BECO-95-085, Marine Ecology Studies Re Operation of Pilgrim Station Semi-Annual Rept 46,Jan-June 1995

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Marine Ecology Studies Re Operation of Pilgrim Station Semi-Annual Rept 46,Jan-June 1995
ML20094B334
Person / Time
Site: Pilgrim
Issue date: 06/30/1995
From: Richard Anderson, Oheim H
BOSTON EDISON CO.
To:
MASSACHUSETTS, COMMONWEALTH OF
References
BECO-95-085, BECO-95-85, NUDOCS 9510310402
Download: ML20094B334 (100)


Text

{{#Wiki_filter:. - - _ . . , . . . _ . .. B BOSTON EDISON Pilgrim Nuclear Power Station Rocky Hill Road Plymouth, Massachusetts 02360 October 17,1995 BECo 95-085 NPDES Program Operations Section (WCP) Environmental Protection Agency P.O. Box 8127 Boston, MA 02114 NPDES PERMIT MARINE ECOLOGY MONITORING REPORT

Dear Sirs:

In accordance with Part I, Paragraphs A.8.b. & e, and Attachment A, Paragraph 1.F, of the Pilgrim Nuclear Power Station NPDES Permit No, MA0003557(Federal) and No. 359 (State), Semi-Annual Marine Ecology Report No. 46 is submitted. This covers the period from January through June,1995.

                                                                                      .W H. V. Oheim General Manager -

Technical Support

Attachment:

Semi Annual Marine Ecology Report No. 46 HVO/RDA/nas/ECOLRPT

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9510310402 950630 PDR ADOCK 05000293 / l$ PDR ~ 'y g

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d M BOSTONEDISON Pilgrim Nuclear Power Station Rocky Hill Road Plymouth, Massachusetts 02360 October 17,1995 BECo 95-085 l Mass. Department of Environmental Protection l Regulatory Granch - 7th Floor One Winter Street Boston, MA 02108 NPDES PERMIT MARINE ECOLOGY MONITORING REPORT

Dear Sirs:

In accordance with Part I, Paragraphs A.8.b. & e, and Attachment A, Paragraph 1.F, of the Pilgrim Nuclear Power Station NPDES Permit No. MA0003557(Federal) and No. 359 (State), Semi-Annual Marine Ecology Report No. 46 is submitted. This covers the period from January through June,1995.

                                                                                                 .   .         2<v     -

H. V. Oheim General Manager-Technical Support

Attachment:

Semi-Annual Marine Ecology Report No. 46 HVO/RDA/nas/ECOLRPT a

marineecologyitucrie/ a .iote a to w s o my im n o e SEMI-ANNUAL REPORT NUMBER 46 JANUARY 1995-JUNE 1995

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BOSTON EDISON COMPANY REGULATORY AFFAIRS DEPARTMENT Qp Boston Edison l i

MARINE ECOLOGY STUDIES RELATED TO OPERATION OF PILGRIM STATION SEMI ANNUAL REPORT NO. 46 REPORT PERIOD: JANUARY 1995 TIIROUGH JUNE 1995 DATE OF ISSUE: OCTOBER 31,1995 C 4 Compiled and Reviewed by: / M w Robert D. Anderson Principal Marine Biologist i Regulatory Affairs Department Boston Edison Company Pilgrim Nuclear Power Station Plymouth, Massachusetts 02360 I

TABLE OF CONTENTS SECTION I

SUMMARY

II INTRODUCTION III MARINE BIOTA STUDIES IIIA Marine Fisheries Monitoring Semi-Annual Report on Monitoring to Assess Impact of Pilgrim Nuclear Power Station on Marine Fisheries Resources of Western Cape Cod Bay, Project Report No. 59 (January - June 1995) (Mass. Dept. of Fisheries, Wildlife and Environmental Law Enforcement; Division of Marine Fisheries) IIIB Benthic Monitoring Benthic Algal Monitoring at the Pilgrim Nuclear Power Station (Qualitative Transect Surveys), January 1995 - June 1995 (Science Applications International Corp.) IIIC Entrainment Monitoring Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station, January

                                         - June 1995 (Marine Research, Inc.)

IIID Imningement Monitoring Impingement of Organisms at Pilgrim Nuclear Power Station: January - June 1995. (Boston Edison Company) IV Minutes of Meeting 83 of the Administrative-Technical Committee, Pilgrim Nuclear Power Station. l l

                                                                                                                             )

ii

SUMMARY

Highlights of the environmental surveillance and monitoring program results obtained over this reporting period (January - June 1995) are presented below. (Note: PNPS was in high power operation during most of this period with the exception of RFO #10 from April - early June.) Marine Fisheries Monitoring:

1. Wilcox and Yankee trawl catch from January - June 1995, outside and inside Plymouth, Kingston, Duxbury Bay, recorded several benthic fish species. Winter flounder stock assessment work was performed to determine population parameters with 2,066 fish marked so far in 1995. Twenty-four recaptures have been recorded to date. Techniques for sampling young-of-the-year winter flounder for spawning success / year class strength studies included diving observations and beach seining.
2. In 1995 fish observational dive surveys fish species were observed in the discharge area. No fish showed abnormal behavior and no gas bubble disease symptoms were observed on routine observational dives to date.
3. Rainbow smelt egg restocking of the Jones River (Kingston), to mitigate for the high PNPS smelt impingement in December 1993, accounted for 1,200,000 fertilized eggs being transplanted for hatching to supplement the River's spawning population of this species. This effort was also accomplished in the early Spring 1994 when 600,000 smelt eggs were stocked from other areas to the Jones River. I
4. The cunner tagging study concentrated on mark / recapture for population estimation as well as recruitment dynamics. Tagged cunner (746) were released in June 1995, and 103 were recaptured.

I-1

Imoinnement Monitoring:

1. The mean January - June 1995 impingement collection rate was 4.36 fish /hr. The rate ranged from 0.59 fish /hr (June) to 9.75 fish /hr (March) with Atlantic silverside comprising 74.1% of the catch, followed by rainbow smelt,10.5%, blueback herring,3.4%, and winter flounder,2.8%.
2. For March 1995, when the fish impingement rate was 9.75, Atlantic silverside accounted for 96% of the fishes collected. Fish impingement rate was notably j higher in 1989-1995 than in 1988 (0.30), primarily because Pilgrim Station had much less circulating water pump capacity than normal that year.
3. The mean January - June 1995 invertebrate collection rate was 1.99+/hr with jellyfish (undetermined numbers), sevenspine bay shrimp (63.0%) and sand worms (19.6%) dominating the catch. Fifteen American lobsters were caught.
4. Impinged fish initial survival at the end of the Pilgrim Station intake sluiceway was approximately 56% for static washes and 50% for continuous washes.

i Benthic Monitoring  ! Early May and June 1995 mappings of the discharge effluent, near-shore acute impact zones were performed. Negligible Chondrus (Irish moss) growth in the i 1 denuded zone was evident for both April (1,198m2 ) and June (1405m2) indicating l continuing impact since the 1986 - 1988 PNPS outage. In June a dense mat of juvenile blue mussels (5-15mm length) blanketed large portions of the Chondrus sparse / stunted zones as was also apparent in June of 1990 and 1992-1994, possibly I because of consistent thermal discharge during these periods. I i I-2

Entrainment Monitoring:

1. A total of 32 species of fish eggs and/or larvae were found in the January - June 1995 entrainment collections: 14 eggs,27 larvae,
2. Egg collections for January - April 1995 (winter-early spring spawning) were dominated by Atlantic cod, American plaice, winter and yellowtail flounder eggs.

May and June (late spring - summer spawning) egg samples were most representative of Atlantic mackerel and labrids.

3. Larval collections for January - April 1995 were dominated by rock gunnel, grubby and sand lance. For May and June larvae, sand lance, mackerel, winter flounder and radiated shanny dominated.
4. No lobster larvae were collected in the entrainment samples for January - June 1995.
5. On several occasions unusually high densities of ichthyoplankton were found, involving sand lance, Atlantic herring, Atlantic mackerel larvae; and Atlantic menhaden, as well as labrid, eggs and larvae.

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6. Labrid entrainment sampling, net mesh size efliciency comparisons were conducted showing 0.202 mm mesh significantly more efficient in capturing eggs than 0.333

( mm mesh. Laival cunner results were variable. l 1 I-3

INTRODUCTION A. Scone and Obiective This is the forty-sixth semi-annual report on the status and results of the Environmental Surveillance and Monitoring Program related to the operation of Pilgrim Nuclear Power Station (PNPS). The monitoring programs discussed in this report relate specifically to the Western Cape Cod Bay ecosystem with particular emphasis on the Rocky Point area. This is the thirty-fourth semi-annual report in accordance with the environmental monitoring and reporting requirements of the PNPS Unit i NPDES Permit from the U.S. Environmental Protection Agency (#MA0003557) and Massachusetts Division of Water Pollution Control (#359). A multi-year (1969-1977) report incorporating marine fisheries, benthic, plankton /entrainment and impingement studies was submitted to the NRC in July 1978, as required by the PNPS Appendix B Tech. Specs. Programs in these areas have been continued under the PNPS NPDES permit. Ame.idment #67 (1983)'to the PNPS Tech. Specs. deleted Appendix B non-radiological water quality requirements as the NRC felt they are covered in the NPDES Permit. The objectives of the Environmental Surveillance and Monitoring Program are to determine whether the operation of the PNPS results in measurable effects on the marine ecology and to evaluate the significance of any observed effects. If an effect of significance is detected, Boston t Edison Company has committed to take steps to correct or nitigate any adverse situation. These studies are guided by the Pilgrim Administrative-Technice.1 Conn..ittee (PATC) which was chaired by a member of the Mass. Division of Water Pollution Control in 1995 and whose l 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 Serdce (NOAA), the Mass. Office of Coastal Zone Management, the U.S. Environmental Protection Agency and Boston Edison Company. Copies of the Minutes of the Pilgrim Station Administrative-Technical Committee meetings held during this reporting period are included in Section IV. I 1 II-1 1

B. Marine Biota Studies .

1. Marine Fisheries Monitoring j
                                                                                                         )

A modified version of the marine fisheries monitoring, concentratmg on indicator species populations' impacts, is being conducted by the Commonwealth of Massachusetts, Division ofMarine Fisheries (DMF). The occurrence and distribution.of primarily cunner and winter flounder around Pilgrim Station and in adjacent areas are being determined. Population parameters and related life history statistics are being studied to address Pilgrim Station impacts from entrainment of ichthyoplankton, and impingement ofjuveniles and adults. Smelt eggs were stocLed in the Jones River (Kingston) in March / April 1995, as was done in 1994, to mitigate for the large impingement of 5,000+ rainbow smelt on Pilgrim Station intake screens in December 1993. Mitigation for another 5,000 + smelt impingement at Pilgrim in December 1994 is being considered. i A finfish observational dive program was initiated in June 1978. SCUBA gear is utilized on biweekly dives from May-October at 6 stations in the PNPS thermal plume area. Results of the marine fisheries monitoring during the reporting period are presented in Section IIIA.

2. Benthic Monitoring The benthic monitoring described in this report was conducted by ENSR Consulting and Engineering, Woods Hole, Massachusetts.

II - 2

Benthic thermal plume analyses were completed and a final report submitted by EG&G (June 1995) to help recommend the most applicable future benthic studies to be performed. Qualitative transect sampling off the discharge canal to determine the extent of the denuded and stunted zones is conducted four times a year (March, June, September and December). Results of the benthic monitoring reported during this period are discussed in Section IIIB.

3. Plankton Monitoring Marine Research, Inc. (MRI) of Falmouth, Massachusetts, has been monitoring entrainment in Pilgrim Station cooling water of fish eggs and larvae, and lobster larvae (from 1973-1975 phytoplankton and zooplankton were also studied). Information generated through these studies has been udEzed to make periodic modifications in the sampling program to more efficiently address the question of the effect of entrainment. These modifications have been developed by the contractor, and reviewed and approved by the Pilgrim A-T Committee on the basis of the program results. Plankton monitoring in 1995 emphasized consideration of ichthyoplankton entrainment and selected species adult equivalency analyses. Results of the ichthyoplankton entrainment monitoring for this reporting period are discussed in Section IIIC.
4. Imoingement Monitoring l

The Pilgrim Station 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, Inc. has been conducting impingement sampling with results being reported on by Boston Edison Company. II - 3

                                                                                                       . I A new screen wash sluiceway system was installed at Pilgrim in 1979 at a total cost of             l 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 determine its effectiveness in protecting marine life were terminated in 1984, and a f l final report on them appears in Marine Ecology Semi-Annual Report #23. Results of the impingement monitoring and survival program for this reporting period are discussed in Section IIID. C. Station Operation History The daily average, reactor thermal' power levels from January through June 1995 are shown in Figure 1. As can be seen, PNPS was'in a normal operating stage except for April - early June during RFO #10. Cumulative capacity factor from 1973 - 1994 30.9 % Capacity factors for the past 15 years are summarized in Table 1. E. 1995 Environmental Programs A planning schedule bar chart for 1995 environmental monitoring programs related to the operation of Pilgrim Station, showing task activities and milestones from December 1994 - June 1996, is included. II - 4

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Table 1. PILGRIM NUCLEAR POWER STATION UNIT 1 CAPACITY FACTOR USING MDC NET % (Roughly approximates thermal loading to the environment: 100%=32 Degrees F A T) Month 1994 _1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981- 1980 January 98.8 99.0 96.6 95.4 99.4 0.0 0.0 0.0 79.5 54.0 0.0 98.0 0.0 85.7- 11.8 Februaq 72.5 96.7 99.4 88.9 97.4 0.0 0.0 0.0 97.7 59.3 0.0 90.0 0.0 67.0 0.0 March 79.5 83.2 80.4 84.6 30.0 10.7 0.0 0.0 26.9 81.8 0.0 97.3 0.0 65.6 0.0 April 63.3 6.4 53.5 92.7 5.4 10.5 0.0 0.0 11.9 90.8 0.0 89.7 44.1 90.7 0.0 May 94.5 0.4 97.8 0.0 77.9 4.6 0.0 0.0 0.0 94.3 0.0 97.3 80.1 94.6 20.8 June 97.2 77.5 97.8 0.0 96.3 16.4 0.0 0.0 0.0 85.0 0.0 66.2 87.5 95.0 83.1 July 97.6 80.3 97.4 0.0 55.1 28.6 0.0 0.0 0.0 96.9 0.0 80.5 97.2 59.8 87.7 August 88.2 86.9 97.4 28.5 94.5 50.8 0.0 0.0 0.0 96.5 0.0 83.1 75.7 72.1 78.7 September 0.0 84.8 94.1 96.4 21.6 52.5 0.0 0.0 0.0 71.4 0.0 86.5 68.3 75.4 93.4 October 0.0 98.0 72.8 94.2 98.7 30.1 0.0 ' O.0 0.0 95.4 0.0 79.0 39.9 0.0 74.9 November 0.2 80.0 13.7  ;;.7 96.8 66.0 0.0 0.0 0.0 88.1 0.0 78.6 88.9 0.0 68.4 December 87.7 94.8 65.2 98.I 94.5 77.1 0.0 0.0 0.0 99.1 0.7 18.I 87.1 0.0 99.6 74.0 80.6 58.4 72.3 28.9 0.0 0.0 17.5 84.4 0.1 80.3 56.0 58.7 51.7 ANNUAL % 65.2 CUMULATIVE CAPACITY FACTOR (1973 - 1994) = 50.9%

                                                                  = OUTAGES > 2 MONTHS
      * = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 27 MARCH - 13 AUGUST,1984
             = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 18 FEBRUARY - 8 SEPTEMBER,1987
             = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 14 APRIL - 5 JUNE,1988
             = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 9 OCTOBER - 16 NOVEMBER,1994
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l $994 1995 1996 - LNOV e DEC JAN i FEB_t_ MAR APR i MAY , JUN JUL i AUG . SEP OCT i NOW . DEC__JAN i FEB 1 MAR APR i MAY . JUN JULJ i ZONE 1 - PATC a f 95 Monitoring Programs (NPDES) to EPA NRC DWPC PATC ull Committee) Review results of 94 Programs FISHERIES (Sub committee) o' Recommend for FISHERIES 96 Progra BENTHIC (Sub-committee) ff Recommend for BENTHIC 96 Progra s PATC (Full Committee) Recommend for % monitori (NPDES) programs BECo meet with EPA DWPC (Potential) o BECO prep NPDES 96 Monitoring Pr ms l BECO approve 96 Monitoring Programs Submit 96 Programs to EPA NRC DWPC Initiate 96 Monitoring Programs f PATC FullCommittee) o Review results of 95 Programs o PNPS 1995 ENVIRONMENTAL PROGRAMS (NPDES PERMIT #MA 0003557)

1994 1995 1996 NOV DEC JAN i FEB_t_ MAR APR i MAY_1_JUN JUL i AUG , SEP OCT i NOV i DEC JAN i FEB MAR APR e MAY , JUN JUL_j Zone 2 - MARINE FISHERIES MONITORING

                                                   <f                                              issue 95 P.O. to MDMF Winter flounder I cunner population studies
                                                                                                                                       !    05/02/95                                                                     06/3k0/95 Underwater observation (Bi-weekly)

I 07 5 09/15/95 Prep semi-annual report (draft) Submit draft report to BECO o BECO review /com nt on draft report Fi i report prep by MDMF Submit 95 s -annual report to BECO  ! Winter flounder I cunner population studies . _ . _ _ _ _ _

                                                                                                                                       !                                                                                      07/03!95                                                                           ___.___f_         10/31195 Underwater observation (Bi-weekly)

Prep annual report (draft) Submit draft report to BECO & Fish Subcom. o BECO! Fish Subcom. reviewlcomment on draft report ===== I 04/03b04/10/96 Final annual report prep. pa! Submit 95 annual report to BECO o PNPS 1995 ENVIRONMENTAL. PROGRAMS . (NPDES PE'IMIT #MA 0003557) .

I 1994 1995 1996 LNOV i DEC JAN , FEB i MAR APR , MAY i JUN JUL i AUG i SEP OCT i NOV i DEC JAN i FEB i MAR APR i MAY i JUN JUL__.! ZONE 4-IMP!NGEMENT CONITORING , , [ Issue 95 P.O. to MRI 01/03/95 Biota sampling p___ _ __ _ I 01103/95 NPO record plent data 02/15/95 01/1W Contractor submit Biota data to BECO 02/15SS  ! PS submit plant data to BECO - I I 03/01!95 l OME ECO prep. & distr. monthly reports _ _ _ _ _ _

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i 09/01/95-10/03/95 BECO prep 95 semiennual report 02/0156 04/02/96 BECO prep 95 annual report ZONE 5 - BENTHIC MONITORING Q l lssue 9503/15/9503/15!95 P.O.to SAIC Qu litative transects sampling (1st) Q Qualtative transects sampling (2nd) Q 06/15/9506I15SS Prep draft semi-annual report

                                                                                                          !                                09/15/9509/15/95 l

Submit draft report to BECO Q l

                                                                                                          !                                       09/15/9510/03/95 i

' BECO tvw/ comment on draft report q 10/03/9510/10/95 l ' Final report prep. jses l 10/11/9510/11/95 Submit 95 semi-annual reportto BECO l lQ 09/15/9509/15/95 Qualitative transect sampling (3rd) Q Qualitative transect sampling (4th) Q i i l PNPS 1995 ENVIRONMENTAL PROGRAMS l (NPDES PERMIT #MA 0003557) l l.

1994 1995 1996 LNOV i DEC JAN i FEB1 MAR APR i MAV1JUN JJL i AUG i SEP OCT i NOV i DEC JAN i FEB i MAR APR i MAY i JUN JULa prep draft annual report Submit draft report to BEC hic Subcom. Q BE IBenthic Subcom. rvwicomment on draft report Final report prep. !ag Submit 95 annual report to BECO Q ZONE 6-ENTRAINMENT MONITORING Q bsue 95 P.O.to MRI

                                                                                    . Plankton sampling by M Sample                              essing & data analysis Submi dataanalysissheetstoBE                                         k>

P ankton sampling by MRI _ _ _ _ _ Sample processing & data analysis Submit data analysis sheets to BE o l MRI prep semi-a ual draft Rvw/ comment by BECO PNPS 1995 ENVIRONMENTAL PROGRAMS . (NPDES PERMIT #EM 7003557) -

I 1h94 1995 1996 . LNOtf i DEC JAN , FEB . MAR APR . MAY i JUN JUL . AUG i SEP l OCT ._NOV , DEC JAN i FEB i MAR APR i MAY i JUN JUL_j MRI final report prep. Submit 95 semi-annual report to BECO h Plankton sampling by MRI _ _ _ Sample processing & data analysis Submit data analysis sheets to BE $ , Plankton sampling by MRI (Bi-weekly) Sample process lng & data analysis Submit data sheets to BECO f MRI prep annual report raft) Rvw/ comment by BECO mumme MRI final report prep. ang Submit 95 annual report to BECO O ZONE 11 THERMIL D!SCHARGE(DIVE & NETS MA!NT.) h issue 95 P.O.to Inner Tech 01 3/95 Barrier nets maint. (weekly) - [if required by regulators] i I l

           #h I    issue 95 P.O. to Motte!Hittier 03/01/95  l                                                               5 Barrier nets rept (If required by regulators) z.

PNPS 1995 ENVIRONMENTAL. PROGRAMS (NPDES PERMIT #MA 0003557)

1 l N 1995 1996 NOV i DEC JAN i FEB i MAR APR i MAY JUN JUL i AUG i SEP OCT i NOV . DEC JAN i FEB i MAR APR C]AY , JUN JtP C ZONE 12-REPOR' T MONITORING PROGRAMS NPDES permit semi-annual report prep. 1 Printing final semi-annual report h BECO rvwicomment/a proval of semi-annual report Submit 95 semi wal report to EPA /DWPCINRC Q NPDES ann report prep Pen,ionai a_ai,e,o,,q'7 r* BECO tvw/coment/ approval of annual report e Submit 95 ual report to EPAIDWPC/NR o PNPS 1995 ENVIRONMENTAL PROGRAMS . (NPDES PERMIT #MA 0003557) ,

SEMI-ANNUAL REPORT ON MONITORING TO ASSESS IMPACT OF PILGRIM NUCLEAR POWER STATION ON MARINE FISHERIES RESOURCES OF WESTERN CAPE COD BAY Project Report No. 59 (January to June 1995) By Robert Lawton, Brian Kelly, Vincent Malkoski, John Chisholm, Paul Nitschke, John Boardman, and Erin Casey October 1, 1995 Massachusetts Department of Fisheries, Wildlife, and Environmental Law Enforcement Division of Marine Fisheries 100 Cambridge Street Boston, Massachusetts 02202 l l

TABLE OF CONTENTS Section Pace

 )

I. Executive Summary 1 II. Introduction 4 III. ' Methods and Preliminary Results 5

1. Winter Flounder Studies and Other 5 Groundfish
2. Cunner Population Studies 8
3. Smelt Restocking 10 IV. Acknowledgments 14 V. Literature Cited 15

) i i l 1 l 11

                  -            --                                                                       i

i LIST OF FIGURES

                                                                                                         . f' 1

1 Eiqure Pace f 1 ( (

1. Study area (dark shading) inside and outside 6 1

the estuary sampled by otter trawls for / i groundfish, with major-emphasis on winter flounder, January to June 1995 (not drawn to scale). ] t 111

I. EXECUTIVE

SUMMARY

Winter Flounder Studies and Other Groundfish our primary objectives are to determine the discreteness (boundaries) of the local winter flounder (Plcuronectes americanus) population and to estimate absolute abundance. This information will be used to assess impact of larval flounder entrainment at Pilgrim Station. Secondarily, we are endeavoring to maintain catch ~ records of other groundfish in the area; results will appear in the 1995 annual report. Using the small Wilcox net, we completed 39 bottom trawl tows. Twenty-one tows were made inside Plymouth, Kingston, Duxbury Bay with the remainder located along the Plymouth shoreline in the inshore sector of western Cape Cod Bay. We tagged (Petersen disc) 19 winter flounder (6 inside PKDB and 13 outside the estuary). No tagged flounder were recaptured with this gear. Our survey of spawning success and resultant year-class strength of winter flounder is on-going; results will appear in th'e 1995 annual report. We contracted a commercial fishing vessel, the F/V FrancesElizabeth, to sample winter flounder from the deeper nearshore waters for density extrapolation and as a source of tagging fish. The boundaries of the sampling area were the waters between High Pines Ledge to the Mary Ann buoy from the nearshore out to the 36.6 m (120 foot) (MLW) depth contour. Between 14 and 26 April,1995, we completed 58 tows within the study area. A total of 2,882 Winter flounder was captured, of

1 i 1 which 2,047 were tagged. Twenty-four of these tagged fish were recaptured during our two-week sampling period. I Cunner Studies l We have studied the distribution and movement patterns of ( adult cunner (Tautogolabms adrpersus) off Pilgrim Station and are now q working to estimate adult population size and recruitment dynamics of cunner in the Pilgrim area. Cunner fecundity by age and length j has been investigated in the Pilgrim Station area, highlights of l which will appear in the next annual report. Cunner are caught in baited fish traps, and cunner 90 mm or larger in total length (TL) l are marked with Floy T-bar anchor tags and released in the capture area. This June, 1,197 cunner were captured, of which 746 were tagged. As for recaptures, 103 tagged fish were taken.- l Emelt Restockina l To compensate for recent impingement of rainbow smelt (Osmems l mordar) at Pilgrim Station, the Massachusetts Division of Marine Fisheries was funded for restoration work by Boston Edison Company. The objectives were to augment instream reproduction of smelt and to enhance the quality of spawning habitat in the Jones River, which hosts the major smelt spawning run in the area. We stocked 1.2 million smelt eggs into the Jones River during the spring of L 1995. To address spawning habitat enhancement and ultimate egg I } survival, we placed an additional 75 egg collecting trays into the l Jones River, filled with sphagnum moss, to collect eggs spawned s l

there naturally. Smelt egg deposition is higher on vegetation, while egg survival to hatching is up to ten times greater on plant substrate than on hard bottom.

II. INTRODUCTION , ( Ecological monitoring of the marine environment off Pilgrim l l Nuclear Power Station is conducted to assess impact of power plant f 1 operation. Investigations are conducted by the Power Plant Team of the Massachusetts Division of Marine Fisheries (MDMF), focusing on f three indicator finfish species in the nearshore waters of western Cape Cod Bay. Funded by Boston Edison Company under Purchase Order l l No. LSP001698 in 1995, this work is ongoing. ) 1 In this report, methodology and progress on sampling programs conducted from January through June 1995 are discussed. Measurements, counts, indices, and visual observations are used in reporting preliminary results and accomplishments for the first half of 1995. l l J l l l t

III. METHODS AND PRELIMINARY FINDINGS

1. WINTER FLOUNDER STUDIES'AND OTHER GROUNDFISH Small Vessel Trawlina Following the sampling protocol established in 1994 (Lawton et al. 1995), we completed 39 bottom trawl tows using a Wilcox trawl (9.8-m sweep, 7-m headrope, 10.2-cm wings, 13-cm cod-end mesh fitted with a 6.4-mm stretch mesh liner) . Twenty-one tows were made inside Plymouth, Kingston, Duxbury Bay (PKDB), with the other 18 located along the Plymouth shoreline in the inshore sector of western Cape Cod Bay (Figure 1). Slightly more than half the trawls were randomly selected, with the unit of effort standardized at a 400-m towing distance. Locations of the remaining tows were haphazardly selected, and the unit of effort was 15 minutes of bottom towing time. The latter effort placed emphasis on towing areas believed to hold concentrations of winter flounder.

Our primary objectives are to determine the discreteness (boundaries) of the local winter flounder population and to estimate absolute abundance. This information will be used to assess impact of larval flounder entrainment at Pilgrim Station. Secondarily, we are endeavoring to maintain catch records of other groundfish in the area. A summary of catch data (species in addition to winter flounder) will appear in the annual report. Winter flounder from all tows were used as a source of tagging fish for our capture-recapture program. During the spawning season, we tagged (Petersen disc) 19 winter flounder (6 inside PKDB and 13 outside the estuary) . In i

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STATION . MANOMET PT. . -- Figure 1. Study area inside and outside the estuary sampled by bottom trawls for groundfish, with mejor enohesis on winter flounder, January - June,1995 (not drawn to scale). 9 - - _ . ____m__._.___..___m _ _ _ . _ _ - _ ._m -

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1994, we had tagged 226 flounder (27 inside and 199 outside the estuary). Trawling for marked fish will be resumed this fall, and tagging will again be conducted in the late winter /early spring of 1996. In addition, an independent estimate of population size will be generated when all data have been collected for 1995 using an area-swept approach (density extrapolation). Juvenile Winter Flounder Survey-The survey of spawning success and resultant year-class strength of winter flounder is on-going; results will appear in the 1995 annual report. Beach seining and SCUBA transect swims are to be conducted through August inside and outside (seining only) PKDB. Larce Vessel Trawlina In April, we contracted a commercial fishing vessel, the F/V FrancesElizabeth, to sample winter flounder for density extrapolation and as a source of tagging fish. The boundaries of the sampling area were the waters between High Pines Ledge to the Mary Ann buoy from the nearshore out to the 36.6 m (120 foot) (MLW) depth contour. Our outer depth boundary was selected based on data from the Division's Resource Assessment coastal trawl program. The gear used was a Yankee otter trawl (18.5-m sweep and 14.8-m headrope, with 15.24-cm stretch mesh and a 7.62-cm mesh liner). The net was fished with 12.9-m legs and 60.9-m ground cables. The trawl doors f \ j l were steel, measuring 1.85 m X 1.1 m and weighing 990 kg each. 4

Warp length varied with depth of water fished; the range was from 73.85 to 92.31 m. The catch from each tow was processed as during small vessel trawling (i.e., winter flounder length measurements, sex, and evidence of maturity were recorded, and Petersen disc tags attached to flounder greater than or equal to 20 cm in total length). Between 14 and 26 April,1995, we completed 58 tows within the study area. Tow duration averaged 30 minutes, while tow length averaged 1.58 km. A total of 2,882 winter flounder was captured, of which 2,047 were tagged. Twenty-four of these tagged fish were recaptured during our two-week sampling period. Tagging will be resumed in the spring of 1996. Results of tagging winter flounder to define hhe population and to estimate absolute abundance along with relative abundance indices for other groundfish will appear in the next annual report.

2. CUNNER POPULATION STUDIES We formerly studied movement patterns and distribution of adult cunner in the vicinity of Pilgrim Station via mark and recapture, with particular emphasis on their behavioral responses to the discharge current. One of our objectives now is to estimate ,

cunner numbers and survival in the local population. A Floy T-bar anchor tag is used to mark cunner. The tag is embedded in the dorsal musculature via a tagging gun. To procure cunner, baited traps are fished overnight, in that they most actively forage at dusk and dawn. Each fish is measured, and a numbered tag is placed in the dorsal musculature of all individuals 90 mm in total length or greater (adults). All cunner are mature by this size. Fish are f released at the site of capture. We are conducting a multiple census of capture and recapture. Recovery information is obtained l using the baited fish traps and by visual diving observations. . This allows for multiple recaptures. i I A paper on age structure and age / length relationship of cunner 1 from the Pilgrim area presently is being prepared for publication in the open literature. The principal findings of this work will appear in the 1995 annual report. In addition, recruitment dynamics of cunner in the Pilgrim area are being examined as part I of a larger effort to assess entrainment impact of cunner eggs and l larvae at Pilgrim Station. Fecundity by age and length has been investigated for cunner in the environs of Pilgrim Station. These data are needed for the Adult Equivalency model to equate eggs and I 4~ larvae entrained to equivalent adults. Highlights of the I recruitment and fecundity work also will appear in the next annual report. Our marking efforts through June resulted in the capture of 1,197 cunner in the immediate Pilgrim area, of which 746 were tagged. As to spatial breakdown, 80 cunner were caught seaward of the outer intake breakwater at Pilgrim Station, of which 58 were tagged. Within the Pilgrim Intake, 7 sampling outings yielded 886 cunner captured, of which 532 were tagged. At White Horse Beach, 231 cunner were caught and 156 tagged during three tagging events. A total of 103 recaptures of fish tagged this year was recorded in s

4 June: 3 from off-the outer breakwater, 92 from the Intake, and 8 from White Horse. . Work is ongoing through the fall to generate estimates of~ absolute' abundance. 3.- SMELT RESTOCKING We completed the second year's work of a two-year stocking program of rainbow smelt (Osmerus mordar) in the Jones River, a tributary to. nearby Plymouth, Kingston, Duxbury Bay. This is a remedial measure to compensate for an estimated- 9,500 smelt impinged at Pilgrim Nuclear Power Station in 1993.- There is compelling evidence that smelt frequenting the area of the power plant are members of a local sea-run population natal to PKDB, with

 'the Jones River providing the major smelt-spawning ground. The                                      ]

local population has been depressed for years, and the magnitude of recent fish kills at Pilgrim Station could seriously impact smelt. J The overall goal of our stocking has been to enhance the smelt run in the Jones River, i.e., to increase the number of adults in the local ' stock. The objectives of this restoration were to augment instream reproduction in the Jones River and to enhance the quality of spawning habitat on the run. To address the first

  . objective,   we   stocked               1.2             million    smelt  eggs  (conservative 1

estimate) into the Jones River during the spring of 1995. These eggs came from two . genetically isolated, wild, anadromous smelt populations - one from the Weweantic River in Wareham and the other i from Back River, Weymouth. We monitored pH and temperature in each of the three systems l l k

4 I during the spawning period. The results obtained from the Back and Weweantic Rivers revealed that pH and temperature 'r/ :!es were similar to the Jones River readings. These two environmental variables should not have had any adverse effects on the transplanted eggs. Within'the two source streams, a total of 96 egg collecting trays [each tray consisted of a 35.6 x 45.7 cm (14 x 18 inch) weighted wooden frame, enclosed with chicken wire and filled with unprocessed sphagnum moss, as substrate for egg deposition) was deployed to collect smelt eggs for transplanting into the Jcnes River. The resulting larvae from hatchout were expected to imprint on the waters of PKDB and as adults to home to this estuary, ascending the Jones River and possibly other tributaries flowing into this system to spawn. To ~ address the second objective - that of spawning habitat enhancement - and to increase the efficacy of our egg stocking, we employed plant substrate which possessed high relief and surface area, i.e. , egg trays fillea with sphagnum moss. Tra'.isplanted eggs were placed in riffle areas on the Jones River spawning ground. In addition to moving eggs from one river system to another, we placed 75 trays in the Jones River to collect eggs spawned there naturally. This was done to it? rove instream egg survival and , ultimate hatching success. The sphagnum in the trays provides a three dimensional surface and concentrates eggs in higher densities than on natural hard bottom (e.g., sand, gravel, and cobble). The only surface competing for higher egg sets and improved survival is x

i i I I attached endemic aquatic flora (macroscopic river plants), which on the Jones River smelt spawning ground comprise less than one- I quarter of the available habitat. The trays were checked every few days to service them and to monitor egg development. Any algae were removed from the trays l using the hook-end of a boat pole. Fouling algae were gently pulled from the trays and discarded downstream. We endeavored to minimize egg disterbance dreing this process. Macro-algae have become a 1 nuisas.a the last few years in the area where much of the smelt upawning occurs. These included a chain-forming diatom - Fragilaria spp.. Other diatoms present were Synedra spp. , Gomphonema spp., and Achnanthes spp.. Three genera of filamentous green algae also occurred - Drapamaldia, Vlothrir, and Stigeoclonium. Eggs that settle on the algae become entangled in long hair-like filaments. There is reduced water flow not only with the entangled eggs but also to eggs which had settled on moss. A reduction in water flow may j hinder egg development and survival. Sutter (1980) found that l smelt egg deposition was greater in areas of high river flow and on river plants. Furthermore, the survival of eggs to hatching on vegetation was about 10% as compared to 1% on other hard surfaces. Saunders (1981) ran a sensitivity analysis, finding that the most l sensitive parameter affecting subsequent smelt population growth was egg survival. Our portable egg trays in the Jones River increased the amount 1 of available plant material for egg deposition. Sphagnum has spaces between its plant fibers giving a depth dimension and thus 1 1 I

  ._.. ~         _    _ _ _ _ _ __  __      __    . _ - - _ _ _ _ _ _ _ _ ._.       -_.-_.

i providing 3-dimensional habitat. Fertilized smelt eggs that land on the trays can attach to the moss at the surface or within the interstices, creating a micro-environment that offers protection, reducing egg " turnover" (loss), yet is well aerated. Water seeps through the porous surface delivering oxygen to the developing embryos and washing away metabolic wastes. 1 I We will again add plant substrate to the Jones River smelt spawning ground in 1996. In addition, we will monitor the run for 1 the abundance of spawning smelt and egg densities. l l I I l l l _ . _ . _ _ _ _ _ _ _ -. y . .. _ . _ _ _ _ _ . _ _ _ - _ . _ _ . _ _ _ . _ . . _ . . IV. ACKNOWLEDGMENTS The authors thank Marine Research, Inc. for identifying macro-algae collected in the Jones River. We appreciate the guidance of Robert D. Anderson of Boston Edison Company, W. Leigh Bridges of the Division, and the Pilgrim Administrative-Technical Committee, specifically for their input and direction on study programs and on project reports. l l I l 1

V. LITERATURE CITED Lawton, R.P., B.C. Kelly, V.J. Malkoski, and J. Chisholm. 1995. Annual Report on Monitoring to Assess Impact of the Pilgrim Nuclear Power Station on Selected Finfish Populations in Western Cape Cod Bay (Vol I). Project Report Ne 58 (January to December 1994). In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report No. 45. Boston Edison Company, Plymouth, MA. Saunders, W.P. 1981. Final report: sensitivity analysis cf a rainbow smelt population dynamics model. In : Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report No. 17. Boston Edison Company, Boston, MA. 19pp. Sutter, F. C. 1980. Reproductive biology of anadromous rainbow smelt, Osmems mordar, in the Ipswich Bay area, Massachusetts. M.S. Thesis, Univ. of Mass., Amherst. 49 pp. d I"-"'"F-#ewa,----l--m49,au,, , , , ,. t e l l I 6 i l 4 1 I t a ' t t 1 3 1 j -f , i I a 4 4 P i s N-r l 4 5 I ( r I a 4 e J T i 4.

FINAL SEMI-ANNUAL REPORT Number 46 BENTIIIC ALGAL MONITORING AT THE PILGRIM NUCLEAR POWER STATION (QUALITATIVE TRANSECT SURVEYS) January-June 1995 to BOSTON EDISON COMPANY Regulatory Affairs Department Pilgrim Nuclear Power Station Plymouth, Massachusetts 02360 From ENSR 89 Water Street Woods Hole,MA 02543 (508) 457-7900 27 September 1995 ' l l l

I l i l l TABLE OF CONTENTS ' E X E C UTIVE S U M M A R Y . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 1 1.0 INTR O D UCTI ON . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.0 M ETII O D S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1 3.0 RE S U LTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1 MAY 1995 TRANSECT SURVEY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2 JUNE 1995 TRANS ECT SURVEY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.0 D IS CUS S I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.0 LITE RATURE C ITE D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1

1 1 LIST OF FIGURES Figure 1. Location of Pilgrim Nuclear Power Station Discharge Canal . . . . . . . . . . . . . . . . . 3 Figure 2. Design of Qualitative Transect Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Figure 3. Denuded and Sparse Chondrus Zones Observed in May 1995 . . . . . . . . . . . . . . . . 6 Figure 4. Denuded and Sparse Chondrus Zones Observed in June 1995 . . . . . . . . . . . . . . . . 8 i 11 ( L

EXECUTIVE

SUMMARY

This report presents results of qualitative surveys of benthic algae in the thermal effluent of the Pilgrim Nuclear Power Station (PNPS) that were completed in May and June 1995. These investigations represent the most recent phase oflong-term efforts to monitor effects of the thermal effluent on the benthic l algal communities within andjust offshore of the PNPS discharge canal. Field survey techmques were identical to those used in previous investigations. The underwater profile of thejetties has changed somewhat over the years. Storms have moved some boulders away from thejetty to positions closer to the central transect line. For the sake of maintaining consistency in calculations of the area of the Chondrus denuded zone, the sa.ne base dimensions of thejetty that have been used in figures for this report for many years, are continued for the current surveys. However, as a reminder that the condition of thejetty is by no means static, those boulders closest to the transect line that are encountered by the divers at the 30-m mark are indicated in both the May and June figures. The qualitative transect studies performed to evaluate the Chondrus crispus community in the s thermal plume area indicated that in early May and late June 1995 the condition of the denuded and total i t affected areas was typical of that seen in years prior to 1995 when the power plant was in full or nearly full

                                                                                                                       )

operation, even though the plant was down for refueling in April and May. The denuded area (1198 m2), in early May, was well within the size range seen in earlier spring surveys taken when the plant was in 2 2 operation (765 m in April 1986 to 1321 m in March 1991). By June, the denuded zone had increased 17% 2 to 1405 m , again an area well within the size range seen in previous summer surveys. As in many prior summer surveys (1990,1992,1993, and 1994) the divers saw a dense mat ofjuvenile (5-15 mm in length) blue mussels (Mytilus edulis) with an associated high density of the predatory starfish Asteriasforbesi. 1

1.0 INTRODUCTION

This report represents a continuation oflong-term (22 yr) benthic studies at Pilgrim Nuclear Power Station (PNPS) that are intended to monitor the effects of the thermal effluent. The 1995 monitoring program is identical to that performed from 1992 through 1994 and consists ofqualitative SCUBA surveys of algal cover in the thermal plume of the effluent within and beyond the discharge canal (Figure 1). Surveys are conducted quarterly during April, June, September, and December. This Semi-Annual Report includes qualitative observations recorded in early May and late June 1995. Work was performed under Boston Edison Co. (BECo) Purchase Order LSP003397 in accordance with requirements of the PNPS NPDES Permit No. MA 0003557, 2.0 METHODS The qualitative algal survey is performed by SCUBA divers in the same location and with the same techniques that have been used since the present monitoring program began, approximately 14 years ago. The effluent area is surveyed by two or three SCUBA-equipped biologists operating from a small boat. To ameliorate the effect of the powerful outflowing current upon the divers it is critical that the survey occur near the time of high tide; the divers generally begin the survey at or within an hour of high tide and are finished an hour later. For the qualitative transect survey, SCUBA observations are made along the axis of the discharge canal. A line is stretched across the mouth of the discharge canal (Figure 2). A weighted central transect line (CTL), marked at 10 m intervals, is then attached to the center of this line and deployed along the central axis of the canal to a distance of 100 m offshore. Using a compass, divers extend a 30-m measuring line, marked at 1 m intervals, perpendicular to the CTL at each 10-m mark. A diver swims along this third line, recording changes in algal cover from the CTL through the denuded and stunted Chondnu areas, until the algal cover looks normal. The terminology established by Taxon (1982) and followed in subsequent. years uses the growth l morphology of Chondnu crispus to distinguish between " denuded" and " stunted" zones. The denuded zone is the area in which Chondnu occurs only as stunted plants restricted to the sides and crevices of rocks. In this area, Chondnu is found on the upper surfaces of rocks only where the microtopography of the rock l surfaces creates small protected areas. In the stunted zone, Chondnu grows on the upper surfaces of rocks I but is noticeably inferior in height, density, and frond development compared to plants growing in unaffected areas. In 1991 the divers began to discriminate between a stunted zone and a " sparse" zone. The sparse

                                                                                                                                        ]

zone is an area with normal looking Chondrus plants that are very thinly distributed. The normal zone begins at the point where Chondnu height is fully developed and density reaches the ambient concentration.

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Discharge anal Barrier Net

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                                        "El                                    Measuring Line (30 meters marked off at 1 - meter intervals)

Central di Transact Line , (CTL) 1# qi Diver Safety Line Anchor g Buoy Anchor and Line 1 Figure 2. Design of Qualitative Transect Survey. 4 ) i I

The dive team must keep in mind while taking measurements that the shallow depths northwest of the discharge canal hamper normal Chondrus growth. In addition to evaluating algal cover, the divers record any un'isual occurrences or events in the area, such as unusually strong storms, and note the location of any distinctive algal or faunal associations. 3.0 RESULTS Qualitative transect surveys of acute nearfield impact zones began in January 1980 and have been  ; conducted quarterly since 1982. Two surveys were performed (May 2 and June 30) during the current reporting period, bringing the total number of surveys conducted since 1980 to 58. Results of surveys conducted from January 1980 to June 1983 were reviewed in Semi Annual Report 22 to BECo (BECo, 1983). A summary of surveys conducted between 1983 and 1994, including a review of the four surveys performed in 1994, was presented in Semi-Annual Report No. 45 (BECo,1995). Detailed results of the. mapping surveys conducted in May and June 1995 are presented in the next two sections. l 3.1 MAY 1995 TRANSECT SURVEY The denuded and sparse Chondrus crispus areas mapped on May 2,1995, immediately offshore of the PNPS are shown in Figure 3. A large boulder that is nearly exposed at mean low water, and that is used as a landmark by both the ENSR and Massachusetts Division of Marine Fisheries dive teams, is plotted in the figure. *Re denuded zone is essentially devoid of Chondrus, whereas sparse zones have normal-looking Chondrus that is thinly distributed. l In May 1995, rocks within the Chondrus denuded zone essentially were bare with only a very few l algal plants attached. As has been often seen in past surveys, algal density beyond the Chondrus denuded zone was greater south of the central transect line than north; most vegetation was located along the south side of the central transect line from the 30-m to 60 m marks. The area (approximately 1198 m2 ) of the Chondrus denuded zone was slightly larger (3%) in May than in February 1995. The typical asymmetrical distribution of the denuded zone around the central transect line was seen; 65% of the denuded Chondrus i area was north of the transect line and at its furthest extent the denuded zone extended 11 m north of the line from the 40-m to 50-m marks. The denuded region extended 84 m along the transect line,6 m less than seen in the February 1995 or April 1994 surveys. Compared to April 1994, the denuded zone was 7% larger in area in May 1995. He divers classified no area as a stunted zone but did define a sparse Chondrus zone that had decreased in size from February 1995 (595 m2 ) to about 450 m2 . Although the sparse Chondrus zone measured in May 1995 was more than twice the area of the sparse zone seen in April 1994 it still fell midway 5

May 1995  % N

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                                                                                   -90 Sparse Chondrus
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l within the range (90 901 m2) encountered during prior spring surveys. The sparse zone occurred as a narrow band along the southeast side of the denuded zone from thejetty to the 70 m mark on the transect line, liowever, to the northwest, the sparse area reached beyond the 80-m mark on the transect line and extended 14 meters beyond the denuded zone at the 60 m mark. The total affected area (1648 m2 ) was slightly smaller (6%) that it had been in February 1995 but was 27% larger than in April 1994 and indeed had not been as large in earlier spring surveys since March 1984. The divers noted biological features such as algal species typically found in warm or cold water and obvious benthic animals Gracilarla, an alga indicative of warmer water, was seen only within the discharge canal and extending along the transect line to the 40-m mark. The kelp, Laminaria, an indicator of cold < water, was observed at several sites from the 40-m to 60-m marks within the study area. Blue mussels, . l Mytilus edulis, were present only sporadically as were their predators the starfish Asteriasforbest. The l gastropods, Littorinalittoria, were very common throughout most of the area. Two species of crabs were seen, Cancer irroratus and the common green crab, Carcinus maenas. No fish were seen. There was no current at the 30-m station at the central transect line. i 3.2 JUNE 1995 TRANSECT SURVEY Results of the divers' survey for June 30,1995 are mapped in Figure 4. There was a dense array of juvenile (5-15 mm in length) blue mussels (Mytilus edulis), as there has been in many prior June surveys (1990,1992,1993, and 1994). The area affected by the dense mussel settlement was along the central transect line from the 40 m mark seaward to the 90 m mark. Mussel density was so high that surfaces of large rocks were completely covered. The Chondrus denuded zone extended 90 m along the central transect line. The area (1405 m2 ) of the denuded zone was larger (17%) than that measured two months earlier, in May,1995 and larger (15%) than that seen in June 1994. The asymmetrical distribution of the denuded zone around the transect line, with more area denuded of Chondrus north than south of the line, followed the pattern seen during most surveys for the past five years. The denuded zone extended furthest from the transect line at the 50-m mark to the northwest, reaching 15 m from the line and at the 80-m mark to the southeast, reaching 7.5 m from the line. The area occupied by sparsely distributed Chondrus plants (367 m 2) was smaller (23%) than the sparse Chondrus area seen in early May (450 m2) and one-third larger than seen a year earlier in June 1994 (249 2 m ). The sparse area, irregularly distributed on both sides of the denuded Chondrus zone with more than two-thirds of the zone to the north, contributed to the asymmetrical pattern of the affected zone. The total 7

Jun3 1995 K i Starish /\/ 100 Chaetomorpha Corallina il Musselbeds

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l 2 affected area (1772 m ) was slightly larger than in May 1995 and midway in areal dimension between the sizes measured in June 1993 (2058 m8) and June 1994 (1472 m2). Sea lettuce, Ulva lactuca, was more common than it had been in the last few years, and along with Gracilarla and Chaetomorphapurpureum, dominated the flora at the head of the effluent canal. Rockweed, Fucus, was present from 10 to 15 meters north of the transect line between the 50-m and 60 m marks. The divers saw no specimens of Laminarla. Four adult fish were seen. *wo winter flounder (Pleuronectes l americanus) and near the end of thejetties, one tautog (Tautoga) and one striper. 4.0 DISCUSSION 3 ne configuration of the Chondrus crispus denuded zone that may extend as far as 100 m beyond I the discharge canal is readily apparent to SCUBA divers and is easily mapped for the qualitative transect survey. The stunted and sparse zones are somewhat less obvious but in May and June 1994 were readily delineated, in June 1995, a dense mussel mat, similar to that seen in June 1990, 1992,1993, and 1994 was present. For May and June 1995, the areas of the denuded and total affected zones were well within those seen in past years when the power plant was in full or nearly full operation. He two month refueling outage that occurred in April and May,1995 had no discernible effect on lessening the size of the affected Chondrus region. 5.0 LITERATURE CITED Boston Edison Co.1983. Marine Ecology Studies related to the operation of Pilgrim Station. Semi Annual I Report No. 22. Boston, MA. Boston Edison Co.1995. Marine Ecology Studies related to the operation of Pilgrim Station. Semi Annual Report No. 45. Boston, MA. Taxon.1982. Benthic studies in the vicinity of Pilgrim Station. In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi Annual Report No.19. 9

ICHTHYOPLANKTON ENTRAINMENT MONITORING AT PILGRIM NUCLEAR POWER STATION JANUARY - JUNE 1995 Submitted to Boston Edinon Company Boston, Massachusetts i by Marine Research, Inc. Falmouth, Massachusetts September 29, 1995 1

TABLE OF CONTENTS ^ SECTION PAGE l I

SUMMARY

1 l II INTRODUCTION 3 III METHODS AND MATERIALS j J Monitoring 4 l Notification Procedures 7

Mesh Extrusion 9 )
IV RESULTS Monitoring 13 1

Mesh Extrusion 18 V LITERATURE CITED 26 l APPENDIX Ak Densities of fish eggs and larvae per 100 m8 or i water recorded in the PNPS discharge canal-by I species, date, and replicate, January-June 1995. ) 1 APPENDIX B* Mean monthly densities and range per 100 m3 of water for the dominant species of fish eggs and larvae entrained at PNPS, January-June 1985-1995.

                                                          *Available upon request.

LIST OF FIGURES FIGURS i l 1 Entrainment sampling station in PNPS l discharge canal, 5 i t i I u.- - . . - _ _ _ - - . - - - _ -- . . _ _ - . - - - - . ,, - - x ,

LIST OF TABLES TABLE PAGE 1 PHPS ichthyoplankton entrainment notification i levels for 1995 by species category and month. See text for details. 11 2 Species of fish eggs (E) and larvae (L) obtained in ichthyoplankton collections

                                                                                  'from the Pilgrim Nuclear Power Station discharge canal, January-June 1995.                                    20 3                                   Ichthyoplankton densities (number per 100 m8                                      j of water) for each sampling occasion during months when notably high densities were recorded, January-June 1995.                                          21 4                                   Densities per 100 m) of water for tautog/ cunner                                  I eggs and cunner larvae taken with 0.333 and 0.202-mm mesh netting on four 1994 dates and three 1995 dates.                                                     23 t

11 i '

l SECTION I J

SUMMARY

i i Entrainment sampling at PNPS during the first half of 1995 was l l completed on six occasions per month during January and February, l scheduled for three times per week from March through June. Due

to a refueling and maintenance outage from late March to early June, several sampling occasions were missed because both main water system pumps were out of service; one of two pumps was I operating when samples were taken. Standard netting was 0.333-mm
,      mesh except during the larval flounder season when 0.202 mesh was used.       On three dates in June 0.333/0.202 comparison samples were j       taken to study extrusion of cunner eggs and larvae by 0.333 mesh netting.

Over the first six months of the year 32 species were repre-sented in PNPS samples. Winter-early spring collections (January-April) were dominated by American plaice, winter flounder, yellow-tail flounder, and Atlantic cod eggs as well as sand lance, grubby, and rock gunnel larvae. Collections in May and June, which together with July encompass late spring-summer, were dominated by Atlantic mackerel and tautog/ cunner eggs plus radiated shanny, winter flounder, sand lance, and mackerel larvae. Comparison of January-June 1995 egg and larval densities with those recorded from 1985 through 1994 suggested that larval sand lance were abundant in February, unusually so on three dates. Larval Atlantic herring were also numerous in March and April, 1

l exceeding the unusually high level on four dates. Atlantic menhaden and Atlantic mackerel larvae were abundant in June, reaching their high density notification level on five and six l consecutive dates, respectively.  ; No lobster larvae were noted in the collections through the 1 l month of June; only five have been collected through June since 1974. Paired sample comparisons indicated that tautog/ cunner eggs were significantly more abundant in 0.202-mesh samples compared with 0.333-mesh samples, the collection ratio being 1.4:1. Results were variable for the youngest (stage 1 and 2), larval cunner data suggesting that consistent extrusion does not occur. Collections i of larger stage 3 cunner averaged somewhat higher in the bigger mesh although the difference was not significant. 2

   ~

l SECTION II INTRODUCTION This progress report briefly summarizes results of ichthyo-plankton entrainment sampling conducted at the Pilgrim Nuclear Power Station (PNPS) from January through June 1995 by Marine Research, Inc. (MRI) for Boston Edison Company (BECo) under Purchase Order No. LSP001616. As a result of studies completed in 1994, conversion from 0.333 to 0.202-mm mesh was initiated from late March through late May 1995 to improve retention of early-stage larval winter flounder. Extrusion of young larval cunner was also a concern at PNPS based on limited data gathered in 1994. Additional 0.333 and 0.202-mm mesh samples were therefore taken in June 1995 to improve that data base. A more detailed annual report f covering all 1995 data will be prepared following the July-December collection periods. l l

                                                                            \

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                                                                                                                                                                                                                                                    ~

l SECTION III METHODS AND MATERIALS Monitorina Entrainment sampling at PNPS has historically been completed twice per month during January and February, weekly during March through June. Following a PNPS fisheries monitoring review workshop in early 1994, the sampling regime was modified beginning April 1994. Tn January and February during two alternate weeks ) each month single samples were taken on three separate occasions. , l Beginning with March single samples were taken three times every j

                                                                                                                                                                                                                                                      )

week. To minimize costs, sampling was linked to the impingement j schedule so that collections were made Monday morning, Wednesday j afternoon, and Friday night regardless of tide. All sampling was completed with a 60-cm diameter plankton net streamed from rigging i mount.ed approximately 30 meters from the headwall of the discharge  ; canal (Figure 1). Standard mesh was 0.333-mm except from late March through late May when 0.202-mm mesh was employed to improve f retention of early-stage larval winter flounder (Pleuronectes americanus). Sampling time in each case varied from 8 to 35 l minutes depending on tide, higher tide requiring a longer interval j due to lower discharge stream velocities. In most cases, a minimum quantity of 100 m2 of water was sampled although at astronomical high tides it proved difficult to collect this amounts even with long sampling intervals. Exact filtration volumes were calculated using a General Oceanics .Model 2030R digital flowmeter mounted in 4 t

l CAPE COD BAY

                       %?;
                         't . , .

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                                          ' T-                                             DISCHARGE CANAL
t., ,

f BRIDGE y bC ~* '

                                                            ,                            /N T4 Ng                                                           i 4 k                                                                                       # A .S Iy
                                                                            ,          ,$R$ho HEA0 WALL                                                                 ,0g .y, i                                UNIT I INTAKE
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C@p - 9 ICHTHYOPLANKTON '* 'kN STATION UNIT t i 1 100 METERS Figure 1. Entrainment sampling station in PNPS discharge canal. 1 5

s the mouth of the net. Near times of high water a 2030~R2 rotor was employed to improve-sensitivity at low velocities, j

                                                   ~

PNPS was taken out of service in late March for refueling and I maintenance which -lasted until early June. During this period only ' one of two main circulating water system pumps was in use on an intermittent basis. Sampling followed the abcVe regime unless both pumps were out of service in which case no sample could be taken. All samples were preserved in 10% Formalin-seawater solutions and returned to the laboratory for microscopic examination. A detailed description of the analytical procedures appears in MRI (1988). As'in past years, larval winter flounder were enumerated in four developmental stages as follows: Stage 1 - from hatching until the yolk sac is fully absorbed (2.3-2.8 mm TL). Stage 2 - from the end of stage 1 until a loop or coil forms in the gut (2. 6-4 mm TL) . Stage 3 - from the end of stage 2 until the left eye migrates past the midline of the head during transformation (3. 5-8 mm TL) . Stage 4 - from the end of stage 3 onward (7.3-8.2 mm TL). , similarly larval cunner (Tautocolabrus adsoersus) were enumerated in three developmental stages: Stage 1 - from hatching until the yolk sac is fully absorbed (1.6-2.6 mm TL). 1 Stage 2 - from the end of stage 1 until dorcal fin rays become  ! visible (1. 8-6. 0 mm TL) . Stage 3 - from the end of stage 2 onward ( 6. 5-14. 0 mm TL) . , f i 6

l l-1 Notification Provisions l When the Cape Cod Bay ichthyoplankton study was completed in 1976, provisions were added to the entrainment monitoring program to identify unusually high densities of fish eggs and larvae. Once identified and, if requested by regulatory personnel, additional sampling could be conducted to monitor the temporal and/or spatial l extent of the unusual occurrence. An offshore array of stations was established which could be used to determine whether circum-stances in the vicinity of Rocky Point, attributable to PNPS operation, were causing an abnormally large percentage of ichthyo-plankton populations there to be entrained or, alternatively, whether hign entrainment levels simply were a reflection of i ! unusually high population levels in Cape Cod Bay. The impact l attributable to any large entrainment event would . clearly be j greater if ichthyoplankton densities were particularly high only - l l close to the PNPS shoreline. In past years when high densities were identified, additional entrainment sampling was requested by regulatory personnel and the unusual density in most cases was found to be of short duration (<2 days). With the change in 1994 to Monday, Wednesday, Friday sampling the temporal extent of any unusual density can be more clearly discerned without additional sampling effort. Until 1994 " unusually 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 sama t 7 l l , __

month from 1975 through to the current year. Restricting compari-sons to monthly periods damped the large seasonal variation so readily apparent with ichthyoplankton. Starting with 1994

        " unusually abundant" was redefined.                                                                                                          On a month-by-month basis for                             ,

each of the numerically dominant species all previous mean densities over three replicates (1974-1993; to be updated each l year) were examined and testea for normality following logarithmic transformation. Where data sets (for example, mackerel eggs taken f; in June) fit the lognormal distribution, then " unusually large" was defined by the overall log mean density plus 2 or 2.58 standard deviations.8 In cases where data sets did not fit the lognormal distribution (generally months when a species was frequently but not always absent, i.e., many zeros occurred), the mean and ] standard deviation was computed using the delta-distribution (see for example Pennington 1983). The same mean plus standard d deviation guidelinc was applied. The decision to rely on 2 standard deviations or 2.58 standard deviations was based on the relative importance of each species.  ! t The more critical criterion was applied to species of commercial, recreational, or biological interest, the less critical to the remaining species (i.e., relatively greater densities were q necessary to trigger notification). Species of commercial,

                                                            ' Normal distribution curve theory states that 2.5% of the measurements in a normally distributed population exceed the mean plus 1.96 standard deviations

(- s , we rounded to 2 for simplicity), 2.5% lie below the mean minus 1.96 standard deviations. Stated another way 95% of the population lies within that range and 97.5% lies below the mean plus 1.96s. Likewise 0.5% of measurements exceed the mean plus 2.58s, 99% lie within the range of the mean i 2.58s, 99.5% lie above the mean + 2.58s. 8

recreational, or biological interest include Atlantic menhaden (Brevoortia tyrannus) , Atlantic herring (clunea harenaus) , Atlantic cod (Gadus morhua), tautog and cunner (the labrids; Tautoca onitid/Tautocolabrus adsoersus), sand lance (Ammodytes sp.), Atlantic mackerel (Scomber scombrus), windowpane (Scochthalmus acuosus), American plaice (Hiocoalossoides p1_qtessoides), and winter flounder. Table 1 provides summary data for each species of egg and larva by month within these two categories showing the 1995 l 1 notification level.. ) A scan of Table 1 will indicate that, in cases where the long-term mean amounts to 1 or 2 eggs or larvae per 100 m8, the critical level is also grite small. This situation occurred during months when a given species was obviously uncommon and mar./ zeros were l present in the data set with an inherent small standard deviation. The external reference distribution methodology of Box et al. (1975) was also employed. This procedure relies on a dotplot of all previous densities for a species within month to produce a reference distribution. Densities exceeding either 97.5 or 99.5% f of the reference set values wera considered unusually high with this procedure. i Mesh Extrusion

To potentially improve enumerecion of cunner eggs and larvae in PNPS entrainment samples, preliminary sampling was conducted in 1994 to see if eggs and young larvae are extruded through the standard 0.333-mm mesh netting. The smallest stage 1 larvae were not present in 1994 and slightly larger stage 2 larvae were 9

t uncommon. The limited data available suggested that substantial extrusion can. occur. Therefore on three occasions in June 1995 collections were made in triplicate with both 0.333 and 0.202-mm-mesh nets. Dates were selected based on previous samples and 1 historical data to correspond to the likely period of occurrence of small, early-stage cunner. All samples were taken at low water when velocity and potential extrusion would be greatest, each collection six to eight minutes in duration. Nets were alternately attached to the rigging until six samples had been taken. Methodology followed that described for the routine sampling. I 1 i I i s 1 i 10 i

Table 1. PNPS ichthyoplankton entrainment notification levels for 1995 by species category and month. See text for details. Densities per Long-term Mean + Mean + 100 m3 of water: Mean' 2 std.dev. 2.58 std.dev. l ;Tanuary LARVAE Atlantic herring 2 0.2 1 Sculpin i' Rock gunnel 0.8 1.4 Sand lance2 5 11 Februan

LAPNAE
Atlantic herring 2 o,1 o,g Sculpin 2 65 Rock gunnel 3 99 Sand lance 2 9 16 March

. EGGS American plaice 2 2 3 LARVAE Atlantic herring 2 0.9 1.3 Sculpin 17 608 Seasnails 0.6 1 Rock gunnel 10.7 723 Sand lance 2 7 164 Winter flounder 2 0.4 0.7 April EGGS American plaice2 3 32 LARVAE Atlantic herring 2 1 2 Sculpin 15 391 Seasnails 6 10 Radiated shanny 3 6 Rock gunnel 4 142 Sand lance 2 21 998 Winter flounder 2 7 12 MaZ EGGS Labrids2 36 3514 2 Mackerel 16 3405 Windowpane2 9 147 American plaice2 2 15 11

( Table 1-(continued). Densities per Long-term Mean + Mean + 100 m8 of water: Me3n' 2 std.dev. 2.58 std.dev.  ! l Mi1X LARVAE Atlantic herring 0.7 1.1 Fourbeard rockling 2 5 Sculpin 3 4 . Radiated shanny 7 236  : Sand lance? 22 32 Winter flounder 2 9 123 June EGGS Atlantic menhaden 2 4 6 l Searobins 3 4 l Labrids2 958 21599 Mackerel 2 63 3515 l Windowpane 2- 27 261 American plaice 2 1 2 LARVAE l Atlantic menhaden 2 6 10 Fourbeard rockling 9 634 Cunner 2 6 265 Radiated shanny 1 15 l Mackerel 2 50 83 l Winter flounder 2 2 20

         ' Geometric or Delta Mean.

2 Species of commercial, recreational, or biological interest for which a more critical notification level will be used. 12

i l SECTION IV l RESULTS I. Monitorina I- Population densities per-100 m3 'of water for each species listed by date, station, and replicate are presented for January-June 1995 in Appendix A (available upon request). The occurrence (of eggs and larvae of each species by month appears-in Table 2.

                                                                                                 -1 Ichthioplankton   entrained       during   January  through        April               l l

generally represent winter-early spring spawning fishes. Many of l 1 i these employ a reproductive strategy relying on demersal, adhesive ~ eggs which are not normally entrained. As a result, more species are typically represented by larvae than by eggs. Over both life $ stages-7 species were represented in the January collections, 8 I were. represented in February, 11 in March, and 15 in April. Egg i collections over the : season as a whole contained six species, i. American plaice , winter flounder, yellowtail flounder (Pleuronec-tag ferruaineus) ,. and Atlantic cod contributing the majority. Plaice eggs were present in March and April accounting for 10 and 45% of those months' egg totals with monthly geometric means of 0.1 and.3.8, respectively. Winter flounder eggs were also taken only l 1 in March and April. Their monthly geometric mean densities of 0.2 . 1 and 1.5 per 100 m2 of water accounted for 10 and 41% of their respective monthly totals. Yellowtail eggs were present in January l and April, cod eggs in January, March, and April. Monthly mean I densities were less than 0.7 per 100 m2 in each case. 13 , 4

Since.they are demersal and adhesive, winter flounder eggs are I i not typically entrained by water intake systems. Their numbers in PNPS samples are therefore not considered representative of numbers in the surrounding area. Those that were taken were probably i

 ' dislodged from the bottom by currents and perhaps other fish and                                                        "
 .large invertebrates.                                                                                                      l k

Larval collections during the winter-early spring season contained 14 species overall. Sand lance , grubby (Myoxocechalus f q aenaeus),'and rock gunnel (Pholis cunnellus) contributed the most j individuals. Sand lance were taken during each weekly sampling period accounting for 40% of the total larval catch in January, 76% in February, 41% in March, and 44% in April; monthly geometric mean densities amounted to 1.3, 29.6, 26.2, and 44.2 per - 100 m3 ) respectively. Larval grubby first appeared in February and increased in number into April. They accounted for 7% of all larvae in February with a monthly geometric mean of 4.4 per 100 m8, 17% of all larvae in March with a mean of 13.6, and 28% of all larvae in April with a mean of 31.3 per 100 m8 Rock gunnel were present each week with the exception of the first week in January. l They represented an additional 48% of the February total with a geometric mean density of 6.4, 29% of the March total with a mean of 8.2, and 18% of April's total with a mean of 8.9 per 100 m8 of water. May and June collections (along with July) encompass the late spring-summer ichthyoplankton period. Egg and larval densities, particularly among species with pelagic eggs, increase with 14

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

O expanding day length and rising water temperature. Considering both life stages,18 species were represented in the May collections, 20 were represented in June. Atlantic mackerel were numerically dominant among eggs in May, ranking second in June. In May, with a monthly geometric mean of 73.2 per 100 m3, mackerel eggs repre-sented 70% of total while corresponding values for June were 24.6 per 100 m8 and 10% of total, respectively. Tautog/ cunner eggs exchanged with mackerel, contributing 23% of all eggs in May at a density of 27.6 per 100 m8 and 89% of all eggs in June at a geometric mean density of 1179.3 per 100 m3 Larval densities over the two-month period were dominated numerically by radiated shanny (Ulvaria subbifurcata), winter flounder, sand lance, and mackerel. Radiated shanny were abundant only in May when a geometric mean density of 29.5 per 100 m8 represented _47% of all larvae. Winter flounder accounted for 17% of the May larval catch, less than 1% of the June total; respective geometric mean densities were 17.3 and 1.3 per 100 m) . Sand lance, a numerical dominant during the colder months, remained numerous in early May, dropping from the collections by June. Overall they represented 7% of the May total with a geometric mean density of 2.3 per 100 m8 of water. Larval Atlantic mackerel contributed little to the collections in May (monthly mean = 0.3 per 100 m8) but represented 73% of the June total with a monthly geometric mean density of 76.8 per 100 m2 Appendix B lists geometric mean monthly densities along with 95% confidence limits for each of the numerical dominants collected 15

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                                                                                                                                                                                                                             \

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                                                                                                                                                                                                                             )

over the January-June period dating back to 1985. Geometric means are reported .because they more accurately reflect the true j population mean when the distribution of sample values are skewed , i to the right as is commonly the case with plankton data. Generally low values obtained for both eggs and larvas during April-June 1987 I l were shaded because low through-plant water volumes during those I months probably affected densities of ichthyoplankton (MRI'1994). Shaded values were omitted from the following discussion. Entrainment data collected from 1975-1984 remain in an outdated computer format requiring conversion before geometric mean densities can be generated. These years were therefore excluded 1 from comparison. Because densities of each ichthyoplankton species rise from and fall' to zero over the course of each respective l season, inter-year comparisons are most conveniently made within monthly periods.. A general review of the data through the first six months of 1995 suggests the following: l

  • Larval sand lance were relatively abundant in February, the 1995 monthly mean exceeding all previous February mean values dating back to 1985. During the week of February 20 all three samples collected (Monday, Wednesday, Friday) surpassed the unusually high criterion for the month (Table 3) . On February 24, the observed density of 373 larvae per 100 m8 exceeded the previous February high of 96 per 100 m8
  • Recent stock size data suggest that the Atlantic herring stock is increasing following reductions in foreign fishing pressure (Smith and Sherman 1993, Sherman 1994, NOAA 1995). Larval 16

J

                                                                                                                                     .l l

] 3 collections in . March and April' 1994 were relatively high

,                        perhaps reflecting stock size changes.                                   -In 1995 values were
                        ' also relatively high for these two months but not exceptional-1 ly so over each month as a whole.                                 Unusually high values were observed on March 24, April 5, 13, and 15, the value on March 1
                        .24 exceeding all' previous' March. values (Table 3).                                                          l
  • American plaice eggs were numerous in May 1995 with a monthly geometric mean density of 5.8 per 100 m2 which exceeded all  !

previous May monthly means dating back to 1985.

  • Larval fourbeard rockling (Enchelyoous cimbrius) were rela-tively abundant-in May and June, the 1995 respective monthly means of 2.4 and 26.7 per 100 m3 exceeding the previous highs of 1.8 (1986, 1991) and 16.3 (1989) per 100 m3
  • Winter flounder larvae were relatively numerous in May with a geometric mean density of 17.3 per 100 m8 This value exceeded that for 1994. (16.8 per 100 m2), the previous high dating back to 1985. No unusually high densities were recorded during the period however.
  • Atlantic menhaden larvae were abundant in June. Over the month as a whole they showed a geometric mean densit" of 6.3 per 100 m2, exceeding the 4.7 per 100 m2 noted in 1965, the previous high. On five occasions from June 16 through June 26, 1995, densities were unusually high for the month of June (Table 3). The highest density recorded during the period (59 per 100 m2) surpassed 98% of all previous June values.

17

  • Lastly Atlantic' mackerel larvae were abundant'in June. The
    - 1995 monthly -.mean of ' 7 6. 8 per1100 m8 exceeded the previous high of 37.8 per'100 m8 noted.in'1989.                                                Densities recorded on.

six dates from June 12 through 23 each exceeded the unusually-  ; high - criterion with four of.the six exceeding 99% of ' all previous values (Table 3) . - Like Atlantic herring, mackerel-spawning stock biomass has rebounded over the last decade

                                                                                                                     .f
                                                                                                                      ~

(NOAA 1995) presumably with concurrent increases in egg and larval production. Although monthly valvas did not prove to be. remarkable, . three single observations, two for Atlantic mackerel eggs and one-for tautog/ cunner eggs were noted to be unusually high. For mackerel one observation occurred-May 26,-one June 9. The May value of 19203 eggs per.100'm8 exceeded the previous high value-for that month of 14967'per 100 m8 (Table 3). This also' proved to be the case-for tautog/ cunner eggs. On June 21 a density of 37283 per 100 m8 was recorded, exceeding the previous June high of 31833 eggs per 100 m8 noted in 1974. No lobster larvae (Homarus americanus) were encountered through the end of June, a total of five having been taken through that month dating back to 1974. 9 Mesh Extrusion Densities per 100 m8 of water for tautog/ cunner eggs and cunner larvae by stage for both 0.333 and 0.202-mm mesh collections completed in both 1994 and 1995 appear in Table 4. Paired sample l t-tests on' log-transformed data indicated tautog/ cunner eggs were 18 1

significantly more abundant in the 0.202-mesh samples (p < 0.004;. n = 21 pairs) . Since the data were highly skewed by high densities on June 28, 1995, geometric means were calculated over the 21 samples within each mesh category. The' ratio of these was 1.40:1. Results for larval cunner were variable making meaningful conclusions difficult to reach. The smallest stage 1 individuals were present in five sample pairs. On June 16 cunner stage 1 densities were consistently higher in the 0.333 samples while the reverse was true on June 26 (paired t, n=5, p = 0.61). Geometric means within mesh over all samples were 9.1 for 0.333, 14.8 for 0.202, providing a ratio of 1.64:1. For somewhat larger stage 2 larvae comparative data were available for nine pairs; 0.202-mesh densities were greater in six of the nine (paired t-test p = 0.94) . Respective geometric means were 10.0 and 9.7 per 100 m8 Summing stage 1 and 2 densities and calculating geometric means over all pairs indicated that densities were essentially identical in the two meshes (11.7 vs 11.6, paired t = 0.96). Collections of larger stage 3 cunner averaged somewhat higher in the larger mesh (7.1 vs 5.7 per 100 m8 of water, paired t = 0.51). These data suggest that , small larval cunner are not consistently extruded through 0.333 mesh. Pairs showing greater densities in the larger mesh may have resulted from random error inherent in a system with naturally high variability among ichthyoplankters or perhaps to clogging of the finer mesh. The 0.202-mm mesh visibly collects greater amounts of small planktonic forms such as diatoms and, although not clearly l l detectable in the flowmeter data, greater back pressure may reduce collection of some larvae. i 19 I l l

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

Table 2. Species of fish eggs (E) and larvae (L) obtained in ichthyoplankton collections from the Pilgrim Nuclear Power Station discharge canal, January-June 1995. Species Jan Feb Mar Apr May June American eel Anauilla rostrata L Atlantic menhaden Brevoortia tyrannus E/L Atlantic herring Clucea harenaus L L L L Rainbow smelt Osmerus mordax L Fourbeard rockling Enchelvoous cimbrius E E/L E/L Atlantic cod Gadus morhuq E L E/L E E/L E/L Haddock Melancarammus aealefinus E Silver hake Merluccius bilinearis E/L Atlantic tomcod Microcadus tomcod L L Hake Urochvcis spp. E/L Goosefish Lophius americanus E Silversides Menidia spp. L Snarobins Prionotus spp. E Sea raven Hemitrioterus americanus L Grubby Mvoxocechalus aenaeus L L L L L Longhorn sculpin M. octodecemspinosus L L L Shorthorn sculpin M. scorolus L L L L Lumpfish cvelooterus lumpus L Seasnail Liparis atlanticus L L L Wrasses Labridae E E Tautog Tautoaa onitis L l Cunner Tautocolabrus adsoersus L5 Radiated shanny Ulvaria subbifurcata L L , 1 Rock gunnel Pholis cunnellus L L L L L 1 Wrymouth cryotacanthodes maculatus L L L L Sand lance Ammodytes sp. L L L L L l Atlantic mackerel Scomber scombrus E/L E/L Windowpane Sconhthalmus acuosus E E/L ) American plaice Hipooalossoides olatessoides E E E/L E/L Winter flounder Pleuronectes americanus E E/L E/L L l Yellowtail flounder E. ferruaineus E E E E/L 1 l 20

l l l Table 3. Ichthyoplankton densities (number per 100 m2) for each sampling occasion during months when notably ) high densities were recorded, January-June 1995. l Densities marked by + were unusually high based on i values in Table 1. Number in parentheses indicates l percent of all previous values during that month l which were lower. Sand lance larvae Atlantic mackerel Feb. 6 11.7 Eqqs Larvae  ; 8 4.6 May i n.s. n.s. I 10 14.5 3 n.s. n.s.  ; 20 31.3 + (97) 5 0 0 22 49.7 + (97) 8 n.s. n.s. 24 372.9 + (100) 10 n.s. n.s. 12 1.9 0 Previous high: 95.8 (1985) 15 n.s. n.s.. Notice level: 16 17 134.7 0 19 12.2 0 l Atlantic herrina larvae 22 24.7 0 l March 6 0.8 24 n.s. n.s. l 8 0 26 19203 + (100) 4.0 10 0.6 29 557.0 0 13 0 31 139.0 0 i 15 0 l 17 0.9 Previous high: 14967 (1989) 26.4 (1991) l 20 0 Notice level: 3405 -- l 22 0 1 l 24 12.6 + (100) June 2 337.7 1.5 27 8.0 5 346.0 0.7 l 29 1.3 7 480.6 0.8 31 n.s.' 9 4754.0 + (98) 15.3 12 2242.7 1965.4 + (99) 1 Previous high: 9.1 (1983) 14 20.5 601.1 + (99) Notice level: 1 16 144.9 1034.3 + (99) 19 12.9 207.3 + (93) April 3 n.s. 21 0 535.3 + (99) 5 4.5 + (90) 23 0 141.6 + (93) 7 0 26 0 62.1 10 n.s. 28 0 35.5 13 5.5 + (90) 30 0 21.2 15 5.6 + (90) 17 0.8 Previous high: 8193 (1990) 2700 (1981) 19 n.s. Notice level: 3515 83 21 n.s. 24 n.s. 26 n.s. 28 n.s. Previous high: 13.8 (1994) Notice level: 2 21

Table 3-(continued). Tautoa/ Cunner ocas Atlantic menhaden larvae June 2 225.9 June 2 0 5 242.9 5 0 7 406.'1 7 0 9 1710.8 9 1.5 12 281.4 12 8.2 14 10510.5 14 0 l 16 1363.9 16 19.9 + (92) 1 19 107.2 19 58.6 + (98) 21 37282.5 + (100) 21 38.0 + (96) 23 2787.7 23 25.5 + (92) 26- 385.7 26 10.0 + (89) 28 17446.7 28 7.7 30 639.9 30 8.0 Previous high: 31833 (1974) Previous high: 495.9 (1981) Notice level: 21599 Notice level: 10 'n.s. = No sample taken due to circulating water pump shutdown. 22

Table 4. Densities per 100 m3 of water for tautog/ cunner eggs and cunner larvae taken with 0.333 and 0.202-mm mesh netting on four 1994 dates and three 1995 dates. Mesh Date Replicate 0.333 0.202 Ratio el EGGS 1994 May 4 1 2.9 16.1 5.55 2 3.2 9.0 2.81 3 5.3 4.4 0.83 May 9 1 1.1 3.9 3.55 2 4.7 4.9 1.04 3 1.8 2.9 1.61 July 21 1 1194 1330 1.11 2 1028 1462 1.42 3 1377 2259 1.64 August 8 1 134 110 0.82 2 134 172 1.28 3 134 152 1.13 1995 June 16 1 1364 1959 1.44 2 1405 1514 1.08 3 1609 1299 0.81 June 26 1 386 675 1.75 2 631 675 1.07 3 515 570 1.11 June 28 1 17447 17658 1.01 2 16432 24925 1.52 3 21671 26357 1.22 Geometric mean 207 290 1.40 0.004 95% confidence limits 50-859 76-1101 1.20-1.63 LARVAE Cunner 1994 Stage 1 May 4 All 0 0 - May 9 All 0 0 - July 21 All 0 0 - August 8 All 0 0 - 1995 June 16 1 59.7 25.0 0.42 2 30.7 18.4 0.60 3 69.3 39.7 0.57 June 26 1 0.6 5.4 9.82 , 2 0.8 7.3 8.80 l 3 0 0 - l June 28 All 0 0 - l Geometric mean 9.1 14.8 1.64 >0.05 95% confidence limits 0.6-138 6-39 0.3-10 23

Table 4 (continued). Mesh Date Replicate 0.333 0.202 Ratio el 1994 Stage 2 May 4 All 0 0 - May 9 All 0 0 - July 21 1 0 2.5 - 1 2 1.1 7.8 7.09 3 2.1 0 - August 8 1 0.7 0 - 2 0 0 - l 3 0 0 - 1995 June 16 1 56.8 60.0 1.06 2 36.3 12.3 0.34 3 72.2 34.0 0.47 June 26 1 16.6 43.5 2.62 2 56.2 90.7 1.61 3 85.9 36.3 0.42 June 28 1 1.5 10.4 6.75 2 4.5 14.0 3.13 3 14.4 0 - a Geometric mean 10.0 9.7 1.03 >0.05 { 95% confidence limits 3-28 3-27 1994 Stage May 4 All 0 0 - l 1&2 May 9 All 0 0 - July 21 1 0 2.5 - 2 1.1 7.8 7.09  ; 3 2.1 0 - I August 8 1 0.7 0 - 2 0 C - 3 0 0 - ( 1995 I June 16 1 116.5 85.0 0.73 2 67.1 30.7 0.46 j 3 141.5 73.7 0.52 l June 26 1 17.2 48.9 2.85 2 56.2 98.0 1.74 3 85.9 36.3 0.42 June 28 1 1.5 10.4 6.75 2 4.5 14.0 3.13 3 14.4 0 0 Geometric mean 11.7 11.6 0.99 >0.05 95% confidence limits 3-36 3-35 24 l l l

Table 4 (continued). Mesh Date Reolicate 0.333 0.202 Ratio D'l 1994 Stage 3 May 4 All 0 0 - May 9 All 0 0 - July 21 1 0 0 - 2 1.1 0 - 3 2.1 2.3 1.10 August 8 1 12.2 13.4 1.10 2 13.5 7.3 0.54 3 2.9 5.1 1.76 1995 June 16 All 0 0 - June 26 1 3.9 14.5 3.74 2 24.8 7.3 0.29 3 28.1 12.7 0.45 June 28 All 0 0 - Geometric mean 7.1 5.7 0.80 >0.05 95% confidence limits 3-17 2-13 3 p = paired t-test f I 25 l

l 1 4

                                                                                                                         )

SECTION V LITERATURE CITED Box,'G.E.P., W.G. Hunter, and J.. Hunter. 1975. Statistics for Experimenters. John Wiley & Sons, New York. MRI (Marine Research, Inc.). 1988. Ichthyoplankton Entrainment

Monitoring at Pilgrim Nuclear Power Station January-December 1987. III.C.1. ID Marine Ecology Studies Related to Opera-3 tion of Pilgrim Station. Semi-annual Report No. 31. Boston Edison Company.
        . 1994.       Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station January-December 1993.                                     III.C.1.              lu

! Marine Ecology Studies Related to Operation of Pilgrim i Station. Semi-annual Report No. 43. Boston Edison Company. NOAA (National Oceanic and Atmospheric Administration) . 1995. Status of Fishery Resources off the Northeastern United States , for 1994. NOAA Technical Memorandum NMFS-F/NEC-108. 140p. a Pennington, M. 1983. Efficient estimators of abundance for fish and plankton surveys. Biometrics 39:281-286. Sherman, K. 1994. The changing ecosystem. Maritimes 37(1):36.

Smith, W.G. and K. Sherman. 1993. Georges Bank herring continue
recovery, sand lance continue decline. p2 10 Research j Highlights. Northeast Fishories Science Center. March-April i 1993. ,

4 i I l 1 1 26 l 1 I J

4 g s 3 t i' i I APPENDIX'A*. Densities of fish eggs and larvae per 100 m8 of water recorded in the PHPS discharge canal by. species, date, and replicate, January-June  : 1995. l l l

                       *Available upon request.

I l l APPENDIX B*. Geometric mean monthly densities and 95% confidence limits per 100 m* of water for the dominant species of fish eggs and larvae entrained at PNPS, January-June 1985-1995. Note the following: When extra sampling series were required under the contingency sampling regime, results were included in calculating monthly mean densities. Shaded columns for certain months in 1987 delineate periods when sampling was conducted with only salt service water pumps in operation. Densities recorded at those times were probably biased low due to low through-plant water flow (MRI 1994).

          *Available upon request.

1 l l l 4

i e IMPINGEMENT OF ORGANISMS AT PILGRIM NUCLEAR POWER STAllON (January - June 1995) 1 Prepared by: - M M/w, Robert D. Anderson Principal Marine Biologist i Regulatory Affairs Department Boston Edison Company October 1995 ]. I ,e

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'* TABLE OF CONTENTS Section Iills hgg 1

SUMMARY

1 2 INTRODUCTION 2 3 METHODS AND MATERIALS 5 4 RESULTS AND DISCUSSION 7 l 4.1- Fishes 7 4.2 Invertebrates 7 4.3 Fish Survival 11 , 1 !' l 5 CONCLUSIONS 13 l 6 LITERATURE CITED 14 l 1 l F i ii

LIST OF FIGURES Eigne Eac.s 1 Location of Pilgrim Nuclear Power Station 3 2 Cross-Section ofIntake Structure of Pilgrim 4 Nuclear Power Station l iii

LIST OF TABLES Table Eagg 1 Monthly Impingement for All Fishes Collected From 8 Pilgrim Station Intake Screens, January-June 1995 2 Species, Number, Total Length (mm), Weight (gms) 9 L and Percentage for All Fishes Collected From Pilgrim Station Impingement Sampling, January-June 1995 3 Monthly Impingement for AllInvertebrates Collected 10 From Pilgrim Station Intake Screens, January-June 1995. 4 Survival Summary for the Fishes Collected During 12 Pilgrim Station Impingement Sampling, January-June 1995. Initial Survival Numbers are Shown Under Static (8-Hour) and Continuous Wash Cycles iv

SECTION I

SUMMARY

Fish impingement averaged 4.36 fish / hour during the period January-June 1995. Atlantic silverside (Menidia menidia), rainbow smelt (Osments mordax), blueback herring (Alosa nestivahs) and winter flounder (Pleuronectes americanus) accounted for 91% of the fishes collected. Initial impingement survival for all fishes from static screen wash collections was approximately 56% and from continuous screen washes 50%. The collection rate (no./hr.) for all invertebrates captured from January-June 1995 was 1.99+. Jellyfish, sevenspine bay shrimp (Crangon septemspinosa) and sand worms (Nere', sp.) accounted for 83%+ of the invertebrates impinged. Mixed species of algae collecter on intake screens amounted to 1,798 pounds. The relatively high fish impingement rates from January-June 1993 (2.58).1994 (3.34) and 1995 (4.36), reflect circulating water pumps operating regularly during most of these periods, and high numbers of silversides impinged in early spring of each year. The invertebrate impingement was not as reflective ofincreased intake flow. The Pilgrim Nuclear Power Station capacity factor was 55% from January - June 1995. l _ - _ _ _ - _ _ _ _ _ _ _ _ - .

SECTION 2 INTRODUCTION Pilgrim Nuclear Power Station (lat. 4156' N, long. 70 34' W) is located on the northwestern shore of Cape Cod Bay (Figure 1) with a licensed capacity of 670 MWe. The unit has two circulating water pumps with a capacity of approximately 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 travelling water screens of 3/8 inch wire mesh (Figure 2). There are two travelling water screens for each circulating water pump. l This document is a report pursuant to operational environmental monitoring and reporting requirements of NPDES Permit No. 0003557 (USEPA) and No. 359 (Mass. DEP) for Pilgrim Nuclear Power Station, Unit I. The report describes impingement of organisms and survival of fishes carried onto the vertical travelling water screens at Unit I. It presents analysis of the cehtionships among impingement, environmental factors, and plant operatianal variables. This report is based on data collected from screen wash samples during January-June 1995.

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4-

SECTION 3 -

                                                                                                                                      \

METHODS AND MATERIALS y Three screen washings each week were performed from January-June 1995 to provide data for 1 evaluating the magnitude of marine biota impingement. The total weekly collection time was 24 hours (three separate 8-hour periods: morning, aftemoon and night). Two collections , represented dark period sampling 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 rninutes each) and all organisms collected. When screens were being washed continuously, one hour collections were made at the end of the regular sampling periods, and they represented two light pedods and one dark period on a weekly basis. Water nozzles directed at the screens washed impinged organisms and debris into a sluiceway that flowed into a trap. The trap was made of galvanized screen (3/8-inch mesh) attached to a removable steel frame and it collected impinged biota, in the screenhouse, shortly after being washed off the screens. Initial fish survival was detennined for static (8-hour) and continuous screenwash cycles. . Variables recorded for organisms were total numbers, and individual total lengths (mm) and weights (gms) for up to 20 specimens of each species. A random sample of 20 fish or invertebrates was taken whenever the total number 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 Resenh, Inc. Intake seawater temperature, power level output, tidal stage, number of circulating 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 organisms impinged per collecting period divided by the

(#/ hour) was calculated as number of organisms impinged per collecting period divided by the total number of hours in that collecting period. All common and scientific names in this report follow the American Fisheries Society (IN8,1989,1991a and 1991b). 1 1 6-

SECTION 4 RESULTS AND DISCUSSION 4.1 Eishn In 318 collection hours,1,386 fishes of twenty-six species (Table 1) were collected from Pilgrim Nuclear Power Station intake screens during January - June 1995. The collection rate was 4.36 fish / hour. Atlantic silverside (Menidia menidia) was the most abundant species accounting for 1 74.1% of all fishes collected (Table 2). Rainbow smelt (Osmerus mordas), blueback hemng (Alosa aestivalis) and winter flounder (Pleuronectes americanus) accounted for 10.5, 3.4 and 2.8% of the total number of fishes collected. Atlantic silverside were impinged in highest numbers during March. These were primarily adult fish that averaged 97 mm total length. Blueback herring imoingerient dominated in May, and rainbow smelt and winter flounder were mostly , impinged in January. The January-June 1995 fish impingement rate increased from the same period in 1989-1994, when rates varied from 0.52 (. r>0) to 3,34 (1994). Rates increased the past seven years compared to the 1988 rate (0.30) and this is possibly attributable to greater circulating water pump operating capacity from 1989 1995 and higher silverside impingement numbers,in general, in the springtime period. 4.2. Invertebrates in 318 collection hours,632+ invertebrates of 13 species (Table 3) were collected from Pilgrim Station intake screens between January-June 1995. The collection rate was 1.99+ invertebrates / hour. Jellyfish were collected in undetermined numbers. Sevenspine bay shrimp (Cningon septemspinosa) and sand worms (Nereis sp.) accounted for 63.0% and 19.6%, respectively, of the total number of invertebrates enumerated. Green crabs (Carcinus maenus) were fourth in abundance and were impinged predominantly in May.

l Table 1. Monthly im 3ingement For All Fishes Collected From Pilgrim Station Inta ke Screens, January-June 1995 Spfeies Jan Feb. March April May - June Total Atlantic silverside 288 39 680 20 1,028 Rainbow smelt 138 2 2 3 1 145

f Blueback herring 1 .

2 38 6 47 Winter flounder 17 6 3 8 4 1 39 20 Grubby 1 2 1 3 4 31 Atlantic tomcod 8 1 2 11 Threespine stickleback 4 1 6 11 Alewife 4 1 1 .4 10 Atlantic herring 6 4 10 Cunner 1 7 8 Lumptish 6 1 7 Atlantic cod 1 4 5 Rock gunnel 1 2 2 5 Radiated shanny 1 2 1 4 Red hake 3 1 4 Windowpane -3 1 4 Northern searobin 3 3 Pollock 1 2 3 Little skate 1 1 2 Mummichog 2 2 Tautog i 1 2 Atlantic seasnail 1 1 Northern pipefish 1 1 Silver hake 1 i 1 Striped killifish 1 1 Striped searobin 1 1 TOTALS 488 53 712 44 53 36 1,386 Collection Time (h'rs.) 58 60 73 19 47 61 318 Collection Rate (#/hr.) 8.41 0.88 9.75 2.32 1.13 0.59 '4.36 8-

Table 2. Species, Number, Total Length (mm), Weight (gms) and Percentage For All Fishes Collected From Pilgrim Station impingement Sampling, January- June 1995 Length Mean Weight Mean Percent of Species Number Range Length Range Weight Total Fish Atlantic silverside 1,028 69-138 97 1-12 5 74.1 Rainbow smelt 145 113-215 121 3-61 10 10.5 Blueback herring 47 72-134 94 3-17 5 3.4 Winter flounder 39 50-347 121 1-575 48 2.8 Grubby 31 39-100 67 1-14 5 2.2 Atlantic tomcod 11 96-198 136 8-63 21 0.8 Threespine stickleback i1 61-70 66 2-3 3 0.8 Alewife 10 80-260 139 4-114 24 0.7 Atlantic herring 10 45-62 50 0.4-2 1 0.7 Cunner 8 54-196 116 2-114 42 0.6 Lumpfish 7 39-65 51 2-11 5 0.5 Atlantic cod 5 61-166 89 2-29 8 0.4 Rock gunnel 5 87-153 129 5-10 7 0.4 Radiated shanny 4 76-90 82 3-6 4 0.3 Red hake 4 95-148 119 4-19 9 0.3 Windowpane 4 52-210 128 l-94 34 0.3 Northern searobin 3 220-255 235 104-184 132 0.2 Pollock 3 75-93 82 38 5 0.2 Little skate 2 315 377 346 - - 0.1 Mummichog 2 55-57 56 2 2 0.1 Tautog 2 64-75 70 3-6 5 0.1 Atlantic seasnail 1 75 75 6 6 0.1 Northern pipefish 1 135 135 1 1 0.1 Silver hake 1 125 125 14 14 0.1 Striped killifish 1 - - - - 0.1 Striped searobin 1 266 266 - - 0.1 l l U - _ _ _ _

Table 3. Monthly Impingement For All Invertebrates Collected From Pilgrim Station Intake Screens, January-June 1995 Species Jan. Feb. March April May June Totals 1 Jellyfish l Sevenspine bay shrimp 171 53 149 24 1 398 Nereis sp. 4 119 1 124 Green crab 12 3 2 14 5 36 Longfin squid 1 22 23 Rock crab 4 4 1 4 3 1 17 American lobster 4 1 7 3 15 llorseshoe crab 2 6 8 Common starfish 1 3 4 Green sea urchin 1 1 1 3 Isopoda 2 2 Glycera sp. I 1 Lady crab i 1 TOTALS 196 178 154 32 29 43+ 632+ Collection Time (hrs.)66 58 60 73 19 47 61 318 Collection Rate (#/hr.)0.80 3.38 2.97 2.11 1.68 0.62 0.70+ 1.99+

  • Undetermined numbers
 ,      Jellyfish were impinged only during the month of June. The collections of sevenspine bay shrimp occurred primarily from January - March, and sand worms in February. In 1989 from January -

June, blue mussels and mussel predators dominated impingement, possibly due to the lack of effective macrofouling controls that year. FiReen specimens of the commercially important American lobster were captured which is much lower than in 1994, and comparable 1990 and 1991 when 16 and 21 were recorded, respectively, for the same time frame. Approximately 1,798 pounds of mixed algae species were recorded during impingement sampling, or 5.7 pounds / hour. Like the January-June, 1989 - 1995 fish impingement rates, the algal impingement rate for these years was notably higher than recorded for the same period in 1988. 4.3 Fish Survival Fish survival data collected while impingement monitoring are shown in Table 4. Static screen was collections provided high numbers of fishes and revealed relatively high impingement survival rates for some species, especially Atlantic silversides. Continuous screen wash collections had lower survival rates, although so few fishes were sampled that they are not a good indicator of continuous wash survival. l l

b ( Table 4. Survival Sununary for the Fishes Collected During Pilgrim Station Impingement Sampling, l January June 1995, initial Survival Numbers Are Shown Under Statie (8 Hour) and Continuous Wash Cycles { Number Collected Number Survivinn ~ ( Stat.ic Cont. (Initial) Total Lennth (nun) Species Washes Washes Static Cont. Mean ~ Range Atlantic silverside 1,015 13 642 8 97 69 138 Rainbow smelt 145 0 19 - 121 83 215 Blueback herring 47 0 0 - 94 72 134

                                              -Winter flounder                            38         1       32               0            121        50 347        i Grubby                                     31        0        26               -            67         39.llX)

Atlantic tomcod 11 0 7 - 136 96 198 Threespine stickleback 11 0 6 - 66 6l-70 t Alewife 10 0 4 - 139 80-260 Atlantle herring 10 0 0 - 50 45-62 Cunner 7 1 6 0 116 54 196 Lumpfish 7 0 4 - 51 39 65 Atlantic cod 5- 0 0 - 89 61 166 Rock gunnel 5 0 5 - 129 87-153 Radiated shanny 4 0 4 - 82 76 90 Red hake 4 0 2 - 119 95 148 Windowpane 4 0 4 - 128 52 210 Northern searobin 3 0 0 - 235 220 255 Pollock 3 0 0 - 82 75 93 Little skate 1 1 1 0 346 315 377 Mununichog 2 0 2 - 56 55 57 Tautop 2 0 2 - 70 64 75 Atlantic seasnail 1 0 1 - 75 75 Northern pipefish 1 0 1 - 135 135 Silver hake 1 0 0 - 125 125 Striped killifish I O I - - - Striped searobin 1 0 1 - 266 266 All Species: Number 1,370 16 770 8 (% Surviving) (56.2) (50.0) f u---___-__--_-_- _ _ _ _ - - _ _ __

SffIlON 5 CONCLUSLQNS [

1. The average Pilgrim impingement rate for the period January June 1995 was 4.36 fish / hour.

The collection rate was notably lower in 1988, than in 1989 - 1995, possibly due to more circulating water pump capacity during the latter years.

2. Twenty six species of fish were recorded in 318 impingement collection hours.
3. The major species collected and their relative percentages of the total collections were Atlantic silverside, 74.1%; rainbow smelt,10.5%; blueback herring, 3.4%; and winter flounder, 2.8%.
4. The hourly collection rate for invertebrates was 1.99+ with jellyfish (undetermined numbers),

sevenspine bay shrimp (63.0%) and sand worms (19.6%) dominating the catch. Fineen American lobsters were caught. Impingement rates for invertebrates were higher and algae lower for this period in 1988 (minimum circulating water pumps operating) then in 1989 - 1995.

5. Impinged fish survival was high overall during static screen washes because of relatively high Atlantic silverside survival.

t 13 - L___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _.

SECTION 6 LITERATURE CITED American Fisheries Society. 1991a. A list of common and scientific names of fishes from the United States and Canada. Spec. Pub. No. 20: 183 pp.

           .1991b Conunon and scientific names of aquatic invertebrates from the United States and Canada: cnidaria and ctenophora. Spec. Pub. No. 22: 75pp.
           .1989. Common and scientific names of aquatic invertebrates from the United States and                       e Canada: decapod crustaceans. Spee. Pub. No.17:77 pp.

4

           .1988. Common and scientific names of aquatic invertebrates from the United States and Canada; mollusks. Spec. Pub. No.16: 277 pp.

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PHILIP G CoATES u//[#cd , v BJJ ar #dC((J- 88888 DIRECTOR (508)888 1155 MEMORANDUM To: Members of the Administrative-Technical Committee, Pilgrim Power Plant Investigations FROM: John Chisholm, Recording Secretary, Massachusetts Division of Marine Fisheries

SUBJECT:

Minutes from the 83rd meeting of the A-T Committee DATE: June 13, 1995 This meeting of the A-T committee was called to order by chairman Gerald Szal at 9:36 I. Minutes of the 83rd meet 1D9 Carolyn Griswold motioned to accept the minutes; Bob Maietta seconded. The minutes were accepted unanimously with no changes. II. Pilcrim Station onorational review Bob Anderson presented the latest station operational status to the committee. Overall operation was 65% for 1994 due to the generator problem from September to November. So far in 1995, the plant is operating at 75% capacity. Bob informed the committee that there will be no more mid-cycle outages. The plant will refuel every two years during the months of April and May. This, Bob Lawton explained, fortunately keeps the plant off line during the same period in which winter flounder larvae are in the water column. Dredging, according to Bob Anderson, will take place next year. It is expected to cost 1.2 million dollars. The project was held up because of traces of Cobalt 60 in some of the sediment samples. However, DECO expects to have the permits by the end of the year. Also, the engineers have considered increasing the power output of the plant. The Delta-t would stay the same, but flow would increase by 13%. Gerry asked Bob to address two letters that he had received. One was about checking the shroud for cracks and the other, addressed to EPA, notifying them of a new corrosion inhibitor that 1 l

engineers wanted to use. III, 1994 Imoincoment Monitorina Resultq Bob Anderson presented the impingement data. The overall rate for 1994 was 6 fish per hour. This is triple the rate of 2 fish por hour which the plant has averaged for the last 20 years. This increase is due to incidents in November and December. In the first incident, 5800 silversides were impinged from November 28 -

29. The second, which occurred in the end of December, involved the impingement of 6100 silversides and 5300 smelt.

IV. 1994 Marine Fish Monitorina Results Bob Lawton presented the Marine Fisheries monitoring. He . began with the smelt restocking efforts. Over a million eggs were moved into the Jones river in the spring of 1995. For next year, Bob recommends putting egg trays in the river to enhance spawning habitat. No eggs will be moved. Money will be needed to fund a seasonal employee to maintain the trays. Bob then described the problems with the yet unidentified alga in the river. Bob Maietta suggested we contact Joan Biskenis to have it identified. He also suggested Boston Edison fund a pamphlet on making smelt egg trays, similar to the bluebird project run by Fish and Wildlife. Next Bob Lawton introduced the idea of substitute mitigation. ' Marine Fisheries suggested using money awarded for impingement incidents to rebuild local fish laddcrs. Bob Anderson was concerned with attaching a price (value) on the fish. He wanted a letter from Gerry Szal supporting the work. Then a discussion ensued on whether Gerry should endorse this. Gerry said he wanted a monetary figure before he did anything. It was suggested earmarking the work at $10-15,000 for enhancement of the fishery. After more discussion Gerry motioned to " ... provide sufficient funds for DMF to continue enhancement of the fishery , for

                      $10,000." Carolyn seconded the motion and it was accepted unanimously.

Bob Lawton then presented the winter flounder work. Tagging efforts utilizing the large commercial fishing vessel resulted in 2050 winter flounder being tagged in the spring of 1995. To achieve good estimates, DMF needs recaptures from fish returning next year to spawn. As part of the marine fisheries investigations, Paul Nitschke presented the cunner fecundity work. Paul collected 250 fish between 61-182 mm for his fecundity work. His preliminary results estimate 50,000 eggs per year. Paul will also do work on recruitment and post-settlement mortality. Paul distributed his outline and then presented his sampling and analysis protocol. 2

V. 1994 Benthic monitorina Isabelle Williams presented the benthic monitoring results. SCUBA surveys are done quarterly to map the impacted bottom area. Divers swim transects perpendicular to the discharge on an axis centered on the discharge canal. In 1994 nothing unusual was reported. The denuded zone was within the range observed in past years. The bottom impact area was 90 meters off by 30 meters. Bob Lawton asked about heat and scouring. Jim Blake said littorinid snails may also affect the denuded area. VI. 1994 Entrainment Monitorina Mike Scherer began by reviewing the changes made as a result of the fisheries workshop. In April of 1994 he switched the entrainment sampling to 3 times a week, Monday-Wednesday-Friday. From January to February, sampling is done biweekly from March to September it is done every week. He also reviewed the modifications made to notification levels. As for sampling in 1994, Mike reported higher values for sculpin, sand lance, and radiated shanny. He pointed out that some samples are now taken at night. Cod eggs are down, while mackerel are on the increase. The committee discussed the value of Mike continuing comparisons using the 202 mesh net. VII. 1995 Marine Fish and Benthic Subcommittees... The next fisheries subcommittee meeting is scheduled for July 27, 1995. No meeting was scheduled for the benthic group. VIII. 1994 Benthic Plume Study Bruce Magnell of EG&G described the array of 59 temperature monitors deployed off of Pilgrim's discharge to map the plume. The full array was deployed and recording from August 26-29. An unexpected generator failure forced the plant to shutdown, which ended the study prematurely. Also, a storm at the beginning of , September resulted in the loss of several temperature recorders. In the end, 44 of the 59 recorders were recovered. The results show the greatest offshore effects of the plume on the bottom are at low tide. Benthic organisms in the area would be subject to temperature fluctuations between ambient and the discharge water. The maximum bottom extent of the plume offshore was 170m from the mouth of the discharge canal with an offshore wind. The greatest l width was 40m at 80m out from the discharge. The maximum area l affected was approximately 1.2 acres. Although the study was cut short, the temperature monitors were - deployed for a few tidal cycles under typical summer conditions. I i 3 p l l 4

A-T Committee Meeting Attendance June 13, 1995 Gerald Sza) Chairman Mass. DEP, Grafton Robert Lawton Mass. DMF, 'Jandwich Mike Scherer MRI, Falmouth Bob Anderson BEco, Plymouth Carolyn Griswold NMFS, Narragansett Don Miller EPA, Narragansett Paul Nitschke UMASS Martha Mather UMASS Jim Blake ENSR Isabelle Williams ENSR Robert Maietta DEP John Chisholm Mass. DMF, Sandwich (recording secretary) 4

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