ML20140J420
| ML20140J420 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/31/1996 |
| From: | Richard Anderson, Oheim H BOSTON EDISON CO. |
| To: | MASSACHUSETTS, COMMONWEALTH OF |
| References | |
| 49, BECO-5.97.037, NUDOCS 9705140075 | |
| Download: ML20140J420 (255) | |
Text
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- l Boston Edlison l
Pilgrim Nuclear Power Staten l Rocky Hill Road i Plymouth, Massachusetts 02360 Henry V. Oheim i oeneral Manager Technical Sectior, April 29, 1997 l BECo Ltr. 5.97.037 l
Planning and Administration (SPA) l U. S. Environmental Protection Agency P. O. Box 8127 Boston, MA 02114-8127 NPDES PERMIT MARINE ECOf.OGY 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. 49 is submitted. This covers the period from January through December 1997.
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Semi-Annual Marine Ecology Report No. 49
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Boeton Edlieon Pilgrrn Nuclear Power Station Rocky Hill Road Plymouth. Massachusetts 02300 Henry V. Oheim April 29, 1997 General uanager Techriscai section BECo Ltr. G.97.037 State of Massachusetts Department of Environmental Protection 20 Riverside Drive Lakeville, MA 02347 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. 49 is submitted. This covers the period from January through December 1997.
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H. V. Oheim
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HVO/RDA/avf/ecostate
Attachment:
Semi-Annual Marine Ecology Report No. 49 l
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O marineecokxjy/tucfw Reloted to Operotion ofAlgrim/totion SEMI-ANNUAL REPORT NUMBER 49 JANUARY 1996 - DECEMBER 1996
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MARINE ECOLOGY STUDIES l'
RELATED TO OPERATION OF PILGRIM STATION i
i SEMI-ANNUAL REPORT NO. 49 REPORT PERIOD: JANUARY 1996 THROUGH DECEMBER 1996
- DATE OF ISSUE: APRIL 30,1997 J
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Compiled and Reviewed by: .
i ' Robert D. Anderson l j Principal Marine Biologist i
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Regulatory Affairs Department Boston Edison Company Pilgrim Nuclear Power Station Plymouth, Massachusetts 02360
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TABLE OF CONTENTS SECTION l
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SUMMARY
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ll INTRODUCTION lil MARINE BIOTA STUDIES !
1 lilA Marine Fisheries Monitorina and Impact Annual Report on Assessment and Mitigation of Impact of the Pilgrim Nuclear Power Station on Finfish Populations in Westem Cape Cod Bay, January - December 1996 (Mass. Dept. of Fisheries, Wildlife and Environmental Law Enforcement; Division of Marine Fisheries) lilB Benthic Monitorina and Impact Benthic Algal Monitoring at the Pilgrim Nuclear Power Station, January - December 1996(ENSR Consulting and Engineering) lilC Entrainment Monitorina and Impact 111C.1 Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station, January - December 1996 (Results) - (Marine Research, Inc.)
lilC.2 Ichthyoplankton Entrainment Monitonng at Pilgrim Nuclear Power Station, January - December 1996 (Impact F, e spective) - (Marine Research, Inc.)
Impinaement Monitorina and Impact l lilD i i impingement of Organisms at Pilgrim Nuclear Power Station: January - December 1996. (Boston Edison Company)
IV Minutes of Meeting 86 of the Administrative-Technical Committee, Pilgrim Nuclear Power Station l l
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SUMMARY
Highlights of the Environmental Surveillance and Monitoring Program results obtained over this reporting period (January -December 1996) cre presented below. (Note: PNPS was operating at high power level during January - December 1996).
1 Marine Fisheries Monitorino:
- 1. In the April- October 1996 shorefront sportfish survey at Pilgrim Station,2,600 angler visits accounted for 3,854 fishes caught. Striped bass (48%) and bluefish (52%) comprised the sportfish catch. The presence of a strong thermal discharge component during most of 1990 - 1996 resulted in good sportfishery success compared with outage and low power years.
- 2. During late July - mid-October 1996 fish observational dive surveys, fish species were observed in the thermal effluent area. Striped bass and tautog were the !
most numerous fishes seen, being abundant in the path of the Pilgrim discharge current. Striped bass observations peaked in late September /early October while tautog were consistent throughout the summer.
Mass. DMF recommendation - Data from the dive and sportfish surveys reveal that certain species are attracted to either the elevated water temperatures l
(spring and fau) or current. This places them at risk of impact from temperature aberrations, chemical releases, and potential gas bubble disease mortalities.
As such, some form of direct visual monitoring should continue for as long as the plant is operational. ;
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- 3. Several hundred cunner were tagged from 1990 - 1996. Many were recovered a
in the Pilgrim vicinity indicating that movement of this species is local consistant with its residential nature. Juvenile recruitment studies will be continued to assess Pilgrim impact on this species, which in 1995 was minimal and in 1996 were inconclusive because of adverse weather conditions (i.e., severe storms), ,
which naturally impacted recruitment and influenced study results during the Fall.
Mass. DMF recommendation - A final evaluation of impact of Pilgrim Station on j
the local cunner population has not been rendered as yet. Minimrl p: wer plant impact was indicated from the recruitment study in 1995, while in 1996 1
recruitment results were inconclusive due to meteorolooical events. We recommend additional years of recruitment (juvenile) studies to ascertain whether recruitment is recruit limited, resource limited, or controiled by post-settlement predation and whether power plant impact is of consequence.
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- 4. Winter flounder tagging in the Plymouth Bay vicinity to estimate adult population size and Pilgrim Station impact has accounted for 7,289 fish with 218 (3%) tag retums by the end of 1996. The 1996 population estimate based on an Area Swept Method in sampling for the Plymouth Bay area was 184,294 adult winter l flounder (age 3+). This equates to roughly an 8.5% adult population impact from PNPS entrainment of 22,500,000 flounder larvae. When enough tag data is available, additional Fpulation size estima+?s will be generated using a more reliable tag return-population model approach for an expanded spawning area.
O Mass. DMF recommendation - We are optimistic that expansion of the study area, and some modifications to the overall sampling regime in 1997, will yield a more accurate but probably no more precise estimate of population size. A few l-2
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'more years of study to define the imnact of Pilgrim Station on this species would
) be helpful but, nevertheless, may not provide a definitive answer.
5.- Rainbow smelt egg restocking of the Jones River (Kingston) to mitigate the h'gh i
'f PNPS smelt impingement (5,100 fish) in December 1993 accounted for 600,000 !
fertilized eggs being transplanted in 1994 and 1,200,000 in 1995. Once
} hatched, these eggs will supplement those produced by the river's spawning :
1 r i population of this species. Another large smelt impingement occurred in
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, December 1994 when 5,300 smelt were caught on Pilgrim intake screens. Both !
i of these impingement incidents have the potential of irnpactir:g + local smelt
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{ population and were further mitigated in 1996 by. improving the smelt spawning
- j. habitat in the Jones River to enhance egg survival, through the use of several l . dozen specially designed egg collecting trays.
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l Mass. DMF recommendation - The Jones River smelt spawning habitat ,
- enhancement project should be considered for continuation for several more
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years or until Jones River spawning-run smelt numbers, which we monitor, L
! substantially increase. From egg densities observed, it is evident that more 3
adults entered the spawning gorunds in the Jones River in 1996 than in the [
i recent past. "
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Impinaement Monitorina:
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' 1. The mean January - December 1996 impingement collection rate was 3.11 l fish /hr. The rate ranged from 0.12 fish /hr (July) to 11.15 fish /hr (April) with Atlantic silverside comprising 59.2% of the catch, followed by rainbow smelt !
1 13.5%, Atlantic menhaden 5.8%, and blueback herring 4.5%. Fish impingement ;
rates in 1989 - 1996 were several times higher than in 1984,1987 and 1988 -
when Pilgrim Station outages had both circulating water pumps off and reduced pumping capacity forlong periods of time.
- 2. The March /Apnl 1996 Atlantic silverside impingement accounted for 65% of this species' annual collection.
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- 3. The mean January - December 1996 invertebrate collection rate was 2.24/hr with sevenspine bay shrimp (78.7%) dominating. Green crabs and rock crabs accounted for 11% of the catch. Thirty-two American lobsters were sampled.
The invertebrate impingement rates in 1989 - 1996 were similar to those I recorded at Pilgrim Station during the 1987 and 1988 outage years, despite l much lower circulating water pump availability in these outage years.
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- 4. Impinged fish initial survival in the Pilgrim Station intake sluiceway was l
approximately 61% during static screen washes and 67% during continuous washes. Six of the dominant species showed greater than 50% surviva' overall. l 1
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1 Benthic Monitoring Four observations of the discharge, near-shore acute impact zones were performed during this reporting period. Denuded, sparse, and stunted zone boundaries were indistinguishable during September 1987 - June 1989 discharge surveys as a result of the PNPS extended shutdown. However, these surveys did note impact zone boundaries in fall 1989 - 1996 primarily because two circulating water pumps were in operation most of the time resulting in maximum discharge curront flow. The scouring impact area in 1996 varied from 1,671 m2 (December) to 2,209 m2 (September). Except for the December denuded zone, the 1996 denuded and total affected zones were the largest ever seen seasonally during this study (since 1983); in part, this was due to 9
heavy mussel settlement on Irish moss and high PNPS operating capacity on a consistent basis.
Entrainment Monitorina:
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- 1. A total of 41 species of fish eggs and/or larvae were found in the January -
December 1996 entrainment collections: 17 eggs, 37 larvae.
- 2. Seasonal egg collections for 1996 were dominated by Atlantic cod, American plaice and winter flounder (winter - early spring); Atlantic mackerel and labrids l
(late spring - early summer); rockling/ hake, windowpane, and labrids (late summer - autumn).
- 3. Seasonal larvae collections for 1996 were dominated by sculpin, Atlantic herring, rock gunnel, and sand lance (winter - early spring); sand lance, winter l
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flounder, Atlantic mackerel, fourbeard rockling, cunner, and radiated shanny (late spring - early summer); rockling, Atlantic menhaden, tautog, cunner, Atlantic herring, and hake (late summer- autumn).
- 4. No lobster larvae were collected in the entrainment samples for 1996.
- 5. In 1996, an estimated 5.443 x 10' fish eggs and 6.300 x 108 fish larvae were entrained at Pilgrim Station, assuming full flow capacity of all seawater pumps.
On an annual basis, eggs were dominated by the labnd-Pleuronectes group and Atlantic mackerel, and larvae by sand lance sp. and sculpin spp.
- 6. Entrainment sampling, net mesh size efficiency comparisons were conducted showing 0.202 mm mesh significantly more efficient in capturing cunner eggs than 0.333 mm mesh. Both meshes had similar results in sampling cunner larvae.
7, On several occasions in 1996, " unusually abundant" ichthyoplankton densities were recorded including Atlantic menhaden, Atlantic herring, Atlantic mackerel, radiated shanny, winter flounder, hake and sand lance larvae for extended time periods. This possibly reflects strong annual spawning production for these i species.
- 8. The mean annual losses attributable to PNPS entrainment for the adult stage of three abundant species of fish over the period 1987 - 1996 were as follows:
cunner 657,401; Atlantic mackerel 8,637; winter flounder 814 - 8,088. None of these losses for the species concemed were fourd to be significant in the context of preliminary population or fishery effects; however, comprehensive 1-6
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1 Population impact studies are presently being conducted for cunner and winter flounder in the Pilgrim area.
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lNTRODUCTION l
A. Scope and Obiective '
This is the forty-ninth semi-annual report on the status and results of the Environmental ,
Surveillance and Monitoring Program related to the operation of Pilgrim Nuclear Power Station 1
(PNPS). The monitoring programs discussed in this report relate specifically to the Cape Cod ;
l Bay ecosystem with particular emphasis on the Rocky Point area. This is the thirty-seventh i i
semi-annual report in accordance with the environmental monitoring and reporting requirements of the PNPS Unit 1 NPDES Permit from the U.S. Environmental Protection
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Agency (#MA0003557) and Massachusetts Department of Environmental Protection (#359). A j 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 1 Appendix B Tech. Specs. Programs in these areas have continued under the PNPS NPDES permit. Amendment #67 (1983) to the PNPS Tech. Specs. deleted Appendix B non-radiological water quality requirements as the NRC felt they were 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 Edison Company has committed to take steps to correct or mitigate any adverse situation.
These studies are guided by the Pilgrim Administrative-Technical Committee (PATC), which was chaired by a member of the Mass. Department of Environmental Protection in 1996, and whose membership includes representatives from the University of Massachusetts, the Mass.
Department of Environmental Protection, the Mass. Division of Marine Fisheries, the National Marine Fisheries Service (NOAA), the Mass. Office of Coastal Zone Management, the U.S.
Environmental Protection Agency, and Boston Edison Company. Copies of the minutes of the 11-1
Pilgrim Station Administrative-Technical Committee meetings held during this reporting period are included in Section IV.
B. Marine Biota Studies
- 1. Marine Fisheries Monitonno A modified version of the marine fisheries monitoring, concentrating on indicator species is being conducted by the Commonwealth of Massachusetts, Division of Marine 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 ichthyopiankton and impingement of juveniles and adults.
Smelt spawning habitat was enhanced in the Jones River (Kingston) in March / April 1996 to mitigate the large impingement of 5,000+ rainbow smelt on Pilgrim Station intake screens in December 1994. Continuing smelt mitigation will occur in 1997 as well as mitigation for the 13,000+ alewife impingment in September 1995.
A finfish observational dive program was initiated in June 1978. SCUBA gear is utilized on periodic dives from May-October in the PNPS thermal plume area. I Results of the marine fisheries monitoring and impact analysis during the reporting period are presented in Section Illa.
- 2. Benthic Monitorino The benthic monitoring described in this report was conducted by Et'SR Consulting and 4
Engineering, Woods Hole, Massachusetts.
Qualitative transect sampling off the discharge canal to determine the extent of the denuded and stunted algal zones was continued four ti.nes a year (March, June, September, and December). ,
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Results of the benthic monitoring and impact analysis during this period are discussed in Section IllB.
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- 3. Plankton Monitorina l
Marine Research, Inc. (MRI) of Falmouth, Massachusetts, has been monitoring entrainment in Pilgrim Station cooling water for fish eggs and larvae, and lobster larvae.
Information generated through this menitoring has been utilized to make periodic modifications in the sampling program to more efficiently address the question of the effects of entrainment. These modifications have been developed by the contractor, and j reviewed and approved by the PATC on the basis of the program results. Plankton monitoring in 1996 emphasized consideration of ichthyoplankton entrainment and l
selected species adult equivalency analyses. Results of the ichthyoplankton entrainment monitoring and impact analysis for this reporting period are discussed in
. Sections tilC.1 and ll1C.2.
- 4. Imoinaement Monitorina 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 l with results being reported on by Boston Edison Company.
A new screen wash sluiceway system was installed at Pilgrim in 1979. This new sluiceway system was required by the U.S. Environmental Protection Agency and the Mass. Divisicn of Water Pollution Control as a part of NPDES Permit #MA0003557.
Special fish survival studies conducted fmm 1980-1983 to determine its effectiveness in protecting marine life were terminated in 1984, and a final report on them appears in Marine Ecology Semi-Annual Report #23.
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l 4 i Results of the impingement monitoring and survival program, as well as impact analysis, for this reporting period are discussed in Section lilD.
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D. Station Operation History 1
The daily average reactor thermal power levels from January through December 1996 4
, are shown in Figure 1. As can be seen, PNPS was in a high operating stage during this i
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reporting period with a 1996 capacity factor (MDC) of 90.5%. Cumulative capacity factor from 1973-1996 is 53.6%. Capacity factors for the past 15 years are summarized in Table 1.
i 4 -- E. 1997 Environmental Proarams i
A planning schedule bar chart for 1997 environmental monitoring programs related to the operation of Pilgrim Station, showing task activities and milestones from December 1996 - June 1998, is included after Table 1.
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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 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 January 92.1 9S.1 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 February 99.4 96.3 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 March 99.3 74.4 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 April 75.9 0.0 63.3 6.4 53.5 92.7 5.4 10.5 0.0 0.0 11.9 90.8 0.0 39.7 44.1 May 98.2 0.0 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 June 94.3 65.1 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 July 95.3 95.7 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 August 92.3 97.7 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 September 51.4 96.7 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 October 94.0 94.3 0.0 98.0 72.8 94.2 98.7 30.1 0.0 0.0 0.0 95.4 0.0 79.0 39.9 November 94.9 99.5 0.2 80.0 13.7 23.7 96.8 66.0 0.0 0.0 0.0 88.1 0.0 78.6 88.9 December 97.7 98.8 87.7 94.8 65.2 98.1 94.5 77.1 0.0 0.0 0.0 99.1 0.7 18.1 87.1 ANNUAL % 90.5 76.4 65.2 74.0 80 6 58.4 72.3 28.9 0.0 0.0 17.5 84.4 0.1 80.3 56.0 CUMULATIVE CAPACITY FACTOR (1973 - 1996) = 53.6%
= OUTAGES > 2 MONTHS
- = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 27 MARCH - 13 AUGUST 1984
= NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 18 FEBRUAP.Y - 8 SEPTEMBER,1987 = NO CIRCULATING SE AWATER PUMPS IN OPERATION . ROM 14 APRIL - 5 JUNE,1988 = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 9 OCTOBER - 16 NOVEMBER,1994 = NO CIRCULATING SEAWATER PUMPS IN OPERATION FROM 30 MARCH - 15 MAY,1995 radmisc/ chart
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1996 1997 1998 LNOtf DEC JQN FEB MQR APR S&QY JUN .RCL C1C3 SEP CCT KDV DEC JQN. FEB MAR (PR MAY JUN _
' ZONE 1 - PATO cIc3
% 97 Monitoring Programs (NPDES) to EPA .1RC DWPC 1 -7 PATC (Full Committee)o I -7 Review Results Of 96 Programs O 07/17 $
FISHERIES (Sut> Committee) O , I orrir enris i Recommend for FISHERIES 98 Programs N. l cven BENTHIC (Sut> Committee) O l om7 oms ;
, Recommen.1 for BENTHIC 98 Programs M voca PATC (Full Committee)f ;
inor i. recommend for 98 monitoring (NPDES) programs p 1 I iair BECo meet with EPA MDEP (Potential) O l { s tei na BECo prep NPDES 98 Monitoring Programs N I saw imis , BECo approve 98 Monl*oring Pro grams m i l oice Submit 98 Programs to EPA NRC MDEP O l o'ves , initiate 98 Monitoring Programs c Okt? PATC (Full Committee) O l oan 7 Review results of 97 Programs o I t PNPS 1997 ENVIRONMENTAL F'ROGRAMS (NPDES PERMIT #MA 0003557) PAGE1 l
iw96 1997 1998 IyFJV DEC JAN FEB MAR _ APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB MAR APR MAY JUN _ qZONE 2. MARINE FISHERIES MONITORING iMT 0l Issue 97 P.O. to MDMF j Dies 6745 Winter flounder / vunner population aludies I mm - Underwater observation - 0723 Oh13 Prep semi-annual report (draft) __ i Dana Submit draft report to BECo O I .i. io.3 BECo review / comment on draft report y l ie0s seis Final report prep by MDMF lM l l seu Submit 97 semi-annual report to BECO O ' l Orcs I inr Vrinter f ounder/ cunner population studies - . __ l cm3 -__.l.- twan Underwater observation . Oi.3 01:4 Prep annual report (draft) esir Submit draft report to BECo & Fish Subcom. O I o.u r ones BECo/ Fish Subcom. review / comment on draft report g 041D % t0 Final annual report prep R
, o4ns Subm:t 97 annual report to BECoo I i
i PNPS 1997 ENVIRONMENTAL PROGRAMS (NPDES PERMIT #MA 0003557) PAGE 2 ,
19 0 1997 1998 _NOV DEC . JAN FEB MAR _ _QPR MAY JUN JUL 000 SEP CCT KOV DEC JQN FEB MQR APR MAY JUP5_
! ZONE 4 -IMPtNGEMENT MONITORING ta15 O Issue 97 P.O. to ERI We3 irn
. _ . - - - _ =~.~\m? .1
_ - _ . - _ _-. NPO record plant data 0315 l ) Ione Cununctus subinit Biota dela tu DECu oris I I I lome l PNPS submit Plant data to BECo om } I omi l r366u peep a uisu noustuny sepuus
.-_______I - ,J3 BEco prep 97 sem%nnual report y 02.93 0492 BECo prep 97 ennu::;1 report !""""""".!
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- ZONE 5- BENTHIC MONITORING san O lesue 97 P.O. to ENSR i iris Qualitative transects sampling (1st) O OS'17 Qualitative transects sampling (2nd) O com owis Prep semi-annual report (draft)
I am. Submit draft report to BECo O l owes ioms BECo rvw/ comment on draft report !"'I 1003 la o Fhat report prep lama io n Submit 97 semi-ennuel report to BEco O l osse Qualitative transect sampling (3rd) O tais Qualitive transect sampling (4th) O I 1 PNPS 1997 ENVIRONMENTAL PROGRAMS (NPDES PERMIT #MA 0003557) PAGE 3 w ee _ __ - * - __ __ _ _ _ _ - . - - - - _ _ _ . _ _ _ _ . _ . _ _ _ _
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I i Jmumm 1996 1997 r NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCT W MC JAN FEB M M my n i OM7 0114 Prep draft annual report m I orir Submit draft report to BECo/ Benthic Subcom. O l oint osos BECo/ Benthic Subcom. rvw/ comment on draft report y osos os,o ! Final report prep jene l ws Submit 97 annual rcoott to BECo O 1 1 ZONE 6 - ENTRkiNMENT MONITORING I ims O !ssue 97 P.O. to MRI owe inn _ _ _ _ _ ,P!ankton sampling by MRI l__.______ loaca mor Sample processing & data analysisimummmme l b w: Submit data analysis sheets to BECo 0 , jo+es os2a Plankton sampling by MRI . .__.-_..m l om ene, Sample processing & data analysis N omar Submit data sheets io BECo o am e owis , Prep 97 semi-annual draft report m t I m. mo3 i Rvw/ comment by BECo summmme i 4 PNPS 1997 ENVIRONMENTAL PROGRAMS i (NPDES PERMIT #MA 0003557) PAGE 4 , I
s 19G 1907 1998 NOV DEC_ _ JAN FEB Mo* APR, MQY JUN JUL CUG SEP OCT GCDV DEC JON FEB MQR W MAY JUN _ s ft303 torf0 MRI final report prepj g I tam Submit 97 semiennual report to BEco O l orm iod . Plankton sampling by MRI i l T,om in, Sample processing & data analysis puumumme , l l iim Submit data analysis sheets to BECo o '. l l tam im Plankton sampling by MRI(Bi-weekly) __. . _ _ - . _ l o,m eim Sample processing & data antaysis N I sim Submit data sheets to BECo o I azca orta MRI prep annual report (draft) N l 01,7 oan r Rvw/ comment by BECo Em"! 0403 C410 MRI final report prep Pu! , I sei, Submit 97 annual report to BECo o ZONE 11 -THE'RMAL DISCHARGE (DIVE N flETfs MAINT.) ets O Issue 97 P.O. to inner Tech I oim se _ _ _ _ _ _ _ _ _ . _ _ _ _ . . Barrier nets / canal maint. oss {-_______._________...__.._____ O Issue 97 Motte/ Hillier osoi om " Barrier nets rept. (if required by regulators) PNPS 1997 ENVIRONMENTAL PROGRAMS (NPDES PERMIT #MA 0003557) PAGE 5 t
i' i 1996 1997 1998
,_NOV DEC , JAN FEB MAR APR MAY JUN .RA. AUG SEP OCT NOV DEC JAN FEB MAR A*9 MAY JUN ZONE 12 - REPORT MONITORING PROGRAMS l
l oser mir i NPDES permit semi-annual l report prep. ____l_ _iont sort Printing final semi-ennual report P! l l vers toat BECo rvw/commentrapproval of semi-annual report um l I ne, ql Submit 97 semi-annual report to EPA /MDEP/NRC O 1 oms w, r NPDES annual report prep _..____ fonar un Printing final annust report su! l *w um BECo rvw/ comment /approvat of annual report M i i ,- Submit 97 annual report to EPA /MDEP/NRC O PNPS 1997 ENVIRONMENTAL PROGRAMS (NPDES PERMIT #MA 0003557) PAGE 6
, - . . - - - _ - - . _ - - . - - - - - - . . . _ . . . . - . - - - . . . - . - _ . ~ _ . . i I i ) i i ANNUAL REPORT ON ASSESSMENT AND MITIGATION l OF IMPACT OF THE PILGRIM NUCLEAR POWER STATION j~ ON FINFISH POPULATIONS IN WESTERN CAPE COD BAY 4 Project Report No. 62 (January to December 1996) e i B.V j Robert Lawton, Brian Kelly, Vincent Malkoski. j John Boardman, and Greg Pintarelli i l l i l l ( nre 1 i i 4 l April 1997 Massachusetts Department of Fisheries, Wildlife, and Environmental Law Enforcement { j Dnision of Marine Fisheries i 100 Cambridge Street j Boston, Massachusetts 02202 j i I 1 d 1 i 1 _ i
l 1 TABLE OF CONTENTS 1 SstliR!! hag I. EXECUTIVE
SUMMARY
I ;
- 11. INTRODUCTION 4 i
111. METHODS AND MATERIALS 6 IV. RESULTS AND DISCUSSION 16 l , A. Physical Factors 15
- 1. Power Output-Thermal Capacity 15
- 2. Pump Operations 15
- 3. Water Temperauire 16
, H. Finfish Species ofimport i8
- 1. Cunner 18
- a. Background 18 i
- b. Eggs and Larvac 19 )
- c. Juveniles 21 l l
- d. Adults 26 l
l
- 2. Rainbow Smelt 30 i
! a. Background 30 i
- b. Eggs and Lan ac 30 I
- c. Juveniles 33 1
1
- d. Adults 33 l
l
- 3. Winter Flounder 33 1
- a. Background 33
- b. Eggs and Lanae 36 ;
4 l ii 4
l Section gag j
- c. Juvemics 37 i
- d. Adults 37
- 4. Other Species 42 )
1
- 5. Impact Perspective 44 )
V. CONCLUSIONS 5() VI. ACKNOWLEDGEMENTS 5[ , i Vll. LITERATURE CITED 52 l l l iii
l l l LIST OF TABLES Table E. age
- 1. Important indicator species off the Pilgrim Nuclear Power Station. 5
- 2. Age-length key for cunner (sexes combined) in the Pilgrim 29 Station area 1996.
- 3. Tag returns by area from 7,289 winter flounder marked during 40 the spawning season in Areas 1 and 2 from 1994 1996 off
- Cape Cod.
'l 4. Estimated numbers (bottom area calculated at MLW), with 40 MA,nlidence intervals, of winter flounder 2 280 mm (TL) 1
~
pooled lengths, collected by otter trawl (not adjusted l l for gear efficiency) in the Pilgrim study area,12 April to 3 May 1996. ' 1 5.- ' Recreational bluefish catches at the Pilerim Station Shorefront in 44 relation to plant operation and resultant discharge of a thermal plume.
- 6. A summary of mechanical impacts of Pilgrim Nuclear Power 45 I
4 Station on selected finfish species and migration undertaken in the offsite waters of western Cape Cod Bay. i l i a IV I 1 l l 1
LIST OF FIGURES Fieurc Pace
- 1. Investigative area inside and outside the estuary (shaded areas) 6 for rainbow smcit, winter flounder, and cunner studies, January to December 1996
- 2. Station locations for cunnerjuvenile recruitment and tagging 7 studies, and bottom temperature monitoring,1996. l
- 3. Survey tool used by divers to estimate abundance ofjuvenile 9 l cunner in the Pilgrim Station area. ,
i
- 4. Tagging gun and styles of T-bar anchor tags used by DMF to 10 mark cunner (shown above) off Pilgrim Nuclear Power Station.
- 5. A collecting unit of the type used to collect and incubate smelt eggs ,12 (smelt shown above)in the Jones River
- 6. Winter flounder with Petersen disc tag attached (tag not to scale). 13
- 7. Annual means and 24-year cumulative Mean Capacity Factor 15 (MDC Net %) for Pilgrim Nuclear Power Station,1973 through 1996. ;
i
- 8. Operational history of the two circulating seawater pumps at 16
, Pilgrim Station by month for the years,1983 through 1996.
- 9. Mean daily bottom water temperatures ('C) recorded January to 17
- December 1995 and 1996, off Rocky Point (0.8 km offshore in ;
12-15 m of water at MLW). ;
- 10. Expanded number of cmmer eggs entrained at Pilgrim 20 Station, 1987-1996.
I 1. Expanded number of cunner larvac entrained at Pilgrim 20 Station, 1987 1196.
- 12. Mean cunner recruit densitics (the average of 10 transects) per 23 !
site per day for the recruitment study in the Pilgrim Station i area,27 June - 8 October 1996 ;
- 13. Smelt egg densitics within Zones A & B of the Jones River 31 !
enhancement area,1996.
- 14. Smelt egg densitics in Zones A & B within the Jones River 32 enhancement area,1995.
v ;
, _.r. , , - - - - . - - n,
f 4 bN E_arq
- 15. Recapture zones of winter Counder (P/curanccres americanus) 39
. tagged in areas 12 by the MA Division of Marine Fisheries in the decade of the 1990's.
1 1 1 I l 1 s vi i
i l 1
- 1. EXECUTIVE
SUMMARY
The following are the 1996 highhghts of study Gndings for selected species. Additional infonnation can 1 be found in the Conclusions'section of this report. l Cunner 9 Cunner (Tauragolabrus adspersus) larval abundance in the Pilgrim Station area appeared to be reduced l in 1996, with !:aai entrainment down 63% from 1995. i e Length and age-specinc fecundity relationships determined for cunner in the Pilgrim area were used to l refine adult equivalency estimates 9 Impingement of cunner at Pilgrim Station was relatively light (211 Gsh) in 1996. However, the entrainment of cunner eggs and larvac was equivalent to the loss of 589,000 adults from the local l 1 population. l 9 A total of 385 adult cunner (: 90 mm total length) was tagged in 1996 at the outer breakwater in the Pilgrim Station area Recapture information con 6rms that cunner hate limited mmements and demonstrate a high degree of site fidelity. No comprehensive estimate of the local cunner population ! has been generated because oflogistics and Gnancial constraints 09 A Gnal evaluation ofimpact of Pdgrim Station on the local cunner population has not been rendered as yet. Minimal power plant impact was indicated from the recruitment study in 1995, while in 1996 recruitment results were inconclusive due to meteorological events. We recommend additional years of recruitment (juvenile) studies to ascertain whether recruitment is recruit limited, resource limited, or controlled by post-settlement predation and whether power plant impact is of consequence. Rainbow Smelt 9 To compensate for impingement mortality of rainbow smelt (Osmerus mordorj a nigrim Station, the Massachusetts Dnision of Marine Fisheries is conducting restoration work. Our objective in 1996 was to enhance the quality of spawning habitat in the Jones River, u.hich hosts the majonly of smelt spawning in the area. S We selectisely placed 130 sphagnum moss-nlled egg collecting trays into the Jones Ris er on the upper smelt spanning ground. The trays proside an ideal depositional surface for the demersal. adhesne rmnbow smelt eggs. O Rainbow smelt egg survival can be up to ten times higher on plant material than on hard bottom. Egg i
l survival is an important parameter to future stock size. 09 The Jones River smelt spasming habitat enhancement project should be considered for continuation for several more years or until Jones River spawning-run smelt numbers, which uc monitor, substantially increase. From egg densities observed. it is evident that more adults entered the spanning grounds in the Jones River in 1996 than m the recent past. Winter FlounAr 4 Plymouth, Kingston, Duxbury Bay, and the surroundmg coastal waters are important spawning areas for winter Dounder (Plcuroncacs amencanus). In the Pilgrim study area, uinter nounder exhibit Odchty (not 100%) to natal spawnmg grounds. They also undertake local seasonal movements which appear to be temperature-dnven e in 1996, an estimated 22.5 million winter Dounder larvae were entramed at Pilgrim Station, which equates to an equivalent loss of 15,727 adults from the local population e An estimated 866 winter Counder - mostly age-0 and age were impinged in Pilgrim Station in 1996. 9 No winter flounder reportedly were angled at Pilgnm Shorefront in 1996. 9 In 1996, we tagged 4,997 winter nounder with Petersen disc tags, bringing the study total to 7,289. As of the end of the year,218 tagged Dounder had been recaptured (recapture rate of 3%). Fifty percent of these were taken from the general area where they were tagged, 9 Density extrapolation using the Area Swept Method provided an estimate of the adult winter Counder population size for the study area portrayed in Figure 1 (Osh a 280 mm TL,i c., age 3 and older Asht This estimate was 184,294 adults. OS Due to the low recapture rate of tagged Oounder (3% to date), and the variability in our arca-suept estimates, we, as yet, cannot con 0dently define the magnitude of entramment impact on winter Counder of Pilgrim Station, where the equivalent adult loss because of entrainment mortality is preliminarily estimated to represent ~8 5% of the possible adults in the local population We are optimistic that expansion of the study area, and some modi 0 cations to the overall sampling regime in 1997 will yield a more accurate but probably no more precise estimate of population size. A few more years of study to define the impact of Pilgrim Station on this species would be helpful but, neier15cless, may not provide a dc Anitive ansucr. 2 l
Other Sycles e Striped bass (Morone saxatilis) and bluefish (Pomatomus saltainx) were the only species re the recreational catch at the Pilgrim Shorefront. l 9 Striped bass and tautog (Tantoga onnis) dominated the SCUBA finfish sightings off Pilgrim Stati Small aggregations of cunner also were observed 09 Data from the dive and sportfish surveys retcal that certain species are attracted to either the elevated water temperatures (spring and fall) or current. This places them at risk of impact from temperature aberrations, chemical releases, and potential gas bubble disease mortalities As such, some (brm of l i direct visual monitoring should contmue for as long as the plant is operational i 3
! 1 II. LNTRODUCTION The Massachusetts Division of Marine Fisheries (MDMF) power plant study team investigations to assess and mitigate negative environmental effects of Pilgrim N 1
In 1996, we worked principally with threeindicator fmfish species that the power statio funded by Boston Edison Company (BECo) under Purchase Order No. LSP005522. Focusing on cunner, winter flounder, m and rainbow s elt, we employed a variety of and equipment to conduct sampling and undenake restorative efforts. Measurements, c estimates of abundance were used in data quantification. Descriptive statistics were summar displayed in Ogures. Statistical procedures were used when appropriate. From r.(tensive field monitoring off Pilgrim Station, it has become evident that -hanical im station operations,i.e., entrainment of Gsh eggs and larvae followed by impingement ofjuvenile an pose greater environmental threats than does the release of waste heat. We primarily are working with threc Dnfish species: cunner, winter Dounder, and rainbow smelt ( 1). In the environs of Pilgrim Station, cunner spawn, have nursery grounds, and resiac as aduks. T reef fish is structure oriented, territorial, and basically sedentary in movements. Important in the local sportfishery at Pilgrim Shorefront in the past, cunner have a localized distribution and are good indicators for local stress. Cunner is primarily affected by early life stage entrainment at PNPS, and is the dominant Gsh entrained there. Winter fiounder also spawn in the Pilgrim area, which likewise serves as nursery and feedin grounds. This Catfish is valued by commercial and recreational fishermen. Like conner, its larvae are entrained in relatively high numbers. Rainbow smelt is a popular recreational species in the nearby Plymouth, Kingston, , Ditxbury estuary. Several incidents of relatively high smelt impingement has e occurred at Pilgnm Station os er the years. Our objectives in 1996 were as follows: (1) to examme recruitment dvnanucs of cunner in relation to l Pilgrim Station, study movement, and age Osh to generate catch at age data which is used to estimate natural i 4 I l
} t k Table 1. !mportant indicator speciec o(Tthe Pilgnm Nuclear Power Station.' t
Background
O'* ' #'" " "** Species as an Indicator Sources Most Signi6eant Source ofimpact , g (Based on Results to Date) Species ofimpact 3 j Cunner gjg d,r s I. E, T C Entiainment . is number one m egg sailection at PNPS (June-Aug) i Rainbow r, s , nip ngenwnt - large in nts in ceinher oP78 RIS Smelt '93,'94 i j Winter d,r,c.s I. li, T/C g Entrainment - large number of lan ac collected ( April. j floander May) , RIS - representative important species selected in the onginal 316 (a and b) Demonstration Document and Supplement to assess hignm Station impact (Stone and Webster 1975 and 1977) d a dominant species in the higrim area r - a local resident c.commercialimportance s recreationalimportance , I-impingement E - entrainment T/C - discharge current eITects: thermal' current
- Note: Indicator species selection rationale: these three gecies were selected because they have show n the most potential for impact olf Pilgrim Station and may be indicative of power plant induced stresses to other marine fish gecien I
mortality needmi for the adult equivalent model calculations: (2) m the case of winter flounder detennine discreteness of the local population and estimate population size; and (3) to enhance the quality of spawning habitat for rainbow smelt in the Jones River, a inbutary to the nearby Plymouth, Kingston, Duxbury Bay (PKDB) estuary, where the local population originates and increase the collection of eggs on good habitat to improve egg survival to hatching. This annual report includes writeups on sampling design with methodology, together with findings and l recommendations. Progress achieved in sun cys and ongoing restorative projects was highlighted for the three indicator <pecies populations in the Pilgrim Station area. t 5
111. METHODS AND MATERIALS The study area is bounded in Figure 1. i;B
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N UCI. EAR HOASC PCVER BEACH, WWOMET PT Figure 1. Mvestigahve arcs inside and outside the estuary (shaded aicas) for raintow smelt, winter flounder, and cunner investigations, January to December 1996. Cunner Eges and Larvae. Entrainment of cunner eggs and larm is monitored at Pilgrim Station by Marine Research,Inc. (see Entrainment section in this report). The Adult Equivalent Model is used to equate entrained eggs and larvae to equivalent adults lost from the local population caused by power plant mortality. Cunner fecundity by age, length, and weight has recently been investigated for fish collected off Pilgrim Station by Paul Nitschke, a UMass Amherst graduate student, working with our cooperation. Funding was provided by Boston Edison Company. Information on the hydrodynamics of western Cape Cod Bay, including the residual and variance flow patterns that constitute circulation and which affect the resultant dispersioa ofichthyofauna, was compiled by 6
Eric Adams of MIT, Cambridge. Area bounds for the origin of cunner eggs and larrac that are entrained at Pilgrim Station (primanly June through August) were identified by modeling. Cunner recruitment to the Pilgrim vicinity can be influenced, in part, by the status of spawning cunner located elsewhere; therefore, we needed to define the geographical limits of the local cunner population. Our definition of the local population may in actuality be more of an abstraction than a natural unit. From our capture recapture study,it appears that adult cunner in the Pilgrim area base a narrow home range. and presumably the only substantial recruitment to this temperate-rcef population results from settlement of their planktonic lan ac. following metamorphosis Juveniles. To address the relationship between recruits and adults, settlement / post-settlement processes alTecting recruitment were investigated. A second year of SCUBA surveys was undertaken as we continued to examine cunner recruitment in relation to Pilgrim Station operation. Locations with similar habitats apin were sampled in 1996. We know that habitat type is important to recruitment success (Levin 1991; Tupper unpublished), and we did not want to mask possible power plant effects by sampling different habi;ats. Recruitment processes are affected by environmental conditions anu demographics. We ! I Rocky Point added a second year of comprehensive data [ N ! collections to our existing database hoping to pagrim siM Discharge j
! station E' White Horse rescal important ;nsights on local recnn.tment =
processes and possib!c power plant pcrturbation i The density of juvenile recruits was T ["' '" _ i Ma ion'et Pt 3
- r., .~ ~
3 quantitled at a site just off Pilgrim Station and at ! two fixed locations away from the plant (Figure 2). 'rigure 2. station Licanou for connerjuvemie recuniment and tagging studies, and bo; tam temperature mom 1oring,19% The null hypothesis is that tl'e power plant does not signibcantly alTect recruitment. In that the plant " crops" young cunner (larvae and new recruits), recruitment at si.nilar habitats may be higher with increasing distance from the power station. As part of our sampling design, 7 1 l I
we collect information on post-settlement densitics by obsen ing recruits over time in comparabic habitals t>ut at spatially different sampling locations. If early settlement differs spatially, we can test the effects of density on recruitment at the end of the recruitment period. We al.so can examine an assumption of the adult equivalent model, viz., that there is a direct relationship between pelagic egg and benthic adult life stages If this is fact, there should be a direct relationship between the number of recruits at the beginning of recruitment and those extant at the end. Stated as a hypothesis -initial settlement is correlated with net recruitment at the end of the recruitment period. Abiotic factors, including temperature and visibility, were measured durmg our sampling because of their importance to recruitment and our sampling of densific,, respectis cly. Three sites of similar substrate and depth were resampled in 1996 One site was located about 20 m southeast of the discharge canal. N other two locations were further from the power plant one 0.5 km nortimest at Rocky Point, and the other 1.5 km southeast at White Horse Beach (Figure 21 The center point of each fixed site location was marked with a mooring block and surface buoy. Painted red rocks were placed on the bottom beside each mooring to aid us in locating the site in case of buoy loss. At cach sampling site,10 transect starting points were establishea so as to radiate out from the center like spokes of a whccl. To insure that our diving would not bias counts along other line transects, the beginning of each was located 5 m out from the center block and was marked with a numbered, painted rock. Line transects were evenly metered at 36" 1 i intervals using an undenvater compass, starting with a heading of 000 magnetic. Prior to our diving recruitment sun cys, and agam at the end of the sampling pmgram, the benthic habitat at exh site was examined to establish similanty between sites and habitat stability over the course of the study. The post-sun ey habitat analysis could not be Anc at Rocky Point folle"ing loss of the mooring buoy after a major October coastal storm. A 1 x 1 m quadrat, divided by strings into 16 25 x 25 cm squares, was placed en the bottom at 50 randomly selected stations at each site. A line marked in meters was laid out on each thed transect to provide a icference for positioning the quadrat. Habitat within the quadrat was quantified by visually i estimating percent composition of the dominant substrate including algal types in each square. Categones 8
included filamentous algae, fleshy algae, crustose algae, sand, and cobble. Cobble was defmed as small rocks (s 15 cm) without algal cover. Boulders acre covered with algae and were not considered a category. We also recorded the algal types at the intersection point of adjacent sampling squares (16 squares rendered nine intersection points). Habitat characteristics were grouped into two functional groups: structure (filamentous and fleshy algae types) and non-structure (sand, gravel, and crustose algae), since habitat differences are important to recruitment ofcunner(Levin 1991,1993). The proportion of structure to non-structure among reefs for each time period was compared using chi square analysis-Rugosity (an index of structural compleuty) was measured by laying a 10-m fme-linked brass chain on the substrate and allowing the chain to conform to the bottom contours. A straight-line measurement of the distance (m) covered by the cham uas made, and the process uas repeated along the entire length of each transect The ratio of the sum of measured chain distances required to sampic the transect to hncar distance (10 m per
'ransect) is the estimate of rugosity for that area Rugosity measurements were compared among reefs using analysis of variance (ANOVA).
Juvenile cunner (recruits) were visually counted while traversing each transect line using SCUBA. To delineate the width of a transect, a one-meter wide t-bar sampling tool (Figure 3), with attached compass and line-reci, was pushed ahead of the swim path by a diver. A second diver recorded the numbers ofjrvemic cunner while swimming ' *
- I I e
above and slightly in front of the navigator. This position insured good 5isual coverage of the suath of the transect. To
"~ *"*" '
avoi%unting variability between dners, the same person was the enumerator throughout the survey. ww.m - a yg _ s,.i \ Transect Line Weather permitting, sampling uas conducted on " mat *r* Top view side vi.w weekdays starting 27 June (prior to the beginning cf the settlement period) until 8 October. Sampling was usually Figure 3. survey tool used by oners to estimate abundance or juvemic cunner in the l'ilgnm Station area , 9
'i '
conducted tuo to three times cach week. Enumeration was completed at all sites within a sampling day to avoid temporal variation. Underwater visibility was measured using a Secchi disk aller all counts ' vere completed. Adults Mark and recapture studies have determined that cunner typically occupy a small area known as a home range (Green 1975). The objective of our cunner mark and recapture study in 1996 was to examine the home range of cunner in the Pilgrim Station area. Mature cunner (2 90 mm total length (TL)) were tagged with a Floy FD.94 Fine Fabric T-bar anchor tag,40 mm long,0.10 g in weight, in the dorsal musculature via a tagging gun during the summer and sampled for recaptures to determine lateral movement (Figure 4). The tag s!ceves are printed with individual fish numbers and our agency telephone number. Fifteen trapping stations acre selected along the seaward side of the southem end of the outer intake breakwater, with an arbitrarily chosen t distance of 9 m between sites. Station locations were marked with paint along breakwater rocks to be visible from the trap-tending boat. Traps were individually numbered and set at the corresponding station number, enabling us to identify both individual tagged cunner mos ement and any trap displacement from a particular site. [ Traps were fished daily on weekday s, weather permitting, but were mos ed into the intake on Fridays to pre cnt possible storm-related trap loss when untended over the weekends. Cunner were captured in baited fish traps set ovemight, and each was measured to the nearest millimeter (TL) and sexed, when possible, through ripeness and/or dichromatism. Fish were ) I
^
released at the station ofcapture. Lateral movements ofindividual 9w fish between stations along the outer breakwater were determined # and tabubted. i I The age structure of the local population (including age.1 I l l l and older) is being examined by aging otoliths taken selected
-$~ 4 specimens over the last several years. Aging information was Figure 4. Tagging ;un and styles ort-bar anchor tags incorporated into the fecundity ' analysis recently perfonned by the used by DMF to mark cunner (shown above) oliP4nm Nuclear Power Station.
10 i l
_- . . . - . . - . . - - _ . - - - . - . . . - - - ~ _ - - - l i UMass graduate student which, in turn, is used in entrainment modeling (Adult Equivalency) at Pilgrim Station (see 1995 annual report). Retained cunner were weighed to the nearest gram, measured for total length to the nearest millimeter, and sexed via internal examination of the gonads. Sagittal otoliths were remos ed, cleaned, labeled, and stored dry in glass vials. Unprocessed otoliths were viewed sulcus side dosm under a dissecting scope with reflected light, and annular rings were counted. This was a practical approach for most Osh through three or four years of age. Annulus formation in cunner was validated by researchers in Newfoundland (John Green, personal communication)', so we are confident that the clear hyaline bands uc read are annuli Otoliths from older Ash or younger Ash difficult to age were mounted in Pro-Texx medium on a microscope slide sulcus side up and allowed to dry at least two days The mounted otolith was ground down with 320 grit sandpaper until the annular rings could be differentiated. Each otolith was aged independently by two readers. If concturence occuTed on their readings, that age was assigned to the Ush. When disagreement occurred amongst the readers, the otolith was viewed again by the readers, and, if a consensus was not reached, that Gsh was excluded from the age analysis. We will continue to collect catch /cffort data (catch per trap haul) and to age selected cunner to generate catch at-age data which will be used to estimate and fine-tune the natural mortahty rate used in the adult equivalent model. Rainbow Smelt Eggs and Larvac. Each egg collecting unit (35 6 x 45.7 cm) was a weighted wooden frame, enclosed with chicken wire, and filled with unprocessed sphagnum moss as substrate for egg deposition. (Figure 5). Egg trays were placal into selected riflies in the upper Jones River smelt spasming ground. They were inspected, every few days, seniced, and monitored for egg deposition, development, and survival. Fouling macro-algae were removed from ' John Green, Biology Department, Memorial University, St. Johns, Newfoundland j l 11
]
1 l
the trays and discarded domstream of the spasming area. We endeavored to minimize egg disturbance and destruction on the river bed and on our trays during this process. Fcilowing egg hatchout, the larvac were expected to be carried downstream and out of the Jones River mto the waters of Ply mouth. Kingston, Du Bay as they develop. As adults they should home back to this estuary, ascending the Jones River and possibly other 4 tributaries to spawn. T Juveniles. There have been three unusually large rainbow smcit impingement incidents that occurred at
$ \ \\ [,(1 \\\(' ' '
= '.,ti1 11\1\\1' 1 Pilgrim Station, in December of 1978, '93, and '94 Tne Z '1 1' 1 '\3 i
majority of smelt impinged were age-0 . Impingemer.1 sm.n c , vr.. I sampling data are collected by Marine Research, Inc. (see Figure 5. A coHecting unit of the type used to collect and incubate smelt eggs (smelt shown above)in the Jones River. Impingement section, this report). Adults _ Adult rainbow smcit (Figure 5) also are impinged at Pilgrim Station (see impingement section). Winter Flounder i Eces and larvae. Data on these tuo life stages (primarily larvac, for winter flounder eggs are demersal)are ce'lected by Marine Research, Inc. in their entrainment sampling program at Pilgrim Lation (see Entrainment section, this report) Juveniles. Juvenile winter Counder are impinged at Piignm Station Monitonn; data are collected by Marine Research, Inc. (sce impingement section, this report). Adults. Our objectives are to determine the discreteness (delimit boundaries) of the local winter Counder population and then to estimate absolute population abundance. This information will be used to assess impact of Dounder entrairment at Pilgrim Station. During tne winter Counder spawning season north of Cape Cod (ca mid March to mid June), some winter 12
Gounder may move in and/or out of PKDB (Figure l), with evidence of spawning both inside and outside this i estuarj. Flounder may aggregate in pre spawning staging areas out in deeper water, with some moving mto the estuary at night on a Good tide to spawn in the shallows. In April 1996 we contracted a commercial Oshing vessel, the FN Frances Elizabeth, to trawl sample winter Dounder, in order to collect catch data for density extrapolation and to capture winter flounder for tagging studies. The boundaries of our samphng arca -
- were extended to include the waters between High Pines Ledge, -
h
- =c=.
Duxbury and the Mary Ann buoy, Manomet from nearshore cut to Q , W< the 36.6 m (MLW) de-A contour (Figure 1) The outer depth
% , F boundary was selected based on the distribution of winter Counder N determined by the MDMF Resource Assessment Coastal Trawl Figure 6. Winter ilounder with Petersen 1sc tag 3113enya (i3, nni go sc3i,3 Project. A Yankee otter trawl (18.5-m sucep,14.8-m headrope, i
15.2-cm stretch mesh,7.6-cm mesh liner,12.9-m legs, and 60.9-m ground cables) was used. Trawl doors were stect, measuring 1.8 m x 1.1 m and weighing 990 kg each. Warp length nas varied with the depth Oshed and ranged from 73.8 to 92.3 m. Catches were processed, winter Cound.:r length (TL), sex, and evidence of maturity were recorded, and 4 Petersen disc tags attached to Gsh 2 250 mm TL (Figure 6). Tow duration and length averaged 30 minutes and 1.6 km, respectively. We genewted an estimate of winter Dounder population size (instantaneous aoundance) from the 1996 contracted commercial vessel trawl catch data using an area-swept approach, based on density extrapelation. As trawl gear efGeiency in our sampling is unknown, we estimated it to bc 50% To estimate density, the number of winter Dounder by tow was divided by the area of bottom covered. Tow length was determined, and tow w h h was estimated from the traw! doors' spread on the bottom. Door spread is used as a measure of the width because 13
. - .- . . . . . - - -_ -- -. - -. . - - . - . - . . . - . - . . ~ . . . - . of the "hcrding" action caused by the sediment cloud generated by the doors and legs while towing. Catch per area was calculated for individual tows. Estimates computed for adult winter flounder 2 280 mm TL and for all sizes pooled of winter Counder captured were doubled to rc0cct the assumed 500'o catch efficiency. Density estimates (number per m') ucre multiplied by the total bottom acreage in the study area to obtain estimates of population size. Bottom area was averaged using a dot grid and navigational charts. Acrcage w as l converted to square meters. d Other Fish Soccies e Eggiand Larvae. Egg and larval information for all DnGsh species entrained at Pilgrim Station are obtained by Marine Research, Inc. (see Entrainment section, this report). Loveniles. We collect data on juveniles of Gnfish species via SCUBA diving and Gsh potting. Impingement data are obtained from Marine Rcscarch, Inc. and BECo. A_dults. (Same as forjuveniles) i l 1 14 l.
l i IV. RESULTS AND DISCUSSION A. PIIYSICAL FACTORS 1 Power Outout Thermal Capacity Pilgrim Nuclear Power Station's capacity factor (MDC net percent) is an index of operational status that . approximates thermal hwling into the receiving waters of the marine environment. This factor is relevant when j assessing long-term thermal impact on marine organi:ms. By permit regulation, Pilgrim Station is allowed a : maximum discharge temperature of 38.9 C and an emuent a T 18"C above ambient. For the 24-year history of plant operations, the long-term mean MDC at Pilgrim Station is 53.6%, with annual averages ranging from 0.0% (outage years) to 90.5% in 1996 (Figure 7). De annual power level has increased over the last three years - 65.2% in 1994, 76.4% in 1995, and 90.5% in 1996. Average monthly . LtdT 1 CAPACITY rACTOR {%) thermal capacity values m. 1996 ranged ion n-
;' 9 from 51.4% in September to 99.4% in so -
n- i t
!, l ff ? !
, m y i ud February, l l , .
c
"~h "
l ? : ' i d n , i t l a !'
- 2. Pump Onerations u -j( y; l, b s j j ; l ,
up
> s ,
j ' 4 g l >
. ? , - -
h Once through, open-cycle uq f ', ? l:.$ E ! 3 l I l ) . j
, 7
,eh ; 3 ,
4 - o 4 4 3 cooling at Pilgrin Station induces a a 4 's I 2
!?2+4 n un n n n n ue, u u u n u nu meoe, u u u u n u ......
localized water current flow. Two - .=a DI ANNUAL MEANS circulating seawater pumps (586.7 kl/ min Figure 7. Annual means and 24.) ear cumulative Mean Capacity Factor (MtX' cach) withdraw water from the Intake Net %) for Ngnm Nuclear l'ower Station.1973 through 1996 I embayment. The cooling water circulates through the plant condenser tubes before being discharged back into i the waters of Cape Cod Bay laden with wast:: heat At ebb tide, emuent velocities can exceed 2.1 m/sec at the egress of the discharge canal. This results in scouring of the benthos and concomitant crosion of substrate along r the bottom path of the discharge plume. 15 t 1
Throughout the operational history of this power plant, there have been station outages, when one or both circulating seawater pumps were not operated (Figurc 8). Such periods have occurred aperiodica l NUMBER OF PUMPS IN OPERATION 3 i l i i 1 l 1 i J s i 4
- m nn O
1000 fees 1988 1980 1987 1000 itse teet Iset 1000 1000 1984 tees l i ' Figurc 8. Operanonal history of the mo circulating seawater pumps at hignm Station by month for the years,1983 through 1996. 1. are short-lived, howes er, prolonged outages occi :d m 1984 and from 1986-1988 (Figure S) Durmg 1996, both i j circulating pumps essentially were in operation throughout the year.
- 3. Water Temperature Bottom water temperature (*C) was recorded continuously throughout most of the year by a constantly recording thermistor (Ryan) secured on the scabed in a cement mooring located at Rocky Point,0.8 km offshore 16
4 l and at 12 15 m of depth (MLW). Figure 9 displays temperature records for 1995 and 1996 It is evident from !
, these records that winter, spring, and summer temperatures were generally higher in 1995, with fall temperatures more aligned. Overall,1996 was a cooler year.
Temperature C , 25 20 ,y' . a ~1. 15 .~#4 10 1/1 2/1 3/1 4/1 5/1 6/1 7/1 8/1 9/1 10/111/112/1 Date
+ 1995 + 1996 <
l 4 Figure 9. Mean daily honom water temperatures ( c) recorded January to December or 1995 and 1996, oir Rockv Point (o 8 , km ofTshore in 12-15 m of water at MLM 1 1 I 1 17 i
l B. FINFISil SPEs'IES OF IMPORT
- 1. Cunner
Background
The cunner (Tautagolabrus adspersus) is a temperate reef fish that sccks the shelter of pilings,jettics, and rocky areas, distributed generally within 10 km of shore (Bigelow and Schroeder 1953). This species is abundant from Conception Bay, Newfoundland to New Jersey; Chesapeake Bay is the southern hmit of their range. Massachusetts Bay, contiguous with Cape Cod Bay, is near the mid-point of the cunner's range. The cunner is a dominant component of many inshore marine benthic fish conununitics (Edwards et al.1982). Cunner do not undertake extensive migrations (Green and Farwell 197I; Olla et al.1975) but may overwinter in their summer habitat in a dormant (non feeding) state (Dew 1976). Olla et al. (1975) and Dew (1976) reported that as fall water temperatures drop to 7-8 C, cunner become inactive and then remain dormant until vernal waters warm above 6 C. Dew (1976) noted that large cunner in Connecticut waters become dormant first and remained so longer in the spring than small fish, resulting in a growing season for age-0 and age-I lish that was a month longer than for older fish. There may be some systematic offshore movement oflarger cunner (Olla et al.1975; Dew 1976). Adult cunner are not known to stray far off the bottom or from night resting sites; they occupy relatively small home ranges (Green 1975), remaining near structure to which they recruited (Olla et al.1975). Cunner often are found in highly localized aggregates, where a population may be spatially separated into subunits, some of u hich occupy patch reefs. As such, they are s utnerable to local perturbations (c g , point-source pollution, soortfishing mortality). Especially sensitis e to stress after dark, they enter a sleep-phase, w hich is characteristic of the labrid family. This reduces their responsiveness to environmental stimuli. Cunner appear to be a good indicator species to assess stress in inshore coastal regions (Olla et al.1975; Dew 1976). At Pilgrim Station, the intake breakwaters and discharge canaljettics augment naturally occurring structure,creatiag additional high-relief habitat. Large boulders with attached macroalgae found off the discharge 18 i l 2
are examples of natural structure. Refuge areas are imperative to the cunner's sleep phase, and, in general, provide both protection from predators and foraging opportunities. Eddies are created at the locations of boulders in the dischacge area, which enable cunner to reside in the vicinity of the power plant's efuuent, where current velocitics would normally limit their maneuverability or es en preclude their presence. The cunner is a numerically dominant fish in the environs of Pilgrim Station. The density of cunner varies spatially in the Pilgrim area, with highest adult densitics found on the seaward side of the outer intake breakwater. Our extensive tagging work shows they have high site lidelity. Eces and Larvac Cunner are impacted by Pilgrim Station by entrainment of their pelagic eggs and larvac during late spring and summer, when the adults are known to spawn in western Cape Cod Bay. Having consistently captured numbers of running ripe male and female cunner oft Pilgrim Station in May and June, we conclude that spanning l does occur locally in the immediate vicinity of the power plant. In 1996, cunner eggs were entrained at Pilgrim Station from May to September, while their larvac ucre entrained from June to September. Over the years of station operation, the Labridae-Pleuronectidae grouping has dominated fish egg entrainment at Pilgrim Station, often comprising over 90% of the eggs collected. Substantially more cunner eggs than larvae are collected which is probably related, at least in part, to high egg mortality and the ability of the larvae to move in the water column. Large numbers ofcunner eggs and larrac have been entrained historically at Pilgrim Station (Figures 10 and 11). For analysis ofimpact, it is assumed they undergo 100% mortality and are thus lost to the local population (Marine Research,Inc.1992). In 1996, Pilgrim Station entrained an estimated 3,176.482 X 106 eggs and 17.160 X 106 larvae,which equates to 588,997 future cunner adults lost to the local population as estimated by the Adult Equivalency Model, utilizing the newly determined average cunner lifetime fecundity of 13.946 19 l l
(Mike Scherer, personal communication)' In 1995, an estimated 4,282.479 X 10* cunner eggs and 46 484 X 10' e=oro avuun sea ma or uuio=.i cunner larvac were entrained, equalmg to 975,729 adults.
- IP I
,, . i 7 The number of eggs entrained in 1996 was 26% lower
{% $ e soo- p
.n R ...
7 x
, lngl W %a 'S, 3 than in 1995, while larval entrainment declined 63% The **
$r ;;;, y $; x 0 h;
,fg i r_ :
lh'I5]
$ f 3 resulting equivalent adult estimate concomitantly fell 40%
o . f k fd j'f: ] L,. . f f hl
^-
in 1996. The SCUBA density observations from our """"2"*"" ve cunner age-0 surveys indicated that recruits were Figure 10. Expanded namher of cunner eggs entrained at pigrim 9&n,1987.tw, a~
\
noticcablyless abundant in the Pilgrim Station sicinity in 1996 than in the previous year, which corroborates the I larval entrainment values reported at the plant for these < = oso=uunataa m uu o si two years, indicating the pool of pre-settiement Ian ac w as g7 iso - g much reduced in 1996. Predation is implicated as
,co . .
1 potentially the greatest source of mortality to marine Gsh $ki g j p larvac. Even small changes in life stage durations can i i l;( lj -
.. -E._: M ,eMe@Gw_EEb
. . . ,,u u m .,
lead to substantialincreases in mortality. Fast growth and vraa
. .. . Figure 11. Expanded number of cunner larvac entrained ai rapid planktome life stage transitions are important, as p,yrim station, 1987 1996 subtle declines in growth rates, e.g., via cooler temperatures, can increase predation mortality by an order of magnitude (Richards and Lindeman 1987). We know that ambient water temperatures in uinter, spring, and summer were noticeably cooler in 1996 oiT PNPS.
While the magnitude of entrainment loss is substantial, its signincance to the local cunner population ' is unknown. At 15.6'C, cunner eggs hatch in 2-3 days, while the larvac remain in the water column for 18-30 days. It is likely that some conner Ian ae recruit into the Pilgrim area from offsite spawning grounds. ohile a
' Michael Scherer, President, Marine Rescarch, Inc , Falmouth, M A 20
t portion of the larvae hatched from eggs produced in the immediate area of Pilgrim Station are advceted from this 4 area by prevailing currents. We now have an estimate of the geographical bounds of this population based on recruitment sources, via hydrodynamic modeling of cunner egg and larval dispersion in the Pilgrim area conducted by Eric Adams of M.I.T., The model predicted that 90% of the cunner eggs and larvac entrained at Pilgrim come from within approximately 8.8 km of Pilgrim Station to the north, from High Pines Ledge to White Horse Beach. The estimation of adult cunner population size, via tag and recapture, has proven unfeasible because of man-power constraints and logistics, so comparative juvenile recruitment success at various locations near Pilgrim Station is used to assess potential Station impact on this species. Juveniles Juvenile cunner are vulnerable to impingement on the traveling-screens at Pilgrim Station, typically l during summer and fall (Lawton and Anderson et al.1984). An estimated 211 lish were impinged in 1996. Impingement numbers from 1979 to 1996 have fluctuated but with an ovcmil decline, with a low in 1992 and a high in 1980. Past survival studies ofimpinged cunner at Pilgrim Station revealed initial survival rates of between 24 and 100% (Anderson 1990,1993). Influencing factors include number of pumps on line and the operational mode of the screen wash system (static vs. continuous) Impingement. when combined with sportfishing and entrainment mortahty at Pilgrim Station, can impact the local population. The Station's discharge, with its high velocity, waste heat, and periodic chlorine load, can influence all cunner life stages - particularly the distribution ofjuveniles in the receiving waters. In addition to thermal stress, the fast-flowing current can be limiting to cunner mobility and maneuverability. Sm.*ll juveniles, e.g.,20-30 mm TL age-0, do not stray far from home shelter and ordinarily avoid the discharge current at Pilgrim Station, which, l l on an ebbing tide, can exceed 2.1 m/sec at the egress of the discharge canal. When the power station is operational, small cunner ollen are seen by our divers in a control area just outside the thermal discharge. Auster r i l 1 0987) reported that adult cunner forage further from reef substrate and on current-exposed surfaces longer than J 21 l l
s i do thejuveniles. As the current velocity decreases, smaller cunner mos e up into the water column out of the reef infrastructure and onto current-exposed surfaces to feed. This process is reversed as current velocity increases. , In 1996, habitat characteristics again were measured at each sampling site at the beginning (June) and end (October) ofour continuation of the recruitment study to establish similaritics amongst sites We generally counted reentits three times per week, weather permitting, from 27 June through 8 October, when the study was terminated because of severe weather and loss of the marker buoy / mooring at the Rocky Point site. As in 1995, the recmit data set was separated into two time periods, settlement and post-settlement, with 16 September being the dividing date in 1996. Ctaner larvac ucre rare in PNPS entrainment monitoring collections after that time (Mike Scherer, personal communicationR Unfortunately. this mid-September period also included a two-week > interval _(16 September - 1 October) in w hich we could not sample due to severe weather conditions. Sampling counts after mid-September (four days in October) represent the post settlement period. Habitat characterization amongst the reefs was investigated to ascertain if habitat was similar at the sites j sampled. No significant ditTerence existed in the proportion of structure to non-structure amongst the three reefs l at the beginning (X2 = 2.54, P = 0.28) or between the two remaining sites (White Horse and Discharge) at the end (X2 = 1.81, P = 0.18) of the study. Again in 1996, there was a noticeable decrease (ca.12%) in the
. proportion of structure over the course of the su vey at two sites (White Horse and Discharge), where pre- and post-study data were available. This probably is due to the less of..'acroalgae from storms over the season. No significant difTerence amongst sites was oberved in the substrate rugosity index, which reficcts structural complexity, when measured at the start of the survey (F = 1.90, P = 0.17).
Recruitment - overallpatterns. No recruits acre obsen cd until 15 July, and recruitment remained low j until after 30 July, with increasing densities (nollo m ) occurring thereafter iFigure 12). Recruitment at the l White Horse site was initially very low, and did not start to increase until 21 August. Bottom water temperatures (point estimates) at the three sites were similar during the period. Recruitment generally peaked in September 2 Michael Scherer, President, Marm Research, Inc., Falmouth, MA ' 22
i 1 Mean Recruit Density Per 10 Square Meters 100 ; Site l
- Discharge so Mwhite Horse
+ Rocky Point eo 40 N
20 s
/
on *
- A Y : m m x x x x x x x- d*
6/27 7/8 7/167/227/8) 8/2 8/78/128/168/238/279/6 9/10 9/16 10/2 10/8 Observation Day Figure 12. Mean cunner recruit densities (the average of 10 transects) per site per day for the recruitnwnt study in the Ngrim Station area. 27 June to 8 October 1996 at all sites, with maximal densities at White Horse (41.4) and at the Discharge (83.2) on 10 September and at Rocky Point (43.1) on 23 August. At all sites. recruitment densitics fell precipitously after 16 September. the last day of counts before two weeks of severe weather. Over a great majority of the settlement period (15 July to 16 September), the Discharge site had higher recruit densities than at Rocky Point and substantially higher than at White Horse, indicating that, on average. settlement was greater there than at the other two sites. This also occurred in 1995. Multivariate repeated-mcasures ANOVA showed the discharge to have significantly grcater recruit counts than the other sites for the overall settlement period in 1996 (Discharge vs. Rocky Point: I 23 j l
~ _ , -_. . . . _ _ _ _ _ _ - .
'l F = 24 81, P < 0.0001; Discharge vs. White Horse: F = 96.92, P < 0.0001), and Rocky Point had significantly greater cunner densitics than did the White Horse site (F = 75.31, P < 0.00011 The extremely limited post settlement data collected in 1996 presented a problem regarding data analysis and interpretation ofpower plant impact. We could not perform the same analysis as in 1995. October recruit densitics in 1996 were reduced at all sites but especially at Rocky Point and the Discharge (Figure 12).
The 1995, recruit densitics were not only higher in the settlement period, but also in the post-settlement period, with initial September values of 95-140 recmits per 10 m: at the three sites declining to the same level of I 2 approximately 55 per 10 m for cach sampling site at the end of the period in late October. In 1996, recruit i densitics at the termination of sampling in October were > l/m at all three sites. Such radical dilTerences (an order ormagnitude) between years i :'ost-settlement densitics make it impossible at this time to formulate any
)
recruitment process generalizations for cunne-in the Pilgrim area. A repeated-measures ANOVA was used to test post-settlement recruit densitics in 1996, for which we found White Horse values significantly greater than at both other sites for this period ( vs. Rocky Point: F = 22.58, P < 0,0001; vs. Discharge: F = 28.21, P < 0.0001). However, due to extremely limited post-settlement data and because habitat characterization could not be donc at Rocky Point in October, any conclusions regarding i i post-settlement processes as to implicatioris of power plant impact for 1996 are speculative. The severe weather during the last halfof September evidently resulted in the marked decline in recruit numbers at the sampling sites towards the end of the recruitment period. There likely was substrate scounng and habitat alteration with redoction of protective habitat (c g., macroalgac), w hich may have caused displacement of recruits to new sites or more likely outright recruit mortality. It ' poss.ble the White Hom site was less impacted by the storm events, and therefore recruits there had better sun ival Another possibility is there also may have been some late settlement at this site which would account for the higher recruit densitics there m October. This is the second year of cunner recruitment studies off Pilgrim Station. In both years, the amount of cunner eggs and larvac entrained at Pilgrim Station versus cunner recruit densitics seen on our dives matched up i i l 24 i
- = - - - . . -. - -. . - - . . - . _ _ _
well, with pre-settlement stages and recruits much greater in 1995. Levin (1996) reported a direct relationship between numbers oflarger cunner larvac in the water column and subsequent settlement otT the New Hampshire coast. Higher initial settlement overall occurred both years at the Discharge site. One could speculate the discharge current from Pilgrim Station produces an cddy which concentrates larvac there. allowing for higher
- settlement.
) Recruitment success for marine fish is known to Ductuate greatly from year to year, due to a host of s physical and biological factors (Sinclair 1988), w hich, in turn, has a major induence on structure of populations. It may well require several years of study to understand cunner recruitment processes near Pilgrim Station and the implications of power plant impact. We do believe that spawning was more successful in 1995. with i 4 substantially more eggs and larvae evident in entrainment sampling at PNPS. Delayed recruitment occurred at White Horse in 1996, which was not observed in 1995. Recruitment in 1995 apparently was more successful 4 than in 1996 and was regulated during the post-settlement stage by compensatory processes, e.g., density-dependent mortality via predation. Storm events may well have overridden other mechanisms driving recruit 1 success in 1996. Recruit sunival is innuenced by habitat structure / quality and how habitat quality (e.g., , macroalgal cover) alTects sunival. A marked efTect of power plant entrainment of pre-settlement cunner (larvac) l on recruitment success is more likely to occur during a recruitment season where larval supply and subsequent
- settlement are low overall. Implicit in this is that there is a direct relationship between larval abundance and d
recmitment success. Although recruitment is a demographic event of relatively short duration, the variation in recruitment, l i witW and among years, has a major innuence on population structure. Recruit levels should always be a major i i consideration when examining adult numbers in a population; however, other factors become increasingly ) important in high recruitment years. In good recruitment 3 cars, settlement is large enough for post-recruitment density-dependent efTects on settledjuveniles to be the major detenninant of adult population size. Conversely, in poor recruitment years, recruit limitation, i.e., density-independent fluctuations in recruitment, is c'.pected to 25 i _2
$ I J l be the major determinant of explaining patterns in adult numbers. At any other time, one may be more important l 1 than the other, Jones (1990) found with a coral reef, sedentary species that with recruitment densitics below I 2 recruit /m , adult numbers are recruit limited, but above I recruiths , post-recruitment density-dependent processes become increasingly important. The lont;-term effects of recruitment on population structure and dynamics are likely to be knowby studies coutmued over a time scale appropriate to the longevity of tbc species of concern (Jones 1990). ' Miks , t Adults also are impinged at Pilgrim Station, but the number has rarely been large. A review of temperature tolerance data on cunner (Kinne 1969) suggests the presence of an esclusion area within and just outside Pilgrim's discharge canal during summc r and fall when the plant is fully operational Howes er. cunner ' kills have not been documented (Lauton et al.1993). Our SCUBA observations in the thermal discharge area at flood tide from previous summers revealed the occurrence of far fewer cunner inside the mouth of the discharge canal than 60 m immediately seaward. We have measured bottom water temperatures exceeding 30 C at the mouth of the discharge, and it appears that cunner avoid the immediate area at this time ofycar. Cunner are susceptible to acute, local sportlishing mortality, because of their apparent smal' home range (Green 1975) and nearshore distribution. In the past, cunner led the shore-based sportfhn catch at Pilgrim Shorehont. None were reponedly landed the last several years, but this may be attributed to incomplete reporting during informal crect surveys conducted there. Tag returns from our multi-year capture recapture program clearly indicate that cunner are relatisely , stationary, at Ic'st during the warmer months off Pilgrim Station Our objective of the 1996 tagging was to monitor local movement of adult cunner along the outer breakwater. From June through August 1996.4,350 cunner (includes multiple recaptures) were captured in baited traps fished overnight at twc locations. Of these. 2,971 came from the seaward side of the outer intake breakwater at Pilgrim Station. From this pool of fish. 385 adults (2 90 mm TL) were tagged and released over 10 sampling days between 2 and 23 Ju y at marked (fixed) 26
}
stations,in order to ascertain short-tenn lateral movement of cunner along the breaku ater. The remaining I.379 cunner captured came from the landward side of the outer breakwater in the intake embayment. Du.ing the past seven years, we have tagged 6,506 cunner in the Pilgrim area. This relatively large sample size has provided tag-recapture evidence of cunner's site fidelity within a year and for consecutive years. For example,in 1996, with recapture efforts continuing through 23 August at the outer breakwater, ne had 161 recaptures of cunner tagged in that year, with all returns coming from the outer breakwater w here :he Gsh were tagged. No Ash traveled around or through the breakwater to the intake side Factors that must be considered when evaluating this > car's tag returns include the spatial shifting of traps ofTstation due to severe weather and the inadvertent movement of our traps by the daily Ashing actisitics oflobstennen in the area. Fortunately, such problems were infrequent, and data from moved traps were ' tracked and excluded from the analysis. There were multiple recaptures, e g ,35 cunner tagged in 1996 were recaptured more than once; one individual was retaken seven times and another eight. Lateral movement of tagged conner l along the outer breakwater during 1996 was minimal. Eighty-Gvc percent of the recaptured Ash had moved no further than 18.3 m or two trapping stations apart; of these, over half of all recaptures did not move from their original capture site. These data provide first-hand evidence that adult cunner in the Pilgrim area have a relatively small home range, a behavioral trait documented for Newfoundland fish (Green 1975) in our trapping efforts in 19%, we also recaptured two cunner tagged in 1992,3 tagged in 1993,36 in 1994, and 176 in 1995. All were f ! recovered from the same side of the breakwater where they had been originally tagged and released. Tag retention can be a problem when external tags are used. Cunner often take refuge under rocky outcrops and within crevices, so there is the potential for snagging and tag loss. In many Gnnsh tagging programs,the percentage of recoveries typically ranges from 3 to 10"; (Matthews and Reavis 1990) How es er, our technique of trappir.g conner and recapturing them in fish traps rendered an overall 9% tag return in 1992, 31% in 1993, i1% in 1994,26% in 1995, and 25% in 1996 (includes multiple recaptures). By recapturing our own tagged fish, we limit unreported tag isums. 27
. _ - . . .- . - - . - .. . . - .~ - --
In a cooperative venture with UMass Amherst, a graduate student, with our assistance, investigated fecundity of cunner collected off Pilgrim Station in 1994; this parameter was needed for the Adult Equivalent Model. We continue to conduct cunner aging work and are developing a synoptic age-length key, which has been ; I used to establish an age-specific fecundity relationship. We collected 145 cunner (67 to 222 mm TL) in our tra from the Pilgrim area for ageing in 1996; of these,125 were successfully aged, using otoliths (Table 2). The oldest 6sh were age 10. ' Most of the otoliths (N=100) were mounted on slides and hand-ground prior to analysis. Four individuals had crystallized, unreadable otoliths, while 17 could not be assigned an age according to our criteria (see Methods this section). Completion of annulus formation, which likely occurs in May in the Pilgrim area. was recently validated for the same time period for ou tetracycline-injected cunner kept in mes in the field under l ambient temperatures by researchers in Newfoundland (John Green, personal communication)\ This correlates , with annulus formation reported for late May June for fish in Buuards Bay south of Cape Cod by Scrchuk and l Cole (1974) and for May in cunner from Connecticut (Dew 1976). Both of these studies utiliecd scales for ageing. Annuli for whole otoliths could only be read reliably for fish up to three or four years of age. The benefit of usmg ground otoliths to accurately age cunner is apparent for Ash age-5 and older. There are larger cunner in the Pilgrim area, but they are excluded from entering our traps due to their si/c. Based on our project diving observations, these larger fish are not common. We have ground the otoliths from a few of these larger fish given to us by lobstermen from their traps and have estimated ages up to and over twelve years. Accurate ageing of these larger fish is difficult due to the crowding of the outermost annuli. 2 John Green, Biology Department, Memorial University, St. Johns, Newfoundland A I B3X9 28 1 ~- - , .-
l l l I t l l Iable 2. Ageirngth he f.a cunner (etsee mihined)in the Pilgrim Staaten arm 1996. A8' ! stalin toes [_eagth jmm) length category sampled ler age i 2 3 4 6 6 7 8 9 la n 5e J J 71 15 2 1 5 76 40 2 2 bl 95 3 3 I 86 H 3 ) 91-94 2 2 ta les 5 1 e 101.105 3 1 4 104 118 1 2 J 111-115 3 1 4 11612# 2 1 J l21 125 4 1 S 126. l je 1 4 5 151 135 3 2 5 3
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- 2. Rainbow Smelt
)
Backcround ; The start of the rainbow smelt (Osmerus mordar) spawning period in Massachusetts begins in late February south of Cape Cod to late-March in areas to the north. Reproduction takes place at night, and although there is no evidence of daylight spawning, small numbers (mostly males) remain on rpawning grounds in the daytime. During the spawning runs at night, the overall sex ratio can be as high as nine males to one female, in that individual males use the spawning grounds for up to eight nights, while female spawning activity spans no more than four nights. River spawning of smell occurs m freshwater or low salinity water, with fertilization taking place extemally. A female spawns up to 44,000 eggs, depending upon size and age. The eggs are demersal and adhere to gravel, rocks, and vegetation. Spawners prefer rif0e areas, and egg deposition is not uniform on the bottont After a night's spawning, most fish move downriver, and no parental care is rendered to the eggs. When spawning is entirely completed, adults vacate the spawning grounds and disperse in saltu ater. Our overall goals in working with smelt are to offset impingement mortalitics at Pilgrim Station and to increase the size of the local smelt population. i Eggs and Larvae The objective of for our 1996 smelt project uas to enhance luahty of smelt spanmng habaat m ihe Jones River, the major smelt-spawning tributary to PKDB, the ongin of the local population (Figure 1) We placed 130 egg collectine trays in a selected area of the smelt spawning ground on the Jones River to collect the naturally spawned smelt eggs and provide an ideal habitat for egg deposition and embrvonic development. Sphagnum moss 611s the trays and provides a depositional surface that has interstices, which in turn, give the depositional matenal depth. This 3-dimensional surface provides a micro-environment that offers protection for the dercloping embryos and thus reduces egg ' turnover' (loss). Water sceps into the moss, carrying away metabolic wastes and providing a continuous supply of oxygen to the eggs. 30 I i l I l 1
Sphagnum consistently collects higher egg sets than does natural hard bottom. The smelt spawning arca in the Jones River is comprised largely of hard bottom (sand, gravel, and cobble). Endemic attached macroscopic aquatic vegetation provides ideal substrate for egg development, but comprises less than a quarter of the bottom area on the spawning ground. Sutter (1980) reported egg survival to hatching was about 10% on vegetation but only 1% on hard surfaces. Our egg trays provided ca. an additional five percent of plant material to the upper spawning area. They ucre placed in areas where smelt ggs are known to accumulate and where natural attached vegetation is sparse. The portable trays allow us to maximiec egg suruvorslup in these areas by contmually providmg optimal habitat which would otherwise be in limited quantity. There was extensive variation in smelt egg densitics on natural substrate and on the egg collecting trays distributed throughout the Jones River smelt spaumng area However, the density of egg sets on the inys was more aligned with sets observed on endemic attached aquatic vegetation in most areas, the various plant substrates had higher egg densitics than the surrounding hard bottom. Ten replicate egg counts (obtained using squarc inch conting screens) of hard bottom in Zone A (Figure 13) had an average egg density of 15 eggs per square inch. Whereas ten seplicate counts on endemic plant material in the same arca averaged 42 eggs per square inch. Overall, egg densitics were r un street omn highest on the upper spawning ground, w hich ,,,, ,, _i g mue,m e. is comprised of Zone A and part of Zone B , cc. .e.
, egg tesys (Figure 13). In areas containing more than 50 eggs per square inch, we identified the sets as
- va zm a heavy; 20-50 per so,uare inch, moderate; and 4 m less than 20,lignt (Figure 13) ,
The 1996 smelt egg set in the Jon:s , ru= " River appeared to be the best of the past three Figure 13. smcli egg densities w nhin zones - ( n or the Jones River habitai years. About 95% of the substrate in Zone A cnhanecment arca,1996. 31
was covered by eggs of varying densities. The upper one third of Zone B was also blanketed by a light egg in 1995, egg sets were patchy, and most of the traditional spawning ground was unutilized (Figure 14). Conditions in the Jones River were favorable in the spring of 1996 for firn Street Darn successful smelt egg production, with
$ 5'"'",="'
mue g .c good water Hows, including many riflies " ' '" for dispersing the eggs and preventmg ett them from aggregating in one area. When zma the density of eggs per unit area is too _ high, i.c , more than one layer 'bick, sursival is usually poor. In many cases, a zu. D*2 fungal infestation will occur on the dead Figure 14. Smelt egg densilies in Zonca A & H wHlun the Jones River habdat enhancemen' area,1995. eggs, which can be detrimental to extant egg development and survival. The abundance of macro- algae, which was problematic last > car in much of the spawning area, was not realized this year Eggs can become entangled in the algae's long hair-like Glaments. resulting in reduction of u alcr How which hinders egg development During the 1996 smelt spawning season, Ecl Ris er, Town Brook and Smelt Brook (other inSutaries to PKDB) were inspected weekly for egg production. We sampled areas in these tributaries of known spawning activity and found little production in these three systems. Egg densities in these inbutaries averaged less than Ave cegs per square inch, with only small areas 'nving egg sets. The Jone- Ris cr. once again, hosted the majority of smelt spawning activity for the PKDB smelt population. In 1997, our focus again will be on habitat enhancement of the smelt spanning area in the Jones Ris er We u111 increase the number of collecting trays to ca 200, placed in areas of the river where attached plants are sparse and egg deposition has taken place in recent years By employing this manipulative procedure, we opt to 32
I 1 increase egg hatching. Saunders (1981) found that the most sensitive parameter dris ing future smelt population growth is egg survival to hatching. l l [uvenilqs Smelt impingement at PNPS in 1996 was estimated to be 3,674 Osh. Impingement in 1993, '94, and '95 totaled 9,560,10,644 and 2,335 smelt, res[x:ctively. A representative sample ofimpinged fish was measured each year. The lengths of these fish were compared to mean lengths of smelt by age-group from an earlier Jones River smelt study (L,wton et al.1990). The majority ofimpinged smelt were apparentlyjuveniles (ages 0+ and some 1+ fish). The Jones Ris er smelt spawning run has been relatively small for wcil over a decade, and these power plant mortality incidents may have impacted existing and future population growth. Mdis The number of spawning adults in the local population was especially depressed throughout the late 1980's and early '90s. It has been dif0 cult to obsen e spanning-run smelt in the Jones Ris er durmg many of our visits to this system even in recent years. The 1996 overall egg density in the Joner River indicated more smelt spawners and spawning activity than in the past few years. However, this increase in eggs and spawning-run smelt is still far below levels we observed in the early 1980's when we conducted con prehensive smcIl studies in the Jones River (Lawton et al.1990). From recent observations, it appears that the majority oflocal spawning has taken place over a relatively short time period of two to three weeks. This is further evidence of a reduced spawning smcit population,in that in the early 1980's, spanning took place over the to six weeks (Lawton et al 1990). Any substantial continued reduction in the local parent stock via impingement will likely be ads crse to fute stock rebuildmg efforts.
- 3. Winter Flounder Backcround Winter flounder (Merironectes amcricames) range along the northwest Atlantic coast from the Gulf of 33 l
I St. Lawrence to Chesapeake Bay (Bigelow and Schroeder 1953). A hardy species, winter Dounder can be found at temperatures between 0 and 24*C, and salinities ranging from 4 to 30L They can form discrete, resident populations, undertaking localinxi seasonal movements (Perlmutter 1947; Saila 1961; Houe and Coates 1975) Flounder movement appears to be temperature driven (Pearcy 1962; McCracken 1963; Scarlett 1988; Powell, unpublished data), with adults emigrating from shoal waters in spring when u ater temperatures rise above 15 *C, ) 1 l and returning as waters cool below this level. Some groups of wmter Counder are apparently nonmigratory. ; Although an avoidance temperature of 24.4 C was reported by Meldrim and Gift (197I), year-round occurrence ; i has been documented in certain estuaries (Olla et al.1969; Wilk et al Io'?) c.t vcaser tempratures as high as 24"C. Additionally, Phelan (1992) found adult winter flounder ycar-round in an area offshore of New York and New Jersey.
' Based on meristics, Pierce and Houc (1977) stated that estuarine groups of winter Oounder do not i necessarily constitute separate genetic or biological units. A group may be comprised of an assemblage of adjacent estuarine spawning units, of which some may be more geographically isolated than others lionung patterns have been documented in some estuarine systems (NUSCO 1986; Black et al 1988; Scarlett 1988.
Phelan 1992; Powell, unpublished data), and several tagging studies (Lobell 1939, Perlmutter 1947; Saila 1961; Howe and Coates 1975) have provided evidence of fidelity to specine embayments for spanning following offshore migrations. At the same tim; some winter Counder disperse to distant locations (Saila 1961; , McCracken 1963; Howe and Coates 1975; Phclan 1992). There may be a random scarch for natal spawning grounds (Saila 1961) or random food scarches (McCracken 1963). Phelan (1992) speculated that populations may be discrete only during spanning, and random temperature-related seasonal movements couU nit m intemiixing at other times eithe year. If the scarch for natal spawning grounds u as also random, winter flounder might be found in non-natal locations durmg the spawning period. From mark recapture s. ort in the inner New I York Bight, Phelan (1992) concluded that ninter Counder there formed a dynamic assemblage. consisting of three reproductively discretc spanning populations.one that " homes" to natal spaninng grounds in ihe Nas esink 34 I l i l
and Shrewsbury Rivers, (2) an aggregation found in Sandy Hook and Raritan Bays, and (3) a group found offshore, with all three capable of intermixing. In Massachusetts waters, Lux et al. (1970), Howe and Coates (1975) and Picrec and Houc (1977) 4 concluded from meristic and tagging work that, for management purposes, winter Oounder consist of three stocks one north of Cape Cod, another south and cast of Cape Cod, and the third on Georges Bank. Extensive tagging of winter Dounder (more than 12,000 Osh) in Massachusetts (2 I tagging locations) during the 1960's by llouc and Coates (1975) revealed that Dounder nugration generally encompasses relatis ely short distances, howes cr. some extensise movement of tagged fish did occur. Flounder dispersal u as more estensis e south of Cape Cod. where many areas are shoal (<!8.3 m), and waters warm considerably during summer. Overatl. returns from release sites north of Cape Cod showed more limited movement, with many marked Osh recovered in respective subarca release sites, even years later. Winter flounder spawning apparently occurs at night and when water temperatures are at or near the nadir i for the year, occurring during late winter and early spring. Most spawning occurs below 6"C. Spawning and nursery areas are found in estuaries (bays, rivers, harbors), over shoals outside estuaries, and on offshore banks. l The eggs are demersal and adhesive, u hile the pelagic larvac are relatively nonhuoyant and can move vertically 1 in the water column, thus somcubat offsetting the efTects of a diffusive pelagic environment Age 0 fish l (juveniles) are demersal and remain in nursery areas (Buckley 1982)
]
l The PKDB estuary, not far from Pilgrim Station, is considered a primarv local spawning ground for winter flounder, although spawning also occurs outside this estuary (Figure 1). The local population is exploited by a regulated otter trawl Oshery that is open from i November to 3 l Januarv; with a minimum legal si/c of 305 mm TL. In past years, the Oshery was open into the spring, but declining Dounder abundance prompted a mandated reduction in effort. Spawning success, recruitment, and population coherence is maintained where physiography and oceanographic circulation enhance larval retention in speci0c geographic areas Size of spawning grounds and 35
,. . . - _ - ~ _ - . ~ _ - - . . ~ . ~ . - . - - - - . . - - - . - - . - _ . - _-
. larval retention areas is a limiting factor to absolute abundance. Winter Dounder population size is a function of the size of the physical system underlying larval retention. Large populations are often found in large bays l and on offshore banks; whereas, smaller populations are associated with coastal ponds and estuarine river J. 1 systems (Howell et al.1992). Clearly, the impact of a given mortality (power plant related or otherwise) is I l
inversely related to the absolute abundance of the population affected. i
- Habitat quality can be an issue on inshore nounder spawning grounds because these areas are typically
- subject to a.athropogenic alterations and environmental degradation. The different Oounder life stages can be r l greatly alTected by the dredging and filling of wetlands, toxicants, disease infestation, and power plant induced l mortality. Direct mortality or the loss of reprochietise and growth potentini can result. Impingemem and a
- entrainment of winter Counder can substantially add to total mortahty. Impmgement inues may be especially 3 1 l problematic when power plant intakes are located in or near nursery grounds (Normandeau 1979), such as at >
Pilgrim Station. All life stages of winter Counder at least seasonally inhabit this arti0cial embayment, which 4 simulates a cove. Eggs and Larvae , 4 i The pelagic larvac of winter flounder are more susceptible to power plant entrainment than are their eggs, a which are demersal and adhesive. The benthi pelagic lavae are generally more abundant near the bottom of the j water column and, thus, are especially vulnerable to entrainment as bottom water is drawn into the intake. At i Pilgrim Station, entrainment ofwinter Counder larvac has ranged from an estimated 3.5 to 22.5 million annually a j over the last 10 years (1987 to 1996); the 1996 estimate was the highest recorded during this period. , Larval monality due to entrainment at pilgnm Station in 1996 assuming no survival and using the Adult 1 Equivalent Analysis, which assumes population equihbrium and no density-dependent compensation. equates ? to the highest loss (15,727 age-3 winter Dounder)in the last 10 y cars. Gibson (1994) exammed data for several j winter Counder populations and found that after taking into account adult mortality, recruitment rates were lowest in the three populations (located in Mt. liope Bay, Niantic River, and off Plymouth) that are subject to ) 36
.i i 4
)
i entrainment by nearby power plants. l i Delimiting the geographic extent of the local population is important to estabbsh the source of not nder 4 l. lan ac entrained at Pilgrim Station.. Pilgrim Station entrains larval winter Gounder produced in PKDIL but aho from sites outside the estuary (Marine Research, Inc 1988). Evidence of winter Counder spawning outside the j cstuary complicates our estimating adult stock size and assessing power plant impact. 1 4 J.iiveniles , In 1996, an estimated 866 winter flounder were impinged at Pilgrim Station. The majority were juveniles 1 2 (age-O and 1). Winter Counder generally are impinged throughout the year. No further studies of age 1 winter flounder were conducted by the MDMF in 1996. I
- Adults j Direct mortality of winter Counder has been rare in the thermal plume olT Pilgrim Station When exposed !
l to high water temperatures, Counder may vacate t.n area. if possible, or try to avoid thermal stress by burving into I the bottom which would be lower in temperature than tN overlying water (McCracken 1963); Olla et al 1969) ! l Occasionally during past summers, bottom water temperatures approached 30"C at the mouth of the Pilgrim discharge canal. Stone and Webster (1977) predicted that adult winter nounder would be excluded by thermal l stress from the immediate vicinity of the Pilgrim discharge during late summer and early fall. This impact area is small and is believed to be less than 4,047 m 2. No winter Counder were reported caught by anglers at Pilgrim Shorefront in 1996. In the 1970's and early '80's, this species ranked among the top five sponfish angled in the recreational fishcrv off the power plant.
.As in 1995,we contractai the F/V Frances Ehrobeth, to catch winter 00t'nder, both for tagging and to l
cstimate absolute abundance via density extrapolation. From 108 tous in the study area in 1996. we caught a total of 6,708 winter nounder, of which 4,997 (2 250 mm TL) ucre tagged Overall, winter nounder length measurements from these catches ranged from 75 to 522 mm TL. From 1994 to 1996, we tagged 7.289 winter Hour Jer during the spring spawning period m Arcas I and 37
2 of nestern Cape Cod Bay (Figure 15). The number of fish tagged by year is: 1994 - 226 fish (d 20 cm TL); , i 1995 - 2,066 fish (2 20 cm TL); 1996 - 4,997 fish (> 25 cm TL). All fish were released in the general vicinity of capture. . Tag returns were obtained from commercial and recreational fishermen, and through our research efforts Through December 1996,218 tagged winter flounder had been recaptured for an overall return rate of l 3% A similar recapture rate (2.8%) was reported by Phelan (1992) from 7,346 winter flounder (2 18 cm) tagged , in the Inner New York Bight in the late 1980's. In many fish mark and recapture programs, the percentage of returns ranges from 3 to 10% (Matthews and Reavis 1990). By way of contrast, Howe and Coates (1975), working in Boston liarbor and Plymouth Outer Harbor, reported overall flounder tag return rates of 58% and - 35.8%, respectively. It should be noted, however, that these return rates were compiled for longer periods of time ; after the flounder were tagged. Poor reporting of rccaptures and spatio-temporal bans on commercial fishing in inshore waters likely contributed to our and Phclan's (1992) low return rates. The matter of poor reporting has been exacerbated by the small amount (MDMF) or absence (Phelan 1992) of a monetary reward for tag returns. I in 1997, MDMF will offer a one-time prize of $500.00 for tag return information. The winner w dl be chosen by lottery from a pool of all returns. Of the 218 tag returns (commercial, recreational, and research catches) from 1994 to 1996. we have - recapture locations for 172 (79%). Of the later, the returns bv reapture area (Figure 15) are found in Table 3. Highest returns (50%) came in the fall, especially in November. Spatially,49% (107 fish) of the total recaptures came from Area 2, where they were tagged during spring spawning. Thirty of these flounder were tagged in 1995, while five were recaptured aller two years at large (1994). Despite the overall low tag-return rate. there i is evidence of" homing", or at least, partial fidehty to the local spawmng area. Nonetheless, geographical isolation is not complete, as some fish were retaken during the spawning period in other /ones i Density extrapolations (Area Swept Method) were made from data collected on the F/V Franccx hhzabc/h to estimate winter flounder population size - one for flounder 2 280 mm 1 o (age-3 and older adults), , 38 , [
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l l l the other for winter Counder of all siics (Table 4). The areal measureme Table 3. Tag returns by mira from 7,289 ninter nounder marked during the span ning season in Areas I and 2 from 1994-1996 off Cape Cod. A rea Number of Perrent of Recaptures Total Recaptures 1 3 1.7 2 107 62.2 3 I o.6 4 29 16.9 5 9 5.2 6 16 9.3 7 7 4.1 Total { 172 Table 4. Estimated numbers (bottom area calculated at M LW), with 95% confidence intestals, of ninter nounder 2 280 mm (TL) and for pooled lengths, collected by otter tranl(not adjusted for gear efficiency)in the Pilgrim study area,12 April to 3 May 1996. Area Number of Upper Lower (square meters) flounder 95% Cl 95% Cl Flounder 155,460,127 92,147 IH2,947 1,346 2 280 mm T1 All flounder 155,460,127 14N,345 26H,920 27,769 Our estimate of winter Counder numbers for the area sampled (see Methods section, this report) using this approach was 92,147 age-3+ (> 280 mr- TL) Osh and 148,345 ::al winter Counder (all ages and si/cs) These estimates are based on a trawl gear emeiency of 100% As gear efliciency is probably s 50%, the adjusted l estimates would be 184,294 adults and 296,690 total Counder. As might be espected, precision varied widely (Table 4), so that comparison with 1995 estimates has limited value. Some variation around the pooled estimate , can be attributed to gear selectivity. As we were using a 7.6 mm mesh cod-end, few small fish were retained. . 40 i
An expanded estimate of abundance is, therefore, biased toward larger fish. It should also be noted that the adult estimate for the study area does not necessarily equal the total number of adults in the local population Spatial variation of this species can be great, as demonstrated by Lawton et al. (1995). As we hase primarily been seeking flounder for tagging purposes, we have not always evenly distributed sampling efTort. Based on modeling predictions of the origins of eggs and larvac, we plan to expand the study area in 1997, and, after tagging, will allocate several days of trawling to a comprehensive sweep of the sampling area. During this time, we will attempt to ensure complete coverage of the area To calculate a percent loss of adult winter nounder, we used the estimate of equivalent adults (15,727) obtained from entrainment monitoring and our estimated number of adults (184,294) residing in the study area, as defined for 1996. The estimated adult loss because of entrainment corresponds to approximately 8.5% of the adults we projected to be found in the Pilgrim Station study area during the 1996 winter Counder spawning season. However,it must be remembered that it would have taken approximately three years for most of those entrained larvac to reach maturity. During that time, natural mortality rates could vary widely, greatly affecting survival. A review conducted by Marine Research, Inc. (1986) of winter Counder early-life studies at Pilgrim Station concluded that stock reductions of 0.7 2.2% (relative to stock size then) were possible. Given that coast-wide winter nounder stocks have been severely depressed, entrainment could be a signiGcant cause of mortality to a very localized population However, we must be cautious in drawing this conclusion as we have not yet fully defined the degree of Odclity to the spawning area, or sampled within the entire boundaries of the local population as denned by modeling. Based on the predictions of the output model created b) Eric .Wms of M i T , we now knm that winter Counder larvac may be coming from up to 17.7 km away from Pilgrim Station Accordingly, in 1997 we will expand our study area further to the north, off Humarock (MarshGeld, M A), to ensure coverage of this potential source oflarvac. 41
i
- 4. Other Soccies Data on other species were obtained from a Pilgrim Shorefront crcel survey. Additionallh several SCUBA dives were made in the Pdgrim Stanon discharge area during the sumn cr to observe fish occurrence and for signs of distress or mortality to biota.
The 1996 crcel sun cy of shore-based anglers at the Pilgrim Shorefront Recreational Area was conducted t between 13 April and 13 October, with 2,599 anglers inteniewed during 130 sampling days over 7 months. The intent was to obtain basic information on sport 6shing activity - Gshing effort and game 6sh catch over time, including catch rates. There were two data collectors, who as seasonal public relations personnel for Boston Edison Company, conducted the survey in addition to other duties. The interviewers focused on surveying Ashing activity la the discharge area Only weekends were inventoried in April and May, w hile only four days in October were canvassed. The daily coverage from June through September was good for activity in the area of the discharge. The overall monthly average number of angler trips per day was 20 and ranged from a low of 2 in April to 27 in July and August. The total recorded catch was 3,854 Gsh, comprising only two species - bluefish and striped bass. The overall mean catch rate (i c., catch per angler trip) was 1.5, while the monthly average ranged from 0.4 (April) to 1.9 (July). In 1996, the percent composition of the recreational gamc6sh catch overall was 52% blue 6sh and 48% striped bass. The highest monthly catch (pooled species) occurred in July (l,550 fish - 40% of total), folloucd by August (1,073 Gsh - 28% of total) and then June (21% of total). Striped bass dominated monthly catches Apnl through June and ucre caught all seven months of the creel
)
l surwy. Of the 1,840 bass reportedly caught, most were sublegal(< 86 4 cm TL), only a dozen bass were legal l 2 86.4 cm TL, with the largest being i14.3 cm TL and weighing 15 8 kg. The highest .nonthly catches ucre ! recorded in June (38% of total bass catch) and July (36% of total), followed distantly by August (12%) and May (7%). The oserall catch rate, as catch per day, averaged 14 2 bass, with monthly rates high in June (24.5), July 9 42 1
f (22.2), and May (20.5). The seasonal catch of striped bass was the highest recorded at Pilgrim Shorefront since its opening to l the public in the early 1970's. A much more plentiful supply of striped bass along the Atlantic coast in recent years ostensibly contributed to the clevated catches of this species at the Shorefront. Pilgrim Station's warm water discharge has consistently attracted feeding bass over the years when the plant is operating and with both circulating seawater pumps in use. Pilgrim Station operated at a station high in 1996 - 90.5*4 of thermal capacity. A few dozen overwintering striped bass were observed in the discharge canal during 1996, which makes them suscepuble to mortality if PNPS were to experience an outage in the winter. BlucGsh were first angled in June of 1996 and led monthly catches July through September. A total of 2,000+ bluefish was caught at the Shorefront, with a variety of sizes landed. including 4 5+ kg individuals. Highest monthly totals were garnered in July (44% of seasonal total) and August (42% of catch) Catch rates (catch per day and catch per angler trip) matched up well with the total monthly catches: the former being 29.5 Gsh per day in July and 27.2 in August, with the latter at 1.1 Gsh per angler trip (July) and 1.0 (August), respectively. The 1996 catch of blucGsh closely parallcis the bluefish catch in 1985 (2,200), which was the highest recorded to date. It is evident that when Pilgrim Station is operating, the uarm-water discharge current. concentrates blocGsh at a point source within casting distance from shore and is ads antageous to sportGshermen. I Recreational catches at Pilgrim Shorefront have been notable as to the number and si/.c of Gsh caught over the years when the station is operating. Power outages at the station maikedly reduce sportGsh catches of blueGsh at the Shorefront (Tabic 5). Our underwater Gnfish observations provided limited visual data on the occurrence and general abundance of finGsh in the immediate area of the themial efiluent. From late-July through mid October (a period ~ 1 l ofhigh ambient water temperatures), monthly SCUBA-dives were made within the mouth of the discharge canal I and adjacent area. Striped bass and tautog were commonly observed, although small aggregations of cunner also l l 43 l l l
k were present. I Table 5.14cercational bluefish catches at the Pilgrim Station Shorerront in relation to plant operation und resultant discharge ora thermal plume Year Number or lleported Perimi l't.mt Status j litucthh j 1973 5(M) September-October On -line 1974 700 September-October On line 1975 14 September-October OtT line 1943 1.2tH) June Nosember On -line 19115 2,200 J une.Nm emiwr On line 19N4 less then 1b0 fish J une.Nm em ber OtT-line .
& ror the two y earn j 19#6 rumbined l
1996 2,014 June / October On -line Striped bass were recorded on all dives. Abundance increased over the summer, peaking in late September /carly October when divers contmonly obsen cd 75+ individuals on cach dive. Tautog also were l observed on all dives. Their numbers were relatively consistent over the season, ranging from 24 in 36 l individuals per dive.
- 5. Impact Perspective Cunner, winter nounder, and rainbow smelt were selected for investigative work, that involves assessing impact of Pilgrim Station (Table 6). The response of these species to perturbation may be illustrative of power plant-induced stresses on other marinc GnGsh in the area in 1993 and 1994, rainbow smelt annual impingement at PNPS was relatis :!y high - ca 9.500 and 10.600 fish, respectively. Impingements of that magnitude under a condition oflow population numbers may have markedly impacted local rainbow smelt. As a remedial measure to offset power station impact, Boston Edison Co. funded our stocking of over 1.8 million smelt eggs into the nearby Jones Ris er in 1994 and 1995. In 1995 and 1996, we also placed egg collecting trays into the stream to enhance spawning habitat for the purpose of 44
Table 6 A summan of mechanical impacts of Pilgnm Nuclear Power Station on selectal fmfish species and mitigation undertaken in the offsite waters of westem Cape Cod Bay. Specie- Irnpact of Pdgnm Nuclear Power Statwn Comments %tigatian isminlure smelt ifigh impingensent incidents occurred in Decensber 197M,'93, 1 o remunerate for 1993 impingement losses, we stocked oeer
'94. In 1993 and '94, alone, an estimated 20,0810 smelt were 1.N million smelt eggs oser the ye. ors - 1994 and '95. into the impinged at the . ant which could has e serious local impact nearby Jones Itiser, the prime smelt spawning ground.
considering popularlost numbers in recent years. As a form of aquaculture,we have enhanced spawning liabitat em the Jones itiser smelt run by adding stilAclat plant substrate for egg degwsition to imprese instream egg sunisat in 1995 and 1996. This helps compensate for the 1993 and 1994 impingement losses, and this effort is recomniended to be omrinued until srnett spanning nm numbers substantia!!y increase them the present iesel of abundance. Winter nounder In 1996, an estimated high of 22.6 niillion winter flounder Abiolute abundance of adedt winter flounder in the study area larsac were entrained, which equates ta the loss of 15,'F27 age.3 during the spring spawning period of 1996 was estinanted to be nounder frwra the torni population. IM4.294 finit I ntrainnwns losses, as related to adults, equa'ed 8.5% of the In April and May 1995, there was a schedeled plant outage possible esisting adults in the study area. t floemder spawning months), when only one circulating water pump mas in operation. This reduced the cooling water stdume An estimated 866 Gounder mere inpnged in 19*8v, the majority drawn into the plant by 50% and concomitant!y entrainneent of were juseniles. =inte r flounder larvae. Plaat outages scheduled at this time of year are desirable and recoenmended to minimire impact on Additional years of data would be desirable of population this spet-ics, as well as other springtime ppewners. estimates for winter bunder to adequately assess inspect. Cunner in 1996, an enimated 3,176.W 2 s 8 0' cunner eggs and 17.1ou s of the reef arvas (natural and artificial) sampled in the study 10* laivw were entrained, which equates to the loss cf 5MM,997 as ca for cunner mari and recapture, the largest sub unds of the 4idts from the local population. local population per eardt area occuri off the outer intake breakuster, where estimates of cunner adults approach 5,noO An estimated 211 runner near impinged in 1996. thh. Constructed to protect the intake from wese-related damage, the breakwater prwvides an abundance of structurnity itecause of the diffuse nature of cunner on rmky reefs in the o.mples habitat critical to canner sun h mL As such, PN PS area,it is difficult to awess population lesels, an-1 a omst rm tion of this structure may hase allowed local cunr:er era nutment approach io impat can he undet14 ken alw nest f
- atmndance to flourish beyond what ovuld be supported y ears. naturally.
Alewife in September 1995, about 13,100 jusenite alewives were Natural repteduction was the esclush e means relied on to impinged and presunned to has e die *t. The potential for this or seplace the lost alewises, and no restocking was recommended.
..ther spettes to be impinged in large numbers make future llones er,we did reconmiend a measure of habitat impingement monitarir.g udsisable, so mitigath e measures can rehabihtstion. To imprese the passage of spanning-run be undertaken as necessary. at
- ben in local streams, we obtained a sum of money frwm HECo to help fund the repair of a fhh ladder in the Pilgrim station art-a.
Atlantic sihesside An estimated 11,900 ANntic whersides were impinged in 2 % o.nipensatory action was taken at this time because the separate incidents at PN PS, occurring in late Ne ember and Tilantic sih ersede is shost-lised, and prohfic. Base December 1991 This species is :)pically dominant and h impinged in high numbers, estimated at ses cral thousasul imfisiduals annually during enany of the past 3 ens, at p3 PS.
l i optimizing egg survival. This latter effort should be considered whenever PNPS impacts large numbers of rainbow smelt and until smelt spanning-run numbers substantially increase . Entrainment ofcunner eggs and Ian ne in 1996 at PNPS equated by the Equivalent Adult Analysis model i to the loss of an estimated 589,000 adults from the local population. Entrainment of this magnitude appears to , be substantial, but the importance of this loss to the local cunner population is unknown. We now have geographical bounds on the local population, which include the area of major recruitment sources. We have recent estimates of abundance for local (PNPS near-field) sub-units of this population only, using mark and capture-recapture techniques. Absolute population estimates may be impossible to obtain because oflogistics and Gnancial constraints, so recruitment, considering the large number of equivalent adults lost because of ; entrainment, trended over a number of years can be used to analyze for power plant effects. The 1995 cunner recruitment study revealed that recruit success that year was regulated primarily at the post settlement stage by compensatory processes, which implies that the plant's impact via entrainment of cunner larvac was probably inconsequential. The 1996 recruitment study was inconclusive as to plant impact. Stomi j 1 events prematurely terminated the study and were the cause for altering the patterns of reenmment at the
]
. termination of sampling. Lan al winter flounder entrainment in 1996 would have resulted in about 15,927 equivalent adults (age-
- 3) lost to the population. We estimated population size h 19ei (184,294 adults) by an area sucpt approach (density extrapolation) using a bottom trawl. We now know uc probably did not sample the entire spatial range I of the local population and, thus, likely underestimated total abundance. Consequently, the impact of the power plant would be overestimated. Again in 1996, uc calculated population abundance by expanding the n crage fish density obtained by trawl oser the sampled area. This equated to an entrainment loss of 8 5% of the possible existing adults in this area. Mark-recapture data of sescral years are necessan to address the question of population discreteness and to generate an independent estimate of population si/c, because of the low number of winter flounder tag returns obtained through the present.
46
In 1994, there were two incidents of high impingement of Atlantic siis ersides (Afenidia menidia) at 1 1 Pilgrim Station: 28-29 November 5,800 fish and 26-28 December - 6,100 Gsh. In 1996,it was the dominant l l i species impinged and typically has led all other species, with an estimated several thousand impinged each year.
]
l No renumeration action was taken because the silverside is a proliGc annual species and has no commercial and only limited recreational value. However, the silverside is an important forage species and should be monitored for impingement. A relatively high impingement of alewives (Alosa pseudoharengus) occurred at Pilgrim Station 8 9 f September 1995, when an estimated 13,100 individuals died. The alewife is important as bait for the lobster and I recreational fisheries,while its roc and flesh are used for human consumption. Employing a special publication of the American Fisheries Society (1992), we assessed 'bc monetary valuation of this fish kill t, be about , $5,000.00. The Division of Marine Fisheries negotiated with Boston Edison Co. for this sum of money, which i was granted to the Division to be used for habitat rehabilitation (i.e., the money will go toward rebuilding or l repairing a river he Ting fish ladder in the local area). Large impingements of alewives have been uncommon in recent years at PNPS. Nevertheless, impingement monitoring chould be continued for species susceptible to high impingements on intake screens, so appropriate mitigation measures can be undertaken when warranted.. 1 l i 47
- - . . . - - ~ - - . . . . . - . . - . -- .-
t V. CONCLUSIONS Conner 1. Impingement of cunner at PNPS is not normally a major problem Annual impingement has been relatively low since 1980, when an estimated 1,683 cunner were affected. Impingement in 1996 totaled j only about 21i fish. 2. Large numbers of ctmner eggs and larvac are entrained routinely at Pilgrim Station cach year. In 1996 alone, the number entrained equated to the loss of ~589,000 adult fish from the local population. 4 3. The settlement phase of cunner recruitment in 1996 differed from that in 1995, as overall recruit densitics were lower from the start, and the White Horse site experienced a substantial delay in onset of 1 ,' recruitment in 1996.
- i. 4. The 1996 recruit survey post-settlement data collections were prematurely terminated in 1996 due to adverse weather conditions (storm events), thus complicating data analyses. Recruitment was not as successful as in 1995, with recruit densities at the termination of sampling in 1996 being an order of ,
magnitude lower.
- 5. Analyses of the 1995 recruit data indicated that density-dependent compensatory processes (difrerential mortality via predation)in the post-settlement period hkely drove recruitment success, with power plant impact (through larvai entrainment) probably of minimal consequence.
- 6. Several more recruitment survey s should be conducted to help us understand recruitment processes near Pilgrim Station and potential power plant impact.
- 7. Stressful high water temperatures la ely cause an avoidance -sponse of cunner to the discharge canal and near. thermal plume during late summer /carly fall.
1 i
- 8. The ef0uent at the Station is of sufTicient velocity to cause a small-scale shin in the distribution of cunner by size, with only larger cunner seen residing in the path of the discharge current at Hood tide.
- 9. No cunner were reported caught by anglers at the Pilgrim Station Shorefront in 1996. however, this is !
4X
l l l likely due in, part, to incomplete surveying and reporting in the informal crect census.
- 10. The tagging of 385 cunner this year and subsequent recapture information help conGrm that this species has limited seasonal movements and shows high reef fidelity. )
l
- 11. A total of 125 cunner (selected specimens) from the Pilgrim area w as aged, fish range up to age-10.
Rainbow Smejl l l 1 1 High impingement incidents of rainbow smch occurred at Pilgrim Station m December of 197X. 93. and
)
'94. For the last four years (1993-1996), smelt impingement at the power plant was estimated to total !
24,835 fish, which would appear to be is a substantial loss to the local population.
- 2. For the past two years,we have enhanced the quality of spawning habitat on the Jones River by placing specially-designed egg collection / incubation trays, filled with sphagnum moss. on the Jones Riwr spawning grounds.
- 3. The Jones her smelt spawning habitat enhancement project should be considered for continuation for several more years or tmtil spawning-run smelt numbers substantially increasc. The run will be moni:ored visually for adults and for afg densitics. Highest quality spawning habitat is limited in this )
l river system. The presence of egg collecting rays resulted in an increased number of their demersal. l 1 adhesive eggs being spawned on ideal habitat, thus optimizing egg survival l i Winter Flounder
- 1. The nearby location of winter flounder spawning (retention) grounds, the relatively limited movement l.
pattems of flounder north of Cape Cod, and the geographic bounds of the local population make this species sensitive to impacts from entrainment and impingement at Pilgrim Station.
- 2. In late summer, water temperatures in the immediate vicinity of Pilgrim Station's thermal discharge can 49 l
\
cxceed ine avoidance temperature (24'C) for winter flounder and exclude them from this relath cly small (~ 4,047 m 2) area of stress.
- 3. In 1996, an estimated 22.5 million winter Dounder larvae were catrained at Pilgrim Station, which i
l equates to the equivalent loss of 15,727 winter nounder from the local population. This is the largest cntrainment of the last 10 years. I
- 4. In 1996, an estimated 866 winter Counder were impinged at Pilgrim Station; the majority were juveniles ;
(age 0+). Impingement is a source of mortality, but is not as major a factor as entrainment. t
- 5. We tagged 4,997 winter flounder in 1996, bringing the total tagged to 7,289 Gsh.. By the end of 1996, ;
218 tags have been recovered from commercial and recreational Gshermen, and our research catches. ! Our recovery rate (3"1) is low, being hampered by the relative number of tagged fhh for the siec of the 1 area, the sporadic reporting of tagged ush, and the seasonal closure of the area to commercial fishing in 1997, we will expand the study area (based on modeling) and the actise time of tagging and Ocid sampling, again contracting a fishing sessel to tag, as well as recapture tagged winter Gounder. !
- 6. We estimated by density extrapolation that in the Pilgrim study area (Figure 1) in spring 1996, winter flounder numbered 184,294 adults (a 280 mm TL). It is noted, however, that precision of the estiniate ,
is not high. ! 9 50 l I i 4
VI. ACKNOWLEDGEMENTS The authors thank Wayne and Dana Bassett of Canal Marine Fisheries, Inc. for donating the bait used during cunner tagging. Erin Casey helped with data entry and field work. Thomas Hoopes of MDMF produced the GIS map of flounder recapture areas. Win Sibley and Harold Daniels of Boston Edison Company collected sportfish data at Pilgrim Shorefront. Jay Burnett from the National Marine Fisheries Service in Woods Hole, MA, and Wayne Chiasson from Guelph University, Guelph, Ontario assisted in the ageing work with cunner. We appreciate the guidance of Robert D. Anderson of BECo, W. Leigh Bridges of our Dit ision, and members of the Pilgrim Administrative-Technical Comnuttee. Their input on various studies and editorial comments on project reports and papers have been most helpful. Si I i
1 l VII. LITERATURE CITED American Fisheries Society.1992. Investigation and Valuation of Fish Kills. Special Publicatl Anderson, R.D.1990. Impingement oforganisms at Pilgrim Nuclear Power Station. In: Marine Eco' Related MA. Braintree, to Operation of Pilgrim Station, Semi-annual Report No. 35. Bcston Edison Com i Anderson, R.D.1993. Impingement of organisms at Pilgrim Nuclear Power Station. In: Marine Eco Related MA. Braintree, to Operation of Pilgrim Station, Semi-annual Report No. 41. Boston Edison Comil Auster, P.J.1987. The effects of current speed on the small scale spatial distnbution of fishes. NO Ser. for Undersea Res. 2(2):7 16. Bigelow, H.B., and W.C. Schroeder.1953. Fishes of the Gulf of Maine. U.S. Fish and Wildlife Ser Bulletin. 53:577 pp. Black, D.E., D K. Phelps, and R.L. Lapan.1988. The effect ofinherited contamination on egg and larval winter Dounder, Pseudopleuronectes americanus. Marine Environmental Research 25:45-62. Bridges, W.L., and R.D. Anderson.1984. A briefsurvey of Pilgrim Nuclear Power Plant effects upon the mann aquatic environment, pp. 263 271. In: J.D Dasis and D. Merriman (editors), Observations on the Ecology and Biology of Western Cape Cod Bay, Massachusetts Springer-Verlag, Berlin. F.R.G 289 i PP. Buckley, L.J.1982. EITects of temperature on growth and biochemical compeitmn oflarval winter Counder, Pseudopleuronectes americanus. Mar. Ecol. Prog. Scr. 8:181-l 86. Dew, C.B.1976. A contribution to the life history of the cunner, Tautogolabrus adspersus, in Fishers Island Sound, Connecticut. Chesapeake Science 17:10I 113. Edwards, D.C., D.O. Conover, and F. Sutter 111.1982. Mobile predators and the structure of marine intertidal communities. Ecology 63 (4): 1175.I 180. Gibson, M.R.1994. Population dynamics of winter Counder in Mount Hope Bay in relation to operations at the Brayton Point Electric Plant. R.l. Division of Fisheries and Wildlife. Kingston, R.I. Green, J.M., and M. Farwell.1971. Winter habits of the cunner, 7'autogo/abrue adspersus (Walbaum 1792), in Newfoundland. Can. J. Zool. 49:1497-1499. Green, J.M.1975. Restricted movements and homing of the cunner 71nnogo/ahrus ad per.un. Can. J. Zool . 53:1427-1431. I Howe, A., and P. Coates.1975. Winter Oounder mos en ents, growth, and mortality off Massachusells. Trans. l Amer. Fish. Soc. 104:13 ?9. ^ , 52
N i J Howell, P., A. Howe, M. Gibson, and S. Ayvazian.1992. Fishery Management Plan for lashore Stocks of Winter Flounder (Pleuronectes amcricanus). Fisheries Management Report No. 21 of the Atlantic States.
- - Marine Fisheries Commission.138 pp.
l Iwanowicz, H.R., R.D. Anderson, and B.A. Ketschke.1974. A study of the marine resources of Plymouth, Kingston, and Duxbury Bay. Monograph Series No.17. Mass. Div. Mar. Fish. 37 pp, i Jones, G.P 1990. The importance of recruitment to the dynamics of a coral reef fish population Ecology 71(5):1691-1698. i
- Kinne, O., (Ed.) 1969. Marine Ecology, "A Comprehensive Integrated Treatise on Life in Oceans and Coastal Waters". Wily-interscience, London. 681 pp.
j i Lawton, R.P., R.D. Anderson, P. Brady, C. Sheehan, W. Sides, E. Kouloheras, M. Borgatti, and V. Malkoski.
- 1984. Fishes ofwestern inshore Cape Cod Bay
- studies in the vicinity of the Rocky Point shoreline, p.
t 191-230. In: J. D. Davis and D. Merriman (editors), Observations on the Ecology and Biology of 4 Western Cape Cod Bay, Massachusetts. Springer Verlag, Berlin, F.R.G 289 pp. 4 Lawton, R.P., P. Brady, C. Sheehan, S. Correia, and M. Borgatti.1990. Final Report on Spawning Sea-
} Run Rainbow Smelt (Osmerus Mordar) in the Jones River and Impact Assessment of Pilgrim Station j on the Population, 1979 1981. Pilgrim Nuclear Power Station Marine Environmental Monitoring i i Program Series - Number 4: 33-43.
- Lawton, R.P., B C. Kelly, V.J. Malko's'ki, J. Chisholm, and P.Nitschke.1993. Annual Report on Environmental
. Impact Monitoring of Pilgrim Nuclear Power Station (Vol 2). Project Report No. 54 (Jan.-Dec.1991).
j In: Marine Ecology Studies Related to Operation of Pilgrin, Station, Semi-annual Report No. 41. Boston 2 Edison Company, Braintree, MA. i. Lawton, R.P., B.C. Kelly, V.J. Malkoski, and J. Chisholm.1995. Final Report on Bottom Trawl Survey (1970 - ) i 1982) and Impact Assessment of the Thermal Discharge from Pilgrim Station on GroundGsh. Pilgrim { Nuclear Power Station Marine Environmental Monitoring Program Report Series - Number 7. 56 pp.
- Levin, P.S.1991. EITects of microhabital on recruitment variation in a Gulf of Maine reef Gsh. Marine Ecology Progress Series 75
- 183-189.
j Levin, P.S.1993. Habitat structure, conspeciGc presence, and spatial variation k We recruitment of a temperate reef fish. 0ccologia 94:176-185. I2 Levin, P.S.1996. Recruitment in a temperate demersal Gsh: Does larval supply matter, Limnology and j Oceanography. 41:672 679 l Lobell, M.J.1939. A biological survey of the salt waters of Long Island,1938. Report on certain Gshes. Winter flounder,Pseudop/curonectes americanus, New York Conservation Department, Albany,28th Annual Report, Part 1, Supplement 14:63-96. 4 Lux, F., A. Peterson, Jr., and R. Hutton.1970. Geographic variation in fin ay number in winter flounder, j Pseudopleuronectes americama (Walbaum), otTMas-sachusetts. Trans. Amer. Fish. Soc. 99:483-512. 1 53 i 4
I I i Marine Research,Inc.1986. Winter flotmder early life history studies related to operation of Pilgrim Station - A stview 1975-1984. Pilgrim Nuclear Power Station Marine Environmental Monitoring Program Report Series No. 2. Boston Edison Company, Braintree, MA. M uine Research, Inc.1988. Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station, Jan.- Dec.1988 (Vol 2). In: Marine Ecology Studies Related to Operation of Pilgrim Station. Final Report. Boston Edison Company. Mattheus, K.R., and R.H. Reavis.1990. Underwater tagging and visual recaptures as a technique for studying movement patterns of rockfish. American Fisheries Society Symposium 7168 172. McCracken, F.D.1963. Seasonal movements of the winter flounder, Pseudop/curonectes americanus (Walbaum) on the Atlantic coast. J. Fish. Res. Bd. Can. 20:551-586. Nicidrim, J.W. and J.J. Gift.1971. Temperature preference, avoidance, and shock experiments with estuarine fishes. Ichthyological Associates,Inc. Bulletin 7. 75 pp. Nonnandeau Associates,Inc.1979. New Haven Harbor Ecological Studics, Summary Report 1970-77 (prenared for United liluminating Co.), New Haven, CT. 720 pp. NUSCo (Northeast Utilitics Service Company).1986. Winter 11ounder population studies, Section 7. In: Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford, Connecticut. NUSCo, Annual Report,1985, Waterford, Connecticut. Olla, B.L R. Wicklund, and S. Wilk.1969. Behavior of winter flounder in a natural habitat. Trans. Amer. Fish. Soc. 4:719-720. Olla, B.L., A.J. Bejda, and A.D. Martin.1975. Activity, movements, and feeding behavior of the cunner, 717utogolabrus adspersus, and comparison of food habits with young tautog, Tantoga onitis, off Long Island, New York. Fish. Bull. 73(4):895-900. Pearcy, W.G.1962. Ecology of an estuarine population of wiri,r Dounder. Bull. Binghant Oceanogr. Collect., Yale Univ.18(1):78 pp. Perlmutter, A.1947. The blackback Counder and its fishcry in New England and New York. Bulletin of the Bingham Oceanographic Collection, Yale Univ. I8(1):1-78. Phelan, B.A.1992. Winter Counder movements in the Inner New York Bight. Trans. Amer. Fish Soc.121:777 784. Pierce, D., and A. Howe.1977. A further study on winter flounder group identiGeation off Massachusetts. Trans Amer. Fish. Soc. 106(2):131-139. Richards, W.J., and K.C. Lindeman.1987. Recruitment dynamics of reef fishes: planktonic processes, settlement, and 6shery analysis. Bull, of Marine Sci. 41(2):392-410. Saila, S.B.1961. A study of winter Counder movements. Limnol. Oceanogr. 6:292-298. 54 I l
i l Saunders, W.P.1981. Final report: sensitivity analysis of 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,19 pp. ~ Scarlett, P.G.1988. Life history investigations of marine fish: occurrence, movements, food l'abits and age structure of winter flounder from selected New Jersey estuaries. New Jersey Department of i Environmental Protection, Technical Series 88 20, Trenton, N J . l ' Serchuk, F.M. and C.F. Cole.1974. Age and growth of the cunner, Taritogolabrris adspersris (Walbaum) in the ; Wewcantic River estuary, Massachusetts. Chesapeake Scie.lec 15:205-213.
- Sinclair, M.S 1988. Marine Popidations
- An Essay on Popsdatton Regidarton and Spectation. Washington ,
Press, Seattie,252 pp. I Stone and Webster Engineering Corporation.1977. Supplemental Assessment in Support of the 316 Demonstration, Pilgrim Nuclear Power Station, Units I and 2. Boston, M A. , Sutter, F.C.1980. Reproductive biology of anadromous rainbow smelt, Osmcrris mordax, in the Ipswich Bay , area, Massachusetts, M.S. Thesis, Univ. Mass.. Amherst. 49 pp. Wilk, S.J., W.W. Morse, D.E. Ralph, and T.R. Azarovitz.1977. Fishes and associated environmental data I collected in New York Bight, June 1974-June 1975. NOAA (National Oceanic and Atmospheric g Administration) Technical Report NMFS (National Marine Fisheries Service) SSRF (Special Scientific
- - Report Fisheries) 716.
i f 4 i i W t i 9 l 1 1 1 I i i 1. I 55 l l l
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._ d
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FINAL SEMI-ANNUAL REPORT Number 49 ! l s 1 1 i BENTIIIC ALGAL MONITORING , 5 AT TIIE l j PILGRIM NUCLEAR POWER STATION 2 (QUALITATIVE TRANSECT SURVEYS) January-December 1996 to
- BOSTON EDISON COMPANY
! Regulatory Affairs Department Pilgrim Nuclear Power Station Plymouth, Massachusetts 02360 ] } l ; ] From ENSR 89 Water Street Woods IIole, MA 02543 (508)457-7900 l 1 April 1997
. _ . _ . . _ _ _ _ . _ . . _ .. ~ ~ _ . . - _ -- ~. -
1 1 1 l l TABLE OF CONTENTS i EXECUTIVE
SUMMARY
...............................................I j 1.0 INT RO D UCTIO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.0 F1E LD ST UDI ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 METIIODS ................................................ 4 2.2 RES ULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2.1 APRIL 1996 TRANSECT SURVEY . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2.2 JUNE 1996 TRANSECT SURVEY . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.2.3 SEI"I'EM.BER 1996 TRANSECT ST.'RVEY . . . . . . . . . . . . . . . . . . . . 14 2.2.4 DECEMBER 1996 TRANSECT SURVEY . . . . . . . . . . . . . . . . . . . . 14 2.3 D I SC US SI O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.0 IMPACT ON ALGAL DISTRIBUTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.1 B A C K G RO UND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.2 QUALITATIVE TRANSECT SURVEYS: 1983-1996 .................... 18 ,
4.0 CONCLUSION
S . . . . ..................................... . . . . . . 23 5.0 LITERATURE CITED ............................................ 24 I a j 4 I I i 1 1 1 i
i I I LIST OF FIGURES l J Figure 1. Location of Pilgrim Nuclear Power Station Qualitative Algal Survey Area ...3 Figure 2. Design of Qualitative Transect Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 3. Denuded, Sparse, and Sparse & Stunted Chondrus Zones Observed in April 1996 ................................................... 8 Figure 4. Denuded, Sparse, and Stunted Chondrus Zones Observed in June 1996 . . . . . 9 Figure 5. Denuded and Sparse Chondrus Zones, and Dense Mussel Area, Observed in Sept em ber 1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 6. Denuded, Sparse, and Stunted Chondrus Zones Observed in December 1996
....................................................... 11 Figure 7. Results of the 1996 Qualitative Transect Surveys of the PNPS Acute Impact Zone off the t)ischarge Canal taken in April, June, September, and December 1996 .................................................. 12 Figure 8. Monthly PNPS Capacity Factor (dashed lines) and Circulating Pump Activity (black bars at 100% = 2 pumps; at 50% = 1 pump; at 0% = 0 pumps)
Plotted for the Period 1983 Through December 1996 . . . . . . . . . . . . . . . . . . 17 Figure 9. Area of the Danuded and Totally Affected Zones in the Vicinity of the PNPS 1 Effluent Canal Plotted with the Monthly PNPS Capacity Factor (MDC) for the Period 1983 Through 1996 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 10. Area of the Denuded and Totally Affected Zones in the Vicinity of the PNPS Effluent Canal Plotted with the Monthly PNPS Capacity Factor (MDC) for the Period 1989 Through 1996 ................................ 20 TABLE a able 1. Qualitative Algal Survey Data for 1996 Compared tc flistorical Baseline Data . 7 APPENDIX Appendix A. Quality Control (QC) Protocol for Qualitative Transect Surveys at PNPS O ut fall A rea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 6 11
-4ss,sA m. m s u su..s ~. a .an a .- uan.w m-s-us..A Lan.m .ae s n s.u msa. a +.sawa ans.4 u. s u -e. no.ae nooma *.a:ss u.s s ' - - - - - -
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EXECUTIVE
SUMMARY
This report presents results of qualitative surveys of benthic algae performed in 1996 in the area affected by thermal efnuent from the Pilgrim Nuclear Power Station (PNPS). The report summarizes the impact of the PNPS on algal distributions near the discharge canal. Field studies for 1996 were conducted in April, June, September, and December 1996 and included transect surveys designed to map algal cover in the area of water outflow. These investigations constitute the most recent phase oflong-term monitoring of thermal efuuent effects on benthic algal communities within and just offshore of the PNPS discharge canal. Field survey techniques were identical to those used in prior years. Starting in 1996, data from each quarterly survey were compared to the historical baseline (maximum measurements recorded prior to the 1996 survey year) for that season. Measurements greater than 15% above the historical baseline triggers a report to the (PATC) Benthic Subcommittee for review. The qualitative transect studies performed to evaluate the Chondrus crispus (Irish moss) conununity indicate that from October 1995 through September 1996 the sizes of the denuded and totally affected areas in the thermal plume were consistently larger for each season surveyed than had been measured in earlier surveys when the power plant was in full or nearly full operation (1983,1985,1989-1995). For all four 1996 surveys, at least two parameters exceeded the 15% trigger level. Chondrus denuded areas were larger than historical maxima in April, June, and September; in December, although the denuded zone was smaller than the historical baseline it was still the second largest ever measured for a winter survey. I Totally affected Chondrus zones were larger than historical maxima in all four 1996 surveys. In June, the sparse Chondrus zone extended laterally farther than 30 m from the central transect line (CTL) for the first time; the divers failed to extend their survey line to the nonnal Chondrus zone, so that the size recorded ; for the total affected area is conservative. This was rectified in September when it was necessary to extend l the survey line 42 m north of the CTL. A dense population of newly settled blue mussels (Myritus edulis), even thicker than seen in previous June surveys, was observed in June 1996. Damage to Chondrus plants from extensive mussel settlement appears to be correlated to the increase in area of denuded and total affected Chondrus zones between the spring and summer surveys. For the first time since qualitative transect surveys began in 1980 the plant operated at over 92% (mean = 97%) capacity for nine rnonths in a row (July 1995 through March 1996); plant capacity for seven of the remaining nine months of 1996 stayed above 92% (mean = 95%). The large Chondrus denuded and totally affected zones seen in each survey since October 1995 may be due to a combination of high plant capacity in effect since July 1995 (mean = 92.5 %), high smnmer wier temperatures, and extremely dense settlement by mussel larvae in late spring that totally covered and damaged the algal plants. I
)
1.0 INTRODUCTION
)
The presence of hundreds of square meters of seafloor where the regionally abundant red alga species Chondrus crispus (Irish Moss) is unnaturally absent, even in the presence of suitable substrata, provides evidence that the nearfield discharge area is intensely affected by bottom scouting produced by
)
the PNPS cooling water outflow. To study this acutely impacted area, a qualitative diver transect study was designed to provide maps showing the effects of thermal effluent on nearby algal distributions. l SCUBA divers perform quarterly transect surveys to measure the extent of denudation and other reductions in size or density of the algal flora, particularly Chondrus crispus, in the nearfield discharge area. This report represents a continuation oflong-term (23 yr) benthic studies at Pilgrim Nuclear Power Station (PNPS) designed to monitor the effects of the thermal effluent. The 1996 monitoring program was identical to those performed since 1992 and involved qualitative SCUBA surveys of algal cover in the nearfield thermal plume of the effluent, within and beyond the discharge canal (Figure 1), that were planned for March, June, September, and December. Currently, no quantitative assessments of benthic ! algae or fauna are being made. Starting in 1996, quarterly reports were prepared that compared data collected during each survey with an historical baseline that tabulated, for each parameter, the maximal sizes measured prior to the 1996 survey season (1983 through February 1996). This Semi-Annual Report , includes qualitative observations recorded in April, June, September, and December 1996, comparison of these data with the historical baseline, and a summary of the potential impact on algal distributions caused i by PNPS. Work was performed under Boston Edison Co. (BECo) Purchase Order LSP005525 in accordance with requirements of the PNPS NPDES Permit No. MA 0003557. PNPS is a base-load, nuclear-powered electrical generating unit designed to produce 670 megawatts of electrical energy when operating at full capacity. The condenser is cooled by water withdrawn from Cape Cod Bay and subsequently returned to the Bay via a discharge canal designed to dissipate heat through rapid mixing and dilution of the outflowing water. Two circulating pumps produce a maximum water flow of approximately 20 m'sd The PNPS cooling system may affect the benthic cornmunity in three ways: 1) by warming ambient waters (aT=32' F),2) through chemical discharge (mainly Cl2 ), and,
- 3) by scouring of the seabed by the rapid (- 7 fps at low tide) flow regime. Increasing temperature and I chemical discharges may stress the algal community so that species composition and community structure change; the extent of such change depends upon season of the year and the influence of local oceanographic conditions. Increased current velocity directly affects the benthos by actually removing benthic organisms and inhibiting settlement and recolonization; where there is intense bottom scouring, rock surfaces may support fewer and smaller macroscopic organisms than would be normally present.
2
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Figure 1. Location of Pilgrim Nuclear Power Station Qualitative Algal Survey Area. 3 i 1
2.0 FIELD STUDIES 2,1 METIIODS The qualitative algal survey is performed by SCUBA divers in the same location and with the same techniques that have been used since the current monitoring program began, approximately 15 years ago. The effluent area is surveyed by two or three SCUBA-equipped biologists operating from a small boat. For all 1996 surveys the divers were able to launch their boat from the regular fishermen's launching site within the PNPS facility, although in December this was only possible because fishermen had cleared a path through a field of large exposed boulders left from scouring by winter storms. 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- l m intervals, is then attached to the center of this line and deployed along the central axis of the canal to a distance of JO m offshore. Usin3 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 th!., third line, recording changes in algal cover from the CTL through the denuded, sparse, and stunted Chondrus areas, until the algal cover looks nomial. Starting in September 1996, a second 30-m measuring line was included in the dive gear to ensure that the perpendicular transect would extend beyond the affected Chondrus zone. A large boulder that is nearly exposed at mean low water, and that is used as a landmark by dive teams, serves as a visual fix for the proper placement of the transect line. To ensure consistency among the surveys the CTL or survey line is adjusted, so that the boulder is always located at 65 m along and just to the north of the CTL. 1 The terminology established by Taxon (1982) and followed in subsequent years uses the growth morphology of Chondrus crispus to distinguish between " denuded" and " stunted" zones. The denuded zone is the area in which Chondrus occurs only as stunted plants restricted to the sides and crevices of rocks. In this area, Chondrus is found on the upper surfaces of rocks only where the microtopography of the rocl: surfaces creates small protected areas. In the stunted zone, Chondrus is found on the upper surfaces of rocks but is noticeaoly 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 Chondrus height and density are fully developed. The dive team must keep in mind while taking measurements that the shallow depths northwest of the 4
l Discharge C Vanal *- Barrier Net Sill
- ___ J , ', Q , __J^ --
) l
** ,o .
, o ,
B0O a os ,o. 0 Effluent Line W 10 ep q) l 20 Weight Marks at 10 - meter intervals 80 si I l
*q> 3 j Diver 1 50 et Diver 3 Diver 2 P
70 81 Reference Boulder 30 Meter Measuring Tape Transact Line ati (CTL) im ei Diver Safety Line Anchor gg Buoy 1 Anchor and Line Figure 2. Design of the Qualitative Transect Survey. ) i l l 5 1 I
discharge canal hamper normal Chondrus growth. In addition to evaluating extent and condition of algal cover, the divers record any unusual events in the area, such as the occurrence of unusually strong storms, and note the location of any distinctive algal or faunal associations. Beginning in 1996, Quarterly Progress reports were submitted to Boston Edison Company. These reports tabulate areal results of each SCUBA survey and compare them to previously measured maximal sizes of Chondrus denuded and totally affected zones, as well as other parameters, for that season. Particular attention is paid to changes in the sizes of impacted regions that exceed earlier results (prior to 1996) by more than 15%, which requires reports to be submitted to the PATC Benthic Subcommittee. Table 1 summarizes these comparisons for 1996. The quality control (QC) protocol for the benthic algal monitoring program is attached as Appendix A. 2.2 RESULTS Qualitative transect surveys of acute nearfidd impact zones began in January 1980 and have been conducted quarterly since 1983. Four surveys were performed (April 29, June 27, September 26, and December 24,1996) during the current reporting period, bringing the total number of surveys conducted since 1980 to 64. 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 1995, including a review of the four performed in 1995, was presented in Semi-Annual Report No. 47 (BECo, 1996). The present report summarizes the April and June 1996 surveys, presents detailed results of the September and December 1996 surveys, and discusses long-term trends. Figures 3 to 7 show the results of the 1996 transect surveys performed by SCUBA divers. The dended ane is essentially devoid of Chondrus crispus, sparse zones are those in which norma: looking Chondrus is sparsely distributed; stunted zones contain smaller than normal Chondrus plants, in April 1996, the divers delineated one region that contained plants that were both thinly distributed and stunted in growth. In September, the dense mussel area within the denuded zone was mapped. Dislodged jetty boulders encountered by the divers along their transects are indicated. The landmark boulder (at 65-m) is pioned in all figures as are positions of the most common algal and faunal species observed by the divers. J,2.1 APRIL 1996 TRANSECT SURVEY The denuded and sparse Chondrus crispus areas mapped on April 29,1996, immediately offshore
- of the PNPS, are shown in Figure 3. In April 1996, the denuded and totally affected zones were much larger than during prior spring surveys. The Chondrus denuded area (1859 m2) in April was 55 % larger 6
i Table 1. Qualitative Algal Survey Data for 1996 Compared to Historical Baseline Data. Spring Summer Fall Winter Measurement April flistorical Percent June Historical Percent September llistorical Percent December IIistorical Percent l 1996 Baseline Change 1996 Baseline Change 1996 Baseline Change 1996 Baseline Change , (Date) from (Date) from (Date) from (Date) from Baseline Baseline Baselir.c Baseline Total 1859 1321 +41% 2194 1835 +20% 2209 2043 + 8% 1671 1961 -15% Denuded (3/91) (6/90) (10/95) 12/96) Area (m') Total 2436 2029 +20% >3473 2135 >+63% 2845 2348 +21% 3111 2328 +34% q Affected (4/83) (6/90) (10/95) (2/96) Area (m') Maximal 115 94 +22% 125 105 +19% 101 100 +1% 100 100 +0% Distace of (3/91) (6/92) (9S0; (12/93; Affectc4 10/95 2/96) Area from Discharge Canal (m) Maximal 34 40 -18% >43 39 +10% 60 42 +43% 52 42 +24% Width of (4/83; (6/84) (10/94) ' (12/83) i A.frected 3/84) . Area (m) i I
,r.-.._, . . . . - ., e - ,wa - +m + ,- - + . - e w:wa r,,-, - mmit-e ee =w . , . --i*_______-r- - - - - -
i 1 1 April 1996 % N
- 120
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Figure 3. Denuded, Sparse, and Sparse & Stunted Chondrus Zones Observed in April 1996. 8
n June 1996 5
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September 1996 % N f20 ffO Asterias
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- . ;p:.t!.t.! ; . . . .- m u^ .. , . ....
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.. 2 Figure 5. Denuded and Sparse Chondrus Zones, and Dense Mussel Area, Obsened in September 1996.
10
December 1996 % N
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-110 I'
s
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Figure 7. Results of the 1996 Qualitative Transect Surveys of the PNPS Acute hupact Zone off the Discharge Canal taken in April, June, September, and December 1996. 12
than in the spring 1995 survey and 41% larger than t'ie previous spring maximum of 1321 m2 seen in 2 March 1991 (Table 1). The total affected area (2436 :a ) was only slightly larger (5%) than in the previous 2 survey, February 1996 (2328 m ), but was much larger (48%) than in the 1995 spring survey, and 20% larger than the historical spring baseline measured in April 1983. The denuded region extended approximately 115 m (10 m farther than ever observed before) along the transect line and, as often seen before, was asymmetrically distributed with 66% of the denuded area north of the line. Other algae present included the warm water indicator, Gracilaria, near the discharge canal and a cold water indicator, the kelp Laminaria, further offshore. Phyllophora spp. was not noted by the divers. An exte isive set ofjuvenile blue mussels, A/ytilus edulis, had already occurred; mussels from 1 - 10 mm in length covered rocks, plants, and other substrata from the 50-m mark to beyond the 100-m mark on the CTL and laterally out to a distance of
- 25 meters. Other invertebrates included
- a few starnsh, Asteriasforbesit periwinkle snails, Littorina linoria; and three species of crab, rock crab, Cancer irroratus, green crab, Carcinus maenas, and a spider crab, Libinia sp. No fish or lobsters were seen.
4 2.2.2 JUNE 1996 TRANSECT SURVEY Results of the divers' survey for June 27,1996 are mapped in Figure 4. The Chondrus denuded and totally afTected areas were much larger than observed in prior summer surveys. The Chondrus denuded zone 2 (2194 m ) extended 125 m (10 m farther than in April) along the central transect line, was 18% larger than two months earlier,in April 1996,56% larger than in June 1995, and 20% larger than the June 1990 summ:r historical baseline of 1835 m 2(Table 1). The sparse Chondrus area extended laterally beyond the 30-m distance norn r,Ily surveyed by the divers; consequently, the sizes of the sparse Chondrus (>l279 m 2) and the totally affected zones (>3473 m 2) were larger than rworted. The sparse Chondrus zone (> l279 m2 ) was more than twice as large as in April 1996 and had more than tripled in area since June 1995. The total l 2 affected area (>3473 m ) was at least 43% larger than in April 1996 and more than 63% !arger than the June 199u historical summer baseline (2135 m2 ). Both the denuded and sparst Chondrus zones contributed to the asymmetrical distribution of the affected area. Gracilaria, Enteromorpha, and Chaetomorphapurpureum dominated the Dora at the head of the effluent canal. Rockweed, fucus sp., was seen; neither kelp, Laminaria, nor Phyllophora spp. were noted. A dense array (thickest seen in 25 years of monitoring) of juvenile blue mussels (A/ytilus edulis), now 5-20 mm in length, similar to that seen in prior June surveys, l was present from the 50-m mark seaward. Dense aggregations of the starfish, Asteriasforbesi, a mussel predator, were seen. Tautog (Tautoga onitis), striped bass (Aforone sc.atilis), cunner (Tautogolabrus adspersus), bluefish (Pomatomus saltatrix), and small winter Hounder (Pleuronectes americames) were seen. 13
2.2.3 SEPTEMBER 1996 TRANSECT SURVEY Figure 5 shows the results of the transect survey conducted on September 26,1996. The area l (2209 m2) of the denuded zone was slightly larger than in June 1996, a not unusual event, and 8% larger than the historical baseline (2043 m2) measured in October 1995 (Table 1). The denuded zone extended just beyond the 100-m mark on the transect line. The greatest lateral extent of the denuded zone was 30 m to the north of the transect line at the 70-m mark. As has been seen oftea in the past, the denuded zone was asymmetrical around the transect line, with more of the area north (65%) of the line than south (35%) of the line. The area of the sparse Chondrus zone was 636 m2 in September, more than double that seen in the previous fall survey (305 m2). The sparse Chondrus area extended 42 m north of the CTL both at the 60-m and 70-m marks on the CTL, a distance farther away from the CTL than had ever been mapped previously. The total affected area in September was 2843 m2 which was smaller than measured in the June 1996 survey but 21 % larger than the historical baselinc 12348 m2) established in the previous tan survey. l Most of the algal plants that had been covered with mussels in June were beginning to recover, but Chondrus appeared colorful and healthy only beyond the impact zone. As usual, the algal species seen within the discharge canal were Gracilaria spp., and C. purpureum. The warm water alga, Gracilaria spp., was the dominant macroalga species occurring close to the CTL ou: to the 50-m mark. Rockweed (Fucus sp.)and the encrusting red alga, Corallina, ' vere seen occasionally between the 40 m and 60-m marks,10 to 20 m north of the transect. Phyllophora spp. again was not noted. Mussels, averaging 1.5 cm in length, did not occur over as large an area as they had e June but v.ere still abundant within the denuded zone within 10 m of the CTL between the 35-m mark to about the 75-n mark along the CTL. A few starfish (Asteriasforbesi) were seen, as were snails (Littorina littorea), rock crabs (Cancer irroratus), and green crabs (Carcinus maenus). Only one demersal fish, a winter flounder (Pleuronectes americanus), was observed during the survey.
;L2.4 DECEMBER 1996 TRANSECT SURVEY l
Tine results of the 1996 winter dive, performed on December 24,1996, are mapped in Figure 6. l The area (1671 m2) of the denuded zone was 24% smaller than it had been in September and was well under (-15%) the historical baseline established during the previous winter survey (Table 1) but was still the second largest denuded zone measured in winter while the power plant was in full operation. The denuded zone extended seaward just beyond the 90-m mark on the transect line. The shape of the denuded l l 14
l l I zone was highly asymmetrical around the transect line with 67% of the area north of the line and 33% south of the line. The greatest lateral extent of the denuded zone observed by the divers was at the 70-m mark where it projected 15 m north of the transect line. The area inhabited by sparse and stunted Chondrus (1440 m2) was more than double that measured in September 1996 (636 m2) and like the denuded zone was arranged asymmetrically around the central transect line with most (84%) of the area north of the line, especially in a northward bulge from the 70-m to 80-m marks on the CTL. The total affected area (3111 m2) in December 1996 was 9% larger than measured in September 1996 (2845 m2) and much larger (34 %) than the historical baseline measured in February 1996 (Table 1). The maximal extent of the totally affect;J area out along the CTL was equal to the historical baseline, that is, near the 100-m mark on the CTL. The maximal width of the affected zone (52 m) was greater than seen in earlier winter surveys (24 % over the historical baseline of 42 m) but less than in September. During this survey, Chondrus was repopulating the region near the CTL but appeared colorful and healthy only outside the totally affected area. The red alga, Phyllophorn spp., was not observed by the divers. Gracilaria and C. purpureum were present at the head of the effluent canal. Fucus sp. was seen only occasionally. Snails, Littorina littorea, were extremely abundant throughout the entire area surveyed. Very few blue mussels, Mytilus edulis, were seen and consequently the starfish, Asteriasforbesi, that often feed on the mussels were reduced in number from the concentrations seen in June. As for fish, only one winter floun. der (Pleuronectes americanus) was seen. 2.3 DISCUSSION The configuration of the Chondrus crispus denuded zone that may extend even farther than 100 m beyond the discharge canal is readily apparent to SCUBA divers and easily mapped from the qualitative transect survey. Stunted and sparse zones are sometimes less obvious, but the sparse zones observed in 1996 were delineated with na difficulty. For April, June, and Septemb r 1996, the areas of the denuded and total affected zones were much ';.:ger than those seen pr.viously (1983,1985,1989-1995) when the power plant was in full or nearly fun operation. In June 1996, an extremely dense mussel mat, similar to those seen every June since 1990, with the exception of 1991, was present. The areas of the denuded and totally affected zones were greater in June than they had been in April, the usual trend when early summer growth of Chondrus is adversely affected by high mussel settlement. In December 1996, the area of the Chondrus denuded zone was exceeded only by that measured during the previous winter survey which at 15
the time was the largest recorded since the quarterly surveys began in 1983. For the first time since qualitative transect surveys began in 1980, the plant operated at over 92% (mean = 97%) capacity for nine months in a row (July 1995 through March 1996). In addition, for seven of the remaining nine months of I i 1996, plant capacity stayed above 92% (mean = 95%). The large Chondrus denuded and totally affected zones seen in each quarterly survey since October 1995 may be due to a combination of the high plant capacity that has been in effect for the 18 1 months since July 1995 (mean = 92.6%), high summer water temperatures, and extremely dense settlement by mussel larvae in late spring that totally covered and damaged algal plants. 3.0 IMPACT OF EFFLUENT DISCIIARGE AT PNPS ON ALGAL DISTRIBUTION
3.1 BACKGROUND
flistorically, operational conditions at the PNPS have provided opportunities to assess long-term J trends associated with the impact on the benthic community. Plant operations have included years of high operation as well as times when :here were complete shutdowns, sometimes for prolonged periods. The longest outage in the history of the pant began in April 1986 and continued until March 1989. During this period the benthic community associated with the effluent canal and nearby areas immediately offshore experienced reduced current velocity as the use of circulating pumps was restricted to one or none (Figure 8). In addition, the discharge water remained at ambient temperature. As a consequence, the benthic community normally affected by these effluent parameters recovered, so that by 1988 there was essentially no difference between the control stations and the areas near the discharge canal. Studies conducted after the power plant resumed electrical generation at full operating capacity, with the consequent themial discharge and consistent use of one or both circu'ating pumps, assessed the j impact of plant operation on a benthic environment that had returned to near ambient conditions. Quantitative faunal and algal monitoring studies, and qualitative transect surveys were conducted through 1991. In 1992, conununity studies of the benthic algae and fauna were discontinued. From 1992 through , 1 1996, the monitoring program consisted of seasonal qualitative surveys of the discharge area. I PNPS operated at very high capacity in 1996. Figure 8 shows the monthly maximum dependable capacity (MDC) factor and circulating water pump operation of PNPS since 1983. The percent MDC is , a measure of reactor output and approximates thermal loading to the marine environment. A maximum MDC value of 100% equates to the highest allowable change in ambient temperature for water discharged to Cape Cod Bay (18' CAT). In 1996, the monthly maximum dependable capacity factor was greater than 16
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- Pump Operation MDC i
Monthly PNPS Capacity Factor (solid lines) and Circulating Pump Activity (black bars at 100% = 2 pumps; at 50% = 1 l Figure 8. pump; at 0% = 0 pumps) Plotted for the Period 1983 Through 1996. t f I
92% for 10 months and between 51 % and 76% for 2 months. These monthly capacity factors resulted in an annual capacity factor of 90.5 % for 1996, much higher than in any previous year (second highest annual capacity factor was 84.4% in 1985). In addition, both pumps were operating virtually all year. 3.2 QUALITATIVE TRANSECT SURVEYS: 1983-1996 Results of the qualitative transect surveys from 1983 through 1996 are summarized in Figure 9. A detailed enlargement showing the most recent 8 years (1989 - 1996) is presented in Figure 10. The total acute impacted area (denuded, sparse, and stunted), the area of the denuded zone only, and the monthly PNPS capacity factor (MDC) are plotted. The difference between the denuded and total acute impact zones represents the area of the sparse and stimted zones. A lag in recovery time in the acute impact zone during and following the 1984 PNPS power outage was reported in Semi-Annual Report No. 27 (BECo,1986). Evidence of this slow recovery included a decrease in the area of the total acute impact zone that began in mid-1984 (5 months after the cessation of power plant operations) and continued through mid-1985. Between December 1984 and December 1985, the total affected area was the smallest recorded between 1983 and 1986, indicating a delay in recovery in response to the absence of thermal discharge and reduced circulating water pump operation in 1984. This delay phenomenon also held true when the situation was reversed, so that the size of the acute impact zone began to increase only 6 to 9 months (September to December 1985) after the resumption of thermal effluent discharge and normal circulating pump operation. These results confirmed a delay of 6-9 months between the causal factors (cessation or resumption of thermal effluent discharge and pump operation) and associated responses (decrease or increase in size of the acute impact zone). In 1987, in response to the 1986-1989 outage, increased recolonization of the denuded and stunted zones by Chondrus crispus made zone boundaries difficult to distinguish (no areal differences could be discerned from September 1987 through June 1989). As in summer 1984, the large size reduction of the denuded zone between December 1986 and June 1987 was primarily the result of the shutdown of the circulating water pumps in late February 1987 that continued into the summer (BECo,1988). Apparently, water current scouring is a greater stress to algal colonization than increased water temperature, Scouring denudes the substratum, whereas elevated temperature results in stunted growth (Bridges and Anderson,1984). In 1988, low circulating water pump activity caused few thermal loading and scouring effects. 'Ihe 1988 transect surveys showed such an increase in recolonization of formerly denuded and stunted zones by Chondrus, because of the centinuing outage, that divers could not cetect zonal boundaries or make area measurements. In March and June 1989, divers were still unable to detect boundaries of denuded or l l 18
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; 2 S Y I i ) l 0 oi a s o n WoWrd My Yd u 'a s 6' u 'a"s"6"u"Y sTu a"s 'o"u iT o u '.i"s Wbs~oTY s' o u l's Wu y's o 0 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 a Denuded of Chondrus = Total Affected Area MDC Figure 9. Area of the Denuded and Totally Affected Zones in the Vicinity of the PNPS Emuent Canal Plotted with the hionthly PNPS Capacity Factor (51DC) for the Period 1983 Through 1996. No area measurements were made from September 1987 through June 1989 because definitive demarcations of denuded and stunted zones were absent.
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stunted zones, and again no area measurements were made (BECo,1990). In September and December 1989, presumably in response to increased PNPS operations with resultant scouring of the acute impact zone, boundaries began to be redefined and area measurements were made of the total impact zone. During 1990, boundaries between the stunted and denuded zones became even more clearly defined and areal measurements of both zones were made. The areas of the denuded and total impact zones in June 1990 were the largest seen since 1983 (BECo,1991). The dramatic increase in total affected area that occurred between April and June 1990 had not been seen before in the 1983-1990 period. The typical pattern seen prior to 1990 was that during the spring, with warmer temperatures and increased sunlight, algal growth flourishes, and the impact area declines even in years when the power plant is operating at high capacity. The pattern seen in 1990 appeared to be anomalous until more recently a correlation was ; made between the appearance of enormous numbers of juvenile mussels and the occurrence of large l denuded and total affected zones. The divers did note remarkable numbers of juvenile mussels present ! during the June 1990 dive and thus the large affected zones result, at least partly, from damage suffered by the Chondrus plants due to the massive settlement of mussels. In 1991, the boundaries of the acute impact zone remained well-defined, except that in June there was no true stunted zone but only an area described by the divers as " sparse", that is, where the algal plants grew normally but were thinly distributed. From March to June, the total affected area and the Chondrus denuded zone decreased in area, a return to the typical pattern seen before 1990 (BECo,1992). This decrease in area continued through the October survey, perhaps aided by the power plant outage from May into August. There was a slight increase in the affected area in December. During 1992, the divers were unable to discern a Chondrus stunted region. Except for June, they noted zones containing normal but sparsely distrit ated ' hondrus plants. An enormous set of mussels that had reached 0.5 cm in length by June, totally obliterated the boundary between the denuded and sparse areas. Parallel to results seen in 1990, the areas of the denuded and total acute impact zones in June 1992 were larger than any seen (except for 1990) since 1983, and the dramatic merease in total affected area that occurred between April and June 1990 happened again in 1992. Thus, the pattern seen in 1990 can no longer be considered anomalous but may be related to oceanographic conditions that lead to a large settlement of mussel larvae and consequent damage to Chondrus plants (BECo,1993). In 1993, the June mussel set that hampers Chondrus growth was not as dense as those that occurred in 1990 or 1992, so that the denuded tone was smaller in June than it had been in April, the opposite of the situation seen in 1990 and 1992 (BECo,1994). The area of the uenuded zone in September was slightly larger than it had been in Se ptember of 1990 and 1992, but the denuded zone in December was 21
much larger than in previous years. In addition, the total affected area in December was the largest seen since 1983, rivaling the areas measured in the summers of 1990 and 1992; this may be partly due to the very early date (Dec. 2) of the survey and partly to damage imposed by a heavy infestation of the i encnating bryozoan Membranipora membranacea. ! 1 In 1994, the denuded and total affected Chondrus areas in all four seasons were similar in size to those fourid during prior surveys at times of full or nearly full power plant operation (BECo,1995). The dense mussel settlement seen in June obscured the boundary between the denuded and sparse / stunted regions and damage caused by the mussels to the Chondrus plants contributed to the enlargement of both Chondrus zones between the April and June surveys. The three-month fall power plant outage (September through November) appeared to have had no effect on the size of either the denuded or total affected Chondrus zones. In 1995, the sizes of the denuded and total affected Chondrus areas were within the ranges seen in earlier surveys only for the early May and late June surveys (BECo,1996). The impacted areas measured in October 1995 and February 1996 were much larger than those measured during any earlier fall and winter survey and most closely approximated the impacted areas seen in September and December 1993. The two-month (April /May) spring power outage appeared to have no effect on the size of the Chondrus affected areas seen in May or June. However, the high plant operating capacity in effect from June 1995 through February 1996, in conjunction w4h a high mussel set in June, may have contributed to the largest denuded and totally affected Chondrus zones seen since the current monitoring program began in 1983. In 1996, the sizes of the denuded and totally affected Chondrus areas continued to increase over the historical baseline measurements (1983 through the 1995 survey season, i.e. February 1996) except that in December 1996 the denuded zone decreased to less than the winter historical baseline measurement although it was still the second largest winter denuded zone observed. The large Chondrus denuded and totally affected zones seen :n each survey since October 1995 may be due to a combination of the high plant capacity that has been in effect for the 18 months since July 1995 (mean = 92.6%), high sununer water temperatures, and extremely dense settlement by mussel laivae in late spring that totally covered and damaged the algal plants. I i 22 l
I
4.0 CONCLUSION
S
- The sizes of the denuded and totally rJfected Chondrus areas of the acutely impacted region for April, June, and September 1996 were larger than had been observed during prior surveys at times of full power plant operation.
- By December 1996 the area of the Chondnis denuded zone had decreased in size to less than that measured in February 1996 (1995 winter survey) but was still the second largest winter denuded zone observed sinc.1983.
- The areas of the denuded and total affected zones were greater in June than in April, the trend usually observed when early summer Chondrus grcwth is adversely aliccted by high mussel settlement.
e The high power plant capacity in effect from July 1995 through December 1996, in combination with an extremely dense mussel settlement in June, and high sununer water temperatures, may have contributed to the generation of the largest denuded and totally affected Chondrus zones measured since the present monitoring program began in 1983. 23 l
P 5.0 LITERATURE CITED Boston Edison Co.1983. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annual Report No. 22. Boston, MA. Boston Edison Co.1986. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annual Report No. 27. Boston, MA. Boston Edison Co.1988. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annual Report No. 31. Boston, MA. Boston Edison Co.1990. Marine ecology studies related to the operation of Pilgrim Station. Semi-Anneal Report No. 35. Boston, MA. Boston Edison Co.1991. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annual Report No. 37. Boston, MA. Boston Edison Co.1992. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annual Report No. 39. Boston, MA. Boston Edison Co.1993. Marine ecology studies related to the opcration of Pilgrim Station. Semi-Annual Report No. 41. Boston, MA. Boston Edison Co.1994. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annua! Report No. 43. Boston, MA. Boston Edison Co.1995. Marine ecology studies related to the operation of Pilgrim Station. Semi-Annual Report No. 45. Boston, MA. Boston Edison Co.1996. Marine ecology studies related to the operation of Pilgrim station. Semi-Annual Report No. 47. Boston, MA. 24 l
I i Bridges, W.L. and R.D. Anderson.1984. A brief survey of Pilgrim Nuclear Power Plant effects l upon the marine aquatic environment, p. 263-271. In: J. D. Davis and D. Merriman (eds.) Observations on the ecology and biology of western Cape Cod Bay, Massachusetts,289 pp. Springer-Verlag. (Lecture Notes on Coastal and Estuarine Studies, Vol.11).
\
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. i I I l 1 I l l ( l l I l I 1 I i l 25 4
I i i APPENDIX A i Quality Control (QC) Protocol for Qualitative Transect Surveys at PNPS Outfall Area 1 Field Operation Planning { Field equipment is organized by the scientist in charge of dive operations; for 1997, the chief diver will be Mr. George llampson, or his designate, of the Woods Hole Oceanographic Institution. Mr. Ilampson i has been a diver or chief diver on every quarterly survey at the PNPS outfall site since April 1990. The , f survey equipment includes a boat and associated safety equipment; anchor and line; buoy and diver safety line; SCUI3A gear, including a collectir.g bag; 100-ft kevlar line to be deployed across the mouth of the I discharge canal; the weighted 100-m central transect line (CTL), marked at 10-m intervals; two 30-m [ measuring tapes; compass; clipboard; data sheets on plasticized paper; two #1 pencils, t Every attempt will be made to perform the dives as scheduled for March, June, September, and '! December. Windows of opportunity, considering times of high tide (less current for the divers to contend { with) and other commitments for both boats and personnel, will be blocked out in advance of each scheduled month. Enough leeway will be planned to allow some flexibility for bad weather days. A trainee diver will i be included for each field operation to decrease the possibilities for postponements caused by illness or conflicting schedules during the appropriate months. ! 2 Pre- and Post-dive Briefings -l The chief diver and ENSR data manager, Isabelle Williams, will hold pre- and post-dive briefings. The pre-dive briefing (may be made by telephone) will be the opportunity for determining the dive schedule, ! for reviewing data collection, and for informing the dive team whether or not any additional observations l are requested. At this time, emphasis will be placed on the importance of the divers exploring the limits, and defining them, of the entire affected area so that a comprehensive survey map can be produced. The post-dive briefing (in person) will give the chief diver the opportunity to tell the data manager his immediate impressions about the region surveyed and whether any problems were encountered that need to be corrected before the next dive. 3 Data Collection l l A diver swiraming perpendicularly away from the CTL, along fsc measuring line, records the l distance away from the CTL line that changes in algal cover occur, from denuded to sparse and/or stunted 26
Chondrus areas, and from sparse and/or stunted Chondrus to normal-looking Chondrus. Positions of other algal species, especially Gracilaria, a warm-water indicator, and kelp (Laminaria), a cold water indicator, are noted. Positions of animals, including mussels, starfish, crabs, and fish, and any unusual activities are also indicated. For 1997 and beyond, detailed observations will be made of Chondrus, including notes on robustness, color, occurrence of epiphytes, and qualitative descriptions of density and height. The divers will look for the presence of Phyllophora, the second dominant algal species in this community, throughout the survey area; if necessary, they will collect an algal sample from the normal Chondrus zone for examination in the laboratory. Particular attention will be paid to the boundaries of the high-density mussel set that appears to often occur in late spring or early summer. A sample blank data sheet is shown. A separate sheet is used for the north and south sides of the CTL. As the diver swims away from the CTL, distances and notes are recorded on the data sheet from left to right. For ease in working in an underwater environment algal cover is coucd as indicated on the data sheet: I - denuded; 2 - stunted; 3 - sparse; 4 - normal. Codes for mussel cover are M I - very dense; M2 - separated clumps; M3 - absent. 4 Data validation The diver recording data during the field survey is responsible for reviewing his work at the end of the survey to ensure that the data are complete and accurate. The chief diver will submit to the data manager the original field notes and a survey report, previously reviewed for accuracy and completeness by other members of the dive team, that includes the data on the total extent of the denuded and stunted Chondrus zones as well as a general description of the area surveyed, including notes on flora and fauna observed. The data manager is responsible for reconciling data in the submitted field report to those recorded on the original data sheets. The data manager will discuss any questions that may arise with the chief diver. The data manager is responsible for constructing maps based on the survey data and for calculating the total areal cxtent of the denuded and totally afTected Chondrus regions. All cc!culations performed by hand are checked for accuracy. The data manager is responsible for proof-reading tne final computer-generated maps against the original maps for accuracy. All reports generated by the data manager will be reviewed by the ENSR Project Manager, Dr. James Blake. 5 Observation ' The data manager will plan to accompany the divers on several of their field trips in 1997. She will 27
l l tend the boat and be on hand to accept any samples collected during those dives and to hear immediately the , impressions of all divers about the conditions of the outfall area, as well as ensure that the entire affected 1 area has been surveyed. ' 6 Meetings The project and/or data manager will attend fiill Administrative-Technical Committee and Benthic Subcommittee meetings when appropriate. This will help ensure communication between ENSR and the A-T Committee so that the quality of the benthic survey will be maintained as guided by the Committee. l 1 l 1 l 28
Date: Wind: Divers Down @: Divers Up @: Visibility: CTL(m) NORTIUSOUTH CHONDRUS 30 1 DENUDED 2 STUNTED 3 SPARSE 40 4 NORMAL MUSSELS 50 M1 V. DENSE M2 CLUMPS M3 ABSENT 60 70 80 90 NORMAL CHONDRUS 100 ROBUSTNFSS COLOR EPIPHYTES >100 HEIGHT COLOR Qualitative Transect Survey Field Data Sheet. 29 l
e I-1 ICHTHYOPLANKTON ENTRAINMENT MONITOR.TNG AT PILGRIM NUCLEAR POWER STATION JANUARY-DECEMBER 1996 Volume 1 of 2 (Monitoring) l
.1 Submitted to Boston Edison Company Boston, Massachusetts by Marine Research, Inc.
Falmouth, Massachusetts j l April 1, 1997
i TABLE OF CONTENTS SECTION PAGE I EXECUTIVE
SUMMARY
1 II INTRODUCTION 3 III METHODS AND MATERIALS 4 IV RESULTS AND DISCUSSION A. Ichthyoplankton Entrained - 1996 14
'l B. Multi-year Ichthyoplankton Comparisons 21 C. Mesh Extrusion 28 D. Lobster Larvae Entrained 30 V HIGHLIGHTS 32 VI LITERATURE CITED 57 j
APPENDICES A and B (available upon request) LIST OF FIGURES FIGURE PAGE 1 Entrainment sampling station in PNPS discharge canal. 5 2 Dominant species of fish eggs and larvae found in PNPS ichthyoplankton samples by season. Percent of total and summed monthly means for- ! all species are also shown. 15 l 3 Mean monthly densities per 100 m8 of water in the PNPS discharge canal for the eight numer-ically dominant egg species and total eggs, 1996 (bold line). Solid lines encompassing shaded area show high and low values over the 1984-1995 period. 34 4 Mean monthly densities per 100 m8 of water in the PNPS discharge canal for the thirteen numer-ically dominant larval species and total larvae, 1996 (bold line). Solid lines encompassing shaded area show high and low vr. lues over the 1984-1995 period. 40 i
. . . . - . . - . . . . - . . - . . . ~ . -- -_ -- .. .- -
E Y u LIST OF TABLES TABLE EAgg 1 PNPS ichthyoplankton entrainment notification levels for 1996 by species category and month. 4 See text for details. 11 3 2 Species of-fish eggs (E) and larvae (L) ob-tained in ichthyoplankton collections from the Pilgrim Nuclear Power Station discharge canal, January-December 1996. 49 3 Species of fish eggs (E) and larvae (L) col-lected in the PNPS discharge canal, 1975-1996. 51 4 Densities per 100 m8 of water for tautog/ cunner eggs and cunner larvae taken with 0.333 and 0.202-mm mesh netting on four 1994 dates, three 1995 dates, and four 1996 dates. 54 LIST OF APPENDICES APPENDIX A* Densities of fish eggs and larvae per 100 m8 of water recorded in the PNPS discharge canal by species, date, and replicate, January-December 1996. B* Geometric mean monthly densities and 95% confidence limits per 100 m8 of water for the dominant species of fish eggs and lar-vae entrained at PNPS, January-December 1984-1996.
*Available upon request.
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I l SECTION I -l l EXECUTIVE
SUMMARY
Sampling of entrained ichthyoplankton at PNPS followed . the , revised protocol initiated in April.1994. In January, February, and October through December six single samples were taken each month. From March through September single samples were taken three times every week. A total of 41 species were represented in the 1996 collec-tions, three more than the 21-year mean of 38 species. Numerical dominants included American plaice, sand lance, rock gunnel, and , sculpin during winter-early spring; cunner, Atlantic mackerel, sand lance, radiated shanny, winter flounder, and rockling during late spring-early summer; and windowpane, cunner, hake, and rockling during late summer-autumn. ! Comparisons of densities over the 1975-1996 time series suggested that the decline in cod-witch flounder eggs has ended but densities remain very low. Eggs of fourbeard rockling, hake, and cunner demonstrated long-term declines in abundance which appear to have reversed for cunner over the past two years. Abundance estimates based on entrained densities were relatively high in 1996 for Atlantic mackerel and windowpane eggs, which is consistent with high stock biomass for mackerel. In contrast, windowpane biomass is relatively low. Among larval species Atlantic herring, radiated shanny, sand lance, and Atlantic mackerel densities were relatively high in 1996. In the case of herring high larval densities are 1
_ __ _ .. ~~___ ._. . . _ _ _ _ . - . - _ l
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l 1 consistent with recent' increases in stock biomass on Georges Bank and Nantucket Shoals. Larval abundance for winter flounder was I
~
{ relatively high in-1996 in spite of region-wide low stock abun-dance. Mesh comparison studies using 0.202 and 0.333-mm mesh nets showed that cunner eggs were retained at significantly higher > densities in the finer mesh with a catch ratio of 1.29:1. A significant difference was not detected for stage 1 or 2 cunner larvae where ratios of 1.10:1 and 1.28:1 were noted, respectively. ' No lobster larvae were found in 1996 entrainment samples, the total dating back to 1974 remaining at 13. 1 4 l f 2
SECTION II INTRODUCTIO}J f This report summarizes results of ichthyoplankton entrainment sampling conducted at the Pilgrim Nuclear Power Station (PNPS) discharge canal on a systematic basis from January through December 1996. Work was carried out by Marine Research, Inc. (MRI) for Boston Edison Company (BECo) under Purchase Order No. LSP005524 in compliance with environmental monitoring and reporting requirements of the PNPS NPDES Permit (U.S. Environmental Protection Agency and r Massachusetts Department of Environmental Protection). Program enhancements continued in 1996 included conversion from 0.333 to 0.202-mm mesh from late March through late May to improve retention of early-stage larval winter flounder and collection of additional 0.202-mm mesh samples for larval cunner to supplement the mesh extrusion data collected in 1994 and 1995 (MRI , 1996). In an effort to condense the volume of material presented in this report, details of interest to some readers may have been omitted. Any questions or requests for additional information may be directed to Marine Research, Inc., Falmouth, Massachusetts, through BECo. . l I 3
SECTION III METHODS AND MATERIALS Monitoring Entrainment sampling at PNPS begun in 1974 was historically completed twice per month during January, February, October-December; weekly during March through September in triplicate at low tide. Following a PNPS fisheries monitoring review workshop in early 1994, the sampling regime was modified beginning April 1994. In January, February, and October through December during two alternate weeks each month, single samples were taken on three separate occasions. Beginning with March and continuing through September single samples were taken three times every week. During autumn and winter months when sampling frequency was reduced, sampling was postponed during onshore storms, the delayed sample being taken during the subsequent week; six samples were ultimately taken each month. To minimize costs, sampling was linked to the impingement monitoring schedule so that collections were made Monday morning, Wednesday afternoon, and Friday night regardless of tide. All sampling was completed with a 60-cm diameter plar.kton net streamed from rigging mounted 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 retention of early-stage larval winter flounder (Pleuro-nectes americanus) . Sampling time in each case varied from 8 to 20 minutes depending on tide, higher tide requiring a longer interval 4
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I due to lower discharge stream velocities. In most cases, a minimum quantity of.100 m8 of water was sampled although-at agtconomical i high tides it proved difficult to filter this amount even with long sampling intervals. On rare occasions no sample was obtained l because flow velocity was too low to inflate the net. Exact i filtration volumes were calculated using a General Oceanics Model 2030R digital flowmeter mounted in the mouth of the net. Near times of high water a 2030 R2 rotor was employed to improve l sensitivity at low velocities.
)
With the exception of a brief maintenance outage in April, all i entrainmenc sampling was completed with both circulating water 1 4 pumps in operation. On April 19 and 22 samples were tahen with one pump out of service. All samples were preserved in 10% Formalin-seawater solutions j 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 adspersus) were enumerated 4 in three developmental stages: 6
l I ! Stage 1 - from hatching until the yolk sac is fully absorbed (1. 6-2. 6 mm TL) . l Stage 2 - from the end of stage 1 until dorsal 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) . Notification Provisions
'When the Cape Cod' Bay ichthyoplankton study was completed in i 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 l 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 high entrainment levels simply were a reflection of unusually high population levels in Cape Cod Bay. The impact attributable to any large entrainment event would clearly be ;
greater if ichthyoplankton densities were particularly high only 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 it has been possible to discern more clearly the temporal extent of any unusual density without additional sampling effort. 7
l 1 1 ! 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 same 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 1
each of the numerically dominant species all previous mean l densities were examined and tested for normality following l logarithmic transformation. For 1974-March 1994 replicates were first averaged. Beginning with April 1994 individual observations were added to the data base which will be updated each year. Where data sets (for example, mackerel eggs taken in June) fit the log-normal distribution, ' then " unusually large" was defined by the overall log mean density plus 2 or 2.58 standard deviations.' In cases where data sets did not fit the log-normal 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 deviation guideline was applied.
' 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 wi'5Ln 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 below the mean + 2.58s. 8
i. 1 k
- 4
, The decision to rely on 2 standard deviations or 2.58 standard ] deviations was based on the relative importance of each species. . l The more critical criterion was applied to species of commercial, i recreational, or biclogical interest, the less critical to the remaining . species (i.e., relatively greater densities were l l necessary 'to trigger notification). Species of commercial, recreational, or biological . interest include Atlantic menhaden (Brevoortia tyrannus), Atlantic herring (Clucea harenaus), Atlantic l cod (Gadus morhua), tautog and cunner (the labrids; .Tgutoaa j onitis/Tautocolabrus adsoersus), sand lance (Ammodytes sp.), Atlantic mackerel (Scomber scombrus), windowpane (Sconhtbalmus aquosus), American plaice (Hionoclossoides olacessoides), and 2 winter flounder. Table 1 provides summary data for each species of a i egg and larva b'; month within these two categories showing the 1996 l- notification level, i A scan of Table 1 will indicate that, in cases where the'long-l term mean amounts to 1 or 2 eggs or 1...e 'ae per 100 m8, the critical i j level is also quite small. This situation occurred during months 1 j when a given species was obviously uncommon and many zeros were present in the data set with an inherent small standard deviation. , The external reference distribution methodology of Box et al. i (1975) was also employed. This procedure relies on a dotplot Of j all previous densities for a species within month to produce a j i.eference distribution. Densities exceeding either 97.5 or 99.5%
- of the reference set values were considered unusually high with
{ this procedure.
! 9 i
il
l l 1 I' Mesh Extrusion To potentially improve enumeration of cunner eggs and larvae in PNPS entrainment samples, preliminary dual-mesh sampling was j 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 uncow. mon that year. Additional paired sampling was therefore completed in June 1995 to gaF more data. Combining information from both seasons pre.,vlect varie.ble results, suggesting that consistent extrusion may not occur. One source of variability was believed to result from the inability to collect paired 0.333/0.202 samples concurrently. The existing sample rig only permitted samples to be taken alternately. In 1996 the rig'was improved to allow two nets to be streamed concurrently. Paired , a i samples were taken on four occasions in late June-early July, three or four replicates per occasion, for a total of 14 pairs; 13 were I analyzed, excluding one pair with low larval cunner densities. Dates were selected based on previous samples and historical data to correspond to the likely period of occurrence of small, carly- I 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. Since flow rates in the canal visibly l vary across its width, the position of the nets was reversed between replicates to compensate for sampling position. Methodolo-gy followed that described for the routine samplina. I i 1 10 I l i i 1
l i l Table 1. PNPS ichthyoplankton entrainment notification 1e.vels for 1996 by species category and nonth. i See text for details. 1 Densities per Long-term Mean + Mean + I 100 m8 of water: Mean t 2 std.dev. 2.58 std.dev. l January i LARVAE Atlantic herring2 0.2 1 l Sculpin Rock gunnel 0.8 1.4 Sand lance 2 5 11 Februarv , LARVAE ' 2 , Atlantic herring 0.1 0.8 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 l Sand lance 2 7 164 i Winter flounder 2 0.4 0.7 I i April EGGS American plaice2 3 32 l LARVAE 2 Atlantic herring 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 4 tLay EGGS Labrids2 36 3514 Mackerel 2 18 4031 Windowpane 2 9 147 American plaice 2 2 15 11 J
-- .-. -- . ~. . . - - - . - . . . _ - . .- - -. . _ . . - - . .- .. -.
i l
-l Table 1 (continued). ]
Densities per. Long-term Mean + Mean + j 200 m8 of water: Mean3 2 std.dev. 2.58 std.dev. j May !
-LARVAE Atlantic herring 0.7 1.1
, Fourbeard rockling 2 5 L Sculpin 3 4 ) Radiated shanny 7- 236 j l Sand lance 2 22 32 i Winter flounder 2 9 123 June EGGS Atlantic menhaden 2 4 6 Searobins 3 4
-Labrids2 958 21599 Mackerel 63 3515 Windowpane t 27 261 !
American plaice 2 1 2 l LARVAE Atlantic menhaden 2 6 10 Fourbeard rockling 9 634 Cunner2 6 265 Radiated shanny 1 15 < ! Mackerel 2 91 155 Winter flounder 2 2 20 Julv EGGS Atlantic menhaden 2 2 4 Labrids2 615 13349 Mackerel' 9 16 Windowpanet 12 156 IARVAE Atlantic menhttden2 2 3 Tautog 2 2 2 Cunner 2 7 318 Mackerel 2 2 3 Auoust EGGS Searobins 4 6 Labrids2 23 936 Windowpan3 2 15 136 LARVE Fourbeard rockling 6 10 Hake 5 9 Tautog 2 1.6 2.2 Cunner 2 10 15 ! 12
1 I I Table 1 (continued). ) Densities per i Long-term Mean + Mean + l 100 m* of water: Meant 2 std.dev. 2.58 std.dev. ! September EGGS l j Labrids2 2 3 Windowpane 2 11 159 LARVAE Fourbeard rockling 4 6 Hake 6 10 Tautog 2 1 2 Cunner 2 1 2 October l EGGS l Windowpane t 1 2 LARVAE { l Atlantic menhaden 2 0.6 1 ' Fourbeard rockling 1 16 Hake 1 2 November i LARVAE I Atlantic herring 2 4 8 December LARVAE Atlantic herring 2 2 3 3 Geometric or Delta Mean. 2 Species of commercial, recreational, or biological l interest for which more critical notification level will be used. 13
i i 1 SECTION IV RESULTS AND DISCUSSION A. Ichthvonlankton Entrained - 1996 Population densities per 100 m* of water for each species by sampling date in 1996 are presented in Appendix A (available upon request). Table 2 lists all species represented in the 1996 collections and indicates the months eggs and/or larvae of each species were found. Ichthyoplankton collections are summarized below within the three primary spawning seasons observed in Cape Cod Bay: winter-early spring, late spring-early summer, and late summer-autumn. Figure 2 shows the dominant species of eggs and larvae and their percent contribution within each season for 1996. Winter-early sorina spawners (December-April) This spawning season is split between the beginning and end of the calendar year. Many species spawning during this season 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 4 species were represented in the January collections, 7 were rapresented in February, 12 in March, and 16 in April. Egg collections over the season as a whole contained six species; winter flounder, American plaice, and Atlantic cod accounted for the majority. Winter flounder eggs were present in March and April i 14 ( l
Winter - Early Spring December- April Eggs Larvae Sculpins ,_ _ Atlantic hening 12.6 % 1.3% All others _._ Rock gunnel All others~ 8.8% 49,9% 0.5% - _Yellowtail flounder g , 6We gs , , s's
~ Cod / Witch flounder
' @T J ^' '
American plai - 21.0 % '"' V 4 ' s Saad lance 16'5 % ' _ -ourbeard rocklmg 76.9 % 6.7% Sum of monthly means = 10.19 Sum of monthly means =711.8 Late Spring - Early Summer Season May - June Eggs Larvae _Tautog/ Cunner Winter flounder _ _ Radiated shanny 62.5 % 88% 15.0 % i Atlantic mackerel _ _ Sand lance 23.0 % 33.0 %
~All others Cunner Atlantic mackerel _
0.3% Rocklin _ - 4.3% 8.7% 37.3 % _All others 7.3% Sum of monthly means =407.70 Sum of monthly means =7003.10 I Figure 2. Ibuunnt species of fish eggs and larvae found in IMS ichthyoplankton sanples by season l for 1996. Ibreent of total and sinned nmthly means for all species are also shown. 15a
Late Summer - Autumn Season August - November Eggs Larvae Atlantic menhader. _.Rockling
~
Win &wpane 9.4% 10.4 % Tautog/ Cunner- 31.7 % Tautog 28.5 % llake 8.8% l 36.4 %- __ All others
~All others 14.3 %
Rockling/llake _ 12.0 % Atlantic hening ~~ _ Cunner 27.8 % 13.6 % 7.1% i Sum of monthly means =128.59 Sum of monthly means =9146.46 i Figure 2 (contin d ). 1 i l 4 4
)
4 l 15b
when they accounted for 53 and 69% of the eggs taken with monthly geometric means of 0.4 and 1.1 per 100 m3 of water. American plaice eggs were also taken in March and April with monthly geometric means of 0.1 and 0.7 per 100 m2 accounting for an additional 6 and
!"S of total. Atlantic cod eggs were present in February, March, and April with monthly geometric means of 0.5 per 100 m3 or less.
They accounted for all eggs taken in February, 23% of total in March, and 6% in April. Since they are demersal and adhesive, winter flounder eggs are l l not often entrained by water intake systems. Their densities in PNPS samples are therefore not considered representative of numbers l present in the surrounding area. Those entrained were probably dislodged from the bottom by currents and perhaps the activities of other fish and benthic invertebrates. l l Larval collections during the winter-early spring season contained 15 species - sand lance, rock gunnel (Pholis aunnellus), i 1 sculpin (Mvxocechalus spp.) and Atlantic herring were numerically dominant. Sand lance larvae first appeared in late January, were taken on most sampling occasions in February, then every date from mid-March through April. They accounted for 99, 27, 52, and 87% of all larvae during the four respective months of the season. Larval rock gunnel first appeared at the end of January, then occurred on all but four dates through April. Monthly geometric mean densities amounted to 0.1, 4, 16, and 9 per 100 m2, respectively, values which represented 0.2, 33, 21, and 4% of each monthly larval total. As in past years three species of sculpin were represented in the 16
l winter-early spring collections. As a group they first appeared in February and were taken throughout the month of April. Pooled geometric mean densities amounted to 3 in February, 20 in both March and April. Shorthorn sculpin (Myoxocephalus scorolus) dominated among the three species in February but gave way to the grubby (M. aenaeus) by mid-March; the latter ranked first over the remainder of the season. Atlantic herring larvae were taken in small numbers occasionally in January and February, regularly at greater densities in March and April. Monthly geometric mean densities were 0.4 in January, 0.1 in February, 0.4 in March, and 3 in April. These values accounted for 0.9, 0.6, 0.3, and 1.4 of each respective monthly total. Late Serina-Early Summer (May-July) This clearly is an active season for reproduction of fishes. Egg and larval densities, especially among species spawning pelagic eggs, typically increase with expanding day length and rising water temperatures. Considering both life stages, 22 species were represented in the May collections, 24 were represented in the June collections, and 23 were taken in July. Numerical dominants included Atlantic mackerel in May followed by tautog/ cunner in June and July. Mackerel accounted for 88% of all eggs in May with a i monthly geometric mean of 134 per 100 m' of water. Tautog/ cunner I eggs represented 11, 84, and 97% of all eggs taken during the three respective months. Corresponding monthly geometric means amounted to 23, 892, and 745 per 100 m 3. Based on a study completed at PNPS 17
in 1975 and 1976 (MRI 1978), most (>90%) tautog/ cunner eggs are believed to be cunner. Larval collections over the three-month period were numeri-cally dominated by sand lance, Atlantic mackerel, radiated shanny (Ulvaria subbifurcata) , fourbeard rockling (Enchelyoous cimbrius) , winter flounder and cunner. Sand lance, which typically decline sharply by early May from a peak in March or April, remained abundant until mid-May being present throughout the month; a single individual was also taken in June. Over May as a whole they accounted for 61% of the larval total with a geometric mean of 15 per 100 m.2 Atlantic mackerel larvae first appeared late in May, were most abundant early in June, and continued to appear in entrainment samples through July 10. They accounted for 4% of the 8 May total with a monthly geometric mean of 1 per 100 m , 51% of the June total with a monthly mean of 14 per 100 m , and 19% of the July 3 total with a mean density of 2 per 100 m. 3 Radiated shanny, a small bottom fish found among rocks and seaweed, were taken throughout the months of May and June as well as the early half of July. They represented 18, 14, and 5% of the three respective monthly larval totals with geometric monthly means of 15, 10, and 0.5 per 100 m 3. Fourbeard rockling, a small bottom species similar in appearance to the hakes, accounted for 2% of the May catch, 12% of the June catch, and 5% of the July total with respective monthly 3 geometric means of 1, 11, and 0.8 per 100 m of water. Winter flounder occurred at geometric mean d'ensities of 6 in May, 7 in June, and 0.1 in July, these values accountirig for 8, 10, and 1% of 18
i l t each respective month's total. Lastly, larval cunner first appeared in mid-June, ultimately contributing 2% to the June total with a 1 geometric mean density of 2 per 100 m' . They occurred on'each i sampling occasion in July, accounting for 44% of the month's total larval catch with a monthly geometric mean of 7 larvae per 100 m'. The occurrence of larval winter flounder on three dates in July was uncommon for PNPS samples. They appeared as late as July S during nine of 21 other years dating back to 1975. Based on intake 1, , water temperature records for the PNPS intake basin, July 1996 was 4 relatively cool which may have resulted in protracted larval ! ' development rates or perhaps an extended spawning season. The
- average for July 1996 was'56.1 F or 2.5 F below the long term mean '
l of 58.6 F (1976-1995; Anderson 1986, 1996). ' j Late Summer - Autumn Soawners (Auaust-November) ' This season is typically one showing marked decline in both I overall ichthyoplankton density and number of species. Over both i, egg and larval life stages number of species declined from 16 in , l 4 August to 11 in September, 7 in October, and 6 in November. ! Numerical dominants included windowpane, tautog/ cunner, and 1-rockling/ hake among the eggs; and hake, cunner, rockling, Atlantic menhaden, tautog, and Atlantic herring among larvae. Windowpane were assumed to predominate among the Paralichthys-Scoohthalmus egg group because, consistent with past years, larval' windowpane were far more . abundant than fourspot flounder larvae. During 1996 a ratio of 4:1 windowpane to fourspot larvae was recorded. These eggs accounted for 30% of all eggs in August, 57% 19
in September, and 8% in November; none were taken in October. Monthly geometric mean densities reached a high of 32 per 100 m 3 in September. Tautog/ cunner eggs contributed an additional 32, 9, 0, and 4% to the four respective monthly totals with geometric mean densities reaching a high of 19 per 100 m in August. 3 Rockling and hake eggs were taken in August and September, hake eggs likely predominating among the grouped eggs based on the ratio of late-stage eggs. Together they represented 30% of the August egg catch with a geometric mean of 22 per 100 m and 29% of the September 3 3 catch with a mean of 2 per 100 m. Larval hake were taken during the months of August (41% of total), September (3% of total), and October (16%), August showing the greatest densities with a monthly geometric mean of 3 per 100 3
- m. Cunner larvae were present in August and September collections with monthly geometric mean densities of 4 and 1 per 100 m, 3 l accounting for 19 and 13% of the two respective totals. Rockling were collected regularly during the season until mid-November.
With monthly geometric mean densities of 3, 0.5, 0.6, and 0.2 they contributed between 4 and 15% of each month's total larval catch. Larval Atlantic menhaden were entrained from August through October, accounting for less than 1% of the August total to 47% of the October total. Monthly geometric means ..:re 0.1, 0.6, and 2 per 100 m during the three respective months. Tautog occurred from 3 August to the beginning of Octcher 'ontributiTg 9, 13, and 3% of total; monthly geometric means amounted t.
- 1, and 0.2 per 100 m 3 respectively. Atlantic herring occurred only in November with a l 20 l
l i l l l L___
geometric mean density of 3 per 100 m' representing 91% of that month's total. B. Molti-vear Ichthyoolankton Comoarisons A master species list for ichthyoplankton collected from the discharge canal at PNPS appears in Table 3; the years during which each species was represented is indicated for 1975 through 1996. A total of 41 species was represented in the 1996 collections, three more than the 21-year mean of 38. The only noteworthy entry was the collection of three prejuenile alewives in July. This represented the first occurrence of Alosa spp. since 1990 and only the seventh appearance dating back to 1975. Since the alewife is an anadromous species, they apparently drifted a considerable distance from spawning tributaries in Plymouth Harbor, Kingston, Duxbury Bay, or locations farther to the north such as the Green Harbor River. Appendix B was prepared to facilitate comparison of densities among years. Geometric mean monthly densities along with 95% confidence limits were computed for each of the numerically dominant types of fish eggs, those accounting for 99% of the 1996 egg total, along with total eggs (all species combined) for each year dating back to 1984. Geometric means are reported because they rnre accurately reflect the true populstion mean when the distribution of sample values are skewed to the right as is 1 commonly the case with plankton data. Generally low values obtained for both eggs and larvae during April-August 1984 and April-August 1987 were shaded because low through-plant water 21
volumes during those months probably affected densities of ichthyoplankton (MRI 1994). Shaded values were omitted from the following discussion. Entrainment data collected from 1975-1983 remain in an outdated computer format requiring conversion before geometric mean densities can be generated. Those years were therefore excluded from Appendix B but are discussed in the multi-year comparisons if noteworthy. To help compare values over the 13-year period, egg data were plotted in Figure 3. For this figure cod and pollock eggs were combined nith the Enchelvopus-Urochvcis-Peorilus group, and labrids and yrilowtail flounder were combined with the labrid-Pleuronectes group. For each category shown, the highest monthly geometric 'seans obtained from 1984 through 1995 were joined by solid lines as were the lowest monthly geometric means, and the area between was shaded, indicating the range of these values. Monthly geometric mean values for 1996 were joined by a solid line. Alongside each plot is a bar graph showing annual abundance indices for each year. These were generated by integrating the area under each annual curve using trapezoidal integration. One set of bars was based on geometric monthly means (1984-1996) and the other, longer time series, on arithmetic monthly means (1975-1996). Appendix B and Figure 4 contain corresponding data for the 13 numerically dominant species of fish larvae, those accounting for 99% of the 1996 catch, as well as total larvae (all species combined). As mentioned for eggs, low values obtained for both eggs and larvae during April through August 1984 and 1987 were flagged in these figures and omitted from the following discussion. 22
. .- . -_. - -. . - - _ - . - - - . . - - - - . - . - . . - . _ - . ~ . _ - 1 l l 1 In many cases densities of fish eggs and larvae vary consider- ) ably from year to year. -For example, over the 13-year geometric mean time series the highest annual abundance index divided by the I lowest for Atlantic menhaden eggs amounted to 292. In spite of l
.such pronounced variation, no consistent upward or downward trend was apparent for many species such as menhaden and windowpane eggs, ,
menhaden, sculpin, seasnail (Linaris atlanticus), tautog, and rock gunnel larvae. Following are noteworthy comments and observations concerning the multi-year time series: i
- 1. Atlantic cod eggs were typically collected in low numbers.(S I
per 100 m3 of water for example) at PNPS during winter months from 1975-1987. Following 1987 they became uncommon particu-larly during January and February. None were taken either } l month in 1993'or 1994 and only one was taken in 1995. In 1996-collections rose to three eggs, all in February. The gadidae- ! G1votocechalus group in general showed a'significant decline ! from 1975 to 1993 (p<0.001) based on a nonparametric sign test -l which is consistent ~ with the downward' trend reported for f Atlantic cod and witch flounder stocks apparently resulting, at least in part, to overexploitation (NOAA 1995, NEFSC 1996) . Annual geometric mean indices suggest the decline has ended l since values for 1994, 1995, and 1996 appear stable at about three times the low value recorded in 1993.
- 2. Eggs of the fourbeard rockling. and closely - related hake 1
(grouped in the early developmental stages with far less j common butterfish as Enchelvoous-Urochvcis-Peorilus) have been 23
uncommon in recent years. Trend analysis using the longer-term arithmetic time series indicated that a significant downward trend occurred from 1978 through 1996 (p = 0.05) in spite of a moderate catch in 1995. Any suggestion of a reversal in 1995 was erased by the 1996 value which was similar to values observed from 1992 to 1994. Fourbeard rockling dominate within this grouping based on late-stage egg as well as larval collections. Since this a small bottom fish with little or no commercial value, stock size data are not available with which to compare trends. Hake on the other hand contribute to the commercial bottom fishery, and stocks in the Gulf of Maine and northern Georges Bank are considered to be underexploited. In spite of this, the Northeast Fisher-les Center survey index showed a sharp decline following 1991 (NOAA 1995) which might explain, at least in part, the apparent decline in grouped egg abundance.
- 3. Tautog/ cunner eggs, composed primarily of cunner (Scherer 1984) appeared to be in a downward trend from the late 1970's through 1994 although a sign test failed to confirm it using l
the conventional 95% significance level (p = 0.055). The 1 arithmetic and geometric indices both showed an increase in density in 1995; the geometric index continued to rise in 1996 l as well. The 1995 arithmetic index appeared exceptional and l l disproportionate to the geometric values due to a single high density in June (37,282 per 100 m3 of water) which greatly biased the arithmetic mean for that month. The downward trend 24
l l through 1994 is consistent with finfish observations in the l PNPS area (Lawton et al.'1995). Changes in sampling protocols at PNPS have eliminated the ability to monitor general cunner population trends which in the past were sampled by gill net ) and trawl. Numbers impinged appeared to systematically decline from 1980 through 1992 then increased slightly in 1993 and 1994, more sharply in 1995 consistent with the egg data.
- 4. The arithmetic indices for Atlantic mackerel eggs clearly indicates that greater numbers were entrained from 1988 {
through 1996 compared with the 1975 through 1987 period. A sign test confirmed this upward trend (p = 0.001). Mackerel eggs typically display a sharp peak in their abundance curve often with one or two very high densities. For example in May 1995 a single density of 19,203 eggs per 100 m'was obtained on May 26 while the next highest density was 4,754 per 100 m on 8 June 9; as a result arithmetic and geometric indices are usually quite far apart (Figure 3). Greater entrainment of mackerel eggs over the past decade is consistent with a dramatic rise in stock biomass attributable to reductions in foreign fishing and underexploitation by U.S. fishermen (Overholtz 1993, NOAA 1995).
- 5. Windowpane eggs, assuming, based on larval collections, that they predominate within this egg group, appear to have been increasing in number over the past three years. The geometric mean index for 1996 ranked third among the 13 years for which that index is available. The arithmetic index ranked sixth 25
over the entire 22-year series. In general these eggs have not.shown wide variations in number, at least not compared with other species regularly entrained. Current indices for windowpane in the Gulf Of Maine and in southern New England are among the lowest of a time series dating back to the 1960's (NEFSC 1996).
- 6. Following the arithmetic mean index over the entire 22-year t.ime series suggests that American plaice eggs dropped in number from the late 1970's to a low point in 1986. Following 1986 densities appear to have gradually increased through 1995. Both the arithmetic and geometric indices declined somewhat in 1996 although they remained well above the 1986 low point. According to NOAA survey results, a strong year- ,
class of plaice was produced in 1987, the stock slowly rebuilding since that time, at least through 1993 (NOAA 1995).
- 7. Larval Atlantic herring were exceptionally abundant in 1994 and 1995, both arithmetic and geometric indices greatly exceeding all previous annual values. In 1996 numbers i declined from the preceding two years but remained relatively high, both indices ranking third overall (the geometric index actually tied with 1990). Herring stocks on Georges Bank and Nantucket Shoals have increased markedly in recent years as !
have larval abundance estimates (NOAA 1995, NEFSC 1996), the increases noted at PNPS being consistent with that trend.
- 8. Larval radiated shanny have been relatively abundant since 1989, 1995 and 1996 densities being particularly high. Among 26
the 12 years for which geometric indices are available, 1995 (927) and 1996 (776) rank first and second, respectively. Dating back to 1975, 1995 (1727) and 1996 (1865) ranked third and second, respectively, behind 1975 (2178) based on the I I arithmetic index. Since this is a small rather inconspicuous 1 botttom fish, relatively little is known of its habits and no i data are available concerning population trends.
- 9. Over the course of the last three years larval sand lance have been very abundant. The geometric mean index for 1996 (6,156) is the second highest of the shorter time series, exceeding all previous geometric values but that recorded in 1994 (12,490). Over the complete time series, 1996 (arithmetic index = 19,512) also ranked second behind 1934 (26,276). The three most recent annual abundance indices appear biased by the fact that sand lance larvae may be more susceptible to entrainment at night, regular sampling during those hours beginning in 1994. For example, among six samples which exceeded all previous densities for the month at the time during 1994, 1995, and 1996 (see Table 1, Vol. 2) , all but one (83%) were night samples.
- 10. Following an exceptionally high-density year in 1995 (arith-metic index = 12,086), larval mackerel densities declined in 1996 (arithmetic index ' 4,104) although they remained abundant relative to past seasons, ranking fifth out of 22 years. Like their eggs, mackerel larvae densities are typically skewed by a small number of high densities. As a 27 i
i l l I result, arithmetic and geometric indices are often wide apart. Within the shorter 1984-1996 time series the current year ranked fourth.
- 11. Winter flounder larvae remain a species of great concern throughout the New England region since stocks are near historically low levels (NEFSC 1996). Larval densities in f
! 1996 were relatively high by both indices. The long-term l arithmetic index ranked fourth out of 22 years, the shorter l l geometric index second out of 13 years. C. Mesh Extrusion Densities per 100 m3 of water for tautog/ cunner eggs and cunner larvae by stage for both 0.333 and 0.202-mm mesh collections completed in 1994-1996 appear in Table 4. Eqqs Paired sample t-tests on log-transformed data for all three years combined indicated tautog/ cunner eggs were significantly more abundant in the 0.202-mesh samples (p < 0.001; n = 34 pairs). Since densities were highly skewed by high values on June 28, 1995, geometric means were calculated over the 34 samples within each mesh category. The ratio of these (also the geometric mean of the ratios) was 1.29:1 with 95% confidence limits of 1.12 to 1.50:1. The arithmetic mean of the ratios was noted to be characteristical-ly higher than the geometric mean at 1.44:1, raising the question of which value provides the better conversion factor. The ratios l were not found to be normally distributed (following Ryan and ] 28 , l
. . . - . - - - - . . . ~ . . -- .- --. . . . - . -
e d -4 Joiner 1976) indicating the geometric mean provided a less biased ' estimate. i i Geometric mean ratios were higher in 1994 (1.58:1) than in d 1995 (1.20:1) and 1996 (1.14 :1) suggesting variability in extrusion , can be expected between years. The similarity between 1995 and
- 1996 at least suggests that great error was not introduced by
- alternately collecting samples (1995) rather than streaming both nets simultaneously (1996).
Larvae Recently hatched larval cunner were common in the 1996 mesh comparison samples, all but two pairs containing individuals in both nets. Combined with 1995 data, 15 pairs were available (stage 1 cunner were absent in 1994). A paired sample t-test failed to detect a statistically significant difference between nets (p = 0.75; geometric mean ratio (0.202:0.333) = 1.10:1 (Table 4). Similar results were obtained for stage 2 cunner. They were taken in all samples in 1996, bringing the number of pairs to 22 when pooled with 1994 and 1995 data sets. Again a paired sample t-test did not detect a significant difference between nets (p = 0.22; geometric mean ratio (0.202:0.333) = 1.28:1, Table 4). As expected, larger stage 3 larval cunner were taken in similar densities in both nets. A geometric mean ratio (0.202: 0.333) of 1.00:1 was obtained over ten pairs (paired t-test p = 0.99). These results suggest that small cunner are not extruded through 0.333-mm resh netting to any significant degree. While the 29
ratio of 1.28:1 obtained for stage 2 larvae may appear important, the t-test indicated there was a 22% chance of obtaining such a difference by chance alone. Power analysis indicated that 140 pairs of samples would be required to detect a ratio of that magnitude with a probability of Type 1 error of 5% and probability 2 of Type II error of 10% (Cohen 1988). One very conservative approach in assessing impact at PNPS would be to multiply the observed ratios times the respective stage 1 and 2 larval cunner densities, realizing that resulting estimates are likely to be overestimates. D. Lobster Larvae Entrained , 1 No lobster larvae were found in the 1996 entrainment samples, j the total, dating back to 1974, remaining at 13. Following is a ) i tabulation of previous collections: i l 1995: 1 larva - stage 4-5, July 28. ) 1994: none found. l 1993: 1 larva - stage 4-5, July 21. 1991-1992: none found. i 1990: 2 larvae - 1 stage 1, June 26; 1 stage 4 August 23. 1983-1989: none found. 1982: 1 larva - stage 1 on June 14. 1981: 1 larva - stage 4 on June 29. 1980: none found, t 1979: 1 larva - stage 1 on July 14. 1978: none found. 2 Type I error occurs when a difference between means is indicated by a statistical test but in fact the observed difference occurred by chance alone. This is commonly set at p = 0.05, the value reported with most statistical tests. Type II orror occurs when a test results in f ailure to reject the null hypoth. sis when it is in fact false. Type II error may typically occur when sample size is small and/or variability within samples is high. It is clearly most common when trying to detect small differences between samples. 30
1977: 3 larvae - 1 stage 1, June 10; 2 stage 1, June 17. 1976: 2 larvae - 1 stage 1, July 22; 1-stage 4-5, August 5. 1975: 1 larva - stage 1, date unknown. 1974: none found. The lobster larvae collected in 1976 were obtained.during a more l intensive lobster larvae program ' which employed a 1-meter net, 1 I collecting relatively large sample volumes, in addition to the standard 60-cm plankton net (MRI 1977). Both larvae taken in 1976 were collected in the meter net; none were found in the routine ichthyoplankton samples. During the three-season Cape Cod Bay neuston study for larval lobster begun in 1974, larvae were found from May through September at monthly mean densities ranging from 0.2 (September) to 3.8 per . 100 m8 (July; Matthiessen and Scherer 1983). Considering that a minimum of roughly 10,500 m* of water were sampled during'these months each year, larval lobster mest indeed be rare in the PNPS : circulating water system. r t 31
_ _ ~- - . - _ - . .- _ _ . _ _ . _ _ _ . ._. m._ __ - _ . _ _ _ . . SEL7 ION V HIGHLIGHTS l
- 1) Numerical dominants among the ichthyoplankton entrained in 1996 included American plaice, cunner, mackerel, fourbeard rockling, hake, and windowpane among the eggs; sand lance, sculpin, rock gunnel, mackerel, radiated shanny, winter flounder, hake, cunner, and rockling among the larvae.
- 2) A statistically significant downward trend in abundance was 1
apparent over the 1978-1996 period for rockling and hake eggs in spite of a moderate catch in 1995.
- 3) Numbers of Atlantic mackerel eggs have clearly increased during the 1988-1996 period compared with 1975 through 1987.
This is consistent with a dramatic rise in stock biomass attributable to reductions in foreign fishery and underexploi-tation by U.S. fisheries.
- 4) Larval Atlantic herring were exceptionally abundant in 1994 and 1995. Densities in 1996 declined from those two years but remained relatively high. These collections are consistent with marked increases in adult stock in recent years on Georges Bank and Nantucket Shoals.
- 5) The long-term arithmetic index for larval winter flounder ranked fourth out of 22 years in 1996, a bright sign in light of low stock biomass throughout the New England region.
- 6) Mesh comparison studies completed for cunner eggs and larvae indicated that eggs were retained at significantly higher 32 i l
l l
. . -. _ - . . - . _ . ...-.. --__-- -. .--.- - . ~ . . _. - - - . . _ .
i l l densities in 0.202-mm mesh samples compared with 0.333 mesh. l 5 An average ratio of 1.29:1 was recorded. No significant I l difference was detected for stage 1 or 2 larval cunner although respective mean ratios of 1.10:1 and 1.28:1 were I recorded.
. 7) .No lobster-larvae were found in the 1996 entrainment samples, the total remaining at 13 dating back to 1974.
i 1 f J i l a r i 1 e 4 4 33 n -
I i 1 k Figure 3. Geometric mean monthly densities per 100 m2 of water in the PNPS discharge canal for the eight
- numerically dominant egg species and total eggs, 1996 (bold line). Solid. lines encompassing shaded area show high and low values over the 1984-1995 period.
Brevoortia tyrannus Labridae-Pleuronectes Gadidae-Glvotocephalus Scomber scombrus Enchelvoous-Urochvcis Paralichthys-Sconhthalmus Peorilus Hiocoalossoides olatesmoides Prionotus spp. Total eggs l To the right are plotted integrated areas under the annual entrainment abundance curves for 1975-1996. An asterisk above 1984 and 1987 marks the two years when values may have been low due to low through-plant water volumes from April-August. An asterisk above 1976 indicates abundance value may be low due to absence of sampling during January-late April; see text for clarification. Light bars represent indices based on monthly arithmetic means, solid bars (1984-1996) indices based j on monthly geometric means. l 34
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M. 6Aoundmue w w a_._.. ._) 37
1 l l Paralichthys - Scophthalmus Eggs !
~ "
gigj=i.= l iniing
~ ~ - ~ ~ ~ ~
>= hh$g;g;;- wwms;g rgh l 'UEj.Y$
= - - - J 5 55.5
]'
^
f
)-
F ' - 8 $Y5$2
.:::::- ^ ~~
$E
==nn YI$ '
= 4 -
_~l Z. < g i173115" HM i H' 2 [ -
-= _ == ; 1 T
"~
~~~V _~~~.-
0 01 y;. g y .g f - 0 7$ 77 79 ei s3 ',8 87 89 91 93 95
- p. ;=.=,7 76 78 80 82 84 86 88 90 92 94 96 212 ;
y, 3EUhM J J A 3 UN d Gi----- J [m w w im) Hippoglossoidesplatessoides io . . ___
. _ _ . Eggs,v
.-~~ l_
'~-~~
s.* ,-
- s 12m -- - - - - - - - - - - -
' = = $h?, . t EW3 i ==-';:3
~_-E ..#,n n" swo - - - - - - - - - - - - -
3 =~ m . r e ?HEi= .5 ::~~ , _ . .
}
i,^
, , ,. & ~# ~~ " ^ ' - ~ ' * ' * ^ * * " ' * ' ~ ' * " ' ' ~ ~ '
{ ~ !
< ~
8 w w! - -4. C~w w== Z g Jf .
'~~Z 4 x y 4 x ..: .,gacrx2 4. ,- -
!r "i
g };$ f,g I . v= =g [
~
Sgj l}
= gew ',,- 1, ,, ,, ,3 L-xJ gj Z ,u g 76 7: so 2 s4 e6 as 90 92 94 96 0"3 7py 3 y , 73 ',- ggg ( Abuh indes based a QAn6mwmc ineens Wcmomeew (OHgh4Apw .81996}
38
Total Eggs 10000 .c --- , m m- ,. .
'3.:-,
- - - - ~25:. =t 35 -5L ' m*;:. i:2 :t5 . h ?- . 'Ti :M S l
.__. _ _ ..C r i
"!"fCM T ttp 400 9.lf TT'.M
====== ===5575 -
100 : s 4.=ym. : q==- . N;.:. r ar*- -m
- ? EE=EEn: 2.g ;' L . ',. .gg g 3)0 -- ---
i to
--- _ _ =: 'E g
J m..
.. - .. c.EA J i$ '.25Lt. l g ,_, _ _,
s y, I y .y 3x g y 4 e.+va. we a=c I gg.6 qg..j; - - -
=r= = .- %. ( 100 g
01 .[ .mm c t== eare=e . ==. y- ;:,;. e ; . = .
.m.:. rz ' r : . : j g 0
, 0 01 1-
}+.y-;= ===;gng.tygg
== : . :== = - .= u
.--e 73 77 y y 79,St g y g g 11 3 83 87 89
, 91 g g g 93 95
.s$ [ I_ZZ-_~__'ZZ .Z . !
'l'- . YW 0 001 f Abundemoe Inden bened est J F M A M J J A 3 O N D Ifll Anthmecc means WGeometric Month (C2High/ taw es1996}
39
Figurts 4. Geometric mean monthly densities per 100 m3 of water in the PNPS discharge canal for the thirteen numerically douinant larval species and total larvae, 1996 (bold line). Solid lines encompars.ing shaded area show high and low values over the 1984-1995 period. Brevoortia tyrannus Tautocolabrus adsoersus Clupea harenaus Ulvaria subbifurcata Enchelvoous cimbrius Pholis aunnellus Urochvcis spp. Ammodytes sp. Myoxoceohalus spp. Scomber scombrus Linaris spp. Pleuronectes americanus Tautoca 2Ditis Total larvae To the right are plotted integrated areas under the annual entrainment abundance curves for 1975-1996. An asterisk above 1984 and 1987 marks the two years when values may have been low due to low through-plant water volumes from April-August. An asterisk above 1976 indicates abundance value may be low due to absence of sampling during Jai.uary-late April; see text for clarification. Light bars represent indices based on monthly arithmetic means, solid bars (1984-1996) indices based on monthly geometric means. 40
l l l Brevoortia tyrannus Larvae 10 '1=
= = ._. = g y
.. -- di{$.. ~ '~ ~~
g _ t .-"-_- . _ . _ . = = = . -- :=-. y x.. 3 300 g jp . . - .$ r ' g ^p' .: 1] _ _ . . y .gg . gf 1 - 600 - - - - - - - - - - - - - - - - - ' j .c :: w h
.~ _ .- .
.. 'k i i -
a _ . _ _ . _ . ._ .._. u:
$m$@m.
$ hf2% Ti' . _
** ' ~ ~ ~ ~ ~ ^~ ^^ ~~ ^
o os ymgi , g y =
===:=_= L g' q 1 n 1 M te U00 lr.s I AvsN 0 1 - -- II D
- h
[4$@8' sMdhi 5 75 77 79 81 83 85 87 39 91 93 95 Jh$$5%f$i@ ISj 76 to a s2 s4 ua m 92 u 96 0.001 , , , , , , . : L YEAR J F M A .M J J A S O N D Mime Abundanos inden bened out p Arnhmehe moons W Gemnetnc menny
}
(GHq#vlow es1996) Clupea harengus Larvae
=._r.E.E._ 'i..5_ N.M-E.5NEbN.Y
.1 1200 - - - - - ----- --
l0 ==- =.. = .=3a 5 . g g- =r ==- r .$d g' 7'- 3 :.;.__ = ] '{ p -{ p34 1000 - - - - - - - - - - - - - - - - - - - - - -- x-- ___._ ___. 3; I 1 --= , g ==,f7:_ :-- .
- ..x -y j/ .=..= E3.3 (. (
- 1. . ;h 44 .-i e.s! 600 - - - - - - - - - -
k -
. ', digd . N # k '
b - - -::. -I% Q' l; li[:{i 0.1 p .. . g _. , _ , , , , , , , , _ l
-r .'". W % ___. -
kV
'}. .
.l 200 - - - -. - - - - - - - - - -
f [Ns h':hEl k *0nnnUn * [$ b S tk h;f',.N
"'~~ ,
g p'h,i
- .5
_.g f 75 77 79 SI 83 83 37 89 91 91 95 h 2% - - - d "ypy 76 73 30 82 b4 86 83 90 92 N 96 WW'. _ 07 - F{: hrM: YEAR J F M A M J J A 3 O N D g Mame pan &menc means MGemnetnc (CSRdVtow to1996} 41
i 1 1 I l l Enchelyopus cimbrius Larvae l _uuma x.me"==s=_3 io m
-m. e_ .e. .m _. =.em__ . _
. _ _ _ I y erst
~
I _ 1r 13 .-- _ 8 's i mme J, 1
-
- Dh eZ 2 - - - - ---- -
; 1 ma1 f : l_ ~. [ ) : i '-
r ~ l iggN r._ , a ! iL n. l l 0I
,,,hl=gyf=inJi ",.",, ,r ,r.r r
~
jp .
,,",, ~, ~,. i x...A
.. 8
- 6. - -c - . J
[ow i996] i i i I l Urophycis spp. Larvae ; s:sss=e r = = e + = l . , i 1
?$b5?$?{h 55$ (
Q.ll- - - p I $
~[Qfe,.T =: 35.:. ~ ' '
_} A ' 55.
~
h s ___
?. 5E Jfn = > - --
~I$iR L iis gi <
= 3 we = i - -- -
"' ^ j jpT? jk g :,g- [Q n y isudl.1[i EE=f - ,1,, ,,
,0 (l I i
-'g -
,, .i o u .,
26 78 80 $2 M F 88 90 92
,i n4 96 g
*iFaA UJ J A 8 0 UU
-- 6 ,, - -c- ,. .-)
- t. ,, ,
42
i Myoxocephalus spp. Larvae ggga=& u= gg
= -
10 _=;= gg := ==sg3 5 - _ _ _ j,
~
1 = - = = - = = = = - g 3besmew __ _. _ _ '{ 01 qq , ; 2 Q-Q'L= f ~~ ~ ~~
-- ~
d -
== _
_ i _, _ _ _ i
=rs t ri
- ' ' ~
p' ~=~~=~c. 77 79 81 83 85 87 89 91 93 95 0 75
- r. I i g6 78 80 82 84 86 88 90 92 94 96
"'7FMAM J lI5 dND (oms u.s u to wim) 6g . - ._) ,
Liparis spp. Larvae , a3E E:.EEE4.E =Lgf gg -- M**. '_.M b5'M PM'*'W d b-[jk' MMMY Nb MJ.INlbI@T .-5
. iff[' j in _ _._ _ _..._.'_ _
xy
=:: 9.g. y zm mm
, = ae ;,. = _ = ' - ' ' . = ,. _ _ __ _ _ ff* g' g oi . t,
- = = =_ =-.._ .._=
s . it -- - Z s___..__ _ . y l
$!( MIE35 , []
h , l l l 7 --- ,, ,, ,,
,. i,, o , o,,, ,, ,,, i , ,, , ,,,
-'Oa..,assas -
-- 6 _.;._ _ _._).
[a mswi.o. mi m ) 43
Tautoga onitis Larvae an _1-5__ _. ===-= g g _ ._ _ ,oo _ I ~. :E'~===fEj . {--)) E
.. s f 400 s "
swes }
- M~ = - .-
---- - - l :n l -~- $h %: } .
l-f-
-e er - 2m -- -
1s!C.[I l_ - [Nd ..[ (
' ' 0
' ll l . . l
$f, 75 77 79 81 83 83 87 39 91 93 9$
j.; .{ 16 78 4 82 84 86 88 90 92 94 96 l N' 7;i g ; y " , , , , o ~ g['g Yw i ( Abundance inden bened at DAndunate means m '- (OHyrNI.aw es1996} l l Tautogolabrus adspersus Larvae h sz;c = m g g fgsgsg ,, 23.9 1 YEiE5YNE:7. Ys!$[:MTT 10
}'~~ '~ ?2 ^dKE}}
io egwg;n A ,= 2 * --- - - - - - - l ~-~~= = - . "' . =.~~""~~']' g'[ .; g:
===
= ]Ig;m=; gg j, ___ _ _ _ _ _ _ _ ___ j 0I w =-
~ - 4 p n =g
=1 m re r , _, . _ .
; ?: ' ; (r o oi
,_- m E r dsm .';n was,n 2
y a ,,g,00 n
*m .
b g s l 74 to so 82 84 # 88 90 92 94 96
'"' i y a x a i , 4 8 sN6 M ( ^
- inden based an QAnthmetw swans WGeomeau (OHgth/ Law 881996}
44
Ulvaria subbifurcata Larvae i 2-l eu,mg.mm = m ia l gy;u re ===r
- p. - _ . .
g y; j i- . _.
=}n ====
.====:
,-=:
s
. ~E=g, 4g = - i >= - ----- -
p =
*^" :f. E }} ' i{yy~ p ~
If :
. . _ . 500 g- ,
n - . _ , . 00I
=m
- a. e 'k aus x..a g,m;_._.
r==
\\
,9 n t
,,,,.,,,,9 s ,, ,, ,,
--- y g fg 16 1s to s2 84 na st 90 92 94 N iiuhw1 J iabNB n._
-i 6--- c_--.J Pholis gunnellus Larvae s e w m. = m A = * =
'Ir ,.
IC &#+ .I[ 3 + if:T:lHX5siH3 gg = _ = _ = = _ - - - - ( 9- _
} .-. . ... .
l I EF:. = a.m.1 = m:E
- .sil
? .fssl55 .
0'
=ss= a : ,. ;ie.E mi EX:-~
===p'{ e=m . ~ _ . _
; r I
$3f5[2 h $:b$sNb5.5 (n f if, F g,,
0 7$ 77 19 31 83 53 87 39 91 93 95 76 75 80 52 54 36 BB 90 92 94 96 l
* "' s ruausiXsoN6 , ,
- _ ._ .c .
(GHagh/ Low es1990) 45
S Ammodytes spp. 1000 0 if::'5)N-!5$:5 5.-b5'.;N ;{.Nj{
~
26276
._~_Z 19,51i
_M_ P li._M:lelDM:-W3 8 - n.ga --. - --- - . . s a 1 - - ~ ~ .
-.g s
& Y===r=_== Y E.$.R ] 6 - - - --- - . _ - . . . _ -._'
3
'h . -
~7___ Z.~~. _
8 p l. ' ' ?2XXWQ 4 --- . . . . _ _ _ ._ ii Mwmk y[CC~ C5;i
. . . 4 OI -
p6%j e .. y,3 y m w. r
~ ~
-kh Nh hh$: [ ~~ l 0 01 N$. - . .
.* f[ C Q5 r wZ if:em 73 , 77 79.0 31 83 85m87 39 ,0 93,, 93, 93,,
, , , 5 "g Y" iF M A M J J' A 3 h ~ ,.e p Mane Amundance inden based n (12HW es19we}
Scomber scombrus
,,, Larvae 5=-.:==.=.==..~_=t__;. *0'~
--==:=..=,=: - --
- . _ . 110t16 l } c30 lo gt:12- n - =
==:.== . . _===:- =====.=
- ^2'..
' '~ .
3df[Q:-} y g Ass rz:r:: e mn d%4 g%.. ,..
- 55. d5 i
4 --
*' ymars j$kk
;.y n zr
= :: = = . =
- Z < ~G5 . . . - . . . ~
2 -L- - _ __ i .j. M . 0 01 y g: g 7 { g ' yj .m.;=.,_=.. !
.b_bh? '[# I-bib 5- 0
" f1 -4 I- A !l
[_] x 7J 77 79 81 0 33 37 39 pg ' g3,4 93
, q- 7s to so e2 s4 m = ,o ,2 53 0 001 ,, . - ., . , ,
3 F M A M J J A 3' dN h Y" M.g Atuuhuma inden beend m {Q)hgh/ Law e81996} 46 I
i Pleuronectes americanus Laivae 300 a. . . _ . _ . . . _ _ 3000 i i = : .: = . .= .g_ =. . =-_ := = . : .2. . =. - --
. _ _ _ . - - - - - - 2500 - - - - - -
E~EOE~S :
/_E. E.TE__7. EfE'
_Z: 2000 kN M b:_kh i 1500 --- - - - r;;.f , ;' ,'q' _ _ ~.- g
- . g__.__._.-... <
~ ~ ~ ~ '
01 = ~ = , r.-- w e-; - :n - 6 5_.:._ h, 5._:_ b _: 5__.i5_.2_
.,.x _ . .. _ '
g. 300 $ , __ g _- - 34, _. , 0 01 y..n .x.[ D
] = 73 x =fr r=: .~ =-
I 3~3 ~d ici '* Ellii E .;E 0 , , ", , ZZ '> ~~Z_ $'" Z- Z:Z C 73 77 79 el 33 33 37 39 91 93 ps _. -.--- 76 18 to 82 N 86 88 90 92 N 96
;;}. jg 0 C31 Year A M J J -A J F--M --S O N D M** PArnhmete means WCm -
(E3HagW14w as1996) Total Larvae 1000 z_ ... _. _ . .
, ...; 60 M
7^'U , j, h, e' .
'M[l'M'. .NT 'N
'$: 5$$k' c -
55.5: = :.I!
- fy&k h %
~
' ~ ~ ~ ~ ~ ~ ~ ~ ~
..,.. [$$$< .
+
5 -- '
$hkb.hi.
g y I fjf ~ ' 4g*;;4ffh. 3 j 30
- '-- - - - - - - - ~ ~ - - -
q g:j,.? y ' " .s
]
g I . .mt E.dr- eYE 9%@M L. Y .: ! '].' ' Y:~ s gg _ . , _ __ __ _ , _ _ _ . _ _ _ .
~
0.1 y == 7 y-- y g.ge=p g " f
- 3. ;_; ., =. = : : ::y__ _m . ;.:.. . ;.. , 10 8 f W- 8 l 0.01
- m. .:=:==
==r=
- 3===
r r s.re..j h..: nz: . = - .-. . _ . - . - 0 l Q, : j
-r.=c 75 77 79 81 33 85 37 39 at 93 95
-.] ] = = =.=- $$
. Vfj 16 70 30 s2 H 86 30 90 92 H 96 o 001 Year iF M A W j j A 8 O N D M-* 6r -. .c =J
- e. _3 47 l
Table 2. Species of fish eggs (E) and tar ae (L) obtamed in ichthyoplankton collections from the Pilgrim Nuclear Power Station discharge canal, January-December 1996. Species Jan Feb Mar Apr May June- July Aur Sect Oct Nov Dec American eel Anguilla rostrata L L ; Alewife - Alosa pseudoharenrus L - Atlantic menhaden Brevoortia tyrannus E E/L L' L E/L L t Atlantic bemng Clupea hareneus L L L L L .L s Bay anchovy Anchon mitchil.li L L Rainbow smelt Osmerus monlax L Fourbeard rockling Enchelvopus cimbrius E E E/L E/L E/L E/L E/L E/L L Atlantic cod Gadus morhua E E/L E/L E/L E/L E/L [ Haddock Melanoen mmus seriefinus E Silver hake Merluccius bilineeds E/L L E/L E/L E/L Atlantic tomcod Microradus tomcod L L L Hake Urophycis spp. E E/L E/L E/L L Goosefish lephius americanus E/L L Silversides }Wenidia spp. L L L L Northern pipefish Synenathts fuscus L L L L ; Searobes E_rionotus spp. E E E i Grubby Myoxocephalus aenaeus L L L L L L Longhorn sculpin M. octodecentwinosus L L L L Shorthorn sculpin M.scorpius L L L Lumpfish Cyclopterus lumpus L seasnail Liparis atlanticus L L L L Weakfish Cynoscion renalis L Wresses labridae E E E E E E t h b _ _ - _ - - _ _ _ - - - = . _ _ _ - - - _ _ _ _ _ - _ _ _ - - - _ _ . _ . _ _ _
r Table 2 (continued). Species Jan Feb- Mar Apr May June Julv Aur Scot Oct Nov Dec Tautog Tauto en onitis L L L L L Cunner Tautomolabms _adspersus L L L L Snakeblenny Lumpenus lumpretaeformis L ; Radiated shanny Ulvaria subbifurcata L L L Rock gunnel Pholis runnellus L L L L L Wrymouth Crsethodes macriatus L L - Sand lance Ammodytes sp. L L L L L L L i Atlantic mackerel Scomber scombrus E/L E/L L E Butterfish Peorilus triacanthus L L Smallmouth flounder Etropus microstomus E E E E L m Summer flounder Paralichthys dentatus L o Fourspot flounder E. oblonrus L E/L L i Windowpene Scophthalmus nouosus E E/L E/L E/L E L EIL Witch flounder Givotocephalus cynoglossus L E/L E/L L American plaice Hiocoelossoides niatessoides E/L E/L E/L E/L L E/L : Winter flounder Pleuronectes americanus E E/L E/L E/L L ; Yellowtail flounder E. ferrucineus E E E E/L E/L f r a b I t i I i _j
Towe 3. Species of f4 eggs (E) and larvae (L) cenected in the PNP $ descharge esmal,197$-l9u6. General penade of accorreare for agge end larwse comtuned am shcon along the nght swie, foe die denument species, permde of poet .'- e are also shnwn in parentheses. Sc-cies 1975 19 % 1977 19 4 1979 19 3 1991 1982 1993 1984 1995 1986 1987 1988 1999 1900 1991 1992 1993 1994 1995 1996 Penad ef C:cerne Anroelle sentrata 3' I 3 3 3 3 3 3 3 3 Fe*> - Jun Aloes app. L L 3 L L 3 L May - Jul Bwis tyrmanus E/L E.1 DL E/L E.1 El E/L E/L E/L E Et Et Et E.1 E.1 E/L Et E/L Et L'L E/L E/L W3en) ttht)Dec Chees bareprus L L L L L L L L L L L L L L L L L L L L L L 3== - Dec2 Anchoe arf- L L L L L L L L L L L L L L L L L L L L Joe - Sep A. outchi'li E E E E E/L E E E E E E E L sun - Sep Osments nwwdas L L L L L E/L L L L L L L E/L L L L L L Apr - Jun Bromme bremme E/L E/L E/L E/L E/L E E E Apr - 3 1 Enche!vteue rwnhek, Et E.1 E/L E/L E/L E/L E/L E/L E/L Et E/L F,1 E/L E/L EL El Et El Et E/L E!L Et Apatsen) - (Sep)Dec Mg morhoe E/L Et Ett E/L t/L Lt E.1 E/L E!L E/L Et E/L FJL E/L Et E!L E/L E/L El Et it E/L lam (Now)- 6ks)Dec Me;saneremmus seatefine L El E/L E,1 L L E E E E E Ape - lut Merhiccies bilinearis Et E/L E/L E/L E/L E/L E/L E/L Et E/L E/L E/L E/L E!L E/L E/L E/L E.1 E/L E.1 Et E.1 MaytMay ) - (jan) Mow Micromedus hmiced L L L L L L L L L L L L L L L L L L 3en - Mey Pollachies vimig E/L E/L E E/L Et E.1 L L E/L L E/L L L L L Et L L 3eelen.Nov.sh L'rwhycis spy. E/L E/L EIL Et E E'L Et E.1 E/L E E.1 E/L E/L E/L F/L E.1 E/L F/L Ed. E/L E1 E/L Apit Aeg) - (SeriNov Ochidme vnert inature L L Aug - Sep Lochies amenenaus Eit E E/L El E/L L E/L EA E/L E/L E/L E E E Et E/L El El E/L E/L F/L Et Mey - Rt Strotuttuen serme L lut Fendules spp. E E sol E. hetesshtus E 3ea E. gLaghe 3 E Ekt Meredie arP. L L L L E!L E/L E Fst L L L L L L L L L L L L L Mey - Sep M. numdie E/L E/L E L E E May - Sep
Tebte 3 (cesesmeed) Specses 1975 1976 1977 19'1 1979 tolto 19T1 1982 1983 1994 1985 1996 1987 1989 1959 1990 1991 1992 1993 1994 1995 1996 Period of Occurrence Synenstbus jLocjg L L L L L L L L L L L L L L L L L L L L L L Apr - Oct Sebenes avverxes L Jun Pnoncese app. Et E E E E/L E!L E Et Et Et E,1 Et E/L E E E E Et E E E MeytJun) - ( Aug)sey Hernitrwterus amence we L L Feb - Mw Myonorechehrs en- L L L L L L L L E/L L Et L L L E/L L E/L L L L L L Du(Mar) - ( Arr2ut M pensens L L L L L L L L L L L L Et L L L L L JamMar) - ( Ape)Jul M octodecemeinosus L L L L L L L L L E/L L L L L L L Je:WMart - ( AprNay M scnepius L L L L L L L L L L L L L L L L Feb - Apr M&ybormdes marmetervetus L L L L Mar - Apr Cockvietwe lurwos L L L L E L L L L Et Et L L L L Apr - Jul Liperia an. L L L L L L L L L L L L L L L L L L L L L L 1 sat Apr)- (Junijet L silenticas L L L L L L L L L L L L L L L L MartApr) tjundet L. ceeny L L L L L L L L L L L L L L JanJeb) - (Mar) Apr Ce:mrterie:s eta L L L L L L L L L L L L Bul - Oct CymmW remarie L L L May - Sep Sterisornos chrymys L L L E L L L L L Jun Jul hierwicirrhus mantihs L L Jul - Aug LAmdes E E E E E E E E E E E E E E E E E E E E E E MartMay)-( Augiser Teutors e L L L L L L L L L L L L L L L L L L L L L L May(Isa) - (Augxh1 1satorolebrus edarersus 1 L L L L L L L L L L L L L L L L L L L L L May(Jun) - (Aug Wkt Laneenus luneretseformie L L L L L L L L L L Jan - Jan L oubbifLasty h L L L L L I L L L L L L L L L L L L L L L L Feb4 Ape) - (JueM kt Dg!!s runnellus L L L L L L L L L L L L L L L L L L L L L L Jandeb) - (Aprpue Crveiscenthodes maculetus L L L L L L L L L L L L L L L L Feb - Apr i _ - - _ - - - - - - - . _ - - _ _ - . _ - - - _ - - - - - _ - - - - . _ _ - ----n-- _ - - _ - - _ _ . _ _ - _ _ . . . _ - .-- . _ . _ _ - - _ _ . _ - . . - - _
Tame 3 ( seeces 1975 1976 1977 19 4 1979 1980 f *81 1992 1943 1984 1985 1986 1987 I*88 1999 1990 1991 1992 1993 1994 1995 1906 Pertad of Oceverence Amrnodvece sp. L L L L E/L L L L L L L L L L L L L L L L L L lan(Mart - tMeyklen On6nenma rinsburn L L L L L L Jul - Sep Scornber scambrus E/L 61 E/L E/L 1L E/L E/L El E/L E/L E.1 Et Et E/L E.1 E/L E!L Et Et E/L El E/L AcetMe))- deeser Eredig enecerehus E!L E/L Et E E E/L Et L Et E/L L E E/L Et L E/L L L E. L L May - tu Etterve sucroskums L L E E/L E E E E E El E.1 Jul - eat Perer, cheiro dermatue E.1 E/L L E/L E L El E E/L L Sep - Now E. cek=was' E/L E.1 E/L El E/L Et E/L EL El E/L E/L Et El El E/L E\L E'L E/L Et E/L May - (M Scoebthelmus souceus' E/L E/L E/L E/L E/L E/L El EL Et E/L E.1 El El E.1 E.1 E.1 EL E.1 Et E/L El E1. AcetMayn - (SepKu Givetocephalus cvarvloesus E/L t/L E/L Et fL E.1 Et El El E/L E/L E.1 E El E/L E.t E.1 E/L Ell. ET. E,1 E.1. MertMay) - Oun)Nov
.mLie plate.enides E/L E/L E/L E/L E/L E/L Ect E/L E/L E/L Et E.t E/L E.1. E/L E/L E.1 E.1 E!L Lt E.1 Eit leetMar) OmanNew Fleuronectes emericence Et E/L L E/L E/L E.1 E/L E/L E/L E.1 E.1 E/L Et E.1 E.1 L1. E!L E/L E/L E/L Et Et len( Ape) - Gun! Aeg E fernremese e.L E/L E/L E/L E/L Et 01. E,1. E/L E E/L Et E/L E,1 E/L E/L EL E/L E1. E/L Et El Feb( Apr) - (May )Now E. retness L E/L L Me,-les Trinecies sesculstas E E E E E E E'L LL E May - Sep Schoroides meculatus L L sus - Aus i
Nomher ef 5 pecks' 48 36 43 35 37 35 40 38 37 34 42 37 36 41 40 42 34 36 34 40 42 41
'l = jovenile.
'Abaeve August and Sepermber; peaks = Maech Mey and November December
'CJth egh these eggs were one idenhfied ahcificeily, they were ensumed to beve OCCus red et Abate based ce the occurrence oflaryge.
'Fc congereuve purposes three speews o! Myosorephafue sere assumed fax 19751978na d twospecies of Lirens fne1975-1980.
m_____. . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ . _ . _ _ _ _ _ _ . . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _
I Table 4. Densities per 100 m2 of water for tautog/ cunner eggs and cunner larvae taken with 0.333 and 0.202-mm mesh netting on four 1994 dates, three 1995 dates, and four 1996 dates. Mesh Date Replicate 0.333 0.202 Ratio n 3 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 4 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 l l June 16 1 1364 1959 1.44 l l 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 1996 June 19 1 1959 2150 1.22 2 1739 2128 1.22 3 1382 1351 0.98 June 24 1 3637 4123 1.13 2 2572 3413 1.33 3 3865 2782 0.72 l 4 2893 3637 1.26 July 1 1 871 1092 1.25 2 495 850 1.72 3 959 794 0.83 July 5 1 4168 4388 1.05 2 3118 3963 1.27 Geometric mean 465 605 1.30 0.001 95% confidence limits 175-1229 245-1506 1.12-1.51 LARVAE 1994 Stage May 4 All 0 0 - 1 May 9 All 0 0 - j July 21 All 0 0 - l August 8 All 0 0 - 54 l
, . _ _ . . _ . . .. . . _ . _ . . . . - . . _ _ . _ . _ _ . . . . _ . _ , . . . __m.. 1 I s l Table 4 (continued)'. I Mesh Date Replicate 0.333 0.202 Ratio el 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 - June 28 All 0 0 - 1996' , June 19 1 8.4 2.2 0.26 2 10.2 26.8 2.63 l 3 5.4 12.7 2.35 l June 24 1 3.0 5.8 1.93 l 2 3.0 2.1 0.70 3 4.1 3.1 0.76 l 4 5.0 9.7 1.94 July 1- 1 20.8 5.0 0.24 { 2 13.0 15.9 1.22 3 14.6 5.1 0.35 July 5 1 0 0 - 2 0 1.4 - 1 i Geometric-mean 7.7 8.5 1.10 >0.05 95% confidence limits 3.6-16.5 5.1-14.0 0.58-2.09 l l Stage _May 4 All 0 0 - 2 May 9~ . All 0 0 - July 21 1 0 2.5 - 2 1.1 7.8 7.09 l 3 2.1 0 - August 8 1 0.7 0 - 2 0 0 - l 3 0 0 -
)
l 1995 June 16 1 56.8 60.0 1.06 l 2 36.3 12.3 0.34 , I 3 72.2 34.0 0.47 June 26 1 16.6 43.5 2.62 l 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 l 3 14.4 0 - l 1996 June 19 1 1.8 2.2 1.22 5 2 1.7 6.7 3.94 !
- 3 2.7 3.3 1.22 i
i 55 l l
__. .m. _ ._ _ .._ __.. - _ _ _ _ _ . . . - _ _ . - _ . . _ _ _ . .._.- .._. . . _ . Table 4 (continued).
' Mesh Date Reolicate 0.333 0.202 Ratio D1 1996 June 24 1 3.0 2.9 0.97 ;
2 6.7 2.1 0.31 i 3 4.1 1.8- 0.44 4 2.8- 6.8 2.43 July l' 1 35.4 24.9 0.70 : 2 39.8 39.3 0.99 3 40.2 41.1 1.02 July 5 1 1.3 4.3 3.31 2 10.9 11.6 1.27 Geometric mean 9.1 11.6 1.27 >0.05 95% confidence. limits 4.5-18.2 6.6-20.4 0.83-1.95 1994 ' Stage May 4 all. 0 0 - i 3 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 - 1996 June 19 All 0 0 - June 24 All 0 0 - July 1 'l 0 1.3 - 2 0 2.8 - 3 0 1.7 - July 5 1 10.1 13.8 1.37 2 14.8 10.8 0.73 Geometric mean 9.0 9.5 0.94 >0.052 95% confidence limits 6.6-12.3 6.9-10.1 0.53-1.68 3 p = paired t-test 56
i l 1
- l. SECTION VI i LITERATURE CITED l 1
l Anderson, R.D. 1986. Impingement of organisms at Pilgrim Nuclear j Power Station (January-December 1985). ID: Marine Ecology j Studies Related to Operation of Pilgrim Station, Semi-annual )
- Report No. 27. Boston Edison Company.
! . 1996. Impingement of organisms at Pilgrim Nuclear Power i Station (January-December 1995). ID: Marine Ecology Studies i Related to Operation of Pilgrim Station, Semi-annual' Report
- No. 47. Boston Edison Company.
! l Box, G.E.P., W.G. Hunter, and J.. Hunter. 1975. Statistics for Experimenters. John Wiley & Sons, New York. Cohen,.D.M. and J.G. Nielsen. 1978 Guide to the Identification of Genera of the Fish Order Ophidiiformes with a Tentative Classification of the Order. NOAA Technical Report NMFS Circular 417. 72p. 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 -7 western Cape Cod Bay. Project Report No. 58 (January-December 1994). IIIA.1-77. ID: Marine Ecology Studies Related to Operation of -Pilgrim Station, Semi-annual report No.45.- Boston Edison Company. MRI-(Marine Research, Inc.). 1977. Entrainment investigations and Cape Cod Bay . Ichthyoplankton Studies, July-September 1976. III.C 1-1-71. ID: Marine Ecology Studies Related to Operation 1 of Pilgrim Station, Semi-annual Report No. 9. Boston Edison l Company. 1978. Entrainment investigations and Cape Cod Bay Ichthyo-plankton Studies, March-December 1977. III.C.2-34-38. ID: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-annual Report No. 11. Boston Edison Company. l 1994. Ichthyoplankton entrainment monitoring at Pilgrim Nuclear Power Station January-December 1993. Volume 2 (Impact Perspective). IIIC.2.1-33. In: Marine Ecology Studies Re-lated to Operation of Pilgrim Station, Semi-annual Report No. 1
- 41. Boston Edison Company.
l I 57
i 1996. Ichthyoplankton' entrainment monitoring at Pilgrim Nuclear Power Station January-December 1995. Volume 1 (Monitoring). IIIC,i-67. ID: Marine Ecology Studies Related
-to Operation of Pilgrim Station, Semi-annual Report No. 47.
Boston Edison Company. Matthiessen, G.C. and M.D. Scherer. 1983. Observations on the seasonal occurrence, abundance, and distribution of larval lobsters (Homarus americanus)- in Cape Cod Bay. p41-46 1.B: M.J. Fogarty (ed.). Distribution and relative abundance of American lobster, Homarus americanus, larvae: New England ' investigations during. 1974-79. NOAA Technical Report NMFS j SSRF-775. ' NEFSC (Northeast Fisheries Science Center). 1996. Report of the 1 21st Northeast Regional Stock Assessment Workshop (21st SAW) . I Stock Assessment Review Committee (SARC) consensus summary of assessments. Northeast Fisheries Science Center Reference Document 96-05d. 200p.
]
NOAA (National Oceanic and Atmospheric Administration). 1995. Status of the Fishery Resources off the Northeastern United I States for 1994. NOAA Technical Memorandum NMFS-NE-108. I 140p. ; Overholtz, W.J. 1993. Harvesting strategies and fishing mortality i' reference point comparisons for the Northwest Atlantic stock of Atlantic mackerel (Scomber scombrus). Canadian Journal of ; Fisheries and Aquatic Science 50:1749-1756. I i Pennington, M. 1983. Efficient estimators of abundance for fish and plankton surveys. Biometrics 39:281-286. Ryan, T.A., Jr. and B.L. Joiner. 1976. Normal probability plots and tests for normality. Minitab, Inc., State College, PA. 19p. Scherer, M.D. 1984. The ichthyoplankton of Cape Cod Bay. In: J.D. Davis and D. Merriman (editors). Observations on the Ecology and Biology of Western Cape Cod Bay, Massachusetts. Lecture Notes on Coastal and Estuarine Studies. Volume II. Springer-Verlag, New York. 289p. 58
1 APPENDIX A*. Densities of fish eggF and larvae per 100 m8 of water recorded ir the PNPS discharge canal by species, date, i replicate, January-December 1996.
*Available upon request.
d I l i i APPENDIX B*. Geometric mean monthly densities and 95% confidence l [ limits per 100 m3 of water for the dominant species of I 4 fish eggs and larvae entrained at PNPS, January- I December 1984-1996. 1 l Note the following: 1 When extra sampling series were required under the l contingency sampling regime, results were included in calculating monthly mean densities. Shaded columns for certain months in 1984 and 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.
, .- .. - - . . ~ .- . . . _ . -. . . . . . . . . , _ . . . . . . . _ - . . . . . . . - . . - . . . . . - . . . . . . . . . - - . . . . . . . . . . . -.
l J
- i. l I
l a E d 4 4 ICHTHYOPLANKTON ENTRAINMENT MONITORING AT PILGRIM NUCLEAR POWER STATION , j JANUARY-DECEMBER 1996 2 J Volume 2 of 2 1 i 1 (Impact Perspective) i I i i , s i 1
- Submitted to t
Boston Edison Company Boston, Massachusetts 1 by Marine Research, Inc. Falmouth, Massachusetts April 1, 1997 w -, <
l t TABLE OF CONTENTS , SECTIO? PAGE i I EXECUTIVE
SUMMARY
1 ! II INTRODUCTION 3 III IMPACT PERFPECTIVE l A. Notification Plan 4 B. Ichthyoplankton Entrainment - General 8 C. Ichthyoplankton Entrainment - Specific 10 IV LITERATURE CITED 30 LIST OF PLATES l PLATE l 1 Plankton net streaming in the discharge canal at i Pilgrim Station for the collection of fish eggs and larvae (lobster larvae are also recorded). A single, six-minute collection can contain sev-eral thousand eggs and larvae representing 20 or more species. LIST OF FIGURES FIGURE PAGE 1 Numbers of eggs estimated to have been entrained by PNPS in 1996 had it operated at full pump flow by species or species group (dominants only) in-cluding all egg species combined. The period of occurrence observed in 1995 is also indicated. 11 2 Numbers of larvae estimated to have been en-trained by PNPS in 1996 had it operated at full pump flow for each dominant species including all larvae combined. The period of occurrence ob-served in 1995 is also indicated. 12 i
. . - .- . -. -- . =. - .._ . .. ~ . ~ .. - .. _ .~ . - ..-... . . - ,-.- . . . . . ~ . . _ _ . . _ . . .
l I l i i I i LIST OF TABLES 1 TABLE PAGE j 1 Ichthyoplankton densities (number per 100 m' of water) for each sampling occasion during months ) when notably high densities were recorded, 1996. 5 2 Numbers of larval winter flounder entrained at i PNPS annually, by stage, 1987-1996. Number of equivalent age 3 adults calculated by two methods ; is also shown. 18 j 3 Numbers of cunner eggs and larvae entrained at
)
PNPS annually, 1987-1996. Numbers of equivalent , adults are also shown. 24 4 Numbers of Atlantic mackerel eggs 7nd larvae i entrained at PNPS annually, 1987-1996. Numbers ; of equivalent age 1 and 3 fish are also shown. 28 1 l i 5 11
SECTION I o EXECUTIVE
SUMMARY
Unusually high entrainment densities as defined under PNPS's notification plan were identified on a number of occasions in 1996 involving Atlantic mackerel eggs and larvae, larval Atlantic menhaden, larval Atlantic herring, larval hake, larval sand lance, larval radiated shanny, and larval winter flounder. High densities occurred at least three times for each species, being particularly prolonged for larval sand lance, suggesting that production, survival, and/or retention were relatively high in the PNPS area durin' each respective season. Total estimated egg entrainment at PNPS in 1996 ranged from ! 1,213,000 for searobins to 3,176,483,000 for the labrids, amounting to 5,442,814,000 for all eggs combined. Corresponding values for larvae ranged from 4,305,000 for seasnail to 340,701,000 for sand lance amounting to 630,010,000 for all larvae combined. Equivalent adult analyses were completed for winter flounder, cunner, and Atlantic mackerel adding to analyses dating back to 1987. Estimates for 1996 were 1,392 or 15,727 age 3 winter l flounder following two sets of survival paramoters. These values i were compared with available commercial and recreational landings l l 1 l . - _ _ _ _ _ _ _ _ _ - _ _ - _ _ _ _ _ _
l ( as well as local population size determined by trawl; in each case losses were less than 9%. Respective EA estimates of 588,997 adult ' i cunner and 10,593 age 1 mackerel or 6,822 age 3 mackerel poten-tially lost due to entrainment effects were also obtained. As for winter flounder, these estimates were compared with commercial, recreational, and local stock size estimates where available. For both species equivalent adult losses represented less than 1% of landing or stock size estimates. No larval lobster were collected in 1996 bringing the 22-year total for PNPS entrainment sampling to 13 individuals. 2 f
c.- - .. . . - - - . . - . . . . . . ~ - - , .. .- -- f 4 a ! SECTION II ^ INTRODUCTION i This report focuses on the potential impact of ichthyoplankton entrainment at PNPS. Discuscions are based on results presented in.
"Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station January-December 1996", Volume 1 - Monitoring. Work was conducted by Marine Research, Inc. (MRI) for Boston Edison Company (BECo) under Purchase Order No. LSP005524 in compliance with i
, environmental monitoring and reporting requirements of the PNPS i j NPDES Permit (U.S. Environmental Protection Agency and Massachu-1 setts Depart 9ent of Environmental Protection) . In a continuing a ! effort to condense the volume of material presented in this and ] related reports, details of interest to some readers may have been I } om!tted. Any questions or requests for additional information may ] be directed to Marine Research, Inc., Falmouth, Massachusetts, through BECO. I j Plate 1 shows the ichthyoplankton sampling not being deployed i ) on station in the PNPS discharge canal. 3
l l l l l
)
i
. yta
.;'< y t
~3
'~^
y, f:.L'l\h
'y , ~
r 5.: C').: !,{<;r .
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f
%f I
f l ~ ,7 ,
. ' _x i
N :* - l 1
** ara.*g i
j 1 Plate 1. Plankton net strear. !ng in the discharge c:nal at Pilgrim Station for the
- collection of fish eggs and larvae (lobster larvae arc also recorded).
A single, six-minute collection can contain several thousand eggs and larvae representing 20 or more species. A I
. ~ .~. - -~ -. .- - . - . - - _ - . - - . . - - . . . . ~ . . .
4 i SECTION III ) IMPACT PERSPECTIVE A. Notification Plan . Ichthyoplankton densities reaching the unusually high level during 1996 occurred on a number of occasions. These involved Atlantic mackerel eggs and larvae, larval Atlantic menhaden, larval Atlantic herring, larval hake, larval sand lance, larval radiated shanny, and larval winter flounder (Table 1). Larval sand lance were found to be abundant on a number of occasions from January to mid-May. In January (337 larvae per 100 m 3 ) and May (639 per 100 m') single densities exceeded all previous values for those respective months. The protracted nature of the high sand lance densities suggests that larvae were abundant in the PNPS area in 1996 also indicating perhaps that spawning stock was high. For j each of the remaining species high densities occurred at least three times during their period of occurrenco suggesting that j production, survival, and/or retention was relatively high for { these species as well in 1996 in the PNPS area. In the case of mackerel larvae in May (59 per 100 m 3 ) and winter flounder larvae in June (154 per 100 m3 ) densities exceeded all previous values for those respective months. l 1 I 4 l i l i
, - _ - . = _ . . _ . - . - -- .- .- . . . . -- i Table 1. Ichthyoplankton densities (number per 100 m*) for each sampling occasion during months when notably high densi-ties were recorded, January-December 1996. Densities , marked by + were unusually high based on values in Table
- 1. Number in parentheses indicates percent of all previous values during that month which were lower.
Sand lance larvae Sand lance larvae (continued) Jan 12 0 May 1 639.1 + (100) ' 15 0 3 n.s.
- 17 0 6 137.7 + (95) 22 0 8 96.4 + (95) 24 0.4 10 187.3 + (97) ;
26 337.0 + (100) 13 48.7 15 42.5 Previous high: 104 (1985) 17 8.6 Notice level: 11 20 11.3
- 22 24.0 March 4 38.3 24 5.6 6 13.1 27 3.9 ;
8 0 29 0 11 47.7 31 1.7 13 74.2 15 179.8 + (96) Previous high: 368 (1978) 18 64.9 Notice level: 32 20 8.4 22 106.5 Atlantic mackerel eacs - 25 388.5 + (98) May 1 0 , 27 178.6 + (96) 3 n.s. 29 52.0 6 0 .. 8 4.0 Previous high: 511 (1994) 10 2.4
- Notice level: 164 13 13.8 '
15 2932.0 April 1 492.7 17 165.8 3 1663.9 + (99) 20 36.8 5 1360.7 + (98) 22 950.2 8 1.5 24 2755.2 , 10 n.s.3 27 5765.0 + (95) i 12 490.0 29 9745.8 + (97) 15 12.4 31 6944.9 + (96) i 17 130.8 19 76.8 Previous high: 197C3 (1995) 22 14.6 Notice level: 4031 24 209.1 26 443.3 29 134.9 Previous high: 2591 (1994) Notice level: 998 5
I l l l J Table 1 (continued). Atlantic mackerel larvae Radiated shanny larvae May 1 0 June 3 39.9 + (99) i 3 n.s. 5 28.7 + (98) 6 0 8 262.2 + (100) 8 0 10 6.5 10 0 12 4.0 13 0 14 3.5 15 0 17 8.8 , 17 0 19 17.9 + (97) ' 20 0 21 15.3 + (94) 22 0 24 0 24 0.8 26 7.3 27 6.9 + (96) 28 0.6 29 22.1 + (98) 31 59.0 + (100) Previous high: 42 (1994) Notice level: 15 Previous high: 26 (1991) Notice level: 2 Winter flounder larvae June 3 5.2 June 3 1318.2 + (98) 5 31.7 + (98) 5 46.8 8 153.8 + (100) - 8 2.4 10 51.9 + (99) 10 6.5 12 7.1 12 9.5 14 16.3 14 14.0 17 1.1 17 41.1 19 0 19 4.8 21 4.6 21 14.5 24 11.1 ' 24 8.9 26 0 26 3.9 28 0 28 1.3 Previous high: 110 (1974) Previous high: 2700 (1981) Notice level: 20 Notice level: 155 _._ =-_
. .. .- . . . . . ~ . . - . .. .
. - . - - - - . . . . . ..- - .- -._-... . ~ - ,
h Table 1 (continued). Hake larvae Hake larvae - Aug 2 2.6 Oct 7 7.0 + (96) 5 8.1 9 n.s. 7 0 11 2.1 9 1.4 17 1.7 12 0 21 0 14 0 23 0.8 16 19.0 + (95) 25 0 19 2.0 21 4.0 Previous high: 14 (1985) 23 0 Notice level: 2 26 16.0 + (93) 28 2.6 Atlantic menhaden larvae 30 130.7 + (98) Oct 7 7.0 * (93) 9 n.s. Previous high: 196 (1995) 11 6.2 + (91) Notice level: 9 17 10.3 + (95) 21 0 Sept 2 n.s. 23 0 4 7.0 25 10.2 + (95) 6 0 9 5.0 Previous high: 12 (1980) 11 12.3 + (87) Notice level: 1 i 13 0 16 2.3 Atlantic herrina larvae 18 n.s. Nov 4 12.1 + (84) 20 17.6 + (91) 6 n.s. 23 n.s. 8 11.2 + (82) 25 4.7 11 3.6 l 27 30.6 + (97) 18 6.2 30 75.2 + (99) 20 11.0 + (82) 22 1.8 Previous high: 122 (1985) Notice level: 10 Previous high: 125 (1995) Notice level: 8
'n.s. = No sample taken due to storm or high water, k
i i 7 I l l l
l 2 i l I . Beginning in 1994 when the sampling protocol at PNPS was 1 revised, sampling included regular collection of night-time 4 entrainment samples. As covered under methods in Volume 1, these were taken on Friday typically between 2230 and 2330 hours. Depending-upon time of sunset, Wednesday samples may also have been taken during darkness. It is possible that some of the unusually high densities noted in recent years can be attributed to time of day rather then an actual unusual occurrence. For example, from 1994 through 1996 unusually high densities have been recorded for larval sand lance on 27 occasions. Nine of those samples were taken on a Friday night, representing 33% of the high occurrences, exactly equal to what would be expected by chance alone. However,
^
1 each of the samples exceeding all previous observations (n = 4) was taken on Friday nights. Dalley and Winters (1987) offer data suggesting that larval sand lance move upward in the water column at night which might make them more susceptible to entrainmu . Entrainment densities have been shown to be significantly higher for some species at night at other locations also (see for example, MRI 1997). B. Ichthyoplankton Entrainment - General Ichthyoplankton entrainment at PNTS represents a direct negative environmental impact since fish eggs and larvae passing 8
through the station are subjected to elevated water temperatures, shear forces, and periodic chlorination. In effect PNPS operates as a predator increasing overall mortality rates in western Cape Cod Bay. When PNPS is not on line, elevated temperaturt is not a factor but fish eggs and larvae may still be subjected '.o mechani-cal forces and periodic chlorination when circulating seawater or salt service water pumps operate. Although survival has been demonstrated for some species of fish eggs at PNPS such as the labrids (45%; MRI 1978) and winter flounder (MRI 1982) and among larvae at other power plants (0-100% initial survival depending on ) species and size; Ecological Analysts 1981), entrainment mortality is conservatively assumed to be 100% in all PNPS assessments. To place fish egg and larval densities entrained at PNPS, l expressed as numbers per 100 m of water, in some perspective in l relation to amounts of water ut.ilized by PNPS, they were multiplied by maximum plant flow rates over each respective period of occurrence. This was completed for each of the numerically dominant species as well as total eggs and total larvae. Mean monthly densities were multiplied by 17.461.44, the full load flow capacity of PNPS in 100 m3 units per 24-hour day, then by the number of days in cach respective month they occurred. Values for each month in which a species or species group occurred were then 9
t l I j summed to arrive at a seasonal entrainment value in each case ' (Figures 1 and 2). For cunner, mackerel, and winter flounder, egg j 1 and larval totals were calculated using individual densities and 1 meus adjustment where ag.;:topriate (see next section). Among the i, eight numerically dominant groups, numbers of eggs entrained ranged i from 1,213,000 for searobins (Prionotus spp) to 3,176,483,000 for j the labrids. Corresponding values among the thirteen dominant larval species varied from a low of 4,305,000 for seasnail (Liparis spp.) to a high of 340,701,000 for sand lance (Ammodytes. spp.). ; s For all eggs and larvae combined, values amounted to 3,844,456,000 t and 630,010,0070 respectively. These totai.. state the extent to i r which large quantities of eggs and larvae can be entrained by the circulating seawater system at PNPS duriag a single year; all are h , presumably lost to the local population. j C. JJdithyoplankton Entrainment - Specific i i Estimated r. umbers of eggs and larvae entrained annually at PNFS were examinof in greater detail for three species of fish using the equivalent adult procedure (EA, see Ho1Jt 1976, Goodyear l l 1978, for example). Somewhat arbitrarily this review dates back to i 1987 so that with the addition of 1996 ten years are included. The adult equivalent methodology applies esthnated survival rates to numbers of eggs and larvae lost to entrainment to obtain a number 10 f i
f Number of Eggs Entrained .- 1996 ' Species (Period ofOccurrence) ! Brcvoortia tyrannus - ' (June-September) 5,053,000 Enchelyopus-Urophycis-Peprilus - 6'392'000 (April-October) Gadidac-Glyptocephalus _ *
^ QQ% 50,450,000
^(
(March-December) Prionotus spp. [ 1'213'000 (July-September) - _ L.abridac-Pleuronectes _ .a "a.
^
(May-November) 3,176,483,000
~
Scomber scombrus _ ; (May-September) T'
^
w ~' 2,099,552,000 Paralichthys-Scophthalmus - ' (May-Octcber) 69 99 739 000 liippoglossoides platessoides - ^ ' (March-July) 3,931,000 Total Esss - - N *^
- _
5,442,814,000 > 1,000,000 10,000,000 100,000,000 1,000,000,000 10,000,000,000 100,000,000,000 Figure 1. Nunter of eggs estinn ed to have been strained by PNPS in 1996 had it operated at full pmp flow by species or , species groups (dominants only) incialing all egg species combined. The period of occurrence observed in 1996 is also indicated. L 1 _ _ - _ _ _ - , _ . , . , , ,., - , - - - . - -,,.-. .--- , , . . , . . ~ ,m . . - - , ___ - _ _ . _ _ _ - - _ _ . _ - . _ _ _
Number of Larvae Entrained - 1996 Species (Period of Occurrence) Bremortia tyrannus _ o ..."
~
(June-October)
@ %000"4 Clupea harengus -#
(January-April) i "8;454,000! Enchelyopus cimbrius _ a. --^ ~ (May-Nowmber) ~ ,%004;0001 Urophyris spp. _ ;z ~ de". .. (June-October)
'^' ?1'4 447 000.'
Myoxocephalus spp. _ 2.; - " -m (January-May)
,* 450,775,000 Liparis spp. -e~
(April-June)
^ '
J !4 0003 ~ Tautoga onitis _ 35,319;dOOL (June-September) Tautogolabrus adspersus _ o- . ji - (June-October)
" ~17161000 w
Uharia subbufurcata _ s 3 -
,,. ' ~3 $9,000?
(May-August) Pholis gunnellus _. > (January-May) -
^
,~ s J33;497 0001 '
Ammodytes sp. _ s, ;;w:; un ? ' (knuary-May) 9340,701;000 Scomber scombrus - gm (May-August) 70;94%000j.
'^
Pleuronectes americanus _ a j*" : 3M569,000: (April-July) Total Larvae - - ^ 9k ^
'd ~ % / l630;010,000]
100,000 1,000,000 10,000,000 100,000,000 1,000,000,000 Figure 2. NL thers of larvae estinated to have been entrained by INPS in 1996 had it operated at full prip flow for each daninant species including all larvae cmbined. The period of occurrence in 1996 is also indicated.
)
l i of adult fish which might have entered the local population had ! entrainment not occurred. The consequences, if any, of the loss l can then be considered if the size of the extant population is l known or numbers can be compared with commercial or recreational landings.
]
Many assumptions are associated with the EA procedure. The ! l fish population is assumed to be in equilibrium, therefore in her j 1 lifetime each female will replace herself plus one male. It is also assumed that no" eggs or larvae survive entrainment and that no 1 density-dependent compensation occurs among non-entrained individu-als. The later two assumptions lend conservatism to the approach. i As pointed out earlier, numbers of eggs and larvae entrained were 4 determined using the full-load-flow capacity of the plant. This value was used even if the station was out of service and less than full capacity was being circulated. In those cases the adult equivalents are conservatively high. l
)
Since plankton densitiec are notorious for deviating from a !t normal distribution but do generally follow the lognormal, l 3 -geometric mean densities more accurately reflect the true popula- !
- c. .!
.f tion mean. For data which are skewed to the right such as plankton . 1 ^ densities, the geometric mean is always less than the arithmetic , s : mean (See Volume Figures 3 and 4). ' 1, In calculating total 4
; 13 4
4 1 4 h
.. _. . . _ . . m , . , . .
1 i entrainment values for the adult equivalent methodology we chose to i use the larger arithmetic mean for all sampling dates preceding I l April 1994 when replicate samples were taken to lend additional conservatism to the assessments. Beginning with April 1994 each l individual sample density was utilized so that no averaging was 1 1 necessary. l i In summary, four opportunities were chosen to overestimate the
)
i l impact of PNPS:
- 1) All eggs and larvae were assumed killed by plant passage.
i
- 2) No density-dependent survival compensation was assumed to !
occur.
- 3) PNPS was assumed to operate at full-flow capacity year round.
- 4) Mean entrainment densities were overestimated by the arithme-tic mean for sampling dates when three replicates were taken.
The three species selected were winter flounder, cunner and Atlantic mackerel. Flounder were chosen because of their commer-cial and recreational value as well as their importance in PNPS ecology studies. Cunner were selected because they are abundant in entrainment samples and in the local area and PNPS finfish studies have been focusing on that species which appeared to be in a declining trend from 1980 to 1994 (Lawton et al. 1995). Mackerel were included because they are abundant among the ichthyoplankton 14
__. . . _ _ _ _ . _ _ _ _ _ . - . _ _ _ . _ _ _ _ _ _ _ _ _ . _ _ _ ..m _ . . . _ _. _. > __ e i entrained, both eggs and larvae being removed from the local population, and they are commercially and recreationally valuable. f Winter flounder T The' annual larval entrainment estimates were converted to equivalent numbers of age 3 adults, the age at which flounder i become sexually mature (Witherell and Burnett 1993, NOAA ' 19 95 ) . Humbers of stage 1 and 2 larvae were scaled upward by 1.62 to correct for mesh extrusion (MRI 1995). Two sets of survival values were used. The first set followed NEP (1978) using data from Pearcy (1962) and Saila (1976). Briefly, this consisted of dividing the total number of entrained larvae by 0.09 to estimate the number of eggs which hatched to produce that number of larvae. The number of eggs was then multiplied in succession by 0.004536, an estimate of survival from a newly hatched egg to day 26; 0.2995, survival from day 27 to metamorphosis; 0.03546, survival of juveniles from 3 to 12 months; 0.3491, survival from 13 to 24 months; and finally 0.33, survival from 24 to 36 months. The second approach followed larval stage-specific mortality rates - derived by NUSCO (1993) as modified by Gibson (1993a). These are as follows: S (stage 1) = 2.36E-01 S (stage 2) = 1.08E-01 S (stage 3) = 1.54E-01 l 15 I i l l'
S (stage 4) = 6.23E-01 S (age 0) = 7.30E-02 S (age 1) = 2.50E-01 1 S (age 2) = 4.77E-01 In using the stage-specific rates it is recognized that NUSCO employs different morphological stage criteria than those used at PNPS. However a comparison of samples from both studies showed stages to be quite comparable until larvae approach metamorphosis, a size not often collected.. Although small numbers are entrained each year, flounder eggs were ignored because they are demersal and j I adhesive and not generally impacted by entrainment. Recently Rose et al. (1996) presented information on a population dynamics model for winter flounder consisting of ! separate young-of-the-year and adult components. The young-of-the-year model includes survival rates for eggs, larvae, early and late juveniles stages. Since the model is designed to mathematically represent numbers of individuals as they develop from one stage to L another, it is difficult to apply their survival rates to the mixed age pool of larvae entrained at PNPS. All individuals would need : to be converted to hatched eggs as is done with the unstaged approach. By using a value of 0.09 to step back from mixed-up larvae to hatched eggs, the rates utilizc3 by Rose et al. produce approximately twice as many fish as the staged survival values 16 i i _ _ _ - . _ _ _ _ _ - _ _ . - _ _ - _ _ _ _' _ _ _ - _ _ _ _ _ _ _ _ _ - - - . _ _ _ w W
provided above. Since the staged survival values were adjusted by Gibson (1993a) to provide an equilibrium population this approach is believed to overestimate EA values. The general, unstaged larval survival values produced an adult equivalent value of 1,392 age 3 fish for 1996 (Table 2). The stage-specific values produced an EA total over eleven times higher at 15,727 age 3 individuals. Based on a weight of 0.6 pounds per fish (Gibson 1993b), these values convert to 835 and 9,436 pounds, respectively. Comparable values for 1988-1995 ranged from 533 to 1,272 fish (mean = 814 fish, 488 pounds) for the general approach and 2,618 to 15,556 (mean = 8,088, 4,853 pounds) for the staged approach; 1987 was omitted here because sampling was not conducted during April that year during an outage period. Values for 1996 exceeded the previous high by 9% within the general, unstaged column, and by 1% within the staged larval column. The relatively high EA values are directly attributable to the relatively high number of larvaa entrained in 1996 (see Volume 1). The large differences between the two sets of survival estimates clearly show how relatively small variations in survival values when applied to large numbers of larvae can result in relatively large variations in adult numbers (see Vaughan and Saila 1976 for example). 17 1
~. ___. _ _ _ _ _ . ._
Table 2. Numbers of larval winter flounder entrained at PNPS ' annually by stage, 1987-1996. Number of equivalent age 3 adults calculated by two methods is also shown. Number of Larvae Entrained (x10') Equivalent Age 3 Adults Staaer 1 2 2 2 3 4 Total General Staaed 1987 # 0 0.432 3.088 0 3.520 217 2 2618 2 1988 1.971 1.635 15.080 0.511 19.197 1184 15556 1989 1.648 5.685 2.225 0.039 9.597 592 2618 1990 0.635 1.141 6.847 0.033 8.656 533 6014 1991 3.429 3.861 5.188 0.038 12.516 772 4960 1992 0.862 0.866 7.035 0.026 8.789 542 6113' 1993 1.576 3.498 4.935 0.089 10.098 623 4953 1994 1.022 6.354 13.060 0.172 20.608 1272 12439 1995 2.645 4.568 8.826 0.376 16.416 1012 9879 1996 0.818 9.426 11.330 0.995 22.569 1392 15727 Mean 1.461 3.747 7.761 0.228 13.206 814 8088 S.E. 0.323 0.907 1.350 0.101 1.958 121 1577 i w/o 1.623 4.115 8.281 0.253 14.282 880 8695 1987 S.E. 0.312 0.927 1.393 0.109 1,829 113 1627 ' Mesh factor = 1.62 applied to Stages 1 and 2. 2 No April sampling, estimates therefore biased. 18
/
)
2 Over the 1988 through 1994 period an annual average of 1,431,651 pounds (s.e. = 186,709) of flounder were landed from NOAA ( i statistical area 514 which covers Cape-Cod Bay and Massachusetts Bay. Based on a weight of 0.6 pounds per fish, the average estimated loss of 528 or 5,217 pounds of equivalent adults ; represents 0.04 or 0.4% of those landings. Area 514 landings for i 1994, the most recent year available, dropped sharply from those ; I recorded in 1993 (328,706 vs 1,057,211 pounds) due to increased fishing restrictions and stock declines. EA values for that year alone amounted to 0.4% of the landings for the unstaged approach or ; l 3.8% for the staged approach. Winter flounder also have considerable value as a recreational i 2 species. Based on NOAA records an annual average of 679,259 fish (s.e. = 271,439) weighing an average of about 1.3 pounds each were landed in Massachusetts from 1988-1995. More recently (1991-1995) recreational landings have been well below earlier years because of Otock declines and area closures; an annual average of 272,995 fish (s.e. = 36,779) were reported landed in the state during that more recent period. Unfortunately these landinw s are compiled by state Area 514 landings were not yet available for 1995 or 1996 at the time this report wao jrepared because NOAA was involved in a change in data methodology (Joan Palmer, NoAA, Woods Hole, MA personal communication).
- Recreational landings data were obtained via the internet at http:// remora. esp nmfc. gov /mrfes.
19 l \-
I and the number of fish taken from a more appropriate area such as Cape Cod Bay are not available. Arbitrarily adding 50,000 pounds of recreationally caught flounder to the 1994 commercial 514 landings would bring that total to 378,706 pounds and the EA values for that year to 0.3 for the general approach and 3.5% for the staged approach. Massachusetts Division of Marine Fisheries personnel made estimates of the number of adult winter flounder (>280 mm TL - age 3+) in the vicinity of PNPS using area swept by a commercial trawl in 1995 and 1996 (see Section IIIA, this report). While reliable estimates of local population size are difficult to make, they often provide more realistic numbers with which to compare EA values since landings data typically represent numbers caught over a very large area. These estimates equalled 61,915 in 1995, 92,147 in 1996 based on gear efficiency of 100%. These numbers would double if gear efficiency were closer to 50% as suggested by MDMF. EA estimates for 1995 and 1996 using the unstayod survival values and 50% efficiency amount to 0.8 and 0.8% of those respective values. EA estimates with the staged values amount to 8.0 and 8.5%, respectively. 20
)
Cunner Goodyear's (1978) basic procedures were used to estimate equivalent adult values. This method converts numbers of eggs and larvae to numbers of fish at age of sexual maturity which occurs for approximately half the population at age 1 (P. Nitschke, University of Massachusetts, Amherst, personal communication). Assuming all labrid eggs were cunner eggs in PNPS entrainment samples (Scherer 1984), cunner larvae: egg ratios were determined I from PNPS samples to provide an estimate of survival from egg to larva. Mesh correction values presented earlier (1.29 for eggs, none required for larvae) wara first applied. From 1988 to 1995 the ratio averaged 0.0184; 1987 was excluded because of extended circulating seawater pump shutdown. Average lifetime fecundity was calculated from fish in the PNPS area provided by P. Nitschke (personal communication). He provided numbers of eggs produced at agr in the second order form: 2 Log F = [4.46 log A) - (2.49 log A) + 2.61 where F = fecundity at age A Age-specific instantaneous mortality was calculated from pot collections (P. Nitschke, personal communication). Pot collections were converted from length to age using a von Bertalanffy growth equation for sexes combined developed by Massachusetts Division of 21
1 l l Marine Fisheries personnel working in conjunction with P. Nitschke ; (B. Kelly, personal communication). ) i Le = 235.9 [1 - e^ (-0.164 (t + 0.869))) where Le = length at age t in mm This growth model was solved for age t providing t = -0.869 - 1 In ( 1 __Le_._) 0.164 235.9 The PNPS area collections provided an annual instantaneous mortality rate of Z = 0.6958 equivalent to an annual survival rate of 0.499 for ages 2 through 10. Utilizing data from Serchuk and Cole (1974) for age 1 through 5 cunner collected with assorted gear, a survival rate of 0.605 was obtained (Z = 0.5025). Since their study was completed in the more temperate, protected waters of the Weweantic River estuary, greater survival there seemed reasonable. Age 1 fish appeared less abundant in the PNPS collections than age 2 fish, suggesting they were not fully l recruited to the pot collections, perhaps due to their sna13 size or behavior. In the absence of additional information the age 2 1 l through 10 value was applied to that age class as well. ) Based on the PNPS area fecur.dity study, 50% of age 1 females were assumed to be mature; complete recruitment was assumed by age
- 2. Following Goodyear (1978) , an average lifetime fecundity of 22
13,946 eggs per female was calculated. Utilizing the survival l estimate for eggs to larvae and average lifetime fecundity, a survival estimate for larvae to adult of 7.67E-3 was calculated. Converting numbers of eggs to larvae utilizing the larvae: egg ratio and then converting numbers of larvae to adult produced an estimate of 588,667 cunner potentially lost to entrainment effects in 1996. Comparable values for 1987-1995 ranged from 228,449 to 1,508,080 adults averaging 657,401 (s.e. = 130,539) over the 10-year period (Table 3). Cunner have no commercial value and little recreational importance (although many may be taken unintentionally by shore I l fishermen) so that current landing records are not available. To shed some light on their abundance in the PNPS area, calculations were performed to estimate the number of adult cunner which would be necessary to produce the number of eggs found there. The PNPS area was defined by Cape Cod Bay sampling stations 2,3,4,7,8 (MRI 1978), the half-tide volume of which was estimated by planimetry from NOAA chart 1208 at 22,541,000 100 m 3 units. Labrid egg densities were obtained at those stations on a weekly basis in 1975; they were integrated over time (April-December) using the mean density of the five stations. The integrated values were multiplied by 1.40 to account for extrusion through the 0.505-mm 23
_ _ . _ . . . . _ . _ - _ . _ . . . . _ _ . _ . _ _ _ . . _ . . _ _ _ ._ m . . _ - _ . - _ , l l Table 3. Numbers of cunner eggs and larvae entrained at PNPS annually, 1987-1996. Numbers of equivalent adults are also shown. l l \ l 8 Total Number Entrained (x10) f Larvae Equivalent Year Eggs Stage 1 2 l , Stage 2 2 Staae 3 Total Adults 1987 4645.627 0.288 0.310 0.244 0.843 672,710 1988 1601.149 2.170 2.595 2.462 7.227 285,821 1989 4649.634 32.346 15.102 2.864 50.311 1,058,146 1990 1389.921 62.309 61.893 44.020 168.223 1,508,080 I
~
1991 /v2.218 5.4w3 3.681 7.246 16.421 228,449 i j 3992 2262.349 0 1.175 1.606 2.782 346,048
'1993 3365.774 0.077 7.119 7.927 15.123 600,285 1994 1621.086 0 5.500 4.435 9.935 309,746 1995- 4282.479 7.550 29.677 9.258 46.485 975,729 1996 3176.483 3.571 8.031 5.559 17.161 588,997 Mean 2769.672 11.380 13.508 8.562 33.451 657,401 4 S.E. 459.263 6.445 6.039 4.046 15.900 130,539 I
'Mosn adjustment = 1.40 ;
2
- Mesh adjustment = 1.00 !
l t 24 4 J s .
-,, . . 4
-- - _. -- .- - . . - -- . . _ . - - ~
1 l mesh used in that survey (MRI unpublished), than by the sector ' volume. Based on the 0.333/0.202-mm mesh data collected from the-PNPS discharge stream in 1994 and 1995, additional upward scaling might be appropriate. No specific data for towed samples are available and an estimated value was not applied to provide additional conservatism to the comparison. The resulting value was divided by 2.2, the estimated incubation time in days for cunner eggs (Johansen 1925), then divided by 17,882, an estimate of mean annual fecundity per female derived from P. Nitschke (personal' communication). Lastly the resulting value was multiplied by 2 assuming an even sex ratio. These calculations resulted in an estimated product. ion of 6.899E12 eggs by an estimated 350,739,000 adult fish. The annual mean loss of 657,401 fish due to PNPS operation represents 0.19% of that value. Massachusetts Division of Porine Fisheries personnel have chosen cunner as an indicator species for PNPS impact investiga-tions. Tagging studies were conducted during the 1994-1996 seasons to estimate the size of the cunner population in the immediate PNPS area. Minimum tagging size and therefore the minimum size fish enumerated was 90 mm TL. Estimates were highly localized since individual cunner have a very small home range measured on the order of 100 m' or less (Pottle and Green 1979). Estimated 25 i
l 1 l I l population size for the outer breakwater and intake areas combined ! Were 7,408 and 9,300 for the two respective years. Combining upper l l 95% confidence limits produced totals of 10,037 and 11,696 fish, respectively. Since the upper confidence limit total is only 0.003% of the egg based population estimate, it is clear that eggs must arrive at PNPS from areas removed from the immediate vicinity of the Station. A hydrodynamic modeling study completed by Eric Adams (see section III.A) predicted that 90% of the cunner eggs and larvae entrained at PNPS come trom within about 5.5 miles of PNPS to the north to White Horse Beach, about one mile to the south. This area extends further to the north than the area 2,3,4,7,8 used in the above egg estimates. The number of eggs entrained indicate that cunner must be abundant in these waters. Atlantic Mackerel 1 Precedures outlined by Vaughan and Salla (1976) were used to f derive a survival rate for mackerel eggs to age 1 fish. This procedure utilize = the Leslie matrix algorithm to estimate early survival from proportion mature, fecundity, and survival within i l .each age class assuming a stable population. Fecundity for I Atlantic mackerel was obtained from Griswold and Silverman (1992) and Neja (1992). Age-specific instantaneous mortulity was obtained ! l from Overholtz et al. (1988) and NOAA (1995). Since two fecundity 26
profiles provide two egg to age 1 survival values: 2.2231E-6 for Griswold and Silverman, 2.3162E-6 for Neja, values were averaged (2.2697E-6). The observed average ratio of eggs to larvae for PNPS of 0.02763 (1988-1995) provided a larva-to-age 1 survival rate of 8.21462E-5. A mesh adjustment factor of 1.56 was applied to the egg data based on 1994 mesh comparison collections (MRI 1995). According to NOAA-(1995) stock biomass consists of fish age 1 and older while fish completely recruit to the spawning stock by age 3. Therefore, adult equivalent values are shown for both age groups (Table 4). Age 3 individuals were estimated using an instantaneous fishing mortality rate of F = 0.02 (NOAA 1995). These values provide an annual survival rate of S = 0.8025. Equivalent adult estimates for 1996 amounted to 10,593 age 1 fish or 6,822 age 3 fish. These compare with an annual average of 9,436 (s.e. = 2,678) and 6,077 (s.e. = 1,724) age 1 and 3 individu-als, respectively, over the 1988-1995 period. Data from 1987 were omitted here because sampling was not conducted during April of that year during an otu. age period. Converting numbers of fish to weight using 0.2 and 0.7 pounds per individual (Clayton et al. 1978) resulted in an estimated average annual loss of 1,887 or 4,254 pou..ds, respectively (1987 excluded). Weight values for 1996 l l alone were 2,119 pounds of age 1 fish ,4,775 pounds of age 3 fish. 27 j l I l i
4 4 Table 4. Numbers of Atlantic mackerel eggs and larvae entrained at PNPS annually, 1987-1996. Numbers 1 of equivalent age 1 and 3 fish are also shown. j' 6 Total Entrained (x10) Equivalent Adults Year Eggs l Larvae Ace 1 Ace 3 1987 2 117.146 0.281 289 186 9 1988 3710.026 3.401 '8700 5603 4
- 1989 6510.097 65.562 20162 12984 1990 3222.258 4.627 7694 4955
- 1991 668.240 66.009 6939 4469 1992 525.958 8.086 1858 1197
1993 2509.062 8.326 6379 4108 1994 725.563 3.419 1928 1241 1995 2462.027 197.690 21828 14057 1996 2099.552 70.947 10593 6822 Mean 2254.993 42.835 8637 5562 S.E. 611.983 19.608 2310 1488 i I Mean 2492.532 47.563 9564 6160 w/o 1987 S.E. 630.574.83121.275 2365 1523 i
' Mesh adjustment = 1.56 for eggs.
28
According to NOAA statistical records, an annual average of 334,'806 pounds (s.e. = 120,177) of mackerel were taken commercially from statistical area 514 over the years 1987-1994. The loss of an 1 average of 1,887 pounds of age 1 Jish (1987-1996) amounts to 0.6% j of those landings and the loss of 4,254 poundo of age 3 fish, 1.3%. ) I In addition to commerical landings, mackerel have considerable recreational value. For example, over the years 1987-1995 an l average of 1,616,720 fish (s.e. = 285,820) were landed in Massachu-i setts with an average weight of about one pound. Unfortunately these landings are available only by state and therefore the portion attributable to Cape Cod Bay ic not known. Arbitrarily adding 500,000 one-pound fish to the commercial landings brings the harvest total to 834,806 pounds and the EA total to 0.2 and 0.5%, respectively. 29 l l
SECTION IV LITERATURE CITED Clayton, G., C. Cole, 5. Murawski and J. Parrish. 1978. Common marine fishes of coastal Massachusetts. Massachusetts Cooperative Extension Service, Amherst, Massachusetts. 231p. Dalley, E.L. and G.H. Winters. 1987. Early life history of sand lance (Ammodytes) with evidence for spawning A. dubius in Fortune Bay, Newfoundland. Fishery Bulletin U.S. 85(3):631-641. Ecological Analysts, Inc. '981. Entrainment survival studies. ! Research Report EP 9-11. Submitted to Empire State Electric Energy Researcb Orporation, New York. Gibson, M.R. 1993a. Population dynamics of winter flcunder in Mt. l Hope Bay in relation to operations at the Brayton Point electric plant. Rhode Island Division Fish and Wildlife, West l Kingston, R.I.
. 1993b. Stock assessment of winter flounder in Rhode Island, 1992: A report to the RI Marine Fisheries Council.
i Rhode Island Division Fish and Wildlife. Res. Ref. Doc. 93/1. 1 Goodyear, C.P. 1978. Entrainment impact estimates using the equivalent adult approach. U.S. Fish and Wildlife Service, Biological Service Project. FWS/OBS-78/65. 14p. < Griswold, C.A. and M.J. Silverman. 1992. Fecundity of the ( Atlantic mackerel (Ecomber gr,mbrus) in the Northwest Atlantic in 1987. Journal of Northwest Atlantic Fisheries Science l 12:35-40. l Horst, T.J. 1975. The assessment of impact due to entrainment of ichthyoplankton. In: Fisheries and Energy Production: A Symposium. S.B. Saila, ed. D.C. Heath and Company, Lexing-ton, Mass. p107-118. l l l 30 l l
Johansen, F. 1925. Natural history of the cunner (Tautocolabrus adspersus Walbaum). Contribution to Canadian Biology new series 2:423-467. 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. Project Report No. 58 (January-December 1994). IIIA.1-7?. In: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-annual report No.45. Boston Edison Company. Marine Research, Inc. 1978. Entrcinment inve7tigations and Cape Cod Bay ichthyoplankton studies, March 1970-June 1972 and March 1974-July 1977. Volume 2, V.1-44. ID: Marine Ecology Studies Related to Operation of Pilgrim Station. Final Report. July 1969-December 1977. Boston edison Company.
. 1982. Supplementary winter flounder egg studies conducted at Pilgrim Nuclear Power Station, March-May 1982. Submitted to Boston Edison Company. 4p.
1995. Ichtniaplankton entra in: ant monitoring at Pilgrim Nuclear Power S u ion January -L o cember 1994. Volume 1 (Monitoring) IIIC.i-57. ID: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-annual Report No. 45. Boc-ton Edison Company.
. 1997. Ichthyoplankton entrainment monitoring at Manches-ter Street Station, Providence, Rhode Island, 1996. Prepared for New England Power Company, Westborough, Mass.
Neja, Z. 1992. Maturation and fecundity of mackerel, (Scomber scombrus L. ) in Northwest Atlantic. Acta Ichthyol. Piscatoria 22(1):125-140. NEP (New England Power Company). 1978. Environmental report NEP 1 and 2. Volume 4, Appendix G. (unpublished). Charlestown site study NOAA (National Oceanic and Atmospheric A%inistration) . 1995. Status of Fishery Resources off the Northeastern United States for 1993. NOAA Technical Memorandum NMFS-NE-108. 140p. 31
NUSCO (Northeast Utilities Service Company. 1993. Monitoring the l marine environment of Long Island Sound at Millstone Nuclear ' Power Station, Waterford CT. Annual 1"; ort. 1 Overholtz, W.J., S.A. Muraski, W.L. Michaels, and L.M. Dery. 1988. The effects of density dependent population mechanisms on
)
assessment advice for the northwest Atlantic :.ackerel stock. l Woods Hole, MA: NMFS, NEFC. NOAA Technical hemorandum NMFS- l F/NED-62. 49p. l Pearcy, W.G. 1962. Ecology of an estuarine population of winter < flounder Pseudonleuronectes americanus. Bulletin of Bingham Oceanographic Collection 18:1-78. I Pottle, R.A. and J.M. Green. 1979. Territorial behaviour of the north temperate labrid, Tautogolabrus adspersus. Canadian Journal of Zoologv 57(12):2337-2347. ; Rose, K.A., J.A. Tyler, R.C. Chambers, G. Klein-MacPhee, and D.J. l Danila. 1996. Simulating winter flounder population dynamics using coupled individual-based young-of-the-year and age- l structured adult models. Canadian Journal of Fisheries and ! Aquatic Sciences 53(5):1071-1091. l Saila, S.B. 1976. Effects of power plant entrainment on winter flounder populations ncor Millstone Point. URI-NUSCO Report I No. 5. Scherer, M.D. 1984. The ichthyoplankton of Cape Cod Bay. In: J.D. Davis and D. Merriman (eds.). Observations on the Ecology and Biology of Western Cape Cod Bay, Massachusetts. Lecture Notes on Coastal and Estuarine Studies. Volume II. Springer-Verlag, New York. 289p. Serchuk, F.M. and C.F. Cole. 1974. Age and growth of the cunner, Tautogolabrus adspersus, in the Weweantic River estuary, Mass. Chesapeake Science 15(4):205-213. Vaughan,D.S. and S.B. Saila. 1976. A method for determining mortality rates using the Leslie matrix. Transactions of the American Fisheries Society 3:380-383. Witherell, D.B. and J. Burnett. 1993. Growth and maturation of winter flounder, Pleuronectes americanus, in Massachusetts. Fishery Bulletin U.S. 91(4):816-820. 32
. - . - . _ . - . . - = .
l l IMPINGEMENT OF ORGANISMS AT i ! PILGRIM NUCLEAR POWER STATION (January - December 1996) i i l l Prepared by: r C8 .x temg Robert D. Anderson Principal Marine Biologist l l l Regulatory Affairs Department Boston Edison Company April 1997
. - _ . . . , . . . - _ . .. .-. . . - . . . - . - - - . . - - - _ . - . . - . . . - . . - - . . - . . - . - . - . . . - _ . . ~ . . . . - . .. ~-... . ..---........
4 1 4 .
, l l
Herring Alewife s-,, 1 Canner commonly . sitversise impinged species l 4
i s TABLE OF CONTENTS i Section Title Paae l 1
SUMMARY
1 i 2 INTRODUCTION 2 3 METHODS AND MATERIALS 5 4 RESULTS AND DISCUSSION - 7 4.1 Fishes 7 4.2 invertebrates 17 4.3 Fish Survival 21 5 CONCLUSIONS 23 6 LITERATURE CITED 25 ii 1
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4
- j. LIST OF FIGURES i
a l Estur_e Paae 1 Location of Pilgrim Nuclear Power Station 3 a 2 Cross-Section of Intake Structure of Pilgrim 4 Nuclear Power Station 3- Trends of Intake Water Temperature, and Number of Fish 12 Captured by month from Pilgrim Station Intake Screens for the Five Most Abundant Species Collected, January-December 1996 - t 4 i a 1 s e d + 1-4 t 1 \ i lii
LIST OF TABLES
.T_a_b_Le Paae 1 Monthly Impingement for All Fishes Collected From Pilgrim Station 8 Intake Screens, January-December 1996 2 Species, Number, Total Length (mm), Weight (gms) and Percentage for 9 All Fishes Collected From Pilgrim Station impingement Sampling, January December 1996 ,
3 Annual Impingement Collections (1987-1996) for the 10 Most Abundant 10 Fishes From Pilgrim Station intake Screens During January-December 1996 l 4 Approximate Number and Cause for Most Notable Fish Moralities at 13 Pilgrim Nuclear Power Station, 1973-1996 5 Impingement Rates per Hour, Day and Year for All Fishes Collected 15 l From Pilgrim Station intake Screens During January-December 1996 6 Impingement Rates Per Hour, Day and Year for All Fishes Collected 16 From Pilgrim Station intake Screens During 1977-1996 7 Monthly Means of Intake Temperatures ( F) Recorded During 18 Impingement Collections at Pilgrim Nuclear Power Station, 1987-1996 8 Monthly Impingement for All Invertebraie: Collected From Pilgrim Station 19 Intake Screens, January-December 1996 1 9 Survival Summary for the Fishes Collected during Pilgrim Station 22 Impingement Sampling, January-December 1996. Initial Survival Numbers are Shown Under Static (8-Hour) and Continuous Wash Cycles iv
l SECTION I
SUMMARY
Fish impingement rate averaged 3.11 fish / hour during the period January-December 1996, which is considerably lower than the past couple of years partially because of no large i impingement incidents. Atlantic silverside (Menidia menidia) accounted for 59.2% of the fishes I collected followed by rainbow smelt (Osmerus mordax) at 13.5%. Atlantic menhaden l l (Brevoortia tyrannus) and blueback herring (Alosa aestivalis) represented 5.8 and 4.5%, respectively, of the fishes impinged. The peak period was March / April when fish impingement was dominated by Atlantic silversides. This time period is typical for high silverside impingement. Initialimpingement survival for all fishes from static screen wash collections was j approximately 61% and from continuous screen washes 67% At 100% yearly (January-December) operation of Pilgrim Nuclear Power Station (PNPS) the estimated annual impingement was 27,318 fishes. The PNPS capacity factor was 90.5% during 1996. The collection rate (noihr.) for all invertebrates captured from January-December 1996 was 2.24. Sevenspine bay !.hFmp (Cranoon septemspinosa) were most numerous. Green crab (Carcinus maenus) and rcck crab (Cancer irroratus) accounted for 6.1 and 5.3%, respectively, of the invertebrates impinged and enumerated. Mixed species of algae collected on intake I screens amounted to 2,718 pounds. l SECTION 2 , 1 INTRODUCTION f Pilgrim Nuclear Power Station (lat. 41'56' N, long. 70*34' W) is located on the northwestern l sh' ore of Cape Cod Bay (Figure 1) with a licensed capacity of 670 MWe - The unit has two I 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 traveling water screens of 3/8 inch wire mesh (Figure 2). There are two traveling water !. screens for each circulating water pump. l l 1 i This document is a report pursuant to operational environmental monitoring and reporting . i requirements of NPDES Permit No. 0003557 (USEPA) and No. 359 (Mass. DEP) for Pilgrim I Nuclear Power Station, Unit I. The report describes impingement of organisms and survival of - i fishes carried onto the vertical traveling water screens at Unit 1. It presents analysis of the relationships among impingement, environmental factors, and plant operational variables. l This report is based on data collected from screen wash samples during January-December I i 1996. j
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SECTION 3 METHODS AND MATERIALS Three screen washings each week were performed from January-December 1996 to provide data for evaluating the magnitude of marine biota impingement. The total weekly collection time was 24 hours (three separate 8-hour periods: morning, afternoon and night). Two collections represented dark period sampling and one represented light period sampling. At j the beginning of each collection penod, all four traveling screens were washed. Eight hours later, the screens were again washed (minimum of 30 minutes each) and all organisms collected. When screens were being washed continuously, one hour collections were made at I the end of the regular sampling periods, and they represented two light periods 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 determined 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 Research, Inc. l 5-
- - ~
Intake seawater temperature, power level output, tidal stage, number of circulating wa 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 collectin divided by the total number of hours in that collecting period. Beginning in 1990, if all four intake screens are not washed for a collecting period then th number of fishes collected is increased by a proportional factor to account for the unwashed screens, as requested by the Pilgrim Administrative-Technical Committee. Common and scientific names in this report follow the Amencan Fisheries Society (1988,1989,1991a an 1991b) or other accepted authority when appropriate. 6- \
SECTION 4 RESULTS AND DISCUSSION 4.1 Fishes in 416 collection hours,1,292 fishes of 25 species (Table 1) were collected from Pilgrim Nuclear Power Station intake screens during January - December 1996. The collection rate was 3.11 fish / hour. This annual impingement rate was relatively low compared to the last two years, primanly because of large impingement incidents of Atlantic silverside (Menidia menidia) and/or rainbow smelt (Osmerus mordax) in 1994, and alewife (Alosa pseudoharenaus) in September 1995. Atlantic silverside was the most abundant species in 1996 accounting for 59.2% of all fishes collected, followed by rainbow smelt at 13.5% (Table 2). Atlantic menhaden (Brevoortia twannus) and blueback herring (Alosa aestivalis) accounted for 5.8 and 4.5% of the total number of fishes collected and identified to lowest taxon. Atlantic silverside occurred most predominately in monthly samples from March and April. Hourly collection rates per month for them ranged from 0 to 9.96. Silverside impinged in March / April accounted for 65% of all this species captured in impingement collections from January-December 1996. They averaged 97 mm total length and 5 grams in weight. Their impingement indicated no relationship to tidal stage or diel factors. They are usually the dominant fish in the annual impingement catch, being the most abundant species caught in six of the last ten years. Impingement histories of abundant species impinged at Pilgrim Station in 1996, over the past 10 years, are documented in Table 3. Rainbow smelt were very abundant in November and December impingement collections and have been most prevalent in the late Fall /early Winter period in the past, ranking first in 1978, 1987 and 1993 in total numbers impinged. In 1978,1993 and 1994, large impingement incidents involving smelt occurred during December. Table 1. Monthly Impingment for All Fishes Collected from Pilgrim Station intake Screens, January - December 1996 Species Jan. Feb. March April May June July - Aug. Sept. Oct. Nov. Dec. Total Atlantic silverside 8 30 226 269 114 1 5 7 75 30 765
' Rainbow smelt 3 2 2 1 5 5 69 87 174 Atlantic menhaden 1 35 10 .28 1 .75 Blueback herring 1 2 2 53 58 Grubby 5 2 5 14 2 1 1 1 4 12 10 57 Winter flounder B 3 5 5 1 3 10 6 41 Tautog 12 13 25 Atlantic tomcod 8 3 3 14 Windowpane 1 1 1 1 3 6 13 Alewife 2 2 6 1 11 ,
Cunner 1 1 1 1 .5 1 10
, Lumpfish - 1 7 8 ? White perch 3 1 1- 1 1 7 Northern pipefish 3 2 1 6 Rock gunnel 5 6 Red hake 1 1 2 '1 5 Threespine stickleback 1 1 .
2 4 Atlantic moonfi.;h 2 1 3 Striped bass 3 3 ' Silver hake 2 2 Butterfish 1 1 Little skate 1 1 Longhom sculpin 1 1 Radiated shanny 1 1 Striped killifish 1 1 Totals 21 35 245 301 11P 6 4 10 53 94 223' 172 1,292 Collection Time (hrs.) 26 60 35 27 47 27 33 40 19 17 56 29 416 Collection Rate (#/hr.) 1.19 0.58- 7.00 11.15 2.51 0.22 0.12 0.25 2.79 5.53 3.98 5.93 3.11 l f. L
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i l Table 2 - Species, Number, Total Length (mm), Weight (gms) and Percentage For All Fishes Collected From Pilgrim Station impingement Sampling, January - December 1996 Length Mean Weight Mean Percent Of Species Number Range Length Range Weight Total Fish 1 Atlantic silverside 765 63-150 97 1-17 5 59.2 Rainbow smelt 174 71-199 114 2-43 9 13.5 Atlantic menhaden 75 58-106 79 2 5 5.8 Blueback herring 58 49-94 69 1-7 3 4.5 Grubby 57 41-141 70 1-34 5 4.4 Winter flounder 41 51-321 100 3.2 f Tautog 25 49-86 59 2-10 4 1.9 Atlantic tomcod 14 114-179 146 14-47 25 1.1 Windowpane 13 36-255 108 - - 1.0 Alewife 11 66-110 81 2-9 4 0.9 Cunner 10 46-175 107 1-104 33 0.8 Lumpfish 8. 29-66 43 1-14 5 0.6 White perch 7 103-152 127 10-41 24 0.5 Northem pipefish 6 125-192 165 1-3 2 0.5 Rock gunnel 6 58-165 123 1-13 6 0.5 Red hake 5 57-108 82 1-6 4 0.4 Threespine stickleback 4 42-72 60 1-3 3 0.3 ' Atlantic moonfish 3 55-60 57 2-3 2 0.2 Striped bass 3 300 300 - - 0.2 Silver hake 2 199-242 221 49-72 61 0.2 Butterfish 1 28 28 - - 0.1 Little skate 1 492 492 - - 0.1 Longhom sculpin 1 100 100 11 11 0.1 Radiated shanny 1 53 53 1 1 0.1 Striped killifish 1 83 83 6 6 0.1 i l l l l Table 3. Annual Imp ngement collections (1987 - 1996) for the 10 Most Abundant Fishes From Pilgrim Station intake Screens During January - December 1996 Number of Imoinaed fishes Collected From January - December i Species 1987* 1988" 1989 1990 1991 1992 1993 1994+ 1395++ 1996 Totals Atlantic silverside 27 35 120 457 275 232 720 3,112- 1,100 765 6,843 Rainbow smelt 41 11 39 38 41 2'i 735 896 162 174 2,162 Atlantic nienhaden 0 4- 82 345 113 2 4 14 73 75 712 Blueback t ierring 1 2 15 103 31 11 25 24 87 58 357-l Grubby 5 5 29 59 46 43 51 98 45 57 438 Winter flounder 10 11 42 31 67 72 90 90 92 41 546 h' Tautog . 5 2 12 6 18 9 23 4 5 25 109 Atlantic tomcod 5 31 17 26 16 11 26 14 15 14 175 Windowpane 2 0 6 15 11 3 10 14 10 13 84 Alewife 4 8 8 131 24 22 52 11 1,871 11 2,142-Totals 100 109 370 .1,211 642 430 1,736 4,277 3,460 1,233 13,568 Collection Time (hrs.) 527 525 618 919.50 930.25+ 774 673.5 737.39 607.67 416 6,599.91 + Collection Rate (#/hr.) - 0.19 0.21 0.60 1.32 0.69 0.55 2.58 5.80 5.69 2.96 2.06 i
- No CWS pumps were in operation 18 February- 8 September 1987. ,
** No CWS pumps were in operaticn 14 April- 5 June 1988. .
+ No CWS pumps were in operation 9 October- 16 November 1994. '
++No CWS pumps were in operation 30 March - 15 May 1995.
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Atlantic menhaden were relatively prevalent in C.:ptember November samples and have been most prevalent in the fall period, ranking third in 1986/1991 and second in 1989/1990. Generally, it has been one of the less abundantly impinged fish over the years. Blueback herring impingement occurred predominately in October accounting for 91% of the total. It has been one of the most impinged fish. although not dominating the annual catch. Monthly intake water temperatures and impingement rates for the five dominant species in 1996 are illustrated in Figure 3. There were several small fish impingement incidents (20 fish or greater /hr.) at Pilgrim Station in 1996 (March, October, November and December) when mostly Atlantic silversides were recorded, but impingement rates rapidly decreased upon subsequent samplings indicating minimal impact. Thera were no large fish impingement incidents (1,000 fish or greater) in 1996 on intake screens. Most large fish impingement mortalities have occurred while bcth circulating water pumps were operating. Fifteen large fish incidents have been documented since Pilgrim operation commenced in 1973, and most (11) have involved impingement as the causative agent (Table 4). However, at least in two of these, the possibility of pathological influence was implicated as indirectly contributing to the mortalities. They were the Atlantic herring (tubular necrosis) and rainbow smelt (piscine erythrocytic necrosis) impingement incidents in 1976 anu is78, respectively. Fish impingement rate at Pilgrim Station has been shown to be related to the number of circulating water pumps operating, in general (Lawton, Anderson et al,1984b). Reduced pump operation has lowered total impingement, particularly during the April to mid-August 1984 and portions of the mid-February to August 1987 periods when no circulating water pumps were operating for extended time frames. l
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Table 4. Approximate Number and Cause for Dominant Species of Most Notable Fish Mortalities at i Pilgrim Nuclear Power Station, 1973-1996 i Date Species Number Cause April 9-19,1973 Atlantic menhaden 43,000 Gas Bubble Disease August / September,1973 Clupeids 1,600 impingement April 2-15,1975 Atlantic menhaden 5,000 Gas Bubble Disease i August 2,1975 Atlantic menhaden 3,000 Thermal Stress August 5,1976 Alewife 1,900 Impingement November 23-28,1976 Atlantic herring 10,200 Impingement August 21-25,1978 Clupeids 2,300 Thermal Stress December 11-29,1978 Rainbow smelt 6,200 Impingement ! March / April,1979 Atlantic silverside 1,100 Impingement September 23-24,1981 Atlantic silverside 6,000 Impingement j j July 22-25,1991 Atlantic herring 4,200 Impingement ! l December 15 28,1993 Rainbow smelt 5,100 Impingement l I November 28 29,1994 Atlantic silverside 5,800 Impingement December 26-28,1994 Atlantic silverside 6,100 Impingement Rainbow smelt 5,300 Impingement September 8-9,1995 Alewife 13,100 Impingement l l l L ! radmisc/ chart I
The significance of this relationship is supported by the fact that total fish impingement and i rate of fish impingement were several times lower in 1984 and 1988 (low-pump operation years) than in 1989 - 1996, despite a greater number of collecting hours in 1984 and an average number of hours in 1988. In 1987, far fewer collecting hours were possible when both circulating pumps were off than in these other years which limits comparisons to them. However, total fish impingement rates in 1984,1987 and 1988 were several times lower than in 1989-1996 when at least one circulating pump was more consistently in operation. Although there were brief penods in 1994 and 1995 when no circulating water pumps were operational, mixed results were noted regarding the effect on impingement of pump operation, possibly influenced by conditions causing large impingement incidents each of these years. Projected fish impingement rates were calculated assuming 100% operation of Pilgrim Nuclear Power Station, under conditions at the times of impingement. during the period January-December 1996. Table 5 presents hourly, daily, and yearly impingement rates for each species captured (rates are rounded to significant figures). For all fishes combined, the respective rates were 3.11,74.64 and 27,318. The yearly rate of 27,318 is fairly normal and only 130% of the last 20-years' (1977-1996) mean annual projection of 20,954 fishes (Table 6). This was considerably lower than the 1994 and 1995 rates which were the highest yearly fish impingement rates since 1981 and greatly exceeded the historical annual average as have other years in which large impingement incidents inflated yearly projections. Relatively high impingement rate years offset low impingement years, and they may be attributed to population variances of the dominant species and/or extreme meteorological or operational conditions influencing species' behavior and vulnerability. Over the past 20-year period (1977-1996), Pilgrim Station has had a mean impingement rate of 2.39 fishes /hr., ranging from 0.13 (1984) to 10.02 (1981) (Table 6). Anderson et al. (1975) documented higher annual impingements at seven other northeast power plants in the early Table 5. Impingement Rates Per Hour, Day and Year For All Fishes Collected From Pilgrim Station intake Screens During January - December 1996. Assuming 100% Operation of Pilgrim Unit 1* Rate / January- Dominant Months Species Rate /Hr. Rate / Day December 1996 Of Occurrence Atlantic silverside 1.84 44.13 16,153 March / April Rainbow smelt 0.42 10.04 3,674 December Atlantic menhaden 0.18 4.33 1,584 September Blueback herring 0.14 3.35 1,225 October Grubby 0.14 3.29 1,204 April / November Winter Flounder 0.10 2.37 866 November Tautog 0.06 1.44 528 November / December Atlantic tomcod 0.03 0.81 296 October Windowpane 0.03 0.75 275 December Alewife 0.03 0.63 232 November Cunner - 0.02 0.58 211 October Lumpfish 0.02 0.46 169 December White perch 0.02 0.40 148 January Northern pipefish 0.01 0.35 127 March Rock gunnel 0.01 0.35 127 April Red hake _
~ 0.01 0.29 106 July Threespine stickleback 0.01 0.23 84 December Atlantic moonfish 0.07 0.17 63 September Striped bass 0.07 0.17 63 December Silver hake 0.005 0.12 42 November Butterfish -0.002 0.06 21 June Little skate 0.002 0.06 21 June Longhorn sculpin 0.002 0.06 21 November Radiated shanny 0.002 0.06 21 January Striped killifish 0.002 0.06 21 January Totals 3.11 74.64 27,318
- Rates have been rounded to significant figures.
1 Table 6. Impingement Rates Per Hour, Day and Year For All Fishes Collected From Pilgrim Station ! Intake Screens During 1977-1996, Assuming 100% Operation of Pilgrim Unit 1* Dominant Species Year Rate /Hr. Rate / Day RateNear (RateNear) 1977 1.06 25.44 9,286 Atlantic silverside (2,735) l 1978 - 4.04 97.03 35,416 Rainbow smelt J (29,357) . 1979 3.24 77.69 28,280 Atlantic silverside (20,733) 1980 0.66 15.78 5,769 Cunner -
- (1,683) i 1981 10.02 240.42 87,752 Atlantic silverside l (83,346) !
1982 0.93 22.39 8,173 Atlantic silverside I (1,696) i 1983 0.57 13.65 4,983 Atlantic silverside U,114) 1984+ 0.13 3.13 1,143 Atlantic silverside (185) 1985 1.14 27.46 10,022 Atlantic silverside 1 (3,278) l 1986 1.26 30.34 11,075 Atlantic herring l (3,760) ! 1987+ 0.28 6.74 2,460 Rainbow smelt (682) 1988+ 0.27 6.48 ' 2,372 Atlantic silverside , (586) 1989 0.80 19.30 7,045 Atlantic silverside 4 (1,701) 1990 1.70 40.74 14,872 Atlantic silverside (4,354) 1991 3.38 81.14 29,616 Atlantic Herring (22,318) , 1992 0.63 15.22 5,572 Atlantic silverside 1 (2,633) 1993 2.78 66.78 24,375 Rainbow Smelt (9,560) 1994+ 5.97 143.18 52,259 Atlantic silversiae (36,970) 1995+ 5,87 141.00 51,464 Alewife (26,972) 1 1996 3.11 74.64 27,318 Atlantic silverside (16,153) Means 2.39 57.41 '20,054
- Rates have been rounded to significant figures.
No CWS pumps were in operation 29 March - 13 August 1984,18 February - 8 September 1987, 14 April- 5 June 1988,9 October - 16 November 1994 and 30 March - 15 May 1995.
1970's. Stupka and Sharma (1977) showed annual impingsment rates at numerous power plant locations for dominant species, and compared to these rates at Pilgrim Station were lower than at most other sites. Recently, Normandeau Associates (1996) compared fish - . impingement at several marine power plant intakes which demonstrated Pilgrim rates to be among the lowest with the exception of incidents that involve one or two species occasionally. However, in terms of the number of fish species impinged, Pilgrim Station displays a greater variety than most other power plants in the Gulf of Maine area (Bridges and Anderson,1984a), . perhaps because of its proximity to the boreal-temperate zoogeographical bodar; presented to marine biota by Cape Cod. Monthly intake water temperatures recorded during impingement collections at Pilgrim Station were normal during most of 1996 compared to une mean monthly temperatures for toe 10-year ~ interval 1987-1996 (Table 7). During the fall of 1996, water temperatures were generally higher than this 10-year period, particularly during September and December whose monthly means were the highest recorded in that period. Overall, 1990/1995 displayed relatively warm water temperatures, 1987/1989/1991/1994/1996 were average years, and 1988/1992/1993 were cold water years. Pilgrim Station intake temperatures approximate ambient water temperatures. However, a dominance of colder water species (i.e., Atlantic silverside, winter flounder, grubby and rainbow smelt) appeared in impingement collections during 1996, with the warmer water species Atlantic menhaden and blueback herring also being well represented. 4.2. Invertebrates In 416 collection hours,933 invertebrates of 16 species (Table 8) were recorded from Pilgrim Station intake screens between January-December 1996. The annual collection rate was 2.24 invertebrates / hour. Sevenspine bay shrimp (Cranaan septemspinosa) dominated, being
Table 7. Monthly Means of Intake Temperature ( F) Recorded During Impingement Collections a: .";igrim Nuclear Power Station, 1987-1996 Month 1996 1995 1994 1993 1992 (f() 1991 1990 1989 1988 1987 1987-1996 January 37.15 41.13 28.21 37.36 36.24 37.56 36.45 38.42 36.80 38.42 36.89 February 35.82 36.61 29.18 32.21 34.32 36.70 38.15 42.97 36.00 38.71 35.84 March 37.38 35.51 30.91 35.24 36.53 39.72 37.87 38.43 36.20 40.70 37.36 April 41.83 41.67 37.95 41.16 43.42 44.46 46.63 41.37 41.30
- 42.72 May 48.56 48.77 44.26 48.33 51.56 53.79 50.86 48.70 48.79
- 49.40 y June 56.03 56.43 45.21 52.70 54.21 60.09 53.63 57.38 50.21 56.68 54.46 July 56.08 58.14 56.85 56.78 55.94 61.67 61.24 61.57 52.83 63.00 58.41 August 60.78 67 31 59.34 53.66 60.40 58.49 64.71 59.80 58.75
- 60.55 September 62.92 62.37 60.45 50.55 57.42 58.63 63.35 58.62 56.86 58.21 59.46 October 57.50 57.93 63.33 43.96 53.83 52.00 55.13 53.92 52.31 52.73 54.61 November 49.63 50.61 55.78 39.97 50.85 47.88 47.88 45.60 47.17 47.49 48.61 December 45.18 40.33 44.88 34.53 43.06 41 74 42.86 35.58 38.90 41.30 40.98 Mean 48.27
- Temperatures were incompletely recorded during PNPS outages in these months.
radmisc/ chart o
. . ~ -
s Table 8. Monthly Impingment for All Invertebrates Collected from Pilgrim Station intake Screens January - December 1996 Species ' Jan. Feb. March April May' June July ~ Aug. Sept. Oct. Nov. Dec. Total Sevenspine bay shrimp 124 109 329 161 2 1 5 734' ., Green crab 5 1 1 5 5 7 21 12 57. Rock crab 1 1 2 3 1 2 3 9 -7 10 7 3 49 American lobster 1 2 6 4 12 5 2 32 Nereis sp._ 7 15 3 1 1 1 28 Longfin squid 1 1 1 2 2 3 10 , Horseshoe crab 4 2 1 7 , Common starfish 1 1 2 1 5 -
, Green sea urchin 1 1 1 3J +
G' Polychaete 1 1 2 i i Actinaria 1 1 Glycerid 1 1 i Isopoda 1 1 Lady crab 1- 1 , O minid 1 1
- Stomatopoda 1 1 Totals 139 126 338 166 5 12 8 24 19 34 38 24 933 Collection Time (hrs.) 26 60 35 27 47 27 33 40 19 17 56 29 416 i
Collection Rate (#/hr.) 5.35 2.10 9.66 6.15 0.11 0.44 0.24 0.60 1.00 - 2.00 0.68 0.83 2.24 ! I k i
..- .. -. . . - - - --- _- . .~ . . - -- - . - . - -
1 captured in greatest numbers from January - April. Green crab (Carcinus maenus) and rock crab (Cancer irroratus) represented 6.1 and 5 3%, respectively, of the total invertebrates enumerated. Unlike the fishes, the 1987 and 1988 invertebrate impingement rates were , comparable to 1989 - 1996 despite relatively low circulating w0ter pump capacity available in 1987 and 1988. l A noteworthy occurrence was the collection of so many blue mussels during 1986-1989. This l could be an effect of the Pilgrim Station outage during the late 1980s (reduced power level in 1989) which precluded the use of regular thermal backwashes for macrofouling control and the migratory / adhesive abilities of mussels. In 1990 - 1996 several thermal backwashes were l performed and blue mussel impingement was minor for those years. During 1996 aggressive biofouling control activities included three effective thermal backwashes during the months of April, June and September. Green crabs were the second most abundant invertebrate impinged, peaking in November. Rock crabs were third, being most represented in October. Thirty-two specimens of the commercially important American lobster were captured in 1996 ranking them fourth. This equals 676 lobsters impinged on an annual basis at 100% operation of Pilgrim Station, under conditions at the times of impingement. This is considerably less than in 1991-1994 and is more comparable to the number of lobsters impinged in most previous years. The lobsters ranged in size from 20-70 mm carapace length and were impinged mostly in October. Approximately 2,718 pounds of mixed algae species were recorded during impingement l sampling, for a rate of 6.53 pounds /hr. This equates to 29 tons of algae annually on Pilgrim intake screens. This rate is considerably higher than the low flow 1984,1987 and 1988 outage years, cornparable to 1989-1992,1994, and 1995, and lower than 1993 which experienced very adverse meterological conditions of high winds and coastal storms (particularly in
- l. December).
1 i
e i i 4.3 Fish Survival I
- Fish survival' data collected in 1996 while impingement monitoring are shown in Table 9.
Continuous screenwash collections provided the fewest numbers of fishes and revealed an T overall survival rate of approximately 67%. Fishes collected during static screen washes fared , a ! worse showing a survival rate of 61%. The relatively high initial survival rate for static screen washes, compared with most years previous to 1991, was influenced by the high initial survival of Atlantic silverside which were impinged in abundant numbers. As illustrated in 1993-1996, a fishes have a noticeably higher survival rate during continuous screen washes because of I reduced exposure time to the effects of impingement. However, reduced intake currents in 1984, associated with limited circulating water pump operation, may have been a factor in I higher static wash survival then because of less stress on impinged individuals; although this ; wasn't apparent from 1987 and 1988 limited pump operation results. I i Among the ten numerically dominant species impinged in 1996, six demonstrated initial survival rates of 50% or greater. Grubby showed 100% survival, winter flounder 93%, alewife 18%, Atlantic silverside 72%, tautog 100%, rainbow smelt 11%, Atlantic tomcod 43%, Atlantic menhaden 37%, windowpane 69%, and blueback herring 66%. Some of these relatively high survival percentages may be explained by the large proportion of fish that were sampled during continuous screenwashes at the times of small fish impingement incidents in March and the fall of 1996.
Table 9. Survival Summary for the Fishes Collected During Pilgrim Station lmpingement Sampling, j January - December 1996. Initial Survival Numbers are Shown Under Static (8-Hour) and Continuous Wash Cycles Number Collected Number Survivina Total Lenath (mm) Static Cont. Species - Washes Washes Static Cont. Mean Range i Atlantic silverside 566 199 404 144 97 63-150 Rainbow smelt 135 39 10 10 114 71-199 Atlantic menhaden 53 22 18 10 79 58 106 Blueback herring 4 54 0 38 69 49-94 Grubby 42 15 42 15 70 41-141 Winter flounder 30 11 28 10 100 51-321 Tautog 8 17 8 17 59 49-86 Atlantic tomcod 5 9 4 2 146 114-179 Windowpane 6 7 5 4 108 36-255 Alewife 6 5 0 2 81 66-110 Cunner 3 7 0 4 107 46-175 Lumpfish 1 7 1 6 43 29-66 White perch 4 3 3 2 127 103-152 Northern pipefish 2 4 2 4 165 125-192 Rock gunnel 3 3 3 1 123 58-165 ' Red hake 5 0 1 - 82 57-108 Threespine stickleback 0 4 - 3 60 42-72 Atlantic moonfish 2 1 2 1 57 55-60 Striped bass 2 1 0 1 300 300 Silver hake 2 0 1 - 221 199-242 Butterfish 0 1 - 1 28 28 Little skate 1 0 1 - 492 492 Longhorn sculpin 1 0 1 - 100 100 Radiated shanny 0 1 - 1 53 53 Striped killifish 1 0 1 - 83 83 All Species: 882 410 535 276 Number (% Surviving) (60.7) (67.3)
SECTION 5 C _ ONCLUSIONS
- 1. The average Pilgrim impingement rate for the period January-December 1996 was 3.11 fish / hour. The impingement rates for fish in 1984,1987, and 1988 were several times lower than in 1989-1996 because of much reduced circulating water pump capacity during the former years..
I
- 2. Twenty-five species of fish were recorded in 416 impingement collection hours during 1996. In 1989-1996 several times the number of fishes were sampled as compared to 1984 and 1988, despite more collection hours in 1984 and an average number of hours in 1988. This illustrates the imponance that the number of circulating pumps operating has on the quantity of impinged organisms. Substantially less collecting hours for portions of 1987 precluded its comparison with other years.
- 3. At 100% yearly operation the estimated maximum January-December 1996 impingement rate was 27,318 fishes. This projected annual fish impingement rate was much lower than 1994 and 1995 rates because of three large impingement incidents involving Atlantic silverside and rainbow smelt in 1994, and alewife in 1995.
- 4. The major species collected and their relative percentages of the total collections were Atlantic silverside, 59.2%; rainbow smelt,13.5%, Atlantic menhaden, 5.8%; and blueback herrino, 4.5%.
- 5. The peak in impingement collections occurred during March / April when 65% of the annual catch of Atlantic silverside occurred.
- 6. Monthly intake water temperatures, which generally reflect ambient water temperatures, '
were typical for most of 1996 of the ten-year monthly averages for the period 1987-1996, with the fall period being warmer than normal.
- 7. The hourly collection rate for invertebrates was 2.24. Sevenspine bay shrimp dominated .
I because of large winter collections. Green crab and rock crab were 6.1 and 5.3% of the enumerated catch. Thirty-two American lobsters were collected which equates to a i Potential 1996 impingement of 676 lobsters. 8. Impinged fish initial survival was approximately 61% during static screen washes and 67% { i during continuous washes for pooled species. Of the ten f nes s impinged in greatest numbers during 1996, six showed initial survival rates of 50% or greater. I SECTION 6 l LITERATURE CITED American Fisheries Society.1988. Common and scientific names of aquatic invertebrates from j the United States and Canada: mollusks. Spec. Pub. No.16: 277 pp. f l l 1989. Common and scientific names of aquatic invertebrates from the United States ! and Canada. decapod crustaceans. Spec. Pub. No.17:77 pp. I 1991a. A list of common and scientific names of fishes from the United States and Canada. Spec. Pub. No. 20: 183 pp. l 1991b. Common and scientific names (J aquatic invertebrates from the Unned States and Canada: cnidaria and ctenophora. Spec. Pub. No. 22: 75pp. , Anderson, C.O., Jr., D.J. Brown, B.A. Ketschke, E. M. Elliott and P. L. Rule.1975. The effects of the addition of a fuurth generating unit at the Salem Harbor Electric Generating Station en
)
the marine ecosystem of Salem Harbor. Mass. Div. Mar. Fish., Boston: 47 pp. ; l l Briges, W.L. and R. D. Anderson.1984a. A brief survey of Pilgrim Nuclear Power Plant effects upon the marine aquatic environment, p. 263-271. M: J. D. Davis and D. Merriman (editors), Observations on the ecology and biology of western Cape Cod Bay, Massachusetts,289 pp. Springer - Verlag. (Lecture Notes on Coastal and Esturaine Studies, Vol.11). Lawton, R. P., R. D. Anderson, P. Brady, C. Sheehan, W. Sides, E. Koulokeras, M. Borgatti, ) and V. Malkoski. 1984b. Fishes of western inshore Cape Cod Bay: studies in the vicinity of j the Rocky Point shoreline, P. 191-230. M: J. D. Davis and D. Merriman (editors), Observations on the ecology and biology of western Cape Cod Bay, Massachusetts, 289 pp. Springer-Verlag. (Lecture Notes on Coastal and Esuarine Studies, Vol.11). !
~
Normandeau Associates.1996. Seabrook Station 1995 environmental studies in the Hampton - Seabrook area: a characterization of environmental conditions during the operation of Seabrook Station. Section 5.0 - Fish. Northeast Utilities Service Company: 103 pp. Stupka, R. C. and R. K. Sharma. 1977. Survey of fish impingement at power plants in the United States Vol. Ill. Estuaries and Coastal waters. Argonne National Lab.: 310 pp. Radmisc/impgJan m W
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PHlLlP G. Co ATes . asulu:Nb. , $taaarbnuN) l'hiG3 (> RECTOR (5001898 1155 TO: Members of the Administrative-Technical Committee, Pilgrim Power Plant Investigations From: John Boardman, Recording Secretary
Subject:
Minutes from the 86th meeting of the A-T Committee Date: September 17, 1996 The 86th meeting of the A-T Committee was called to order by Gerry Szal at 10:15. I. Minutes of 85th meeting Bob Maletta motioned to accept the minutes; Bob Anderson seconded. The minutes were accepted unanimously with no changes. II. Pilgrim Station 1995-1996 operational review Bob Anderson presented the current Pilgrim Nuclear Power Station (PNPS) operational status to the Committee. The plant operated at approximately 93% capacity from January to August 1996. iiiis was the best production over an eight month period since operation commenced. Bob told the committee the Semi-annual Marine Ecology report should be out by the end of October. He reported that PNPS has had no significant impingements in is96. Bob informed the Committee a planned refueling outage will take place in February. The outage will not take place in April or May, as the Committee suggested, because of a low supply of fuel at the plant, Bob explained that high operating levels in 1995/1996 have depleted the nuclear fuel supply more quickly than anticipated. However, future outages will be scheduled in April or May (on a two year basis) whenever possible. Bob also confirmed that Boston Edison Co. will grant the Massachusetts Division of Marine Fisheries (DMF) $5000 as mitigation for an alewife impingement last September at the plant. The money will be used in repairing a local fish ladder. III. Benthic Monitoring Program Bob Anderson and Bob Lawton summarized a letter from Don Miller to the A-T Committee. The protocol for QAQC and the
- benthic sampling proposal for 1997 will be sent to the Benthic l Subcommittee for review. The A-T Committee voiced their concernc I
about the insufficient data collected by the benthic divers 1
regarding the outfall area size and mussel sets in 1996. These recent sampling problems were discussed. Bob Anderson confirmed that the sampling problems will be addressed before the next quarterly dive. The committee agreed that the consistent high operating level at PNPS was probably a primary factor effecting the increased size of the outfall area. Cost = $32,000 for 1997. IV. Marine Fisheries Monitoring Bob Lawton presented to the Committee the proposed smelt work for 1997, which will again focus on spawning habitat enhancement in the Jones River. Egg trays (n = ca. 200 trays) will be deployed in the Jones River to collect the smelt's demersal, adhesive eggs. Bob stated that egg survival on plant material is much higher than on hard bottom. He also explained that egg survival is the most sensitive parameter driving future smelt population growth. Bob then discussed the winter flounder work. DMF has been tagging winter flounder with Petersen disc tags to determine the discreetness of the local winter flounder population. In the spring of 1995, ca. 2,500 winter flounder were tagged. This spring, 5,000 flounder were tagged. He also mentioned the 1997 flounder study area will be expanded further north, following a modelling analysis completed by Eric Adams of M.I.T.. Unxt, . Bob addressed the cunner work. He told the Committee that eatimating cunner absolute abundance would have to be done ledge b;r ledge throughout the study area. The size, heterogeneous compositian of the study area, and limited personnel make estimating abundance of the local population infeasible. Bob told the Committee his project would continue to collect trap catch / effort data and to age selected cunner to generate catch at age data which will be used to estimate natural mortality needed for the adult equivalent model. To address PNPS impact on cunner, DMF will continue Paul Nitschke's work on recruitment. Bob described the sampling protocol at the three fixed sampling stations to the Committee. He noted that the creel data from the Pilgrim shorefront will continue to be collected and reported. Underwater visual observations of fish and other biota will be made using SCUBA off the discharge canal in the plume area during the summer and early fall. Two dives also will be made during the winter to look for overwintering striped bass or other species. The committee approved and endorsed by u ?nimous vote Bob's proposal for 1997. Cost = $275,000 for 1997. V. Impingement Monitoring Bob Anderson reported that the impingement rata for the first six months of 1996 has averaged 3 fish pcr hour. There have been no significant impingement incidents during this time period. The Atlantic silverside was the most abundant species impinged. Bob informed the Committee that the plant installed a 2
differential alarm system. This system allows more continuous wash samples to be taken. The Committee was somewhat concerned about this system. Bob assured the Committee that the intake screens would be monitored for any significant numbers of impinged fish. Bob also mentioned that Mike Scherer, to date, has not collected the large number of fish needed to begin the proposed tagging study of the recycling of impinged fish. Bob Maietta motioned to continue the impingement monitoring program. The motion was accepted unanimously. Cost = $30,000 for 1997. VI. Entrainment Monitoring The Committee reviewed Mike Scherer's letter on cunner egg and larval entrainment. The Committee accepted Mike's suggestion to use a .333 mesh plankton net instead of a .202 mesh to collect cunner larvae. However, the Committee was unclear about Mike's recommendation regarding mesh size for egg entrainment collections. The Committee concluded that Carolyn Griswold would ask Mike for clarification on this matter. The Committee agreed to accept the other facets of the entrainment monitoring program including the sampling schedule. Cost = $70,000 for 1997. VII. Barrier Net The Committee concurred on keeping the barrier net out of the discharge a tal again in 1997. VIII. Other Business Bob Lawton nominated Jack Parr as chairperson of the Benthic Subcommittee. Bob Maietta seconded the motion. The committee endorsed Jack Parr as chairperson for 1997. Bob Anderson asked Gerry Szal to send a letter to members of the A-T Committee regarding the importance of attending meetings. Gerry agreed to contact Leigh Bridges and discuss plans to initiate a new monograph for publication. Bob Anderson informed the committee that the dredging of the intake embayment would take place this winter. Public notice would be given in about two weeks. Approximately 45,000 to 50,000 square yards of material will be removed from the area closest to the intake. The material will be deposited at an offshore disposal site. The o"ter half of the intake embayment, also scheduled for dredging, did not completely priss the biological testing requirements. Dredging plans for thjo area are not yet finalized. IX. The meeting adjourned at 14:55. 3
X. Attendees at the 86th meeting of the A-T Committee: DEP - Gerry Szal Bob Maietta DMF - Bob Lawton John Boardman PNPS - Bob Anderson NMFS - Carolyn Griswold 4
PILGRIM NUCLEAR POWER PLANT ADMINISTRATIVE-TECHNICAL COMMITTEE Robert D. Anderson Jack Paar Boston Edison company U. S. Environmental Protection Agency Pilgrim Nuclear Power Station New England Regional Lab 600 Rocky Hill Road Surveillance and Analysis Plymouth, MA 02360-5599 60 Westview Street (508) 830-7935 Lexington, MA 02173
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W. Leigh Bridges MA Division of Marine Fisheries Nicholas Prodany State Office Building U.S. Environmental Protection Agency 100 Cambridge Street Region 1, Industrial Permits Section Boston, MA 02202 JFK Federal Building Boston, MA 02203 (617) 727-3194 (fl?) SC5-3387 carolyn C: svold National Marine Fisheries Service Rick Zeroka 28 Tarzwell Drive MA Coastal Zone Management Narragansett, RI 02882 100 Cambridge Street, Flc.r 20 Boston, MA 02202 (401) 782-3273 (617) 727-9530 Brian Kelly MA Division of Marine Fisheries Gerald Szal 18 Route 6A Division of Water Pollution Control Sandwich, MA 02563 P.O. Box 116 (508) 888-1155 40 Institute Road N. Grafton, MA 01536 Ted Landry (508) 792-7470 U.S. Environmental Protection Agency Region I, Industrial Permits Section JFK Federal Building Boston, MA 02203 oTHER CONTACIS (617) 565-3508 Dr. James Blake Robert Lawton SAIC MA Division of Marine Fisheries 89 Water Street Woods Hole, MA 02543 18 Route 6A Sandwich, MA 02563 (508) 540-7882 (508) 888-1155 Derek Mcdonald Robert Maietta Marine Biofouling Control Corp. Office of Watershed Management g508) 668-4431 40 Institute Road N. Grafton, KA 01536 Dr. Michael Scherer (508) 792-7470 Marine Research Inc. 141 Falmouth Heights Road Dr. Martha Mather Falmouth, MA 02540 MA Coop Fish & Wildlife Unit Holdsworth Hall Dr. Jan Praeger University of Massachusetts U.S. Environmental Protection Agency Amherst, MA 01003 Environmental Research Lab (413) 545-4895 27 Tarzwell Drica Narragansett, RI 02882 Dr. Don Miller (401) 782-3090 U.S. Environmental Protection Agency Environmental Research Lab Steve Halterman 27 Tarzwell Drive Dept. of Environmental Protection Narragansett, RI 02882 One Winter Street, 8th Floor Boston, MA 02108 (401) 782-3090 (617) 292-5993 e.
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