 263-271. In: J. O. Davis and O. Merriman (editors). Observations on the ecology and biology of western Cape Cod Bay, Massachusetts, 289 pp. Springer-Verlag. (Lecutre Notes on Coastal and Estuarine Studies, Bol. II). Lawton, R. P., R. O, Anderson, P. Brady, C. Sheehan, H. Sides, E. Koulokeras, M. Borgatti, and V. Malkoski. 1984b. Fishes of western inshore Cape Cod Bay: studies in the vicinity of the Rocky Point shoreline, P. 191-230. In: J. D. Davis and O. Herriman (editors), Observations on the ecology and biology of western Cape Cod Bay, Massachusetts, 289 pp. SpringerVerlag. (Lecutre Notes on Coastal and Esuarine Studies, Vol. II). 1 Maine Yankee Atomic Power Company. 1978. Impingement Studies. In Final J Report, Environmental Surveillance and Studies at the Maine Yankee 3 i Nuclear Generating Station (1969-1977). Section 3: 40 pp. 1 Smith, R. I. (Ed.). 1964. Keyes to Marine Invertebrates of the Woods Hole
}
Region. Marine Biological Laboratory. . Woods Hole, Massachusetts , i Stuoka, R. C and R. K. Sharma. 1977. Survey of Fish Impingment at Power Plants in the United States Vol. III. Estuaries and Coastal Waters. Argonne National-Lab. 310 pp. 4 r 5 J t i t i 1 l
h
SUMMARY
REPORT: FISH SPOTTING OVERFLIGHTS IN WESTERN CAPE C00 BAY IN 1987 Prepared by: / dre% , Robert D. Anderson Senior Marine Fisheries Biologist April 1988 Regulatory Affairs and Programs Boston Edison Company
SUMMARY
REPORT: FISH SPOTTING OVERFLIGHTS fN WESTERN CAPE C00 BAY IN 1987 Weekly fish spotting overflights were made north, south and in the vicinity of Pilgrim Nuclear Power Station (PNPS) from March-November 1987. Five main groupings of fish were noted by the overflight pilot who was trained to spot fish for commercial fishing operations. The five groupings are: 1) herring, consisting primarily of Atlantic herring (Clueea harenaus harenaus), alewife
-(Alosa pseudoharenous) and/or blueback herring (Alosa aestivalis); 2) Atlantic menhaden (Brevoortia tyrannus); 3) pollock (Pollachius virens); 4) Atlantic mackerel (Scomber scombrus); and 5) baitfish, consisting primarily of any species too small to identify but most likely being composed of Atlantic silverside (Menidia menidia), rainbow smelt (Osmerus mordax), sand lance (Ammodytes spp.) or the juveniles of other species. In addition, sightings of other marine species, such as bluefish (Pomatomus saltarix) or whales (Cetacea), are occasionally reported, Figure I shows the general area covered by the PNPS fish overflight program, although reports of fish concentrations are received from further north or south, also. Plates 1 and 2 show an overflight airplane and a typical fish school as it appears when viewed from the airplane.
This summary report is meant for general information purposes only, as it is not possible to quantify with reasonable accuracy the data from this qual-itative a program. Nevertheless, this program is very valuable and useful in being responsive to NPDES Permit requirements, documenting barrier net effec-tiveness by confirming large quantitles of fishes in the Pilgrim area, and alerting BECo. and regulatory personnel of the potential for a discharge-related fish mortality. Figure 1. FISH SURVEILLANCE OVERFLIGHTS (Critical Area)
\ .. / MASS.
N \p j s , ._aa PH-0B N SCALE m heetES L g ,w % l T Prymoutti H N - g . PV g ]- Pilyimh \ g cape cod s.y
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_bT_ - Barnstable Harbor dashed line in the vicinity of the specific j locations noted. Generic observations should also be made in the course of the plane's flight to and from the critical area. 1
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n i Plate 1. The airplane used for fish spotting overflights in the Pilgrim Station area is typical of the ones used in commercial area fishing operations.
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._. - .i Plate 2. A fish school appears as a dark shadow fro;n the airplane, and it takes an experienced pilot to distinguish its composition from subnerged objects.
7able i summarizes location. approximate councage and ' seasonal informagion for the five groupings of fishes defined above. Selcw are some Interpretive com-ments based on general trends illustrated cy fish coservation data for the ' five predominant fish groups from March-November 1987: , i
- 1. Herrino - This is a mixed spectes category but probably consists ;
i mostly of Atlantic herring. These fish were in the Cape Cod Say { region primarily in the fall, in the area of PNPS. The alewife and I blueback herring were prevalent in April and June. All of the i herring observed during these months, north and south of PNPS, probably represented these species. The majority of pounds of herring observed by fish overflights represents Atlantic herring as borne cut by commercial catch statistics. Relatively low poundage sightings _ were made of herring during 1985-1987, possibly reflecting population fluctuations for these species. However, 105.000 pounds of Atlantic herring were observed 1/2 mile east of PNPS on October
- 19. No fish morta11tles occurred, although in November 1976 over 10,000 Atlantic herring were killed by impingement on PNPS Intake traveling screens.
- 2. Atlantic Menhaden - This species is of concern at Pilgrim because of s
l past gas bubble disease mortalities in the discharge canal and thermal plume. As can be seen from Table 1, menhaden may occur over the entire Cape Cod Bay region in millions of pounds frem late-spring j tnrougn fall. Overflight pilots are carticularly adeot at iden-l
- tifying this species as commercial ventures depend heavily on 1
- curite observations for success. The 't rst eenhaden nort3 of Ca:e l Ced in 1937 were otterved on May 10 in he11 fleet Eny. The grea:
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majority of nenhaden tere sighted north of PNPS during June and I July. On June 21, 18,000 pounds of menhaden were spotted 1/2 mile east of PNPS. Regulatory agencies (EPA and Mass. OHPC/0NF) are notified when fish are in the thermal plume area, but with a year-long outage at PNPS no thermal discharge was present. The last menhaden observed in 1987 were 12,000 pounds in Plymouth Harbor on October 19,
- 3. Pollock - No pollock were obset ved from 1985-1987 which is unusual.
No serious incidents have occurred involving them at PNPS although they have been seen schooling within the intake embayment near the traveling screens. Pollock, while at times schooling in the inta<e, have never been impinged on the PNPS intake screens in proportion to their abundance.
- 4. Atlantic Mackerel - These fish support a valuable commercial fishery and are reported most frequently south of PNPS. In 1987, there were five observations made of Atlantic mackerel schools, all in July. On July 7 30,000 pounds were spotted 1/2 mile south of PNPS and 200 yards offshore. The other sightings were mostly well south of the Station, in the vicinity of the Cape Cod Canal.
Mackerel occur in relatively large numbers usually during the Summer early Fall months, and no notable incicents involving them have occurred at Pilgrim Station. They are an offshore soecies for the most part but have been observed in previous years schooling in the PNPS Intake embajment, where bluefish predation on them has occurred.
- 5. 51?1'M - Tnis :ste;:ry !s a catena11 and 9aj 19 :ude 's ;+ Pc:e i of small unidentified fish. On April 21 5.000 councs of sano lance 5-1
core observed eas? of 9he Cape Ced Canal. Sand lance, as cell as most species in this grouping, regularly inhabit the PNPS Intake area in numbers too small to be seen by overflights. Baltfish could represent the offspring of fishes in the above categories as well as Atlantic silversides, rainbow smelt and sand lance. Some of these species are significant in impingement collec-tions at PNPS.
- 6. Other - There were several other spottings made in 1987 which fall outside the above categories. Included were bluefish, whales, and sharks. Bluefish were seen in July and September within a few miles of PNPS. Finback whales were noted in March and September, also in the proximity of the Station.
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MmW TO: Members of the Administrative-Technical Comittee. Pilgrim Power Plant Investigations TROM: Robert Lawton, (Acting)* Recording Secretary, Massachusetts Division of Marine Fisheries
SUBJECT:
Minutes of the 68th meeting of the Pilgrim Administrative-Technical Comittee DATE: September 30, 1987 The 68th P12 grim Administrative-Technical (A-T) Committee meeting was called to order by Chairman Szal on 29 September,1987 at 10:16 a.m. at the headquarters of the Massachusetts Division of Fisheries and Wildlife in Westborough, Massachusetts. The following agenda items were addressed.
- 1. Minutes of the 67th Meeting l
l Corrections to the 67th Committee minutes were tendered by Mr. Anderson ! and are attached in an addendum to these minutes. Mr. Szal motioned that the 67th meeting minutes b4 accepted with the corrections incorporated. Mr. Maietta seconded the motion, which passed unanimously.
- 11. Pilgrim Station Operational Review f Mr. Anderson reviewed the plant outage which began in April 1986. To l date. Pilgrim Station has been "off-line" for 18 months. Reloading fuel at the plant began the weekend of September 26-27, 1987; the procedure should take 10 days to accomplish. Plant officials anticipate "start-up" of Pilgrim Station by mid-to-late November 1987; and if no cetbacks are encountered, full power operation should be obtained four to six weeks later (January 1988).
III. Fisheries Subcornittee Report l Mr. Finn (Chairman) presented the recommendations of the Fisheries j subcommittee. It was recoemended to the full A-T Cormittee that the Mass. l Division of Marine Fisheries continue to conduct environeental =tudies at l l
Pilgrim Station, with no major changes in scope of work for 1988 and 1989. A six-point monitoring program would be carried out in 1988.
- 1. Lobster Catch Program The entch of one commercial lobsterman will be monitored biweekly in the vicinity of Pilgrim Station throughout the inshore fishery season (approxi-mately April-October). In addition, 50 research lobster traps will be fished with standardized effort from June-Geptember. This program provides an impor-cant check on a valuable resource. Two years of data from the research pots during the outage can be compared with data to be obtained during plant operation.
- 2. Demersal Fish (Nearshore Trawl) i Trawl data were examined to determine if major events would be missed l by reducing effort to monthly sampling of the groundfish community. The j analysis showed that monthly samples during winter (Jan.-Mar.) are adequate, but that monthly samples for the rest of the year would miss much information.
As a result, it is recommended that sampling be reduced to monthly during winter but be kept biweekly from spring through fall.
- 3. Gill Net (Pelagic Fish)_ .
l Although this program is funded by the Radiological Monitoring Program, j it provides information on the occurrence and abundance of pelagic and benthi- i pelagic fishes not sampled by other gear types. Sampling is conducted a minimum of once a month throughout the year. j l
- 4. Fish Observational Dives This program continues to provide qualitative data on the impacts of the plant on fish, especially mid-August to mid-September, when weekly SCUBA dives l can provide an early warning of a possible fish kill. This study also provides corroborative information on the width of the "denuded and stunted" zones during the summer for the benthic program. A supplemental station will be sampled when time and conditions allow off the outer intake breakwater, but otherwise the program wil' go on as it is at present.
- 5. Shorezone Fish (Haul Seine) l l
An additional smaller seine was added in 1987 to better sample flatfish. I This program is especially important if the power plant increases capacity by 10% in the future, as it measures fish populations that could be adversely affected by entrapment and impingement.
- 6. Shorefront Sport Fish Survey The watchmen at the Shorefront have voluntarily carried out this creel survey in conjunction with the Division since 1986.
A discussion followed on funding for the study. Mr. Anderson then discussed with the Committee the policy of Boston Edison Company for selecting b-~ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - . _ _ _ _ . _ _ _ _ _ _ _
l contractors to conduct environmental studies at Pilgrim Station. The policy for many years has been sole source funding for the major contractors. The A-T Committee recommended that Boston Edison retain the same contractors in ) 1988 in order to ensure quality and continuity of the data bases. The Committee acknowledged the work of the Division of Marine Fisheries - their proven prior performance both in field sampling and in publications. It was also felt that there is a certain credibility in a state agency doing the werk. Dr. Finn moved to accept the recommendations of the Fisheries subccmmittee. Dr. Deegan second, and the motion was carried. The two Division Committee members abstained from voting. IV. Benthic Subcommittee Report The proposed benthic monitoring program at Pilgrim Station for 1988 was presented by Mr. Anderson in the absence of Dr. Don Miller, chairman of the Benthic Subcommittee. Battelle, the benthic contractor, had recommended to the Benthic Subcommittee that a 10-year data base be obtained at the present level of effort which will take us through 1991., Subsequently, Battelle will give a long-term look at the data by doing a time-seriec analysis. The results will serve as guidelines for future monitoring ef fotts. The subcommittee report presents a prcgram of study thzt is believed to represent the very least that should be done to maintain a prognosticative monitoring program. The 1988 program includes to quantitative samplings (March and September) and four qualitative transect sampling events (March, June, September, and December). Mr. Szal moved and Mr. Bridges seconded to accept the program of study recommended by the Benthic Subcommittee; the motien passed unanimously. V. 1988 Impingeeent and Overflight Monitoring Mr. Anderson reported that the 1986 impingement rate at Pilgrim Station was the highest recorded since 1981 and the sixth highest overall. Atlantic herring (34%), rainbow smelt (27%) and Atlantic menhaden (11%) were the dominant species impinged. For January-June, 1987 the impingement rate was very low as both circulating water pumps were not operated from March-June. Mr. Anderson recommended to the Committee that impingement monitoring ~ continue in 1988 to keep a data base going because impingement is a definite source of impact at the plant. Modifications are planned for the intake structures in the near future, and data will be needed to assess their effectiveness. Dr. Deegan moved to continue impingement monitoring at the present sampling schedule of three times per week. Dr. Finn seconded the motion which was unanimously supported by Committee members. As to overflight monitoring of fish in western Cape Cod Bay, Mr. Anderson recommended continuing this program on a weekly basis from March-November. A motion was made by Dr. Deegan and second by Dr. Finn to continue the program as outlined into 1988. The A-T Committee voted unanimously to continue the
overflights as a warning iriicator of approaching schools of fish to the t immediate vicinity of Pilgrim Station. VI. 1988 Entrainment Monitoring Mr. Anderson recommended continuing entrainment monitoring at Pilgrim Station in 1988 adhering to the present program which consists of collecting triplicate samples in the discharge canal twice monthly in January, February, October, November, and December; veekly sampling is done March through September. A contingency sampling plan will also be retained in the event eggs and/or larvae of any dominant species prove to be "unusually abundant" 1a the plant's discharge samples. A motion was made by Mr. Maietta and seconded by Mr. Bridges to continue entrainment monitoring at Pilgrim Station in 1988 adhering to the sampling regime of 1987. The motion received unanimous suppot t from the Committee. VII. Environmental Radiation Monitoring Mr. Bruce Dionne, Senior Radiological Engineer for Boston Edison Company, was an invited guest at the meeting and spoke on their radiological environ-mental monitoring program at Pilgrim Station. He spoke specifically on monitoring narine life - lobster, shellfish, finfish, and Irish moss (red algae). The Division of Marine Fisheries collects the samples, Yankee Atomic Environmental Laboratory does the radiological analysis, and Boston Edison Cotrpany interprets the data and prepares any written reports.
! e(fluent water at Pil rim E Station is a pathway through which reactor radiai :1 is released into the environment. 'iquid releases at the plant are batch releases into the vaste-water discharge. Radioactive isotopes, such as cesium-137 and cobalt-60, are produced directly as major fission products in the reactor and are long-lived. Cesium-137 has a half-life of 30.2 years and is initially strongly radioactive when produced.
There was a large build-up of blue mussels in the discharge canal this year, and with the plant in an outage there var no heat and a significantly reduced flow of water through the discharge canal. This concerned Boston i Edison in that with a reduction in the volume of water discharged, dilution l of waste releases is diminished and mussels in the canal would likely concentrate radioactive isotopes. It is known that fission products present in discharge water even in small amounts can be concentrated in biota by preferential uptake by finfish and shellfish which, in turn, can be eaten by man. With this in mind, samples of mussels were collected from the dis- , charge canal and a reference site this past June. Composite samples were ! l analyzed with the following results. The concentration of cobalt-60 in I control mussels was 100 picoeuries/kg of mussels (background). The concen-trations found in mussels within the discharge canal were: at the headwall or outlet pipe - 2,000 picocuries/kg, halfway down the canal - 600 picoeuries/ kg, and at the mouth of the canal - 300 picoeuries/kg. Also found at two to three times the typical concentrations were cesium-137 and magnesium-54.
Mr. Dionne calculated that the dose that would be found in a human / ingesting 14 pounds of these mussels in a year would be only 0.2 millirems / [ year (whole body dose) or 0.4 millirems / year in the G.I. tract. To put this in perspective, the International Council on Radiation Protection recommends a dose limit of 500 millirems / year whole body exposure for any member of the [ public. This places the radiation level obtained by eating mussels from Pilgrim's discharge canal clearly well below the recommended limit. Boston Edison Company, nevertheless, considered several alternatives to rid the discharge canal of these contaminated mussels. After much considera- *j tion, they believed the most cost-effective way was to leave the mussels in the canal and let them depurate via the large volu=es of circulating water ' when the plant resumes operation. In addition, they believed that many of the mussels would detach next su=cer because of elevated temperatures and be carried out of the canal. In the mean time, large numbers of mussels began dying in the effluent canal, possibly due to crowding and to siltation produced ' by work done at the plant. Mr. Dionne told the Committee that Boston Edison Company plans to prepare a brochure for the public on health hazards from radiation exposure. They also plan to refine their annual technical report on radiation monitoring at the plant by adding more explanative text and graphics. VIII. Other Business .p There was none. , LX. Adjournment Meeting adjourned at 2:45 p.m.
\
O 8
Pilgrim Administrative-Technical Committee Meeting September 29, 1987 Attendants Name Agency Gerald Szal, Chairman Mass. DEQE/DWPC Robert Lawton (Acting) Recording Secretary) Mass. DMF Robert Anderson BECo Michael B11ger U.S. EPA, Lexington Linda Deegan UMass, Amherst John Finn UMass, Amherst W. Leigh bridges Mass. DMF Bruce Dionne BECo (non-voting) Robert Maietta Mass. DEQE/DWPC 9
MEMORANDUM TO: Members of the Administrative-Technical Committee, Pilgrim Power Plant Investigations FROM: Robert Lawton, (Acting) Recording Secretary, Massachusetts Division of Marine Fisheries
SUBJECT:
Addendum to the 67th meeting minutes of the Administrative-Technical Committee DATE: September 30, 1987 Corrections to the 67th meeting minutes are as follows: Page 1, Section II, 3rd paragraph, 3rd line: Change "was nct current discharged by the plant as both circulating water pumps were generally of f." to "was limited current discharged by the plant as one of the two circulating water pumps was generally off. Page 2, Section III, 2nd paragraph, 4th line: Change ". . . menhaden or pollock were sighted and only one aggregation of baitfish was . . ." to
". . . menhaden or polock were sighted in the Station vicinity and only one aggregation of bairfish was . . ."
Page 2, Sec' tion IV, 1st paragraph, 3rd line: Change ". . . current . . ." to " . . . temperature increase or current . . ." Page 3, Section VI, 2nd paragraph,1st line: Change "Mike said that the l summary report of entrainment . . ." to "Mike said that the long-term progress and recommendations' summary report of entrainment . . ." Page 5, the affiliation of Derek Mcdonald should read MBC,and not MBI. RPL/cm
f 4 aosa msm Executive Offices 800 Boylston Street Boston, Massachusetts 02199 BECo 88- 028 April 30, 1988 Senior Vice President - Nuclear Hass. Division of Hater Pollution Control Permit Section - 7th Floor One Hinter Street Boston, MA 02108 License DPR-35 Docket 50-293 NPDES PERMIT MARINE ECOLOGY MONITORING REPORT
Dear Sir:
In accordance with Part I, Paragraph A.7.b & c, and Attachment I, Paragraph I.G, of the Pilgrim Nuclear Power Station NPDES Permit No. HA0003557 (Federal) and No. 359 (State), Semi-Annual Marine Ecology Report No. 31 is submitted. This report covers the period from January through December 1987.
. I
Attachment:
Semi-Annual Marine Ecology Report No. 31 RDA/amm/1292 cc: Mass. Division of Water Pollution Control Lakeville Hospital Lakeville, MA 02346 q
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