ML20042G573
| ML20042G573 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/31/1989 |
| From: | Wagner E BOSTON EDISON CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| BECO-90-014, BECO-90-14, NUDOCS 9005150097 | |
| Download: ML20042G573 (376) | |
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!, BOSTON EDISON 4
25 Braintree Hdi Office Park Braintree, Massachusetts 02184-f
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Nuclear Engmeermg - April 23, 1990
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United States Environmental Protection Agency ! Region I - Permits Processing Unit - Room-2109 L John F. Kennedy Federal Building Boston, MA 02038-NPDES PERMIT MARINE ECOLOGY MONITORING REPORT-
Dear Sir:
In accordance with Part I, Paragraph A,7.b & c, and Attar.ba.ent 1. Paragraph I,F, of the Pilgrim Nuclear. Power Station NPDES Permit Nr MA0003557 (Federal)- and No. 359 (State), Semi-Annual Marine = Ecology Report Nu; 35 is submitted. This covers the period from January through December 1989. E.-
Attachment:
Semi-Annual Marine Ecology Report No. 35 !c RDAlamm/3732 f 900515o097 891231 PDR R ADOCK 05000293 bN'l PDC i
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, BECo 90- 014 Nuclear Engineering April 23, 1990 0
-Mass. Division of Water Pollution Control-
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Permit Section - 7th Floor One Hinter Street Boston, MA 02108 . [LPDES PERMIT MARINE ECOLOGY MONITORING REPORT' I t
Dear Sir:
-In accordance with Part I, Paragraph A.7.b & c. and Attachment 1, Paragraph I.F. of the Pilgrim Nuclear. Power Station NPDES Permit No, MA0003557-(Federal) '
and No. 359 (State), Semi'-Annual Marine Ecology Report No. 35.is. submitted. This covers' the period from January through December 1989. t E...- er
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- Semi-Annual Marine Ecology Report No. 35 , RDA/amm/3732 cc: Hass.- Division of Hater Pollution Control Lakeville Hospital Lakeville, MA 02346 1 ; L n l ll s s
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TAB!E CF CONTENTS SECTION
'I
SUMMARY
II INTRODUCTION III MARINE BIOTA STUDIES . IIIA Marine Fisheries Monitoring i IIIA.1 Annual Report on Monitoring to Assess Impact of the Pilgrim Nuclear Power- Station on the Marine Fisheries Resources of
.- Western Cape Cod Bay, January - December 1989 (Characteriza-tion of Fisheries Resources) - (Mass. Dept. of Fisheries -
Wildlife and Environmental Law Enforcement: Division of' " Marine Fisheries) IIIA.2 Annual Report on Monitoring to Assess Impact of the Pilgrim Nuclear Power Station on the Marine Fisheries Resources of I(- Western Cape Cod Bay, January - December 1989 (Impact on. the Fisheries Resources) - (Mass. Dept. of Fisheries, Wildlife
. and Environmental Law Enforcement; Division of Marine Fisheries)
IIIB Benthic Monitoring and Impact ' IIIB.1 Benthic Algal and Faunal Monitoring at the Pilgrim ' Nuclear. Power Station, January 1989 - December 1989 (Characterization of Benthic Communities) - (Battelle New England Research Lab) l III.B.2 Benthic Algal and Faunal Monitoring at the Pilgrim Nuclear Power Station, January - December 1989 (Impact on Benthic Communities) - (Battelle New England Research Lab) L IIIC Entrainment Monitoring and Impact IIIC.1 Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station,. January - December 1989 (Results).. - (Marine Research, Inc.)
~I IIIC.2 Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station, January - December 1989 (Impact Perspective)
- (Marine Research, Inc.)
IIID Impingement Monitoring and Impact Impingement of Organisms at Pilgrim Nuclear Power Station: January
- December 1989. (Boston Edison Company)
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.i1
IV FISH SURVEILLANCE L:- t ' IVA Overflichts Summary Report: Fish Spotting Overflights in Western Cape Cod Bay in 1989.- (Boston Edison Company)
- V ' Minutes of' Meeting 72 of the Administrative-Technical- Committee, Pilgrim- E Nuclear Power-Station g i
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. Highlights of the Environmental Surveillance and' Monitoring Program re- ;
sul_ts obtained over this reporting period (January - December 1989) are I presented below. (Note: Pilgrim Station, was operating at low power
- levelsJduring most of' 1989 (29% annual capacity factor) so data reflects
'a reduced thermal influence on aquatic resources.) ,
liarintfhherteLBooltoring:
- 1. In the June-August 1989 shorefront sportfish survey at Pil-I grim Station, 750 angler visits accounted for 200 fishes caught. Cunner. (56%) and bluefish (34%) dominated the
; sportfish catch. The presence of. a moderate thermal component .
during the 1989~ Pilgrim restart resulted in an increased sportfishery success rate compared with outage years covering-the shorefront angling season. I
- 2. Pelagic fish mean CPUE (Catch Per Unit Effort) for 1989-at the t gill net station (84.4 fishes / set) declined' 65% from 1988 to
-the lowest level recorded in the nineteen ~ years of sampling l~_ '; since 1970. Pollock (44%) and Atlantic herring.(20%)_ were-64%
l . f' 'of the total catch. Both Atlantic herring and pollock L decreased substantially from 1988. A significant -positive correlation was found for cunner catch (third highest in 1989) and seasonal, Pilgrim Station operational output (thermal l loading to the environmenti. 1 , 1-1
-i . '
- 3. 1 Shrimp- trawl catch for 1989 recorded 23 benthic fish species with winter flounder (47%), little skate (22%) and windowpane l
'(7%) composing'76% of the total. Mean CPUE for all species was ,
2.9 (Iowest) at the Harren Cove station, 8.7 (highest) at the intate surveillance station and 7.3 (27% less than in 1988) for The presence of substantially all stations pooled in 1989. larger numbers of small winter flounder caught - in the intake. - embayment, ' compared to the other stations each year, suggests . j its attract 1'on as a possible nursery area. -
- 4. Adult lobster mean monthly catch rate per rot haul, in May -
October '1989, was 0.45 lobsters which isE18% greater than the
-1988 rate (0.38). The surveillance area (thermal plume) catch -
rate was 0.41 while the reference area (control) was 0.34. The. legal -lobster catch rate - for preoperational/ outage years - has not been significantly lower in the thermal-plume area than in control areas. A negative correlation, approaching - significance, was noted between legal lobster catch' rate for thermal plume areas, and mean annual and seasonal (May. - l December) Pilgrim Station output for the period from 1973 - ' 1983, 1985. The lobster research study, which commenced in , 1986, continued to assess two parameters for identifying l potentia.1 PNPS impact when the Station resumes normal operation
- legal catch rate and size frequency comparisons.
l! ( I I-2
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- 5.
5.- . In.. May October - ' 1989 fish observational dive surveys, , 11 species were observed in the - thermal plume area. Cunner 1 ( 66%) , - tautog (20%) and striped bass (6%)- were the most I . numerous fishes seen, the latter two species being most a abundant in the ' direct path of the Pilgrim' discharge current. j Total number- of fishes obsarved decreased 9% 'from 1988, . relatively low compared to the early 1980's. Most fishes were in greatest concentrations at stations in the discharge zone I (58%), followed by the control zone '(36%)- and the stunted zone
-I (6%). .These results were intermediate between 1984/1987/1988-(outage years with reduced discharge current), when most fish were observed relatively evenly divided between discharge and control zones, and 1985/1986 (higher discharge current years)
'. when fish. Seemed to greatly favor being in the path of the effluent.
- 6. Atlantic silverside accounted for 81% of the 1989 large-- haul-seine '(shore zone) fish catch with a total of 33 species col.lected. The PNPS intake showed higher species diversity-compared - to exposed coastal stations.- fish captured in 'the L
PNPS intake embayment were dominated by Atlantic silverside, L Atlantic menhaden. and sand lance spp., and included winter l-flounder among. the more numerous species. A deeper seine net (10' compared to 6'), to more effectively sample the intale, 1 ' was utilized beginninu in l 'JM and results have aenerally indicated this area is more similar in fish fauna attraction to L L an estuary than exposed coastal areas. Results of additional sampling with a smaller foot-seine confirmed findinas from the : l. I-3
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- q, s
. larger- seines with Atlantic silverside, and' winter. flounder r
-dominating its catch, m-
~ b!ip.) n9ftDieRLilq0.1 toLLOg:
- 1. The' mean January - December 1989 impingement collection rate [
was 0.80 fish /hr. The rate ranged from 0.12 fish /hr (January) t'o 5.08 fish /hr (November) with Atlantic silverside cc:nprising' = 24.1% of-the catch, followed by Atlantic menhaden 16.5%, winter-flounder 8.4% and rainbow smelt 7.8%. Fish impingement rates i in 1985,1986 'and 1989 were several times higher than in 1984, 1987 and 1988 when Pilgrim Station outages had both circulating water pumps off for various periods of time.
- 2. .In April 1989, Atlantic silverside impingement accounted for I:
39% of this species annual collection. They have been one of the most abundant species impinged on an annual basis at Pilgrim Station, predominating in-7 of the last 9: years.
- 3. The mean January - December 1989 invertebrate collection rate was 1.38+/hr with blue mussels dominating, - and common starfish ,
and sand shrimp accounting for 19.8%, and 10.0% of the , enumerated catch, respectively. Twenty-nine American lobsters ! were sampled. The invertebrate impingement rates in 1985, 1986 and 1989 were similar to that recorded at Pilgrim Station during the 1987 and 19RR notage years, despite lower-circulating water pump availability in the outage years. I-4
- 4.- TImpinged- fish,-initial survival at the end of the Pilgrim Sta-j
. tion intake sluiceway was approximately 27% during static screen
- , washes and 55% during continuous washes. Only three of the dominant species showed greater than 50% survival, overall.
I: fBh._Surte10ane: Fish overflights in 1989 spotted four of five major species categories: herring, Atlantic menhadens Atlantic mackerel and i baltfish. Three sightings of fish in the nearfield Pilgrim vicinity were- made. On May 15, 5,000 pounds of river herring, June 5, 125,000 pounds of sea herring and July 13, 80,000
; pounds of -menhaden were observed within 1 mile of Pilgrim-Station, but these occurrences were not reported to regulatory authorities as the Station was in a reduced operating condition with only a partial thermal plume present during 1989. -From 1985 - 1989 there have been no observations'of pollock.
I RenthIc Jionttpr_ing:
- l. Eleven new taxa of invertebrates (mostly arthropods) were added to the list of = blota for PNPS benthic surveys as a. result of analysis of the 1989 samples. This brings to 483 the types of l invertebrate fauna recorded.
- 2. No notable difference in species richness existed between the
. - Effluent and Reference stations based on results of 1989 and
.g fall 1988 sampling. The reference stations, which have char-atteristically ranted ahead of the Effluent station in species I
I-5 I ,
)
numbers, .- appeared more similar to the discharge- area in- late I 1988. and- 1989 indicating a delayed recovery from PNPS . thermal-i ' effluent effects. l
- 3. Review of overall faunal community structure, via cluster an-. -
alysis, showed that the Effluent Station had a low degree of-l. similarity l compared with the reference stations in' spring 1989, 1 but higher in the fall. Faunal clusterings and. algal community overlap values, although somewhat consistent. with -past - observations, show general recovery of benthic community . . structure at the Effluent site when compared with reference l sites during the three year outage ended in early 1989.
- 4. The warm-water species, GrAc_UAr_in 1RYAt11Ae., decreased in the area of the Effluent station during 1986, was completely absent l l
in .1987. and 1988, and reappeared in: the f all. of 1989 during PNPS operation. It was also rare in 1984, after it had normally colonized in 1985, indicating a direct relationship to-L the lack of thermal effluent in 1984, 1986, 1987 and ,1988;
n Additional evidence of PNPS impacts in the Effluent < discharge zone was the prevalent appearance of the cold-water alga, -c p LamlngLil, in the Effluent area during 1984, 1987, 1988 and the spring of 1989 transect surveys.
- 5. Four observations of the neai-shore acute impact zones wei o l'-
[ performed during this reporting perlod. Denuded . and stunted i zone boundaries were indistinquishable during the spring 1989 discharge surveys as a result of the PNPS shutdown. These l' I-6 g.
. E
p . < . L 1 , [ ,. surveys noted delineated, denuded ' . impac t areas in S'eptember
' (1,382 m) 2 and December (1,235 m2 )J because two circulating water pumps were consistently in operation - the latter half .of ; $ 1989=, resulting in maximum discharge current flow. Evidence of PNPS-induced scouring Im- pacts was. the most obvious it. had been since the June 1987 transect surveys.
l{ ,
.. _ In.trALnmeAL11onttorlng:
- 1. A' total of 42 species of fish eggs and/or larvae were found ,
in the- January - December 1989 entrainment collections (22-eggs, 37-larvac).
- 2. ~ Seasonal egg- collections for 1989 were dominated by yellowtail flounder, Atlantic . cod and American plalce (winter - early spring); Atlantic mackerel -and labrids (late spring - early summer); labrids and windowpane (late-summer - autumn). a
- 3. - Seasonal larval collections for 1989 were dominated by rock gunnel and sculpin (winter - early spring); Atlantic.
mackerel and cunner (lato spring - early summer); hates,
, fourbeard rockling and cunner (late summer - autumn).
- 4. No lobster larvae were collected in the entrainment samples for 1989, and only nine have Imon sampimi f rom 1974-198'i.
I-7
5, In 1989 an estimated 7.872 x '109 fish eggs and - 3,310 x 10 8 g fish . larvae were entrained at Pilgrim Station, assuming .
~ full- flow capacity of all seawater pumps, On an annual .
basis, eggs were dominated by the labrid - IJ!n6nda group and Atlantic mackerel, and larvae by Atlantic mackerel, - sculpin and cunner.
- 6. Total numbers of fish larvae collected for similar volumes 1' of water sampled, in spr.ing and summer 1984 and 1987, were noteably lower than for the same periods in 1983, 1985, 1986, 1988, and 1989. These results were shown to be t related to the fact that both Pilgrim . Station circulating .'
water pumps were offline during most of the spring / summer period 1984/1987, but at least one circulating water' pump was operating during the majority of this period in other years,
- 7. On no occasions in 1989 were high-larval densities recorded j
-in samples as defined by the entrainment contingency: plan
(" unusually abundant" ichthyoplankton densities). l l h, 1 1 l 1 I-8 g e =i
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]
I : INTRODUCTION >
.A'.- Scope and Objective l This' is the ' thirty-fif th semi-annual report on the status and _ results of ;
the Environmental Surveillance and Monitoring Program related to the opera-
- I- tion of Pilgrim Nuclear Power Station (PNPS). Tr.e monitoring programs-dis- l cussed in this report relate specifically to the Cape Cod Bay ecosystem with particular emphasis on the Rocky Point area. This is the twenty-third semi-annual report in accordance with the environmental monitoring and re-l porting requirements of the PNPS Unit 1 NPDES Permit from the U.S. Environ- 1 mental Protection Agency (#MA0003557) and Massachusetts Division of Water Pollution Control (#359). A multi-year (1969-1977) report incorporating marine fisheries, benthic, plankton /entrainment and impingement studies was submitted to the NRC in July.1978, as . required '-by the PNPS Appendix B, ;
Tech. Specs. Programs in these areas have been continued under -the PNPS NPDES permit. Amendment #67 (1983) to the PNPS Tech. Specs. deleted t-Appendix B non-radiological water quality requirements as the NRC felt they are covered in the NPDES Permit. > The objectives'of the Environmental Surveillance and Monitoring Program are to determine whether the operation of PNPS results in measurable effects on i the marine ecology and to evaluate the significance of any observed ef-l fects. If an effect of significance is detected, Boston Edison Company has committed to take steps to correct or mitigate any adverse situation. l + { II-l
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]
i Y These studies. are guided s by the . Pilgrim Administrative-Technical Committee l (PATC) which was' chaired by a member of the Mass- Division of Water Pollu-tion Control in' 1989, and -whose membership includes representatives from , the University of Massachusetts, the Mass. Division of Water Pollution Con-
.)
trol', the Mass. Division of Marine Fisheries, the National Marine Fisheries Service (NOAA), the Mass. Office of Coastal Zone Management, the U.S En- j l: vironmental Protection Agency and Boston Edison Company. Copies of the l Minutes of the Pilgrim Station Administrative-Technical Committee meetings' held during this reporting period are included in Section V. 1 l l- B. Marine Biota Studies [ 1, '
- l. Marine Fisheries Monitorino l
ll l- A modified version- of the marine fisheries monitoring, initiated in 1981, is being conducted by the Commonwealth of Massachusetts. .j l Division of Marine Fisheries (DMF). ' I The occurrence and distribution of fish around Pilgrim Station and at sites outside the area of temperature increase are being monitored. . Pelagic species were - sampled using gill net (1 station) collections (Figure 1) made at monthly intervals. In 1981, shrimp- trawling and - haul seining were initiated which provide more PNPS impact-related sampling of benthic fish and shore zone fish, respectively. Shrimp
- trawling was done once/ month (January - March) and twice/ month -(April .
l
- December) at 4 stations (Figure 2) and haul seining twice/ month -j during June - November at 4 stations (Figure 1).
II-2 t l l lm '
, y 7 I .Honitoring is conducted of local -lobster stock catch statistics for areas in'the proximity of Pilgrim Station (Figure 4).- Catch statistics are collected. approximately b1 weekly throughout the fishing season (May-November).
I A finfish' observational dive program was initiated in June 1978. SCUBA L gear is utilized on b1 weekly dives from May-October (weekly mid-August-
.to mid-September) at 6 stations (Figure 2) in the PNPS thermal plume area.
In 1986, an experimental, lobster pot trawl monitoring effort was 4 initiated to eliminate any biases . associated with the collection of g
; lobster stock catch statistics ~for determining PNPS effects. Ten 5-pot lobster trawls- were fished in the thermal plume and control areas i around PNPS during 1989 (Figure 3),
l'. .? Results of the marine fisheries monitoring during the reporting period ' are presented in Section IIIA.1 and IIIA.2. j
- 2. Benthic'Monitorina 1 >
- 5: - The. benthic monitoring described in this - report was conducted by Battelle Ocean Sciences. Duxbury, Massachusetts.
I l ' II-3 w l-
I. l The benthic flora and fauna were sampled at three locations at depths of 10 feet (MLH) (Figure 1). Quantitative (rock substratum) samples were collected, and the dominant flora and fauna'in each plot were re-corded. Sampling was conducted two times per year (March and Septem-ber) to determine blotic changes, if any. Transect sampling off the discharge canal to determine the extent of the denuded and stunted . zones is conducted four' times a year (March, June, September and: December). Results of the benthic surveys and impact analysis during this period are discussed in Section IIIB.'1 and IIIB.2. d 3.' Plankton Monitoring Marine Research,-Inc.-(MRI) of Falmouth, Massachusetts, has been mont- - toring entrainment in Pilgrim Station cooling water of fish eggs and larvae, and lobster larvae (from 1973-1975 phytoplankton and zoo-plankton were also studied). Figure 5 shows the entrainment contingen-cy sampling station locations to be sampled should the number of eggs / ' larvae entrained greatly exceed recorded historical averages. Informa- > t!on gen'erated through this monitoring has been utilized to make perto- , dic 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 reviewed and approved by the I:> Pilgrim A-T Committee on the basis of the program results. Plankton monitoring in 1989 emphasized consideration of ichthyoplankton entrain- ' ment. Results of the ichthyoplankton entrainment monitoring and impact analysis for this reporting pemd are discussed in Section IIIC.1 and IIIC.2. I II-4 I I I
I- !
- 4.- Impinoement Monitorino The Pilgrim Station I impingement monitoring and survival program speciates, quantifies and determines viability of-the organisms carried' onto the four intake traveling screens. Since _ January 1979, Marine l .
Research, Inc. has been conducting impingement sampling with results i' being reported on by Boston Edison Company. A new. screen wash sluiceway system was installed at Pilgrim in 1979 at a total cost of approximately $150,000. This new sluiceway system was required by the U.S. Environmental Protection Agency and the Mass..
.I Division of Water Pollution Control as a_ part of NPDES' Permit
#MA0003557. Special fish survival studies conducte'd from 1980-1983.to determine its effectiveness in protecting marine life were terminated in 1984, and _a final report on- them appears in Marine Ecology w
Semi-Annual Report #23. Results _of impingement monitoring and survival program, as well as - impact analysis, for this reporting period are discussed . in- Section-IIID. i C. Fish Surveillance Studies I March - November, weekly fish spotting overflights were conducted as part . o of- a' continuing effort to monitor the times when large concentrations of L fish might be expected in the Pilgrim vicinity. Inspections were con-LI . ducted of the Pilgrim discharge canal in order to evaluate fish barrier net II-5
- [ .
i i durability and effectiveness in excluding fishes from the discharge canal., ,
~
after the neth ' installation in March 1989 (thef barrier net was removed from the canal in August 1986 for-the 1986-1988 Station outage). Anf annual summary report for this effort for 1989 will be presented in- l?~ Section IVA. :. i a D, Station'0peration History a The daily average, reactor thermal power levels from January through
^
-t
' December, 1984-1989 are shown ' in Figure 6. As can be seen, PNPS1 was ,
operating at low power levels during_ most of the 1989 reporting . period;- however, environmental monitoring programs were performed to obtain control data for impact comparison with past and future-high-operational-years,- J
.1 1990 Environmental Programs E.
g 3L A' planning schedule' bar chart for 1990 environmental monitoring programs l; related to ' the operation of Pilgrim Station, showing task activities 'and _ milestones from December 1989 - June 1991, is included as Figure 7. Il i-l 1 p 1 g II-6
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1 I l! l ANNUAL REPORT ON I MONITORING TO ASSESS. IMPACT ; OF PILGRIM NUCLEAR POWER STATION ON MARINE FISHERIES RESOURCES OF WESTERN CAPE COD BAY (CHARACTERIZATION OF THE FISHERIES RESOURCES) Project Report No. 48 (January-December, 1989) ' (Volume 1 of 2) I , t By Robert P. Lawton, Brian C. Kelly, Vincent J. Malkoski, Mando Borgatti, and Joseph F. Battaglia I I l I I ' I April 4, 1990 . Massachusetts Department of Fisheries, Wildlife, and Environmental Law Enforcement Division of Marine Fisheries 100 Cambridge Street t Boston, Massachusetts 02202 s
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I y
I TABLE OF CONTENTS I Section ERER I. EXECUTIVE
SUMMARY
1 II. INTRODUCTION 2 III. METHODS AND MATERIALS 3 IV. RESULTS AND DISCUSSION 14 A. Hydrography 14
- 1. Water Temperature 14
- 2. Salinity 15 B. Fisheries - Lobster 16
- 1. Commercial Lobster Pot-Catch Fishery 16
- 2. Research Lobster Trap Fishery 17 C. Fisheries - Finfish 20
- 1. Nearshore Benthic Finfish 22
- 2. Pelagic _and Benthi-Pelagic Fishes- 27
- 3. Shorezone Fishes 31
- 4. Underwater Finfish Observations 36
-5. .Sportfishing 39 V. HIGHLIGHTS 42 VI. ACKNOWLEDGEMENTS 45 VII. LITERATURE CITED 46
- l I
I g u g
I> LIST OF TABLES Table Pace
- 1. Monthly mean surface and bottom water temperature in 14 Centigrade recorded while sampling at various locations in the Pilgrim area during 1989.
- 2. Checklist of finfish species (following classification 20 >
of Robins et al. 1980) collected or observed in the adjacent waters of Pilgrim Station, 1989.
- 3. Expanded catch and percent composition of groundfish 23 captured by bottom trawling at four stations in the vicinity of Pilgrim Station, January-December, 1989.
- 4. Bottom trawl catch data for dominant groundfish in the 25 g vicinity of Pilgrim Station, January-December, 1989. m*
- 5. Number and percentage composition of selected finfish 28 3 species captured by gillnet (7 panels of 3.8-15.2 cm E mesh) in the vicinity of Pilgrim Nuclear Power Station, January-December, 1989.
l'
- 6. Shore-zone fishes captured by haul seine at four stations 31 in the vicinity of Pilgrim Nuclear Power Station, June-November, 1989.
- 7. Shore-zono fishes captured by foot-seine at five stations 35 in the environs of Pilgrim Nuclear Power Station, g June-November, 1989.
g E. Abundance and distribution of finfish species observed 37 during underwater observations, May-October, 1989. ' I I. Il l I I 111
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F LIST OF FIGURES ' I Fiaure Pace I 1. Location of Marine Fisheries sampling areas for trawl, gill net, haul seine, lobster, dive, and sportfish surveys in the Pilgrim study area. 4
- 2. Lobster pot sampling grid for the commercial lobsterman 4 monitored in the Pilgrim Power Plant area (surveillance (H-11, H-12, I-11, and I-12) and reference (E-13, E-14, and F-13) quadrats are shaded) and distribution of his traps sampled in 1989.
'I 3. Location of experimental lobster gear (five-pot trawls) for Marine Fisheries studies in the vicinity of Pilgrim Station, 6
l ! 4. Location of bottom trawl stations for Marine Fisheries 6
- studies off Pilgrim Station.
1 - iM51 5. Location of diving stations for the Marine Fisheries observational study off Pilgrim Station. 9 ,@ 6. Location-of gill net sampling for Marine Fisheries 9 lJ studies off Pilgrim Station.
- 7. Location of beach seine sampling in the environs of 12 Pilgrim Station for Marine Fisheries studies.
- 8. Creel data form used at Pilgrim Shorefront to record 12 sportfishing information.
- 9. Ambient bottom water temperatures recorded in Warren 15 i Cove during spring, 1983-1989.
- 10. Monthly commercial lobster catch per trap-haul in the 16 Pilgrim area, 1989.
- 11. Size distribution of lobster captured in the research 19 trap study off Pilgrim Station in 1989.
- 12. Size distribution of lobster captured in the research 19 trap study off Pilgrim Station from 1906 - 1989.
- 13. Catch rates for selected species (all stations pooled) 23 caught by nearshore trawling in the environs of Pilgrim Nuclear Power Station, 1981-1989.
- 14. Spring Resource Assessment Survey winter flounder 24 abundance in Stratum 25 (less than 9.1m) in Cape Cod Bay, 1982-1989.
I
I Ficure Pacte I
- 15. Seasonal mean trawl catch rates for winter flounder 24 by station in Pilgrim area, 1989.
- 16. Spring Resource Assessment Survey little skate 25 abundance in Stratum 25 (less than 9.1 m) in Cape Cod Bay, 1982-1989.
- 17. Seasonal mean trawl catch rate for little skate by 26 station in Pilgrim area, 1989.
- 18. Spring Resource Assessment Survey windowpane abundance 27 in Stratum 25 (less than 9.1 m) in Cape Cod Bay, 1982-1989.
- 19. Seasonal mean trawl catch rate for windowpane by 27 station in Pilgrim area, 1989.
- 20. Indices of relative abundance (CPUE) for pooled 28 finfish species captured near Pilgrim Station based on 5 panels of 3.8 - 8.9 cm mesh, 1971-1989.
- 21. Indices of relative abundance (CPUE) for pollock captured 29 near Pilgrim Station based on 5 panels of 3.8 - 8.9 cm mesh, 1971-1989.
- 22. Indices of relative abundance (CPUE) for Atlantic herring 29 ;
captured near Pilgrim Station based on 5 panels of t 3.8 - 8.9 cm mesh, 1971-1989.
- 23. Indices of relative abundance (CPUE) for cunner captured 30 near Pilgrim Station based on 5 panels of 3.8 - 8.9 cm mesh, 1971-1989.
- 24. Average number of fish caught per seine set i 2 standard 31 errors - pooled species and pooled stations - in the vicinity of Pilgrim Station, 1989.
- 25. Average catch per seine set for shore-zone fish in the 32 "
vicinity of Pilgrim Station from 1984-1989.
- 26. Monthly seine catch rates i 2 standard errors - pooled 34 species and pooled stations - in the vicinity of Pilgrim Station, 1989.
- 27. Total number of species caught per station in seine 34 study 1984-1989 in the vicinity of Pilgrim Station.
- 28. Index of relative abundance (fish / dive) for all species 37 observed by diver at Pilgrim Station, 1981-1989.
i v
I Ficure Page I. 29. Index of relative abundance (fish / dive) for cunner 38 observed by diver at Pilgrim Station, 1981-1989.
- 30. Index.of relative abundance (fish / dive) for tautog 38 i I
observed by diver at Pilgrim Station, 1981-1989. I ; i LI s 'I .i 'I ! LI: l. l. I "I g: . T vi .m-___ _ - _ _ _ - _ _ _ _ - - - . - _ _ _ _ _ _ . _ _ _ _ _ _ _ _ __- - - - -- _ 4'-_ +- _ -+4---e._ - ee4s k w+ a-- t'- * * *
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I ! I I. EXECUTIVE
SUMMARY
A modified version of marine fisheries monitoring for Pilgrim I Nuclear Power Station, initiated in 1981, was conducted by the Massachusetts Division of Marine Fisheries in 1989. The occurrence, distribution, and relative abundance of finfish and lobster were monitored according to standardized sampling schemes to identify trends and relationships in the sampling data collected from the study area over time. We directed most of our efforts to commercially and recreationally important fisheries resources. Nearshcre bottom trawling and haul seining sampled groundfish and shorezone fish, respectively, while an experimental gillnet monitored pelagic fish. Monitoring of the local commercial lobster I stock catch statistics was conducted during the inshore lobster season. Experimental lobster trapping, also conducted, eliminated many biases associated with the collection of commercial lobster catch statistics. A finfish observational dive program and a sportfishing creel survey rounded out investigations. l Catch rates in the Pilgrim area declined from 1988 to 1989 for . the top three groundfish (winter flounder, little skate, and l- windowpane) trawled. The gill net catch of pollock and cunner
- decreased from last year. The seine catch rates of Atlantic silverside and Atlantic menhaden increased substantially from last year. Overall, few fish were sighted during the diving study.
Angling effort at the Shorefront increased, with sportfish catches I doubling last year's meager catch. Lobster catch rates in both the experimental and commercial lobster studies increased this year. I
II. INTRODUCTION A field marine monitoring program das conducted in 1989 by the Massachusetts Division of Marine Fisheries (DMF) in an ongoing effort to detect environmental changes in the aquatic ecosystem caused by the operation of Pilgrim Nuclear Power Station (PNPS), under Purchase Order No. 66228 to Boston Edison Company (BECo). Our sampling design includes the use of several kinds of collecting gear and sampling strategies that would allow accurate characterization of the lobster and finfish populations present in the study area. With each gear type, the proper pairing of impacted stations with reference stations has always been one of our prime considerations when sampling. We have endeavored, when ' possible, to have more than one control site. Data collected at reference locations are of value to estimate natural rates of change in populations (background noise). Data on the occurrence, distribution, and relative abundance of. lobster and finfish were collected following a standardized sampling regime. Measurements, counts, percentages, and indices t I are used to characterize the study area. Volume 1 focuses on the fisheries' resources in the Pilgrim area as a whole. Only essential information is presented, whereas, detailed analyses including statistical tests and supportive data with l synoptic results are availatle from DMF upon request. Our intent is to condense subject matter but maintain clarity of data reporting and interpretation in a readable format. I I 1 l I
I III. . METHODS AND MATERIALS Commercial Lobster Catch I Many commercial lobstermen harvest American lobster (Homarus americanus) in the marine waters off Pilgrim Nuclear Power Station. Thore are different landing sites for their catch along the western shore of Cape Cod Bay, and it is not feasible to directly monitor the entire local lobster fishery. Instead, we have opted to sample the trap-catch of a cooperating lobsterman in the Pilgrim study area (Figure 1) and to use his catch statistics as an index of harvest. We sampled the entire day's catch of the same lobsterman biweekly from May to early November, which is the height of the inshore lobster season. To facilitate data collection and subsequent analysis, the study area was partitioned into a grid (0.8 km quadrats) on a nautical chart (Figure 2), and trap-catch 2 was associated with quadrats located by LORAN bearings and/or i visual sightings in the field. Data were pooled later for the , reference and impact areas. Our analysis included data from 1983-1989, because prior to '83 we had sampled the catches of another lobsterman who differed intrinsically in fishing power and gear i design. Research Imbster Trao Fishina 1 In 1989, we completed the fourth year of a field research lobster study, which was implemented to assess more accurately the impact of the thermal discharge current from Pilgrim Station on the local lobster population. This study allows us to control I
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LI I sampling effort in time and space and, in general to standardize sampling operations. We conducted experimental trap fishing from June-September in the area of the thermal plume (impact) and at two presumed comparable reference (control) locations within the experimental area using uniform procedures and gear to reduce bias and improve precision. Natural populations are rarely ever uniform in distribution over space. Ten permanent stations marked with an anchor-buoy arrangement were sampled: four (E-H) in the discharge area and six (A-D; I-J) in the two reference areas (Figure 3). Randomization was initially applied in our selection of stations from within an area. Fifty standard commercial vinyl coated wire lobster pots (91 x 51 x 30 cm) were fished in ten trawls, consisting of five traps (spaced 30 m apart) per trawl to provide spatial replicates - one trawl at each of the stations. Pots were hauled at a regular time interval, i.e., every other day in the morning, weather permitting. Thus, soak time (duration of a set) was generally controlled., Each sampling day provided replicates over time. At each station, water temperature was measured on each sampling outing. Traps were emptied of their contents, rebaited, and relocated on station. Flounder racks were used exclusively as an attractant to standardize any effect of bait typ$ on catchability. For each pot-haul, the lobster were counted, measured, sexed, and examined for missing claws, presence of eggs, shell hardness, and disease, and then released in the area of capture. A small sub-sample occasionally was retained for radiological analysis. I ,
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r, e i Three seasons (1986-88) of base line data were collected under essentially pre-stress conditions since the power plant had been in I a prolonged outage. In 1989, the discharge site was monitored for the first time in this study under the influence of waste heat. Furthermore, the current was generally stronger as both circulating seawater pumps were often operated simultaneously. This year can be considered transitional in that the power plant gradually increased operational status while the lobster sampling progressed. I Bottom _Trawlina ' Groundfish in the naarchore Pilgrim area were again monitored via small vessel (6.7 m) bottom trawling, which was begun in 1981. Four stations were sampled monthly from January-March and biweekly from April-December during the daylight hours (Figure 4). The curveillance stations were T-3 (Discharge) and T-6 (Intake). The primary reference station, T-1, was in Warren Cove, while another reference site, T-4, was northwest of Priscilla Beach. Station " selection was based on available substrate for trawling, water depth contours, bottom type, and known patterns of the thermal plume. Duplicate 15-minute tows were made at each station to obtain groundfish catch / effort data (CPUE) using a 9.8 m Wilcox trawl (9.8 m sweep, 7.0 m headrope, of 11.4 cm stretch mesh; and fitted with a 6.4 mm stretch mesh cod-end liner). If a standard tow could not be completed, catch values were extrapolated using a weighting function. Standard survey techniques and trawl log shoots were used. Fish were identified, enumerated, measured, and released alive, I I
I except for quarterly samples which were retained for radiological analyses. Invertebrates were identified and counted; lobster were . also gauged as to size (legal or sublegal). Surface and bottom water temperature measurements were taken during sampling operations at each station; I observational Divina The finfish observational program consisted of underwater '
. inspections at six permanently marked stations by biologist-divers '
using SCUBA (Figure 5) . Two sampling sites were in the area denoted ' as ' denuded', two in the ' stunted' zone, and two were controls as defined by Boston Edison Company (1980). The present sampling ,, stations were first occupied in 1981. Sampling dives were made biweekly during the spring and early summer, weekly from mid-August until mid-September, and then biweekly through october. During each diving operation, which occurred around high tide, two divers , descended to the bottom from a boat just outside the discharge canal and occupied each station consecutively, recording visual observations of marine life. The major emphasis was on fish identification, numbers, approximate sizes, and general' condition and behavior. Bottom water temperatures were'taken with a hand-held thermometer, and visibility estimates made with a Secchi disk. I Gill Net Samolina , Pelagic and benthi-pelagic fish in the Pilgrim area were sampled by fishing a gillnet parallel to shore at a depth of three ' 8 s-
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I; meters (MLW) near a ledge extending north from the mouth of the discharge canal (Figure 6). The sampling site is partially within the discharge impact area. Sampling was conducted monthly throughout the year. To standardize sets on a yearly basis, the net was set before sunset and retrieved at sunrise the following day to take advantage of the greater sampling efficiency of this passive gear during the dark. We employed a sinking monofilament gillnet (213.4 m long x 3.0 m deep), which was anchored on station, fishing the entire water i column at low tide. To counter the bias of gear selectivity, an
,s>erimental net was fabricated, consisting of a single " gang" of deven 30.5 m panels of different mesh sizes. To further reduce sampling bias, the end of the net positioned closest to the '
discharge canal was reversed on alternate sets. Water temperatures were taken when the net was set and hauled. Our objectives were to provide systematic collections of finfish for radiological analysis and to obtain time series records ; of relative abundance for dominant species. Haul Seinina To monitor finfish occurring in shallow waters, i.e., the intertidal zone and the shallow part of the subtidal zone, haul _ seining was conducted. We sampled biweekly at five stations during the daytime from June-November, when fishes normally inhabit the shoreline (Figure 7). Winter /early spring sampling was omitted because cold temperatures reduce fish distribution in the shoals. , Fishes found along the shore include forage species and the
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I juveniles of many important commercial and sport species in the size range most susceptible to power plant impingement. We employed a standardized quantitative seining technique, modified after conover and Ross (1982). The net used at Stations ; S-2, S-4, and S-5 was a 45.7 x 1.8 m haul seine with a 1.8 x 1.8 x 1.8 m bag of 0.48 cm square mesh (twine #63). Because sampling was constrained by the greater depth at the surveillance site (Station _ S-3, Intake), a deeper seine (45.7 x 3.0 m ) set from a small , powered skiff was used. Duplicate hauls were made at each station. All sites were sampled within 12 hours of ebb tide. Surface water temperature and salinity were measured at each station. Using a smaller seine (6.1 x 1.8 m of 0.48 cm square mesh), we sampled all five stations S-1 - S-5 at low tide. The smaller seine, with its double-lead weighted foot-rope, is designed to retain demersal fish, especially flatfish. For each station, the area (m 2 ) seined was kept constant to maintain a consistent effort within a site over time. Captured fish were identified and enumerated. Up to 50 individuals of each species captured were measured. Unusually large catches were j subsampled to reduce mortality, and total catch was extrapolated j from volume-unit counts. Mean catches per standard set were calculated for dominant species. Seine data have been collected since 1981. WI Snortfish Survev The sportfish catch at Pilgrim Station's Shorefront recreation q area was monitored from late June through August by public I 12 I'
I I relations' personnel at the waterfront in a cooperative effort with us to maintain a database on recreational fishing in the Pilgrim area. A questionnaire was used to record daily catch data (Figure g e>. I I I B B B B I: B I B I I g l 13
,B
Il IV. RESULTS AND DISCUSSION i A. HYDROGRAPHY ; 1
- 1. Water temoerature l 1
In the inshore marine waters neighboring Pilgrim Station, surface ambient water temperatures have been as low as -1 C in mid- ' winter and as high as 23C in mid-to-late summer. Bottom l temperatures have ranged from -1C (mid-winter) to 21C (late summer). Warming begins in March or April, and a thermocline normally forms by early summer at a depth of between 5 and 10 m, lasting into the fall (Table 1). Surface to bottom temperature I differentials have been highest in summer, ranging to 4.8 C. The temperature profiles were similar during spring and fall. Water , temperatures during spring were considerably higher at Long Point I located at the mouth of the nearby estuary - Plymouth, Kingston, Duxbury Bay. I Table 1 . Monthly mean surface and bottom water tenperature in Centigrade recorded white senpling at various locations in the Pilgrim area during 1989 L ocation Season Winter (Jen. Mer.) torinatAor. June) S m efJutv seet.) Fett (Det. Dee.) Long Point - (-) 17.4 (-) 18.3 (-) 10.4 (*) Warren Cove / 3.1 (2.5) 12.4 (10.5) 18.6 (15.4) 11.6 (11.3) Rocky Point Olscharge 2.3 (2.0) 11.8 ( 7.9) 16.5 (14.3) 11.5 ( 9.8) Intake 2.7 (3.0) 5.2 (11.7) 18.5 (13.7) 12.0 ( 9.3) White Horse Beach / Manoment Point 3.5 (3.3) 12.3 (11.3) 17.3 (14.9) 11.0 (10.2) Grand Mean 2.9 (2.7) 11.8 (10.4) 17.8 (14.6) 11.3 (10.2) I
- 1e m eratures not recorded because no senpling was done at this site during winter.
I 14
- ,.y -
Over the last seven years (1983-1989), water temperatures overall were highest in the Pilgrim area in 1983 and 1985. Noteworthy also was the markedly lower temperature regime during w all seasons of 1984. A
~
plot of bottom water temperatures for the .,,, , vernal season revealed 50- .. a .. ~5 there were perceptibly cooler springs in 1984 and "#' I 1987 4 . (Figure 9). The ' I spring of 1989 began quite ~ S83
~ 1967
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~' ~ 58' cool, but by the end of Figure 9. mient tettom water temeratures recorded in Warren cove during spring, 1883 1989.
May, the temperature had risen sharply. A regime of lower spring water temperatures translated into lower commercial lobster catch rates in the Pilgrim area for 1984 and 1987. Lower temperatures probably reduced molting, which might have resulted in lower recruitment to legal size.
- 2. Salinity Salinities in the study area were relatively high, with monthly means ranging from 29 - 31.3 */ . There is a minimum of fresh water influence at our sampling locations. Tidal exchange is such in Cape Cod Bay that its waters exhibit little salinity variation from Massachusetts Bay and the Gulf of Maine (Davis 1984).
15
I; B. FISHERIES - LOBSTER Ii '
- 1. Commercial lobster cot-catch fisherv g) i gi l
Monitoring the commercial American lobster (Homarus americanus) fishery in 1989 in the Pilgrim study area began in May
~and concluded in October. Lobster catch statistics and biological data (i.e., carapace length - CL, sex, shell hardness) were i collected for six months during 12 sampling trips aboard a g commercial lobster boat. Data were recorded on 4,690 lobster taken gI I
i ! from 2,120 lobster pot-hauls. Overall catch per pot for all lobster (comprised of legal - CL I 282.6 mm - and sublegal lobster) for the Pilgrim area was 2.2, up substantially from last year's value of 1.6. Twenty percent (947) of the total catch were legal-sized lobster for an annual legal I catch rate of 0.45 lobster / trap-haul, an increase from last year's I-value of 0.38. The lowest monthly legal catch rate occurred in June ! (0.26), and the highest (0.81) in September (Figure 10). The monthly catch rate of both MONTHLY COMMERCIAL LOBSTER CPUE 1989 ; sublegal and legal lobster m y ptn7 nip , i 80 + paralleled that of the total pooled ** - lobster catch rate. The annual 3., m ..- m .__ ..._.. '\ l g,g . . . . . . . . . . .. I . . ratio of sublegal to legal lobster ..- T 1 e..
.j was 3.9:1. uw a sut aua up ocr uosts '
Females comprised 49% of the - tout toosrta catro ta amisuoteo ta Figure 10. Monthly coninercist tobster catch annual catch. Monthly sex ratios per trap haul In the Pilgrim arca,1989. l approximated 1:1. There were 71 i ovigerous (egg-carrying) females sampled (3.1% of the female catch), of which 28 (1.2% of all females and 39% of all ovigerous I 16
r I females) were sublegal. The overall percentage of ovigerous females [ was greatest in late summer-early fall (August 6.1% and October 6.5%) and lowest in summer (1.1% in June) . The seasonality of ovigerous females is typical of the two-year reproductive cycle of i the American lobster (Aiken and Waddy 1982). Female lobster generally mate after the summer molt, but do not extrude fertilized eggs until fall of the following year. The eggs are then carried I externally throughout the winter'and hatch in the spring. 1 i I 2. Research Lobster Trao Fishina i 1 We trapped lobster from early June through September 1989 in the environs of Pilgrim Station. This year, the fourth of our research fishing, consisted of 56 sampling trips. Effort equaled , 2,761 trap-hauls while sample size was 9,502 lobster of which 13.2% were legal-sized. In 1989 the legal retention size for lobster in Mawsachusetts increased from 2 81.8 mm CL to 2 82.6 mm CL. This size change is reflected in the annual catch ratio of sublegal to legal lobster which was 5.8:1 in 1988 and 6.6:1 in 1989. The number of lobster of all sizes captured in the study t I ranged.from 0 to 14 per trap-haul, with legal catch ranging from 0 to 5 and sublegal, O to 12. In 9% of the hauls, no lobster were
- taken. The overall mean catch-per-trap-haul (CTH) in the study area for lobster pooled for all sizes and of both sexes combined j has increased stesdily over the four years, ranging from 1.2 in i
l 1986 to 3.4 in 1989. Monthly catch rates (legal and sublegal) in the study area generally increased within 1989. Beginning of the molt occurred in June as indicated by relatively low catches then, I
i followed by a marked increase in catch per pot and total catch in subsequent months. Males again predominated, comprising 56% of the pot catches, j conversely, commercial catches of females have outnumbered males in the deeper waters of western Cape Cod Bay (Kelly et al.1987) . The preponderance of males in shoal water pot catches also was found by Briggs and Muschacke (1979) in Long Island Sound. only 28 egg-bearing (ovigerous) females were sampled which represents 0.7% of the female catch. The percent females ovigerous l was 0.7% in last year's research catch as well. Over the years this value often has been below 1% in commercial catches of Cape Cod Bay - but has been as high as 14% of the catch in Buzzards Bay (Collings ! et al.1983) . This year's value in Cape Cod Bay was 3.1%. The mean l size of female lobster at maturity is considerably lower in the warmer waters south of Cape Cod (Aiken and Waddy 1980; Van Engel 1980). l Culls, i.e. , lobster with missing and/or regenerating claw (s), i captured during research fishing in 1989 represented 27% of the l catch, up from 23% in 1988 and 20% in 1987. In general, the cull 3 1 rate in commercial catches has increased in the pilgrira area during g ! the decade of the '80's concomitant with a rise in lobstering effort. As required by law, the commercial lobster traps employed in , this study contain rectangular escape vents (44.5 x 152.4 mm) E designed to retain legal-sized lobster; however, sublegals are g, ce.ptured to an extent. The size range of lobster sampled the summer of 1969 was 41 to 126 mm CL. The overall mean size was 76.0 I 16 E L
I ; mm, which is 1.1 mm greater than the mean in 1988. This likely reflects the change in the legal size in 1989. Sublegals averaged 74.3 mm CL, and legals, 86.4 mm CL. , Size-catch distributions were plotted for 1989 data
~~~
(Figure 11) and for all four ,,,,,,,,, , I years, 1986-1989, together n-(Figure 12). These histograms ,1 I' i '"j display the combined effects of { [ availability, vulnerability, and
- ggh exp1oitation. The genera 11y " " ** *' 7g,y ,,*,' ,,"in,",,$, "
e ,,,,,,,t ,ng, stepwise increase in catch from C *" Figure 11. sine distribution of Lobster 50 to 75 mm CL suggests that at captured in the research trap study of f Pilgrim Station I the latter sizes, lobster are in 1989, I increasingly vulnerable to retention in the traps. The 12 I mode was once again at the i I tof sq (V
#l f jl l pre-recruit size of 80 mm. of A j ; I Reduced catches of lobster 2
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I below 75 mm is probably the '8 " " 7' 7' 8 Carapace Lenght (mm) in 1 mm increments result of gear design (vent . a nu c ast sun wes O wne l2' ' ' escapement). The lower numberc ,Fat n tn ruuren t so stN oIf Pi grim on from 1984-1989. of lobster just below legal size and at legal size and greater most likely reflects the intensive commercial and recreational lobster fisheries of the Pilgrim area. In 1988 and 1989, markedly more larger lobster (.>_ 80 mm CL) were sampled (Figure 12). Enhanced recruitment of sublegals into 19 7
-the pre-recruit and' legal size range was most likely the reason, since the Cape Cod Bay lobster resource is over-exploited (Estrella T and Cadrin 1989). This phenomenon was apparently widespread at least in 1988, for Estrella and Cadrin (1989)' reported that the mean catch rate of marketable lobster in Massachusetts coastal waters was 11% higher than in 1987, while -the total state commercial landings increased 8%. Ennis (1983) found that with lobster exploitation rates as high as 94% in the Comfort Cove area '
of Notre Dame Bay, Newfoundland, recruitmant was the main factor , influencing the abundance of legal-sized lobster in a given year. C. FISHERIES - FINFISH WE g-_ A species check list of fish observed or collected by all gear types in the Pilgrim area in 1989, complete with scientific names (Robins et al. 1980), is found in Table 2. Table 2. Checklist of finfish species (following classification of Robins et al. 1980) collected or observed in the ad-jacent marine waters off Pilgrim Station, 1989. E; Class Chondrichthyes Order: Squaliformes Family: Carcharinidae requiem sharks Mustetus ggnis (Mitchill) smooth dogfish Family: Squalidae - dogfish sharks Savatus acanthies Linnaeus - spiny dogfish. . Orders Rajlformes a Family: Rajidae skates RgigerinaceaMitchfll-littleskate 1 R,alg ocettete Mitchill winter skate Family: Torpedinidae - electric rays Torpedo nobiliane Bonaparte Atlantic torpedo Class: Osteichthyes Order: Clupelformes = Family: Clupeldoe - herrin09
- Alosa oestivalls (Mitchill) blueback herring Atosa pseudoherenaus (Wilson) alewife Brevoortia tyrannus (Latroue) - Atlantic menhaden l 3
Clupea barenaus barenqus Linnaeus - Atlantic herring Atosa saoidissima (Wilson) American shad 20 I
h E Family - Engraulidae anchovies bag,,h,23 h mitchitti (Valenciennes) bay anchovy I order Saloontformes Family: Osmeridae smelts Osmerus ag,rsing (Mitchill) Order Gadiformes ralnbow smelt ? Family: Gedidae codfishes i gglyg morhua Linnaeus
- Atlantic cod Mertueetus bilinearls (Mitchill) silver hake Microcedus ,tgggg! (Walbem) Atlantic tomcod Pottach us vitens (Linneaus) pollock Urochve' s igngit (Mitchill) white hake I-..
Urochve' a g,h,ygg (Walbem) red hake Urochve a reale (Walbe m ) spotted hake j Family: Zoarcidae eelpouts Macrozoarces americanus (Schneider) ocean pout Order Casterostelformes Family: Gasterosteldee sticklebacks I Gasterosteus aculeatus Linneaus threespine stickleback ADettes QuadraCus (Mitchill) fourspine stickleback Family: Syngnathidae pipefishes and seahorses Synonathus fygt,yg Storer ' northern pipefish Order: Atheriniformes Family: Atherinidae silversides e Menidia menidia (Linnaeus) Atlantic silverside ! i Family: Cyprinodontidae killlfishes Fundulus malalls (Walbaum) - striped killif tsh Fundutus heteroclitus (Linnaeus) - mm michog Order Perciforms t - Family: Percichthyldae - tenperate basses Morone saxatilis (Walbaum) striped bass Family: Serranidae - sea basses I - centrocristes striata (Linnaeus) black see bass Family:- Pometemidae - bluefishes 1 Pomatomus saltatrix (Linnaeus) bluefish Family: Carangidae - Jacks Serlota 1,q ata (Mitchill) banded rudderfish I Family: Scleenidae - dr a s Menticirrhus saxatilis (Bloch and Schneider) - northern kingfish Family: Scombridae meckerels and tunas Segnbe,t scombrus Linnaeus Atlantic meckeret Family:: Speridae porgies. Stenotomus chrysops (Linnaeus) scup ,
~ Family: Labridae wresses Teutoen onitis (Linnaeus) tautog Tautocotebrus adsoersus (Walbaum) cunner Family: Mugilidae
!:,ugilgufr,gmgValenciennes-whitemullet u
Family: Pholidae gunnels Pholls cunnet t,u,s, (Linnaeus) i0ck gunnel W Family: Stromoteldae butterfishes ! PeorilVS triacenthus (Peck) butterfish I 21 I
I h Family: Triglidae searobins Prionotus carolinus (Linnaeus) nothern searobin lI ' Prionotus gypjg g (Linnaeus) striped searobin Faally: Cottidee sculpins i Manftrioterus ameriennus (Gmelin) sea reven Mvoxocephatus.W M (Mitchlll) grubby Myoxocephalus 0, tutecemspinosus (Mitchl(L) - longhorn Sculpin , myoxocoonatus peorolus (Linnaeus) shorthorn scu; pin fccity: Cyclopteridae Lunpfishes and snellfishes ' Evrtorterus itagna Linnaeus '- (tmpfish ( L1Daris attenticus (Jordan and Evermann) seasnell Family: AmmoW.idae send lances Amodytes m Order: Pleuronectiformes- '
-l Family: Bothidae Lefteye flounders !
Paratichthys dentatus (Linnaeus) - sunner flounder . Paretichthys pblonnus (Mitchill)
- fourspot flounder ScochthatpsJs acuosus (Mitchitt) windowpane , ;
Family: Pleuronectidae righteye flounders Limanda ferruninea (Storer) yellowtalt flounder Pseudooleuronectes americanus (Walbaun) Winter flounder _ orders' Lophilfocus Family:. Lophildae - goosefishes , 3 Lophius americanus Valenciennes goosefish Order: Tetraodontiformes Family: Tetraodontidae -. puffers Sohoeroides maculatus.(Block and Schneider)
- northern puffer 1
- 1. Nearshore benthic finfish '
o l We completed 106 bottom trawls in the study area in 1989. A . total of 770 fish, representing 23 species, was collected I (Table'3). Three groundfish - winter flounder, little skate,.and l windowpane - comprised 75% of the catch. The average catch per tow l l (our measure of catch-per-unit-effort, or CPUE) for the study area (all species and stations pooled) was 7.3, a decline of 27% from
=1 last year. The Intake Embayment (Station 6) and Priscilla Beach I (Station 4) yielded the highest CPUEs (pooled species) of 8.7 and 7.7, respectively.
l
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l: cI Table 3. Expanded catch l and percent conposition of groundfish captured by lettom trawling at i four stations in the vicinity of Pilgrim Station, January Deconber,1989 l Etetton l 1 3 4 6' Warren Plterim Priscitta Pilgrim- Percent of I species Winter fIounder Cove-87.7 Discharge k 7026I ' Beach 95.1 n intake b;e6M ' Totals 360.2 total catch 4(.7 Little skate 22.5 E 56.73 ' 67.4 Q 20.9 a m 167.5 21.7 Windowpane 11.0 !b 12.6yg 19.0 10.T ? 53.5 6.9 Ocean pout . 12.0 M-r 9.0 D-= 8.0 $p 7.50 { 36.5 4.7 l- Longhorn sculpin 2.0 Nil$.6? 8.0 7.0 6 22.1 2.9 Atlantic silverside 12.0 5.0 4lh!E0$ 22.0 2.9 Yellowtait flounder 1.0 h:=5.0)1
>L13.8 s 6.0 G-'t.0 s!M 21.8- 2.8
; Rainbow smelt 9.0 14.16 0.0 ,[i7,619 20.7 2.7 Cunner. 1.0 :: 4.1 y 5.2 -. 2.5 ? " 12.8 1.7 Seannell 1.0 l0.0: 6.0 8r,3.3: 10.3 1.3 Rock gunnet 2.4 ! -I t.0 :e 2.0 %.0% ' 8.4 1.1 Other species 2 4.0 8.0 34.5 4.5 g12.1? 70%
Ntaber of species 15 (19 k 16 $145 g ~ 23 Ntaber of tows 28 ;'27/yp".{ 30 p 21 s. 3 106 Total fish 165.6 fi93.6h 229.7 770.3
' I~. -
Catch per tow 2.9 hs7.2[ 7.7 418147& Ir 8.7 / t 7.3 Percent of catch 21.5 ft$1j 29.8 y t3.6;.(,i fCatchrateswereexpandedfortowslessthanthestandard15minuteduration. Represents pooled totals from 12 species of Low catch abundance. Shaded cotteria are data collected at surveillance stations.
- S Winter flounder Winter flounder again CATCH / TOW FOFI DELECTED BPECIES ranked first in catch (47%-all so""""'"""* t 1I. . stations pooled) for the study ,
area and .was numerie.'.lly 1o-8 dominant at each station. The
- e. ,
I ' mean CPUE for the study area *' -
~
o_+ j_ , ..
,. ;._ ; _ y E;..E 7 declined for the fourth " *'* * " * * * ' " " " "
" " ' ' ' ' ' ' ' C """* ** * " " " ' " ' " ' ' '
consecutive year from 5.1 (1988) .......4.,....
- to 3.4 winter flounder / tow in Figure 13. Catch rate for selected species (att stations pooled) caught by nearshore trawling in the 1989 (Figure 13). Ilowever, the envir na of Pilgrim Nuclear Power Station, 1981 1989.
I index of winter flounder abundance (mean number of fish per tow) for water < 9.1 meters deep in Cape Cod Bay generated from the 23 I
I
-co3stal spring bottom -trawl S ring Survey Abundance: Winter Flounder Stratum 26 - Cape Cod Bay survey, conducted by the ,_
120
~
Resource Assessment Project of the Massachusetts Division of 80- - Marine Fisheries, increased 80-
"O somewhat over the 1988 estimate 20-(Figure 14).
#82 M83 #84 M85 1988 M87 M88 M89 The Intake (Station 6) ,,,
ranked first in winter flounder Figuro 14. sprine Resource Assessment survey winter flounder abundance in stratum 25 (less than 9.1m) catch with an annual mean CPUE of 5.1 (Table 4); however, this value represents a decrease of 31% from last year. The Discharge site (Station 3) had the lowest winter flounder catch index (2.6); this also represents a decline from 1988. Additionally, annual mean CPUE at the other two stations (Warren Cove and Priscilla Beach) declined this year-(4.7 to- 3.1 and 5.4 to 3.2, respectively). Winter 11 under Seasonal catch / tow
~
NUMBER OF FISH / TOW Seasonal, trawl catch rates ,. , ,, , - ie- a ears o'..a.<e. - of winter flounder (Figure 15) ,o. as m.m. mea es..... followed a pattern of lowest catches in winter, moderate e g
= a catches in spring, slightly "
.45 i .~ 5 depressed summer catches, and
'i o
wanta b$ senmo M _RE.$_ suuuen m SEASON slightly higher catches in the Figure 15. seasonet mean trewi catch rates for . fall. Examination of size data (Table 4) reveals a continuation of the trend toward a smaller I-i
-. _. - - .. -- ~ -.- - - -. .- . . .
I' annual mean size of winter flounder in the ' Intake embayment rela'tive'to the other stations as noted by Lawton et al. (1988). I . l for dominant groundfish in the vicinity of Pilgrim Table 4. Bottom trawl catch deta Station, January Decenter,1989. Winter Little- [ flounder skate' Windowpene , STAfl0N 1-f ' . Mean catch / tow 3.1 0.8 0.4
- . Mean size (ce) 28.6 37.4 26.7 Size range (cm) 9 39 27 50 16 33
'Fsh den (37 ' @ ' .' s 97 ' '- ' tj@Ms?w?P o
s
'I .ji$d$ #]3AQgd dh3)
[Meen! catch /t Q ' s
- l. i:Meen:siteMeell:..r. < ,
% (24111
~ .336.9'iii'" '
< !?242; x.taera.ngel(omiis4 iis iC 6439 8 . ' ;M213;grijggggg.jg s 'h34301 jgy.g s , 7 sq , _'s' 7 c ;;;g;c .-
s
*49is q STAfl0N 4 "
L' Mean catch / tow 3.2 2.2 0.6 i: .= Mean size (cm) 30.2 33.2 24.4 Size range (cm)' 10 46 18 50 5 30 I
' BTAT!DN 6 '" 'M:S 's"'"'s .' . ' . /Mi s
'O 3. 's ' ' :M0i. f. . . e IMeancatch/ ten s:! ' s 'J.5$i11 .,idION s jo3!
i.mean? streitcut)3:iii 5(s.s if21 1i;' l 335.9ss 32410l l41a*fg{ coq S
,' 'i;!gM) s ; {26py ,
s s y20fK! I Catch rates were expanded for tows less than the standard l' . 15 minute duration. i
- l. - -
Shaded rows are data collected at surveillance stations. Little skate-Sprin9 Survey Abundance:Little Skate L I Little skate ranked second,
" " * ' " * * ~ *** # "'# '
120
- i. comprising 22% of-the overall ,
catch. A mean annual catch per ,o tow cf little skate for all 80 stations pooled of 1.6 was 40' nearly'the same as a 1988 value 0 g of 1.8. The spring Resource 1982 1983 1984 1985 1988 1987 1988 1989
..I. abundance Figure 16. Spring Resource Assessment survey Assessment Project
- Little skate abundance in stratum 25 (less than 9.1m) in Cape Cod Bay, 19824989.
index for little skate in Cape cod Bay waters of less than 9.1 m increased in 1989 (Figure 16). 25 t
7 E' As in 1988 (Lawton et al. 1989), this species was not ! numerically dominant at any of the stations. The highest annual-station ' catch rate (2.2 little skate / tow) was recorded at the ! Priscilla Beach site. When compared with the 1988 rate (2.6 little-skate per tow), there was little difference between the two years. Warren Cove had the lowest' annual CPUE of 0.8. Seasonally, catch rates for little skate (Figure 17) exhibited-more fluctuation than those for ' winter. flounder. Values were Little skate seasonal catch / tow generally low in winter, while , NUMBER oF FISH / tow peak catches occurred in the 5 ,$",". .[...-:- am e. ..
.~ ,,, I _
==
spring- at the Discharge and E3 '""' '"" [ [ . Priscilla Beach. Catches , generally declined in summer l li with the exception of an , , l50 kj . 3El $ _p;hN WINTER SPRINO SUMMEA FALL - unusually precipitous surge in SEASON : Figure 17. Seasonal mean trawl catch rate for rate in the Intake (possibly a Little skate by station in Pilgrim area, 1989. - sampling artifact due to the low W number of tows made at this site in sur.aner) . There was a further decline in the fall. The highest c3tch rate was obtained in the Discharge (4.5) in spring. , Windowoane Windowpane was third in overall abundance in the trawl catch - S~, (7%) for the seventh consecutive year. Mean annual CPUE for all - stations combined was 0.5, a slight decline from 0.9 windowpane / tow in 1988. The spring Resource Assessment project abundance index, I-26
I l for Cape Cod Bay waters, for ,,,,,%,,,.,%,,, Stratum 26 Cape Cod Bay windowpane also decreased- ,,,,,, slightly in 1989 (Figure 18). ,,.
~
Annual CPUE for windowpane 3,. was nearly identical among the so. m. - I four stations, ranging from 0.4- s-0.6. Seasonally, windowpane were o ,,, g 4 ,,, ,,, ,,, ,,, ,,g
'I absent from winter groundfish Figure 18. sprino source Auenment survey windowpene abundance in Stratun 25 (less than 9.im) in catches (Figure 19). Catches cape cod say, 1982 1989.
were by far the highest- in windowpane seasonal catch / tow spring, followed by reduced NUMBER of FISH / TOW levels in summer and fall, o *= a.~ am . -- I. a .m . . ; Ocean Pout g
?
Ocean pout, nearly absent fl f h ff from project trawl catches in .o ,,,,,, ,,so uuuta SEASON recent years, ranked fourth I comprising 5% of the- tota 1 Figure 19. seasonst meen trawl catch rate for catch. This species was most abundant at Warren Cove. Annual mean CPUE for all stations pooled was 0.3 fish / tow.
- 2. Pelaaic and benthi-nelaaic fishes Gill-not collections from 12 overnight sets in 1989 yielded 27
.I finfish species totalling 1309 individuals (Table 5). No sampling was performed during February and December due to inclement 27
;a
. -. ~. .. . . - . . . - ._ _ --- . - - .
weather. Two sets were made during the months of January and March. l i Table 5. Number and percentage composition of selected finfish species captured by gill net (7 panels of 3.515.2 cm mesh) in the vicinity of Pilgrim Nuclear Power I' :l Station, January-Decenber, 1989. -)
~
Percent of Species N aber tatal catch Pollock 577 44.1 Atlantlc herring 266 20.3 Cunner 147 11.2 Other* 319 24.4 Total 27 species 1,309
*The remaining species were not found in abundance.
J Annual mean catch per unit effort (CPUE) for pooled species (5 1 panels of 3.8-8.9 cm mesh) declined sharply to a time series low of , 84~.4 fish / set. (Figure 20). A marked decrease in Pooled Species 'I 6-panet Totale catch abundance of- u. n c.icn ,,, oiii.u.i s.,
- j_
Atlantic herring and ,3o. as-. pollock as compared with em-1988 catches contributed 100-to' 'the lower overall 60- 5 catch rate. , .,, . . , ! 7172 73 74 76 76 77 78 70 '00 *81 'Be '83 '84 '05 '80 'B7 20 *B0 ; The dominant species Year ll3 I Figure 20. Indices of relative abundance (CPUE) for in the 7-panel gillnet pooled finfish species captured near Pilgrim Station based. on 5 panels of 3.8 8.9 cm mesh, 1971-1989. j catch totals were , pollock, (comprising 44% of the total catch), Atlantic herring - (20%), and cunner (11%). These three species have dominated the , gi'll-net hierarchy since 1971, with the exception of 1985, when the relative abundance of Atlantic herring was unusually low. gl i 28 5'l I
g .
'I.' Pollock 6-panet Totale
, A comparison of
,,,_._.,0.,
,,o.
LE annual- CPUE for pollock 100- {r reveals that relative co-I co-abundance decreased from 1988 to 1989 (Figure 21). l As the time series ar
; illustrates, pollock are Figure 21. Indices of relative abundance (cPUE) for ,
l: pollock captured near Pltgrim Station based on 5 penets l - f 3.8 8.9 cm mesh, 1971 1989, sub eCt tO wide. 7 fluctuations in local abundance. E Atlantic Herrino Most of the
$.*p",$i 7Eif l horring catch (96%) came i4o ;
I $5 from one set made in ico. April.- A traditional 8o. gill-net dominant, , 40-Atlantic-herring was all
- L A
but absent from project oL.It a ' mRL =
.,,,,,.,,,,,,,,,,,,,7.,,.,,,,,.,,.,,,,3.,,,,3.,,,,,,,,g, Year catches in 1985 (5 fish),
with continued low lj '77j'f98 PI 9 I M In 5 Pamts of 3.8 8.9 abundance through 1987 (Figure 22). A marked resurgence in 1988 followed by a subsequent drop 'in 1989 are indicative of their highly migratory nature and/or l . wide variation in local abundance (Bigelow and Schroeder 1953).
;I 29 8
Il p Cunner CPUE for cunner in 1989 was 11.3 fish / set. As seen in Figure 23, relative abundance of cunner in the Pilgrim arca has experienced marked reductions since 1984, with this year's value I the lowest of the 18-year time series. This lowered c 3., ,,,. abundance was also noted by so e onme om se project divers in the ,o. discharge area. Poor 39 t recruitment and mortality ,,, from ll recreational l
. fishing .
pressure over the years at Pilgrim Shorefront may have contributed to this decline. Figure 23. Indices of relative abundance (CPUE) for . , cunner captured near Pitorim Station based on 5 panels of 3.8 8.9 cm mesh, 1971 1989. ' other Soecies The remaining species captured by gill-net in 1989 were taken in relatively low numbers, with no single species comprising more than 6% of the total 7-panel catch. Some, such as tautog, experienced slightly increased relative abundance, while Atlantic mackerel and Atlantic cod underwent substantial declines. Others, such as striped bass and bluefish, have an affinity for the thermal effluent (Lawton et al. 1986); their numbers are generally low in the Pilgrim area when the plant is not fully operational. With the plant at 29% capacity in 1989, catch / set of bluefish increased while striped bass were down. The majority of these 'other' species 30 I 5
I ( are captured only ' sporadically and never have occupied positions of dominance.in gill-net records.
'3. Shore-zone fishes A total of 25,344 finfish representing 33 species was captured )
in the 45.7 meter haul seines.from June-November, 1989 (Table 6)'. Four taxa - Atlantic silverside, Atlantic menhaden, sand lance spp., and winter flounder I Average Catch per Seine Set 1984 - 1989
* * * " ' * * ~ ' ' '
comprised 98% of the overall io= catch. Mean catch of finfish per sa standard seine set (291.3) for all ** stations and species pooled da -
; increased 73% from 1988. As shown 8a "-~n
-in Figure- 24, the 1989 pooled . , .. ..
catch rate was higher than - for 1984 (120.1) and 1986 (109.1), but Figure 24. Average ntsber of fish caught I considerably lower than the 1985 and p oted stations. per seine set t 2 standard errors pooled species (424.9) and 1987 (367.6) rates. 4 Table 6: Shore
- zone fishes captured by haut seine at four stations in the vininity of I Pilgrim Nuclear Power Station, June
- November, 1989.
Species Cove Intde Station Warren Pilgrly Manomet Point Long Point Totet % Total-Catch rate Atlantic silverside 5610 =1204 :: 5099 8628 20542 81.05 236.11 Atlantic menhaden 1894 19995 26 23 2942 11.61 33.82 Sand Lance opp. 26 (1049_. 1 1 1077 4.25 12.38 Winter fl g r 8 T151; 26 29 214 0.84 2.46 other species 33 > 280 : 29 227 569 2.25 6.54 Total 7571 c.3683r 5181 8908 25344 Number of Sets 21 22 22 87 Catch / set 360.52..L167M1: 122 ; . ' 235.50 404.91 291.31 Total ntaber of species 15 1 25 ' 12 17 33 Percent of total catch 29.87" :14.53. 20.44 35.15 100
?
j45.7mx3.0mseine;othersitessampledwith45.7mx1.5mseine Itepresents pooled totat for 29 species of infrequent occurrence Shaded colum is date from surveit tance station I " I
Substantial increases in the abundance of Atlantic silverside l and Atlantic menhaden contributed to the increased catch rates in ;
-1989. In contrast, winter flounder and sand lance spp. catch rates . 'i decreased slightly from last year. Overall catch rates increased substantially at Warren Cove, Manomet Point and Long Point, while catch rates at Pilgrim Intake decreased (Figure 25).
Seine ~ catches were highest - t overall at Long Point where 35% , , , , , , , , , , , , , , , , g!.i 1 of the total was obtained
?
- 4 (Table 6). This was primarily a '"'
j '
}
,....q .
result of the abundance of- . .....m. u, , . . . 5 H Atlantic silverside there. Catches
- mf1 : Id- i N....... .Ik u ..b[.] - i .
,,,o ,, ,,, ,,,, ,. ,,,,
war ; at Manomet Point were higher than as e- to . . . am .. . ca t . in the past four years. Catch Figure 25. Averese catch per seine set for shore zone fish in the vicinity of Pilgrim Station -lB 1 rates at Pilgrim. Intake were the from 1984 1989, lowest since 1984. As the Intake station seine catch is typically dominated by sand lance, the low Intake overall catch rate in 1989 may be attributed to an' undetermined number of very small juvenile sand lance observed escaping through the seine mesh. The catch y rate at Warren Cove was anomalously higher relative to the previous ' three years. Atlantic silverside The Atlantic silverside dominated seine catches as it has every year since the implementation of seining in 1981, accounting for 81% of the fish caught. Of the total silverside catch, 42% came from Long Point and 27% from Warren Cove. Silversides were absent at all - stations in June, while both juveniles and adults were B 32 5'
I caught in July. This species dominated catch-per-unit-effort (catch per set) at all stations. In percent frequency of occurrence in catches, it ranked first at all stations. The catch rate increased at all stations from 1988 levels. Atlantic menhaden Atlantic menhaden ranked second (11.6% of the total catch). Most (98%) were caught in July. Menhaden were most abundant at Warren Cove followed by the Intake embayment. I Sand lance son. Ranking third, sand lance spp. were caught almost exclusively ( > 97%) in the Intake embayment at Pilgrim Station in the months of June _and July. Sand lance spend a substantial proportion of-I' their time burrowed in sand bottoms, but may undertake seasonal migrations to deeper waters of Cape Cod Bay in winter (Bigelow and Schroeder, 1953). The mean catch rate of sand lance in the Intake is subject'to-bias as a result of juvenile escapement. Winter flounder Winter flounder juveniles comprised 0.8% of the total catch. Catch rate was highest at the Intake (6.8), with this species occurring in approximately 91% of the sets at this station. Of the flounder seined, 71% were taken from the Pilgrim Intake. Seasonality and Diverr.ity. Seine catches (all species pooled) werE -lowest in June and highest in July (Figure 26). Larger catches were linked tc higher ambient surface water temperatures. This relationship occurs every year. In November, reduced catches were made at the Intake, Manomet Point and Long Point stations; silverside, winter flounder I 33 l 8
I and menhaden, in reduced numbers, , , , , , , , , , , , , , , , ,
,m ,
still inhabited the cooler shallow im p , waters in late fall. m " The highest number of species . . __ 1 (25) sampled on an annual basis " ' 4 + ] , was at Pilgrim Intake 25 species ,, Jtme July August september October Neuember , (Figure 27). Of the 33 species Figure 26. Monthly seine catch rates a 2 seined overall, 8 were taken at standard errors - pooled species and pooled =l stations - in the environs of Pilgrim Station, ' all stations while 15 were taken at' single sites. a"""**'"*" ,, Based on past records, this u- -c "- .--
- p. 7. g year's data appear to be atypical, u-7}
j y j -r
-9) i.. ; 2 . .
fy in that there was little s- - 0 - j ~ - p
.. +. ut_.
similarity between Pilgrim Intake y..,'"' l sm . . ca . em m. and Long Point. These stations ca 6 .e. a.. Figure 27. Total runoer of species caught share two characteristics - both per station in seine study 1984 - 1989 -in the vicinity of Pilgrim Station. are protected from heavy surf and possess . some , degree of cover or vegetation, providing suitable habitat for small fish. Contrasted with these stations, Warren
- Cove and Manomet Point have sand substrate with little cover and are- ~ periodically subject to heavy surf. The importance of vegetation in shore-zone areas that serve as nursery grounds for fish was reported by Reid (1954), who found the least populated areas were those whose substrate was composed of just sand, where protection was lacking and food not abundant. This is evident by the' consistantly higher number of species sampled at the Intake and Long Point (Figure 27). The number of fish caught at Warren Cove 34 I
I
E and Manomet-Point surpassed that in the Intake, due primarily to
- large catches of Atlantic silverside at these sites in September
? 7 - and October. Briggs and O'Connor (1971) found the Atlantic
- l 1
s'ilverside preferred sand-filled bottoms, although large. numbers were. also taken in some vegetated areas.- { Additional Foot-seine Samolina Using a smaller foot-seine (6 m) also at low tide, a total of 57G0 fish representing 18 species was sampled in the shore-zone from June through November (Table 7). The mean catch per standard L seine haul of 53.8 for all stations and species pooled. With a
'small salinity variation (range 32 /,, ) amongst stations, temperature (range 9.5 -
21 C) is a more important factor ! 1 l: influencing the seasonal occurrence and abundance of fish along the l- - shoreline. l l^ W Table 7: Shore tone fishes captured by foot seine at five stations in the environs of Pilgrim Nuclear Power Station, June - Novenber,1989. Station ' I' Speeles Attentic silversloe Long Beach 1359 Warren Pilgrim Manomet Long Cove 496 intake 11394w Point 162 Point 2184 Totet % Total 5595 97.14 Catch-rate 52 <.29 - Winter flounder 1 6 1192 11 20 57 0.99 0.53 I Windowpene-Northern pipefish Cunner Atl antic menhaden 9 1 0 10 7 1 1 0
?Oj{
(6l[ ,
, 80 <
424 0 2 0 2 6 10 15 0 22 20 16 14 0.38 0.35 0.28 0.24 0.21 0.19 0.15 0.13 Blueback Herring 0 1 !Ya!!; O 4 11 0.19 0.10 Longhorn scut 1n 0 0 S9j - 0 1 10 0.17 0.09
' I _- other species 9-Totat 1380 0
519 7 ( 01 1 178 7 2247 15 5760 0.26 0.14 a 1436 8 Nunber of sets 22 22 . ' 122 i . , 19 22 107 Catch / set 62.73 23.59f 665;27; 9.37 102.14 53.83
- Total nwber of species 5 12 .,'t6 5- 13 18 eereent of total catch 23.96 9.01 T24;93< 3.09 39.01 100.00
' Represents pooled total for 10 species of tow abundance Shaded cott.snn is data f rom survelt t ence station Overall catch (number of fish) of the 6m seine was highest at
. I '.
Long Point followed by the Intake at Pilgrim Station. Species - number was highest at Long Point, followed by Warren Cove. g; 35 33
1 Atlantic silverside and winter flounder comprised over 98% of the catch. The former was by far the dominant fish in numerical - abundance caught in the shore zone of the Pilgrim area; over 97% of, the fish captured with the foot-seine were silversides, collected. at all seining. stations, this species comprised 91% or more of the catch at each site. Atlantic silverside catch per standard seine haul was highest at Long Point at 99.3 per/ haul, followed by the Intake at 63.4 and then Long Beach at 61.7. Winter flounder catches were greatest'at Long Point and the Intake (20 and 19 fish, respectively). Thus, , based on species diversity and dominant finfish catches at the , stations, the 1989 foot-seine data were more " typical" in portraying Long Point and the Intake as being similar.
- 4. Underwater finfish observations I
Observational diving began in early May, with a total of 12 dives made through mid-October. Eight hundred fish, comprising 11 . species (Table 8) were observed in the study area. Invertebrates - noted included blue mussel (Mytilus edulis), lobster, starfish '(Asterlag spp.), and jonah and rock crabs (cancer-borealis and a irroratus). Qualitative observation of Irish moss (chondrus criscus) growth and distribution in the discharge area continued as , in 1988. Estimates of lateral visibility (obtained with a diver-held secchi disk and metered line) ranged from 3-9 m (averaging 6.6 m), depending on sea condition and incident light. l 36 I . Ei
?
l:J g . i , L Table 8.' Abundance and distribution of finfish species observed n . during underwater observations, Ney October, 1989 , Nuiter Station (s) I Species . Cunner observed by divers
$30
% of total 66.3 where most abundant
-C 3
Teutog 161 20.1 D 2 i il Striped bass ' 52 6.5 D 2 L gi Pollock 21. 2.6 $ 2
?
b BtuefIsh 18 2.3 D 2 Other* 18 2.3 total 11. species 800 !
- Winter flounder R Shorthornsculpkn,ockgunnel, and Atlantic Grubby,Longhornsculpin, stLverside I
I The number of fish sighted in 1989 (800) was very close to the 1988 total'of 883 fish. Using fish / dive as an index of relative
. abundance, we plotted data from 1981-1989 (Figure 28) . As noted
~
n.
...nfoiv.
for 1988 (Lawton et al. 1989)', ,oo relative abundance was up from ,,,, .. .
=
- n the nadir of 1987. - However, the
,oo-l - -
~ ' - "
1988 and ' .1989 values are far lower than pre-1985 levels. In 1989, fish were most often **i ' ma ** wu *** ** mr ** ' ms
~
/I observed in the discharge area cs! sumo,u aus om.=,.. A,
..u,.w....,,,,,..,...
- m Co@ W A,a 3 (58%) Stations D1 and D2. Of Figure 28. Index ~of relative abundance (fish / dive) for all sycles observed by diver at Pilgrim g "' * "'
the remaining fish, 36% were sighted in the control area - Stations C1 and C2- and 6% in the stunted area - Stations S1 and S2. I-
.I 37
, , E:
- _- . ~ . - . . - - -. . - -- - -- - . . .. . -.
1: 1 Cunner . Cunner was the species most ', often seen by project divers, I.I too 1
. constituting 66% of the fish 1 1
iso recorded (Table 8) . Found at all ) stations, cunner were most ) common in the control area at Station C. 3 The index wei wet 'i 'm toet was wee wer wee iona - w., l cunner / dive was slightly lower es toic u.. l than'in 1988 (Figure ' ' 29), and fffs$/dv)for cer observ by ver at m Station, 1981 1989. I far less than in the early
'80's, reflecting a decline in local stock abundance as reported by Kelly et al. (1988).
Tautoa Ranked second in fish- ,,,,,,o,, 20 sighted (Table 8), tautog were found exclusively in the . l discharge area. Relative abundance increased dramatically 3 o - }]
.. g over .1988 (Figure 30) and was at 208) ioe2 iosa ioe4 toes ioee toe 7 $o88 toeo the second highest level "S^'"
Figure 30. Index of relative abundance recorded for the study. The (fish / dive) for tautog observed by diver at Pilgrim number of tautog observed in the Station, 1981 1989. g 3 discharge area has fluctuated widely since the inception of - observational diving. I 38 I I
E Striced Bass observed only in the discharge zone, striped bass ranked third (Table 8) in diver observations. This species - has not been observed in abundance since 1985 (148 fish); no striped bass were observed in 1988 and only 11 for 1986 and 1987 combined. Striped bass have a known preference for fast moving water, and the resumption of two pump operation at Pilgrim Station has no doubt
.I. attracted the bass to the discharge current.
Pollock Observed primarily in the stunted zone (76% of all sightings), pollock ranked fourth (Table 8). However, our observation of pollock may not necessarily equate to local abundance, as this species is highly mobile and sightings sporadic . Other species The remaining species comprised only 2% of the total sightings (Table 8); these-fish were observed infrequently. D 5. Soortfishina-During the 1989 informal creel survey (68 sampling days) of recreational fishing at Pilgrim Station Shorefront, which was conducted from the last week of June through August, a reported 750 angler-trips were made by shore-based anglers to the area. Forty-five percent of the trips occurred on weekends. Four fish species were recorded in the catch, two resident (winter flounder and cunner) and two migratory (bluefish and striped bass) marine fish, totaling 200 individuals. g 39 HI
I The Shorefront was opened seasonally to the public in 1989 on April 1 and closed the end of November. During the daytime, anglers are allowed access by Boston Edison Company to fish from the outer intak.e breakwater, the two discharge canal jetties, and the sandy beach and rip-rap at the head of the intake embayment. Quantitative catch data were obtained from June 23 through August 1 31 when public relations personnel were stationed daily at the Shorefront. Before and after this time period, we made spot checks at the Shorefront to assess sportfishing. Our observations indicate that angling prescure was relatively light in the spring when compared to those years when the plant was fully operational. Fishing pressure was substantially greater in the fall compared to outage years, as the potential for catching bluefish and-striped .I . bass engendered. considerable angler interest. Activity markedly declined in November. ~ From the outer intake breakwater, anglers preferred-to fish primarily for groundfish on the' seaward side. From the discharge , jetties, the preference was to cast artificial lures into the effluent current for bluefish and striped bass. From the head of the intake, bottom fishing for winter flounder prevailed. The majority of winter flounder were taken in the intake, cunner on the seaward side of the outer breakwater, and bluefish and striped bass in the thermal discharge. i l Fishing pressure was highest the week of July 4th, followed by the last week of July and first week of August. July and August 'have been the traditional months of enhanced fishing effort at Pilgrim Shorefront because of favorable weather conditions, l Lo Il l
.n i
I availability of fish, and the concurrent summer vacation period (Lawton et al. 1987). Highest sportfish catches were garnered in July (65%), especially during the first two weeks of the month.. Cunner (56%) and bluefish (34%) comprised the bulk of the catch, while winter flounder (9%) and striped bass (1%) accounted for the remainder of the landings. Over the years, cunner has been first in overall sportfish catch at the Shorefront with catches peaking in July. In the 1989 creel survey, 73% of the cunner catch occurred in July.- This species has an affinity for inshore
.I- structures, e.g. ledges, reefs, breakwaters, pilings, and occupies
=
a small home range for long periods. As such, it is highly available to shore fishermen. However, this exposes the fish to increased fishing mortality while also placing it in proximity to I potential effects of inshore pollutants. Bluefish reportedly were not caught in June but were taken in about equal numbers ir July cnd August. Only a few striped bass were taken during the survey in June and August. Angling trips were up by 25% from 1988 for the same time period, while the total catch doubled, increasing from about 100 to 200 fish. Nevertheless, catch and ef fort were lower by an order of magnitude than recorded in the '70's and first half of the '80's when the power plant was fully operational. I E I I. a I 1
4 I'I.- V. HIGHLIGHTS Lobster - Commercial Fisherv
- 1. Catch statistics and biological data for the commercial lobster fishery in the Pilgrim area were collected from 4,690 1 lobster sampled.from May through October 1989.
- 2. Catch per. unit effort of total lobster increased 37% from 1988.
- 3. Legal catch rate was up 18%, averaging 0.45 for 1969; the range was from 0.26 in' June to 0.81 in September.
~
Lobster - Research Studv
- 1. Fifty-six sampling days of research pot fishing (June-September 1989) yielded 9,502 lobs,ter (56%' male; 44% female) captured from 2,761 trap-hauls, with legals comprising 13% of the W; catch, j
2'. Study area catch rates (i.e., mean catch per trap-haul-CTH) of legals (.>_ 82.6 mm carapace length - CL) and sublegals (< 82.6 mm CL) were higher than in 1988 having risen since 1986,
- 3. Only 0.7% of the research catch of female lobster were ovigerous (carrying eggs).
g ;
- 4. Carapace lengths of lobster in research catches ranged from 41- ll 126 mm,.and averaged 76.0 mm, which is 1.1 mm larger than the .
mean,for last year. l S..The cull rate increased from 23% in 1988 to-27%. 1 Groundfish l
-1. Twenty-three fish species were collected by bottom trawling in the nearshore area of Pilgrim Station.
I 42 Il 1
~ 2. The average catch per standard tow for all species and stations combined declined to 7.3 fish / tow.
- 3. Winter flounder ranked first in total catch (47%) and was the numerical dominant at each station; total flounder catch declined from last year.
- 5. Little skate again ranked second in total catch (22%) ; overall abundance remained the same as last year.
I.. Pelaaic and Benthi-oelaaic Fishes
- 1. Comprising 27 species, 1,309 finfish were netted during 12 overnight sets.
I
- 2. Annual mean.CPUE of pooled species (84.4) declined sharply to the lowest recorded in the 18 year timeseries.
- 3. Pollock ranked first, comprising 44% of the catch. Atlantic
_ herring was second (20%) and cunner was third (11%). Shore-zone Fish
- 1. Thirty-three fish species were captured in the 45.7 m haul seine study from June-November 1989.
- 2. Increases in the catch rates of Atlantic silverside and Atlantic menhaden contributed to.the rise of the overall 1989 I mean catch per seine haul for all species corbined..
- 3. Catch rates for-pooled species increased-at three of.four sites.
; 4. Atlantic silverside continued to dominate catches, comprising 81% of the total catch and ranking first in both overall CPUE and overall percent frequency of occurrence.
- 5. Atlantic menhaden was second in numerical abundance (11%) but low in frequency of occurrence.
I 43 I.
n l 6 '. Total number of fish caught was greatest at Long Point, but , L species diversity was highest in the Intake. .
- 7. Two species (Atlantic silverside and winter flounder) comprised i 98% of the (6 m) footseine catch with silverside far 6
- ' dominating.
Underwater Finfish Observations
- 1. A total of 800 fish, comprising 11 species were observed during .
12 dives in 1989.
'2. Total number of fish observed remained nearly the same as 1988;
~
58 % were sighted in the denuded zone, 36% in the control zone, and 6% in the stunted zone. '
- 3. Cunner was the most common species (66% of the total) and was
.l found at all stations. ,
I:. Soortfishina
- 1. An informal creel survey of sportfishing was again conducted at-
~
the Pilgrim Shorefront. recreational area but was attenuated - (late June-August) because of financial constraints.
- 2. ' Reportedly 750 angler trips were made by shore fishermen to the 1
area and about 200 fish, representing 4 species, were caught. g 31 L 3. Cunner (56%) and bluefish (34%) dominated the catch. ; L
- 4. Effort and catchac were up from last year; both parameters had :
reached all time lows in 1988. I I' I l 44 l j IL
l
;I VI. ACKNOWLEDGMENTS We acknowledge the contributions of numerous staff members of the Division of Marine Fisheries (DMF), who assisted in various phases of data collection, computer programming, and data analysis, especially Theresa Ritchot, Neil Churchill, Steve Cadrin, and Dan McKiernan. We thank Chris Kyranos, commercial lobsterman, for I allowing us to sample his lobster catches, and Raymond Dand and ,
Robert Ellenberger, Boston Edison (BECo) public relations' l personnel, for gathering sportfish data at the Shorefront area. Also . greatly- appreciated is the work of Kim Trotto of DMF for word-processing sections of this report. Finally, we thank Robert l I-l D. - Anderson, BECo Senior Marine Fisheries Biologist, W. Leigh ! i Bridges, Assistant Director of Research for DMF, and the. Pilgrim Administrative-Technical Committee for overseeing the entire study program. l 11 l 45 I ,
1 I
.VII. LITERATURE CITED
'Aiken, D.E., and S.L. Waddy. 1980. Maturity and reproduction in-
.the American lobster. Can. Tech. Rep. Fish Aquat . Sci. 4 932:59-71 'l i
Aiken, D.E., and S.L. Waddy. 1982. Cement gland development, ! ovary maturation, and reproductive cycles in the American 1 lobster, Homarus americanus. Journal of Crustacean. Biology i 2 (3): 315-327. Bigelow, H.B., and W.C. Schroeder, 1953. Fishes of the Gulf of Maine. U.S. Fish and Wildlife Service Fishery Bulletin 53:577 p. -! Boston Edison Company. 1980. Benthic map overlays and assessment of benthic monitoring programs, Vol. 2. Nuclear Engineering Dept., Environmental Sciences Group. Boston Edison Company, Boston, MA, USA. 25 p. Briggs, P.T., and J.S. O'Connor. 1971. Comparison of shore-Zone fishes over naturally vegetated and sand-filled bottoms in-Great South Bay. New York Fish-and Game Journal 18 (1): 15-41. Briggs, P.T., and F.M. Mushacke. 1979. The American lobster in : western Long Island Sound. New York Fish and Game Journal 26 (1): 59-86. ) Collings, W.S., C. Cooper-Sheehan, S.C. Hughes, and J.L. Buckley. l 1983. The spatio-temporal distribution of American lobster, j Homarus americanus, larvae in the Cape Cod Canal and - approaches, p. 35-40. In M.J. Fogarty (ed.), Distribution and relative abundance of American. lobster, Homarus 'l americanus, larvae: New England investigations during ' 1974-79, 64 p. NOAA Technical Report, NMFS SSRF-775. l Conover, D.O., and M.R. Ross. 1982.. Patterns in seasonal abundance, growth,'and biomass of the Altantic silverside, Menidia menidia, in a New England estuary. Estuaries 5 o =(4): 275-286. 1 Davis, J.D. 1984. Western Cape Cod Bay: hydrographic, geological, i ecological, and meteorological backgrounds for E.: E environmental studies, p. 1-18, In: J.D. Davis and E-L D. Merriman_(editors), observations on the Ecology and L Biology of Western Cape Cod Bay, Massachusetts. Springer- l ll Verlag, Berlin, FRG. 289 p. l [ Ennin, G.P. 1983. Annual variations in standing stock in a L Newfoundland population of lobsters. North American Journal of Fisheries Management 3:26-33. l 46 I
- ~ - , , -
I , Estrella, B.T., and S.X. Cadrin. 1989. Massachusetts Coastal
. Commercial lobster trap sampling program May-November, 1988.
- Commonwealth of Massachusetts, Division of Marine Fisheries.
- 23 p.
Kelly, B.C. , V.J. Malkoski, S.J. Correia, R.P. Lawton, M. Borgatti,
- I .and B. Hollister. 1987. Annual report on monitoring to assess
' impact of the Pilgrim Nuclear ' Power Station on marine fisheries resources of western Cape Cod Bay (Vol.1) . Project '
Report No. 42. h: Marine Ecology Studies Related to
. Operation of Pilgrim Station. Semi-Annual Report No. 29. BEco, Braintree, MA.
L
- Kelly, B.C. , V.J. Malkoski, S.J. Correia, R.P. Lawton, M. Borgatti, '
and B. Hollister. 1988. . Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources No. 44. D: Marine Ecology l Studies'Related to Operation of Pilgrim Station. Semi-Annual Report No. 31. Boston Edison Company, Braintree,MA. Lawton, R.P., E. Kouloheras, P. Brady, W. Sides, and M. Borgatti. 1983. Distribution and abundance of larval American lobster, llomrarus americanus, (Milne-Edwards), in the western inshore region of Cape Cod Bay, Massachusetts,
- p. 47-52 2: M.J. Fogarty (editor), Distribution and relative abundance of American lobster, Homarus americanus, 3' larvae: New England investigations during 1974-1979, 64 p. ,
g NOAA Technical Report, NMFS SSRF-775. L Lawton, R.P., V.J. Malkoski, S. J. Correia, J. B. O'Gorman, and i l M. R. Borgatti. 1986. Annual Report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay. Project Report No. 40 -(Jan . -De c . 1985). D: Marine Ecology
~I .
Studies Related"to Operation of Pilgrim Station. Semi-Annual q Report. 27. Bostor Edison Company, Braintree, MA. Lawton, R.P., V. Malkoski, S. Correia, B. Kelly, C. Sheehan, i M. Borgatti, and~P. Brady. 1987 Final report on Marine ;
;. Recreational Fishing at the Pilgrim Station Shorefront:
. 1973-1975, 1983-1986. Pilgrim Nuclear Power Station Marine t Environmental Program Report Series No. 3. Boston Edison Company. 53 p.
! Lawton, R.P., B. Kelly, V.J. Malkoski, and M.R. Borgatti. 1986. ;'
Annual Report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fisheries resources of western Cape Cod Bay. Project Report No. 46 (Jan.-Dec. 1988). h: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report. 33. Boston Edison Company, Braintree, MA. I e g
Ii Reid, G.K., Jr. 1954. An ecological study of the Gulf of Mexico fishes in the vicinity of Cedar Key, Florida. Bull. Mar. Sci. Gulf and Caribbean 4 (1): 1-94. Robins, C.R., R.M. Bailey, C.E. Bond, J. R. Brooker, E. A. Lachner, R.M. Lea, and W.B. Scott. 1980. A list of Common and Scientific Names of Fishes from the United States and ' Canada. 4th Edition. Special Publication No. 14. American Fisheries Society. 174 p. ; Van Engel, W.A. 1980. Maturity and fecundity in the American lobster, Homarus americanus - a review. Can. Tech. Rep. Fish. Aquat. Sci. 932: 51-58. " I. I.1 I; I' P I E I I I l 48 I
I I I ANNUAL REPORT ON I MONITORING TO ASSESS IMPACT OF 3 PILGRIM NUCLEAR POWER STATION g ON MARINE FISHERIES RESOURCES OF WESTERN CAPE COD BAY (IMPACT ON FISHERIES RESOURCES) Project Report No. 48 (January-December, 1989) (Volume 2 of 2) By I Robert P. Lawton, Brian C. Kelly, Vincent J. Malkoski, Mando Borgatti, and Joseph F. Battaglia I I I April 4, 1990 Massachusetts Department of Fisheries, I Wildlife, and Environmental Law Enforcement Division of Marine Fisheries 100 Cambridge Street Boston, Massachusetts 02202 I I I lI;
t 4 I[ s TABLE OF CONTENTS Section EASA 1L I. EXECUTIVE
SUMMARY
1 II. INTRODUCTION' 2 III. RESULTS AND DISCUSSION 3 A. Physical (Abiotic) Factors 3
- 1. Power Output and Thermal Capacity 3
- 2. Discharge current 3
- 3. Water Temperature 5 B. Impact of Pilgrim' Station on Fisheries Resources 8
- 1. Commercial Lobster Pot-Catch Fishery 8
- 2. Research Lobster Trap Fishing 13
- 3. Nearshore Benthic Finfish 17
- 4. Pelagic and Benthi-Pelagic Fishes 22
- 5. Fishes of the Shore Zone 27
- 6. Underwater Finfish Observations 32
- 7. Sportfishing 35 p IV t. IMPACT PERSPECTIVE 38 V. CONCU.'SIONS 41 VI. ACKNOWLEDGEMENTS 45 VII. LITERATURE CITED 46 I
I I y u I - . . - . . . - - . . g
LIST OF TABLES Table Page
- 1. Catch per unit effort from experimental 16 )
lobstering in the Pilgrim area for 1989. CTH I represents catch per trap hault CTHSOD indicates catch per trap haul per set-over-day. Catch data area presented in numbers of l lobster caught. Mean i2 standard errors is I an estimate of precision. ,
- 2. Mean catch per standard gillnet set (5 panels 23 I of 3.8 - 8.9 cm mesh) for various time periods and the percent differences for selected species caught in the vicinity of Pilgrim I
Station, 1971-1989.
- 3. Mean catch per standard haul seine set for 28 i selected species collected along the Plymouth l
l shoreline, western Cape Cod Bay, 1983-1989. ] J
- 4. A summary of impact assessment by study of 32 -
I Pilgrim Nuclear Power Station (PNPS) on marine fisheries' resources in western Cape Cod Bay during the operational history of the power I plant.
- 5. A summary of impact assessment by study of 39 !
Pilgrim Nuclear Power Station (PNPS) on marine , fisheries' resources in Western Cape Cod Bay. ' I i I . I I 111 l
I LIST OF FIGURES Floure gggg
- 1. Annual means and 17-year cumulative mean 4 Pilgrim Station capacity Factor (using MDC net percent) for 1973-1989. MDC Net %
approximates thermal loading to the aquatic environment (100% = 32' F T).
- 2. Circulating seawater pump operation at the 4 plant for 1983-1989.
- 3. Surface water temperatures in the vicinity 7 m of Pilgrim Station averaged by season for g the years of high plant operational status (1983 and 1985) and for the transition year (1989).
- 4. Annual legal lobster catch per trap-haul 9 in control and impact areas near Pilgrim Station, 1983-1989.
- 5. Mean annual catch per standard tow of 18 dominant groundfish by bottom trawl at reference Station 1 and surveillance Station 3, 1982-1989.
- 6. Seasonal mean trawl catch rates with 19 vertical error bars for winter flounder by station in the Pilgrim area, 1989.
- 7. Seasonal mean trawl catch rates with 19 vertical error bars for little skate by station in the Pilgrim area, 1989.
B. Seasonal mean trawl catch rates with 20 vertical error bars for windowpane by station in the Pilgrim area, 1989.
- 9. 14ngth frequency distributions by station 21 g for winter flounder trawled in spring, g summer, and fall 1989, near Pilgrim Station.
- 10. Average standard 5-panel gill-net catch 22 for pollock and yearly MDC Net % at Pilgrim Station, 1971-1989.
- 11. Average standard 5-panel gill-net catch 24 for Atlantic herring and yearly MDC Net %
at Pilgrim Station, 1971-1989. iv - a m
. s.,
I
- 12. Average standard 5-panel gill-net cunner 25 catch and seasonal MDC Net % at Pilgrim I
Station, 1971-1989.
- 13. Average catch per seine set for four 29 common shore zone species (1 2 standard I errors) in the vicinity of Pilgrim Station, 1984-1989.
I 14. Distribution of finfish observed by divers off Pilgrim Station, 1983-1989. 33
- 15. Distribution of cunner observed by divers 34 off Pilgrim Station, 1983-1989.
- 16. Distribution of tautog observed by divers 34 off Pilgrim Station, 1983-1989.
I I . I I I I I I I I V I
Ii ! LIST OF PLATES Plate 1. Biologist collecting length-frequency data from the catch 3 of'a commercial lobsterman in the proximity of Pilgrim g Station. Lobsters constitute the area's most valuable fishery resource. , Plate 2. Operations aboard a fishing vessel used during the 1986 experimental lobster study. This investigation is designed to better assess the impact on lobsters of the thermal effluent at Pilgrim Station. 4 Plate 3. Retrieval of the experimental gill net after a g standardized overnight set in the thermal plume area.
-Caught in the net is a smooth dogfish, a common summer g
migrant in the Pilgrim area. Plate 4. Fishes caught by gill-net in the area of the thermal plume at Pilgrim Station. Gill-net catches include commercially important species, e.g., Atlantic cod, g pollock, Atlantic mackerel, striped bass, and winter E-flounder. Plate 5. Bottom trawl being set to sample groundfish in the inshore waters of western Cape Cod Bay. Catches are used to measure potential impacts of Pilgrim Station on the benthic fish community. Plate 6. Typical trawl catch is processed which includes identifying, enumerating, and measuring the different a species for environmental assessment. Catches of winter g' flounder have been consistently larger at . the Pilgrim Station intake trawl station. Plate 7. Haul seining in the intake embayment at Pilgrim Station: the net is being set from a powered-skiff to enclose a rectangular area. Seir.e catches can be integrated with 3~ impingement data for a more comprehensive evaluation of 3' potential impact on shorezone fishes. Plate 8. Haul seine catch processed on the beach near the Pilgrim Station intake (fish are enumerated and measured) . Among the shorezone fishes are important forage fish such as the Atlantic silverside and sand lance, and the juvenile stages of several commercial species such as the winter flounder and Atlantic menhaden. Plate 9. Biologist-diver deploying a transect line between observational stations. Diving observations have recorded the greatest number of fishes in the " denuded" zone directly off the discharge canal. ! vi l I
I I Plate 10. A tautog foraging at the mouth of the discharge canal , (Station D) at Pilgrim Station. A popular catch of I recreational fishermen, tautog are in the Pilgrim area . from spring through autumn and have been used as an '
" indicator" organism to assess stress imposed by the release of the heated effluent.
Plate 11. Pictured is the thermal effluent discharging into Cape . cod Bay and anglers fishing off the discharge jetties and I from boats in the plume which background by the calm water. Striped bass and bluefish, is visible in the
- which are attracted to and concentrate in the thermal
'I current, are the dominant species sought by sport fishermen at this location. ;
Plate 12. Anglers seeking sportfish at'the mouth of the discharge canal. Casting artificial lures is the most popular method of fishing the discharge current which attracts a variety of species. I : I L I LI LI I I I ' vil I- .
-w ,n -- . . . , . , . . , . - -
I I. Executive Summary In accordance with the Pilgrim Nuclear Power Station NPDES Permit requirements of the Massachusetts Division of Water Pollution control and the U.S. Environmental Protection Agency, marine fisheries monitoring and reporting were continued in 1989. Fisheries data were collected from comparable reference and surveillance stations to assess plant impact. We emphasized data comparisons between 1983/1985 (high operational years, >80% thermal capacity) and the years of low or no output: 1984 (outage), 1986 (low output), 1987 and 1988 (outage), and 1989 (low output). The recent extended outage at Pilgrim Station underscored the following findings. Sportfish catches of bluefish and striped bass were markedly lower without a strong thermal discharge current, as both species are attracted to moving water, i.e. currents, to feed. Cunner show an attraction to the effluent at the plant based on gill net sampling and diving observations. There is evidence of an inverse relationship between the commercial legal lobster catch rate in the discharge area and the release of the cooling water discharge. While diving, we have observed few lobster residing in the immediate area of the discharge canal when the plant is operating because the velocity of the current limits their mobility. Winter flounder, the dominant groundfish in the Pilgrim area, was seasonally more abundant in the Intake embayment of the plant. Furthermore, the Intake is a seasonal haven for small winter flounder in the spring and/or fall.
- I 1
I
. . . ._ ._ _ . ..._.........__.___.__m
p I II. Introduction The Massachusetts Division of Marine Fisheries has conducted . a field sampling program to assess environmental impact of Pilgrim Nuclear Power Station on marine fisheries resources in the surrounding waters of Western Cape Cod Bay. This investigation was funded by Boston Edison Company under Purchase Order No. 66228 in 1989. Focusing on finfish and lobster populations in the Pilgrim area, impact and comparable reference sites were sampled at regular intervals over the year employing a variety of gear types, thus obtaining replicates over time for analytical analyses. Measurements, counts, percentages, and indices of abundance are used to identify relationships in the data both spatially and ! temporally. Data are summarized and displayed in exploratory i graphs, plots, and tables to suggest patterns and appraise assumptions in relation to past findings. Descriptive and inferential statistical procedures are employed to test for station differences. Volume 2 is an assessment of power plant impact on the local I 1 marine environment. We have emphasized data comparisons from 1983 ! and 1985, years of high power output (> 80% thermal capacity), with 1984 (outage year) , 1986 (low output year: 17.5% capacity), 19'87 I and 1988 (outage years). It is noted that Pilgrim Station was in a power ascension mode in 1989 (low output year: 28.9% capacity) as - it was returning to full operational status, f The plates on the next several pages depict field sampling I .. operations of our assessment program. gi at
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Plate 10. A tautog foraging at the mouth of the discharge canal (Station D) at P ilgr im St at i:+ A pepalat catch of rec reat ional fishermen, tautog are I in t h e P i ' :; r i n area fram spring through autumn and have been used as an "ind ic at or' organism t o as sess <, t r e s s irrposed t1y t he release of t he heated eff'ue't l l I 1
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[ [:hI {p [# Q! );h!,YS k - g , I Plate 11. Picture 5 is the t hermal ef fluent discharging into Cape Cod Bay and angler: fishing eff the discharge jetties and from boats in the ciu9'e which is visicle in .he backg'ound by the calm water. Striped bass and bluefish, which are z.t tracted to and concentrate in the therma' current, are the domina*1t species sought by sport fishermen at this locatlon. 1 I l *
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.WW Plate 12. Anglers seeking sportfish at the mouth of the discharge canal. Casting artificial lures is the most popular method of fishing the discharge current which attracts a variety of species.
I I
I III. RESULTS AND DISCUSSION A. PHYSICAL (ABIOTIC) FACTORS
- 1. Power Outout and Thermal CaDacity When assessing impact of the thermal discharge at Pilgrim Station on marine fisheries resources in the receiving waters of western Cape Cod Bay, one must consider the station's maximum capacity factor (MDC net percent). This index of operational output approximates thermal loading (waste heat elimination) to the A aquatic environment, At 100% MDC, there is a maximam temperatyre rise (AT) in the coolant water of 18' C above ard>iont . Mnco
{ commancement of power pit.nt operation in July 1972, the annual MDC at the station has ranged from 0.0% in 1967 and 1988 (6utage years) to a high 84.4% in 1985 (Figure 1). Power level capadty was extremely low at 0.1% in 1984 (essentially an outage year). Other high output years, eYcceding 80%, were 1979 and 1983. The output in 1989 averaged 28.9% of capacity. In this report, we have stressed data comparisons for the pooled years of 1983 and 1985 (high operational output) with the years of low or no output: 1984, 1986-1989. To date,. Pilgrim Station has operated at a cumulative capacity of 45.3%, or less than half of its possible output. With a relatively low historical operational regime, the potential extent of plant impact on marine life likely has not been realized.
- 2. Discharae current B Pilgrim Station's circulating seawater system induces localized curren*s. The once-through cooling system removes waste 3
I
Unit 1 Capocity rector (t) I: 100 90-W < 80- . T0 i I' ~l l ' 60- 5 50- "
-:! .. . :. .;.j ,: -
3 - i i i
'72 '73 '74 '75 '70 '77 v8 '79 'ed 't,1 '02 '01 '04 '66 'On 87 '60 '80 Mar
- T
- Ye a r ccuplative Mt t< ~ (45.3%)
CD t. naval Mo6a
- Commer:ct0 opu at;an !1973 1920) 71gure 11 Annual r.aans and 1*/-year cumulatice mean Pil Erin, station Capacity Tsctor (using l'DC lj e
net percent) for 1973 198'). MDC net % ,
.jproximate*,t'nera l loading tc the aquatic environment (PJ6; = 32'FL T).
g, 3 2 ' y 7 , i l I .
.E j '"u 1 ' ' '
i '
's
- s. ,
JMSJMSJMSJMSJMSJM$JMS Months l 1983 1984 1985 1986 1987 1988 1989 Tigure 2. Circulating seawater pump operation by month at Pilgrim Station for 1983-1989 4 R m
5 I heat from the plant which is discharged in a current of water. The moving water, in of itself, has the erosional effect of scouring on the bottom, i.e., creates an abrasive action on the benthic environment. There are two circulating seawater pumps; each draws in 586,739 liters / minute (155,000 gal / minute) of ambient water from I the intake embayment, discharging the water laden with waste heat back into Cape Cod Bay. The maximuu discharge velocity is approximately 2.1 m/sec (7 ft/sec), which occurs tit ebb tide with . both circulating pumps operating. Durjug the outage at Pilgrim Station in 1984, one or both pumps were off (late March to mid-August), thus markedly reducing the discharge flow (Figure 2). In 1986, both pumps were opereted from January to etsrly March; but thereafter, during the outage, only one pump was operated. As the outage continued through 1987, both circulating pumps were off from about late February through early September, while one pump was generally operated during the other months. In 1988, with the outage ongoing, one circulating
- water pump was operated for much of January-March and June-3 December, but from mid-April to early June, both pumps were off, i g In 1989, as the plant gradually increased to power production, one pump was operated January, February, May and October; otherwise l both pumps were run. Both circulating water pumps were operated for most of 1983 and 1985.
l 3. Water Temperature .I Water temperatures on the surface of the study area were highest in the discharge zone (Area 3) during all seasons of 1983 I " I
and 1985 (>80% power plant capacity), directly attributable to the waste heat discharged (Figure 3). By way of contrast, surface temperatures in the impact zone were markedly lower for the outage years - 1984,1986-88 (pooled), when heat and current were minimal. However, in 1989 with Pilgrim's thermal capacity averaging 28.9%, l there was some thermal elevation at the surface in the immediate
- j. receiving waters.
With the power station fully operational, the near-field area j impacted by the discharge current has included a 1,100-1,400 n'
' denuded' zone, primarily resulting frou scouring (Rrldges and i Anderson 1984). A periphera) zone of ' stunted' algal growth of about 1,900 - 2,900 m' has resulted from the thermal component of the effluent (Bridges and Anderson 19ac). Recolonization of the Ii !
l discharge area occurred throughout the recent extended outage, and by 1988, the former ' denuded' and ' stunted' zones could not be distinguished from the surrounding ' normal' growth areas (Boston Edison Company 1989). When Pilgrim Station has been at 100% operating load, a I, temperature differential approaching 18' C can occur in the summer - between discharge and ambient waters. The temperature in the I thermal plume has peaked at 32* C, both at the surface and bottom. Conversely in 1984 (outage year),1986 (outage April-December), and 1987-88 (outage years), water temperatures in the discharge area mirrored ambient (Figure 3). llI e I l I! .
E E E E E E E 'E E E E E E E E @ E W. E was a toes ag !T" *
- n. .
3 _ . _
,g 1[ ._.
Mean Surf ace Water Temperature " Discharge Aresa f ...il _ p .g, o!- ili ; t
. il
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- 1. Grays Beach & Long Point e.
- 2. Warren Cove & Rocky Point
- 3. Discharge Area 7 , , , , ,,,,; ; , ., , , ,,,;,
- 4. Intake * **, s- r.n S. White llorse Beach and Manomet Point Figure 3 Surface water temperatures (C) in the Pilgrim ar.'s svaraged by season and displayed for the discharge area 1 1983-1989,. and in other key sampling areas for the years of high plant crersticnal status (1983 and 1985) and for the transition year, 1989;
I B. IMPACT OF PILGRIM STATION ON FISHERIES RESOURCES
- 1. Commercial Lobster Pot-Catch Fishery Pooled lobster catch statistics from the surveillance (discharge) quadrats (H-11, H-12, I-11, and I-12) were compared with data from the reference quadrats (E-13, E-14, and F-13) located in Warren cove (see Figure 2 in Vol.1) to assess impact of ,
Pilgrim Station on the local lobster population and fishery. Realistically, we can compare catch rates from 1984-89 Rsta (1985 being the only high output on-line yeur) because the cane lobsterman has supp! led most, if not all, of the impact / control dat I 1983 catch data are included in our discursion for an additional datum point from an on-line ycar of the plant. Males slightly outnumbered females in the commercial catch for the entire Pilgrim study area in 1989, comprising 51% of the total. . This sex ratio also existed at both the surveillance and reference areas. As in the previous three years, the percentage of culls in the surveillance area in 1989 was markedly lower (18%) than in the reference area (39%). A chi-square test (Sokal and Rohlf 1969) showed this difference to be highly significant (P 5 0.01) in 1989. An increase in lobster cull rate is promoted by both lobster fishing and bottom trawl activity (Keser et al.1983; Estrella and McKiernan 1986). Both study locations are subject to intensive 5 E commercial lobster fishing. However, in Warren Cove (reference area), commercial bottom trawling is seasonally (November-March) conducted for groundfish; this may account for the higher cull I I
I 1 rate there. l The 1989 mean legal-lobster catch rate (expressed as catch por trap haul, or CTH) increased at both sites (Figure 4). In the surveillance area, CTH rose 21% to 0.41 legals / trap-haul, while the reference area increased 36% at O.34. Catch rates in the impact McAh ANwuAL LEGAL LOBSTER CPUE COstth0L V8 IWmCT area do not appear measurably I e,, n ,, ,, ,,, different during on-line/off- n. .
.. x. ..._..
9 I line plant status, in that CTH u. f] v ht;
;f-i rates from the on-line years of k 1983 and 1965 are comparable W o.. '. ._ .. b_ d.
with the off-line years of 1984 von and 1986 (Figure 4). _ Figure 4. Annual leget totater catch per trap-The mean legal catch rate y,y,7WdW =*NNM% in-the discharge (impact) area declined from 1983-1988, with a reverse in this trend in 1989. This contrasts with commercial lobster catch rates and landings for the
. Pilgrim area overall and for Massachusetts coastal waters in general. A cooler ambient temperature regime in 1984 (Estrella 1985) apparently depressed or at least delayed the early season lobster molt, which, in turn, would have affected recruitment to legal size and impeded lobster activity (Campbell 1983; Estrella 1985). The mean catch rate of 0.32 legals / trap-haul in western Cape Cod Bay reflected a reduction of 50% or more in 1984 when compared to 1983 (0.61), 1985 (0.66), and 1986 (0.77). Catch rate ~
for western Cape Cod Bay declined in 1987 to 0.51, subsequently I ' I
I rose to 0.74 in 1988, but then declined again in 1989 to 0.56. Annual CTH in our control area (Warren Cove) did not parallel these findings. Actual commercial landings (in pounds of lobster) for all of Cape Cod Bay in 1989 increased 20% from last year, which suggests that the overall CTH value for western Cape Cod Bay in 1989 may be a sampling artifact (Bruce Estrella, personal communication)1 According to Estrella (1985) and Estrella and McKiernan (H3G), the constvide commercial catrh rate (catch per trap haul) i < of marketable lobstar in 1984 was lower than in 1983 and 1955 by ; 19% and 20%, respoctively. Record 1-obster landings were documented along the entire Massachusetts censt in 1985 and 1986 [ (Estrella a3G McKiernan 1986). Cape Cod E4y lobstermen had T.o 3 contend with cooler spring temperatures again in 1987, and a 34% reduction in commercial catch rate resulted. The upswing in the 1988 catch rate in Cape Cod Bay may well have been the result of a more normal spring bottom water temperature regime. Using several nonparametric statistical tests, which are not dependent on a given distribution but usually work for a wide range of distributions (Sokal and Rohlf 1969), we had previously tested annual legal lobster catch rates (CTH) for the discharge and reference areas for block periods of time. The Kruskal-Wallis test revealed no significant differences (P > 0.05) between areas for the entire survey, for the preoperational/ outage years, or for E g . the operational years. With the Wilcoxon signed-ranks test of
. _____ ..... ________.-_ ____ .. _......._'s_________
'B. Estrella, Aquatic Biologist III, Coastal Lobster Investigations, Massachusetts Division of Marine Fisheries.
10 E'
=l l
t I CTH for operational years arranged as paired observations (surveillance versus reference), we found no significant differences in CPUE (P > 0.05) between control and test areas (Lawton et al. 1988). A review of past records revealed that our selection of reference quadrats has changed during the timeseries. The present reference quadrats, all located in Warren Cove, have been in use since 1984, during which time there has been only two years when the plant was operating to some extent. Therefore, any meaningful impact / control comparisons must await the compilation of
- additiond years of operational data using this reference area. ;
- l. Catch data and plam, thermal output have been examined for a relationship using correlation analys).s (Sokal and Rohlf 1969)
I- of Unit I Pilgrim Station Capacity Factor (MDC Net %) versus mean l . t legal catch rates for operational years. Sublegals were not
- l. examined this way because commercial pots do not render unbiased samples of sublegal lobster. When we tested legal lobster catch l
rates for the thermal quadrats pooled versus the annual mean MDC Net % Capacity Factor for the on-line years of 1973-1983, we found a significant negative correlation (p 5 0.05). However, a correlation analysis of the mean Unit I thermal output for the period of May-December, which encompasses the inshore lobster fishing'/ data collection season, versus legal catch rates for the surveillance area during operational years (1973-1983, 1985, and 1989) rendered a negative R value of -0.318, which is not : significant at the traditional 0.05 level. Running the same correlation analysis without the 1989 data (a low thermal output lI I G
~
I; year), we obtained an R vale of -0.477 which approaches significance. When two variables are negatively correlated, cause and effect is not validated, but an inverse relationship between the variables is suggested. As to the limiting e'ffect of current on catch rate, Auster (1985) reported that a water flow above a critical velocity (46 cm/sec) will retard the foraging behavior of lobster by inhibiting mobility. It is reasonable to expect there would be reduced trap catches in the immediate discharge area, where current velocity can reach over 2 meters /second (7 feet /second). In fact, our diving observations have revealed fev lobster in the immediate area of the discharge canal. However, a direct cause and effect relatienchip betv6en the thermal discharge current and the commercial lobster pot catch is difficult to substantiate because ; we have no control of fishing effort including the location of the traps fished. In 1988, with considerably more current (at ambient temperature) emanating from the discharge canal than in 1987, the commercial catch rate of legal lobster remained unchanged in the surveillance area. In 1989, with thermal capacity at 29% and with one or both circulating water pumps operating, CTH in the impact . area increased substantially. Commercial gear sampled in the impact quadrats is often deployed far enough out from the discharge canal so that the effluent current is not a major limiting factor affecting lobster distribution and resultant catch. In an effort to standardize commercial lobster catch data with our experimental lobster data, the commercial legal lobster catch 12 5
lI information in the discharge and surveillance areas were weighted by immersion time (days between pot-hauls) of the pots to generate catch / trap-haul / set-over-day (CTHSOD) , a nore appropriate measure of catch per unit effort. In 1989, the legal CTHSOD was 0.11 and 0,17 in the control and impact areas, respectively. These catch rates were not significantly different (P > 0.05).
- 2. Research Lobster Trao Fishina Research lobster pot-catch sampling was conducted for the fourth consecutive late spring /sumn.er period (June-September 1989) .
Our objecthe is to determine whether the operation of Pilgrim station unsurably impacts the local lobstor population, The fc11owing parameters were examined: catch rates of legala (2 82.6 nn carapace length - CL) and sublegals (< b 2 s. 6 m CL) , size frequencies, sex ratios, culls (f.obster with missing and/o:: regenerating claws), and ovigorous (egg carrying) females. We sampled 9,502 lobater from 2,761 trap-hauls in the study area. Catch / effort data for sublegal lobster, as measured by catch per trap haul (CTH), averaged 2.99, significantly (P $ 0.05) up from 2.24 last year. CTH for legals in 1989 was 0.45 but when weighted by immersion time (days between pot-hauls) of the pots (CTHSOD), which is a more appropriate measure of catch per unit of effort than is CTH for legal lobster, averaged 0.21 for the study area. Last year's standardized value was 0.17 legals per pot-haul. The catch rate of sublegals was substantially higher than for last year at both reference areas and at the surveillance area. However, as to legal catch rate, only at the Priscilla/ White Horse 13 L
E< Beach reference area was there a significant (P S 0.05) increase between '88 and '89. The overall study area sex ratio of males to females in the catch was 1.3:1 (M:F) in 1989. In 1987 and 1988, the ratio was 1.1:1 and approximately 1:1 in 1986. Within the respective curveillance and two reference areas, males have outnumbered females in the catch all four years of the study, with the exception of 1986 at Priscilla/ White Horse Beach. The percentage I> . of males caught in 1989 was greater than the three previous years at all three sarpling areas. Deviations from a 1:1 sex ratio may be the result of aampling bias, differential vulnerability to the gear, actcal diff erencen in sex compositicn of lobster from inshorc waters, or differential molting and growth. Lwton et al. (1984aj t, reported that. the overall growth increment per molt for male lobster was significantly greater (P $ 0.05) than for females in the inshore waters of western Cape Cod Bay. The percentage of females ovigerous was again low in the population at 0.7%, as it was in 1988. No pattern has emerged within the sampling zones. In 1986, over 80% of the ovigerous females were taken at Priscilla/ White Horse Beach, whereas in 1987 and 1988 about 50% of the egg-bearing females were captured in the discharge area. In 1989, 39% were collected at the latter location. Lawton et al. (1984b), monitoring commercial lobster , trap catches of the Pilgrim area in the '70's, found a larger number of relatively small ($ 82 mm CL) ovigerous females in the
- discharge area than in comparable reference quadrats.
14 i
I The percentage of culls in the Pilgrim area increased from.23% in 1988 to 27.1% in 1989. In 1986 and 1987, the cull rate was '
- about 20% each year, over the four years, the cull rate has been
; lowest in the Discharge area. The rate was highest at Priscilla/ White Horse Beach in 1986 and 1987,_ at Rocky Point in '
1988, and about equally high at both reference areas in 1989. Our field lobster pot study conducted June-September ftr the years 1986-1988 was in effect a modified trial experiment under-o somewhat non-stressed conditions, i.e., the prolonged power plant outage resulted in no waste heat discharged but there was a current flow, albeit reduced to one circulating seawater pump operating in , 1986 and 1988, while flow was minimal during the study in 1987. During the 1989 pot study, most often both circulating water pumps were run, while the vean monthly thermal capacity ranged from 16 - 52%; hence, this ww a transitional year as to power plant operation. These data will be compared with that to be collected from future-high operational years. l The outage at the plant provided us with a baseline period, where our work became a uniformity trial of fishing standard I-- commercial traps in a standardized manner in the defined study area. The proper pairing of a potentially impacted / surveillance area (with stations randomly selected- within) with non-impacted / reference areas was a prime concern. We believe the station pairs selected would reflect environmental changes in a ' similar way. Two parameters offer promise for assessing impact of Pilgrim
~
3 15 gi
I Station on the local lobster population. Data will be analyzed for l alteration in catch rate (relative abundance) and size composition. [ Using the sample mean with estimates of precision (Table 1) and the equality of means test for the difference between'two group means I with known variance (Sokal and Rohlf 1969), catch rates of legals (CTHSOD) and r>ublegals (CTH) were compared by pairing up sampling areas (Discharge,_ Rocky Point, and Priscilla/ White Horse Beach). No sampling area pair has been statistically similar between all the years for legal or sublegal catch rates during the pre-stress period. Table 1. Catch per unit effort lfrom experimental lobstering in the Pilgrim area for 1989. I CTH represents catch per trap haul; CTHSOD indicates catch per trap haut per set *over day. Catch data are presented in rubers of tobster caught. Mean 12 standard errors is an estimate of precision, l g i Legal sized Lobster Sublegal Lobster n82.6 non CL) (<82.6 mn CL) i Mean 12 Mean 12 Area CTHSOD Standard Errors CTH Standard Errors Olscharge Area 0.190 0.170 0.210 2.780 2.654 2.906 . (Surveltlance) Rocky Point (Control) 0.210 0.188 0.232 3.240 3.110 3.370 Priscilla Beach (control) 0.250 0.220-0.230 2.870 2.700-3.040 W-i Legal catch is adjusted for soak time, white subtegal catch is not. Limited to a single impact site (treatment) and having l established two control sites, we used the extended outage (pre-stress) period to establish the relationship between stations, using the ratio of the biotic measure obtained at the treatment site to the average of the two control sites. The grand mean ratio 3 for legals was 0.826 and for sublegals was 0.819 for the three 16
I outage years. For 1989, a transitional year in power operation, the ratio for legals equaled the three-year average, 0.826, whereas the ratio for sublegals climbed to its highest value, 0.910. We have yet to collect data with the power-plant fully operational. The Kolmogorov-Smirnov procedure (Sokal and Rohlf 1969) was used to test size distribution of lobster caught in the different areas. It was found that size frequency data of legals at both reference I areas were not significantly different (P > 0.05) and therefore could be-pooled to increase sample size and then tested against size distribution of legals in the Discharge for power plant impact.
- 3. Nearshore Benthic Finfish In 1989, estimates of thermal loading on the local environment by Pilgrim Station (approximated by MDC Net %) were highly divergent, confounding characterization of the year as operational or non-operational. For purposes of analyzing the trawl data we have elected to term 1989 a low operational year. Though current was_ produced, relatively little waste heat was discharged. As in past years, Station 1 (Warren cove) was considered the primary reference site, Station 3 (Discharge) the primary surveillance site, and Station 6 (Intake) a secondary surveillance _ site for impact analysis.
Mean annual catch rates for the three dominant groundfish - winter flounder, little skate, and windowpane - were examined for differences between primary reference and surveillance sites (Figure 5). No relationship between catch rate and plant operation 17 I
_ m.s. e sec., , mas.* e .onaw I:
..aen e . ore
,,, s. p t k. . w.
. ; :l l
I ' I I R$ h. - 1 $ xx --- _---- Figure 5. Mean annual catch per standard tow of dominant groundfish by bottom trawl at reference station 1 and survelttance Station 3, 1982 1968. can be discerned from a comparison of operational and non-operational years, although it is readily apparent that locally these species are all in a period of depressed abundance. We believe that variations in annual catch rates for these species are largely independent of plant operation.
- To investigate seasonality in trawl catch rates for 1989, partitioned catch data for winter flounder, little skate, an windowpane as. fellows: winter (January-March) , spring (April-June) ,
summer (July-September), and fall (October-December). Choice of seasonal demarcations was based on bottom trawl catch rates and sea water te5tperature data collected at sampling stations in the Pilgrim area o'v e r the last decade (Lawton et al. 1983). , Examination of overlap in seasonal CPUE standard error bars (i 2 , std. errors) gives an approximation of the magnitude- of any differences in catch rates between stations. Trawl data inherently ' are highly variable, hence the large standard error bars for means in catch data (Figures 6-8) . Winter CPUE's for the selected species ' were extremely low and will not be considered further. I 18
In 1988, the spring ,,,, .
,.me- ,, - .re winter flounder catch rate ...
was highest at Station 1 and ",?- '"~"', - ... I lowest at Station 6 (Lawton et al. 1989)'. In the spring
.. a. - --
m =, +m A. .m - gr- .
. m
~
; "' "" ~
of 1989, however, catch rate . . _ . {-
~~
for this species was highest ;T"' ...' - -- I
*"~ "
. .. . g". .
at Station 6 (Figure 6). In ; .. .b. .. i" "" J '
, Sll3.
. CQ:.~"
M . ,Jui4 . T.T.*
.7.2, S:34 *=.'
I summer, Intake catch rate in the declined slightly, Figure 6. pi$**I'['ge ,. seasonal mean trawl catch rates with n f r winter Her W stati n in the and then peaked in the fall. Given the fairly constant catch rates for spring and fall, the summer decline may be due more to gear conflicts than distributional shifts. Heavy concentrations of ,,,,,, ,,,
.--.s.- .ps~~
I lobster embayment gear in severely the Intake hampered
~~"- -
+ 1 s g; m ,. gssur
~ ~
trawling during the summer months, I reducing tow length and in ' some months prevented sampling. Catch
.-- r ~~
7
.-- e-
* ~"""
... ..p .. 4.. . . .
rates at the other stations were 4
. . g- %r - g s s. er generally low.
Examination of catch rate Figure 7. seasonat mean trawl catch rates with vertical error bars for tittle skate by plots for little skate (Figure 7) station in the Pilgrim area, 1989 revealed variability in distribution between stations for each season, but no pattern 19
1 was discernible. Windowpane catch
,m,~
I j rates (Figure 8) for all seasons g
.. T gI were very low; no windowpane were , ..
w ax_a e captured during the winter months. .- t - o=m-**,, I'i l Low levels of abundance make it *((],
]" g"fr ' l 1
difficult to' ascertain +- l distributional patterns. N@3 m w ~anc e
'"' 1 Figure 8. seasonal mean trawl catch rates Previous analyses of trawl with vertical error bars for windowpene by station in the Pilgrim area, 1989, data (Lawton et al. 1985, 1986, 1989; Kelly et al. 1988) indicated the Intake embayment (secondary surveillance site) at Pilgrim Station to be a haven for small winter flounder (<22 cm total length), presumably due to the algal cover, structure, and sheltered environment it provides. This finding was affirmed in 1989. We tested seasonal flounder .
length-frequency data for differences in distribution between the Intake and the other stations with the Kolmogorov-Smirnov two- , sample test (Sokal and Rohlf 1969) . We found that the distribution of length frequency data from the Intake was significantly Is different from the other stations at_P < 0.01. An examination of the length frequency distributions from catches in the Intake (Station 6) for the spring through the fall seasons (Figure 9) , reveals a clustering of values at the lower end of the X-axis
'(lengths < 10 cm) during the spring and fall; conversely, distributions from the other stations show highest numbers of flounder grouped in the 25-35 cm range. As noted in the past, concentration of small flounder in the Intake embayment, a 20 I
1 I. L
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!^
i' SPRING 1989 q l FAEQUENCf
~
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)
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0 > >i, . .i..-. ii.... ..., .... ....., 4 7 10 13 to to. 22 25 28 31 34 37 40 TOTM, LENGTH (CM)
~
SUMMER 1989 FAEQUENCV + 0- - 3'
/ f 1 t
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! TOTAL LENGTH (CM) , ll, -; FALL 1989 '. FAEQUENCY B- .j 7-6- ,- s- ..#
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'- I Ib_ ilk &hI_f j.f l$ ' . Ik$ !
I O i 0 8 ' 11 14 - 17 20 23 20 29 32 35 30 41 44 TOTAL LENGTH (CM) E stAtlON 1 C STATICN 3 CSTATION 4 M station 6
.. g Figure 9. Length frequency distributions by station for I' winter flounder trawled in spring, summer, and fall 1989, near Pilgrim Station. t I
I potential area of plant impact, predisposes these fish to potential gI impingement and/or thermal backwash effects from Pilgrim Station.
- 4. Pelaaic and Benthi-celaoic Fishes A gill net is a passive sampling device; hence our survey ,
abundance 'index (fish / overnight gill net set) was influenced by species availability and gear selectivity. We accepted the assumptions that gear efficiency did not change over time and fishing effort of the net was uniform . for all mesh sizes. We assumed that the number of fish already caught did not influence the capture of additional fish and that the vulnerability of each species was constant. Pollock This benthi-pelagic species was most abundant, comprising 44% '" i of the 1989 7-panel gill-net catch. Relative abundance estimates, generated from standardized- 5-panel CPUE data, reflect local population fluctuations over the survey years (Figure 10). Since Pilgrim Station Pollock operated during 1989 at only 29% i ec "" '" *""*' *"'"* * * "" "* ~ "" ' oo i 'i 140 - of its potential mean annual ,,o. _
~
80 ; capacity,1989 gillnet data were '( _]- assigned to the outage / low power *l output year category in CPUE 8 y - o (_ n 1 []
,ne,s i< kiedriekeo e,&eskesicirieia
- trend analyses. An increase in year -
l
~ " " "
relative abundance occurred from " " * ' ' Figure 10. Average standard 5-panel gill-net l' 3 1971-1972 (preoperational catch for pollock and yearly MDC Net % at Pilgrim Station, 1971 1989. years), followed by a substantial reduction from 1973-1975. Stock index rebounded in 22 I
I 1976-1977 to exceed past levels and remained relatively high through 1981; CPUE declined markedly in 1982 and subsequently fluctuated at a reduced level,. declining overall through 1987. Catch rate in 1988 (83 fish / set) was a marked increase'over the 1987 level (40 fish / set). Comparing means of CPUE for the preoperational (1971-1972) and operational (1973-1983,1985) study years, and between 1983/1985 when Pilgrim Station operational
-I output. exceeded 80% and 1984/1986-1989 (low power output / outage periods), revealed, respectively, that relative abundance was 13%
lower overall during the operational years than in pre-operational years and 20% higher in 1983/1985 than 1984/1986-1989 pooled (Table Comparison of the annual index for Pilgrim Station operational output and 5-panel CPUE data for pollock revealed no
'I apparent relationship (Figure 10); when statistically tested, we found no significant correlation (r = 0.225; P> 0.05). 'I Table 2. Mean catch per standard gillnet set (5 panels of 3.8 - 8.9 cm mech) for various time periods and the percent differences for selected species caught in the vicinity of Pilgrim Station, 1971 1989.
Species Atlantic y, ear Pottock Curer herrina 1971 1972 93.8 18.8 7.8 1973 1983. 1985 81.3 32.9 32.2 Preoperattonet vs operationet 13.3 75.0 312.8 percent difference 1984, 1986 1989 52.2 17.1 39.2 (low output / outage years) I 1983 and 1985
& 80% capacity) 1984/1986 1989 vs 1983/1985 62.4 19.5 25.9 51.5
.1 76.8 percent difference p
23
Atlantic herrina Atlantic herring ranked second comprising 20% . of the 1989 i total 7-panel gill-net catch. Over the survey years, abundance in-the Pilgrim area has fluctuated greatly. Following an initial decline in 1972, the standardized 5-panel CPUE generally increased during the operational years of 1973 to 1976, declining again in M nk Hen N ;
,-.m....... e.,~,,.
1977 and 1978. From 1979 to go . _
~
' ' ~
1984, catch varied,' but declined E
.o. __
eo g to an all-time low in 1985, no. - Beginning in 1986, relative
** ] b _ . -so abundance increased; the annual Y
% )
o .,, ,,, ,,,},j, .j, .j, ,,, ,,, .j, .,0 4 g, .,g, g, q,4, .,, ,, o Year catch rate of 116.5 fish / set in _ ,,,,,,,, gg ,,c ,,, , i, 1988 was the' highest recorded Figure 11. Average standard 5 panet gitt net catch for Atlantic herring and yearly MDC Net % at for this species. .CPUE in 1989 Pilgrim Station, 1971 1789. subsequently declined sharply to 34.8..'A, plot.of annual Pilgrim Station operational . output (MDC) and annual catch data is found in Figure 11. When tested statistically, sea herring catch rate and plant MDC were not { significantly correlated (r = -0.209; P >0. 05) . Comparison of 5-panel CPUE between years of operation and preoperation/ outage were inconclusive (Table 2). The grand mean catch rate for the operational study years (1973-1983, 1985) was much higher (313%) than the average for the preoperational period (1971-1972), while catch rate was 77% lower for the average of 1983 and 1985 (> 80% plant capacity) than the average for 1984/1986-1989 (outage or low plant output). We therefore conclude that 24 a.
I . fluctuations in sea herring abundance in the Pilgrim area are the result of natural variation. Cunner Cunner ranked third in the total 7-panel gill-net catch
. (11%). There is evidence of population consistency in the- Pilgrim .
area from 1971-1976, (Figure 12) ' cunner
.with a grand mean standardized so "~ "~ "* " " "*"""~~~""*"~"'oo i 5-panel CPUE for these years of "-
_O\~~ s
- 22 fish. per gill-net set. Catch -
go- ^ ~ ! . s 40 L rate peaked in the operational - v_ * , to- _ -20 t years of 1978 and 1980. From p 1977-1983 annual catch rates $ i ~ " " " """ were about double (grand mean l' Figure 12. Average stenderd 5 panet gitt net c m r catch and seasonal MDC Net % et Pilgrim CPUE . of 41 cunner per set) Stetton, 1971 1989, those obtained in the first six 1 l years of the survey, indicating a marked change in distribution j and/or abundance of the local population. Relative abundance i^ exhibited a marked decline for 1984-1989, averaging 17 fish per < l l set. Pooled 5-panel CPUE for cunner captured during operational l years was 75% higher than the average for the two pre-operational years (Table-2). Similarly, a 52% increase was noted for 1983/1985 (high thermal output) over 1984/1986-1989 (outage / low output l years). A plot of seasonal (April-September, when cunner are
.I present in the area) plant output versus annual cunner CPUE suggests there is a relationship between the two variables (Figure 12). When we tested CPUE data and seasonal plant MDC, we found.a 25 I
i significant positive correlation (r =0.627; P $ 0.05) . Regression analysis of catch rate on seasonal plant capacity factor yielded a highly significant F ratio (Fs = 10.36; P < 0.01) . Specifically,
~ 39% of the variability in cunner CPUE can be explained by variation '
in plant operational load (MDC). Supporting evidence for a positive relationship between cunner abundance in the Pilgrin Station discharge area and plant thermal outflow / current comes from our observational diving program. During operational years, when the plant produced a warm
. discharge current, divers sighted more cunner in the discharge zone than in the reference areas. Even if-no waste heat was released, the generation of current by at least one circulating seawater pump was sufficient to produce a similar distributional pattern.
Conversely, during years when little or no current was released, cunner were more often observed at reference stations. In conclusion, cunner are attracted to the heated effluent at Pilgrim Station. In the near-shore marine environment, active cunner occupy - small home ranges for long periods making this species appropriate for monitoring long- and short-term changes in local environmental conditions (Green 1975). As such, they are at risk from potential nearfield plant impacts such as thermal or cold shock and/or exposure to chlorine. Cunner are especially vulnerable at night since low responsiveness, characteristic of the sleep state of labrid fish, reduces their ability to avoid environmental stresses that may occur (Olla et al. 1975). . I 26 I
o I
- 5. Fishes of the Shore Zone Waste heat, gas supersaturation, scouring, and the [
mechanical / chemical effects of impingeraent and entrainment can adversely affect fish occurring in the area of the Pilgrim Station. The shore-Zone seine program has allowed us to catalog finfish species (juveniles and adults), including their occurrence,. distribution, size range, and relative abundance in the intertidal The and shallow subtidal zones of the Pilgrim area over time. rocky shoreline, jetties, and outer breakwater in the area of the discharge precludes seining; however, a suitable surveillance seining site (to address thermal backwash / mechanical effects) occurs at the head of the Intake embayment (Station 3). Fish in l the Intake are predisposed to mechanical and periodic thermal l-l- backwash effects of the power plant. Reference stations include two locations along open coastal beaches and a site at the mouth of-the nearby estuary. , Relative abundance data (i.e., mean catch per standard seine L haul)'of the dominant' species were examined to assess potential
' plant impact . (Table 3) . There are large natural variations in s
L. relative abundance amongst stations and years for many species with l- . because the exception of winter flounder of their regular L distribution (Figure 13). Natural variability confounds the quantitative detection of other than large ecosystem level effects 1
- (mechanical or from waste heat discharge) of power generation.
L Using correlation analysis, we tested the relationships between l monthly mean densities of the Atlantic silverside, the study area's dominant species, in the Intake at Pilgrim Station and the monthly 27 I
Table 3. Mean catch per standard haul seine set for selected species collected along the Ptpouth shoreline, western Cape Cod lay, 1984 1989.
- j. Stettons Varren Cove Lone Pt. PNPS Intake Menomet Pt. W .
Year Mean Catch Per Haul seine set Atlantle silverside 1984- 51.2 220.9 : 741;49? 101.7 1985 413.5 165.4 ' :12;9? 201.5 i s 1986 21.5 107.0 ; J:2.9 3 28,1* 42.9" - - 1987 123.9- 837.9 470.8s.:- 58.5 287.4** 1988 174.7 187.9 139.4? 45.3 107.3** 1989 267.1 392.2 ' f 5417? ' 231.8 236.1" . i l Mean 175.3 318.6 M7.01' 90.9 162.8 l Winter fIounder l l 1984 1.1 2.9 ? 2.0?: 1.8 1985 1.0 7.4 54.81 4.5 l 1986 0.4 4.3 :: 9.3 ? 1.1* 3.6** 1987 0.6 1.1 J9.0e 2.8 3.3** -
-l .
- 4. 6"
~
1988 1.5 2.2 h13.6li: 2.0 -l 1989 0.4 1.3 L 6.8):! 1.2 2.5" l Hean 0.8 3.2 "7M 1.8 3.4 Attantie menhaden l 1984 0.0 0.0 10.2 t 0.0 'l 1985 10.2 0.1 t 5.8 s 5.3 . , 1986 4.8 1.8 (33;1:i 0.0* 9.3** 1987 1988- . 0.2 0.0 0.0 0.0 M2.6:6
, ! 5.1 k 0.0 0. 6" .i 0.2 1.3** 1 1989 90.2- 1.0 7:45.43 1.2 33.8** 'l Mean 17.6 0.5 *1554 0.4 8.4 Sand tonce soo. . 'i 1984 0.5 0.2 d40.6 Li 10.7 1985 0.0 0.0 6 449.5 t 140.5 l 1986 0.0 2.0 R-:72.3 M s' -0.0* 16.7'* 1 1987 . 0.1 0.0 ::<102.81 0.2 25.2**
1988 0.0 0.0 :: 84.2 ; 0.0 20.2 " ;
- j. 1989 1.2 0.0 ?4T.7) 0.0 12.4 " '
F 132.Bi -l
- 1. Mean 0.3' O.4 0.1 37.6 Pooted sDecies l 1984 54.3 233.8 j 9EO 120.1 1985 854.5 186.9 f688.6s 569.0 1986 30.9 150.5. ?225;91: 34.8* 109.1**
1987 130.0 847.5 !!380.44i 63.4 368.1** 1988 177.0 194.4 iC179.7 s 53.6 151.2 " 1989 360.5 404.9 l[167,4h 235.5 291.3 " l l Mean 267.9 336.3 E289.0F 96.8 268.1 l
*First full season of data collected at this site.
" Includes data from Manomet Point in the calculations. 'i Shaded colunn is data from survelltance station. -
l 1 28 L Il s . !. . 1
I . l;k Menhaden Sandlance app.
,,esom ser esse ese esen ser eenes ese se ._ ese ~ ~ ~ - - --~~~------ --
* """~"
I' ee . ._ 10e se . -. e, = .. . h I se - - -- - e 2 4 -T e
+ .e.
een see see ser mee ses ines ses see ser ese see
-I' %er %er g Atlantic aliverside Winter flounder ete e_ _ _ ,e _ _ _
see -- -- ~. e " ** W 4ee - . . , . e "'
~. ,,,,
""""~
4 .-* see I
.a., ..
_ e . .. . .. .. .
~~~~~ ~~ ~ ~~
g . .. . tse .~.u....... .. -_ _ -- IL. '
== == ion
%er
.or *
.se year
.e, .es ll- W-Figure 13. Average catch per seine set for four comon shore zone species (t 2 stendard errors) .
in the vicinity cf Pilgrim Station 1984 1989. mean Pilgrim Station thermal capacity (MDC net %) ; and between the former and the monthly average . plant pump capacity. No statistically'significant correlations have been found (P > 0.05). Haul seine collections from the Intake embayment identify finfish species subject to impingement. Of the 25 fish species seined in the Intake during the 1989 survey . (June-November) , 11 were impinged on the power plant's intake screens during the same
. time period. With the station coming on-line and resultant increase in pumping capacity, impingement diversity during our six-B' month survey period rose from last year (23) to 35 species totaling I 29
\
I only 290 fish (86 fish in 1988) of which Atlantic menhaden . comprised 27%. Atlantic silverside, sand lance and Atlantic menhaden numeric ely dominated seine catches in the Intake. Numbers caught in the seine were highest in July, while impingement numbers were greatest in November. No statistically significant correlation (P > 0.05) has been found between impinged species and those caught in the haul seine. These results are not surprising-since impingement is a passive and qualitative method of sampling and seining is an active and, by our design, quantitative sampling method. The Intake at Pilgrim Station is an artificially created embayment or cove formed by man-made breakwaters and includes a dredged channel. This area is a microcosm of a naturally formed bay or inlet of the sea and has proven to be a haven for shore-zone - fish in an otherwise open coastal region. The Intake offers a l variety of-fish habitats: shallows and a relatively deep channel;' sand substrate devoid of macroalgae and vegetated areas; and l
-l glacial boulders, cobble, and gravel. The area has reduced wave 5 l action because of protection afforded by the outer breakwater which also provides shelter for marine life. Unchecked waves of I l
sufficient size can limit the distribution of biota as turbidity of the water increases and substrate shifts. Rocks and macroalgae both l provide structure / cover for' juvenile and forage fish and harbor the prey organisms on which these fish feed. Marine shore zones that are without aquatic vegetation or rocks generally are the least populated by fish because protection is lacking and food is scarce. 30 g 5
I Relative to the number of species collected the Intake was highest (25) followed by Long Point (17). The latter is an -I. estuarine sampling location on the inside of Long Beach, a barrier beach that forms the outer bound of Plymouth Harbor, providing a sheltered haven from storm waves. By contrast, seine catches at the exposed coastal beaches were markedly lower in number of species but not in total catch. Seine abundance indices (catch per standard haul) were examined over the last seven years (two on-line years of high operational output - 1983 and 1985;-four essentially outage years 1984, 1986, 1987, and 1988; one high stress due to pump capacity 1989). No relationship between catch and plant operation is suggested. However, some generalizations can be made from the most recent six-year seine data base in regards to the Intake, catch rate of winter flounder has been highest in the Intake for the last four years. Sand lance populate the subtidal sand of the Intake every June and July, while menhaden schools-frequent this sheltered I embayment, the site of potential impingement incidents. To date, no correlations to plant operation have been detected in the seine data. The construction of the intake embayment has nevertheless altercd the habitat at Rocky Point allowing for the development of a more diverse community in it, with more niches to be filled. This finding was confirmed by supplemental foot-seine data (Table 4). I I- 31 1 I
ll I l }' 1able 4. Mean catch per standard foot seine set for selected species collected along the Plymouth shoreline, western Cape Cod Bay, 1987 1988. Stations tona Beach Warren Cove Lonn Pt. PNDS Intake Manon t Pt. W Year Mean Catch Per Haul Seine set , Attentle silverside 1987 38.9 27.3 69.0 stE6.0M 12.5 30.8 1988 26.8 12.3 52.6 !!32.1ll 7.5 26.6 ,' 1989 61.8 22.5 99.3 [63.4j! 8.5 52.3 Mean 42.5 20.7 73.6 (33)4.Ij 9.5 36.6 M , Winter flounder 1987 0.0 0.3 0.6 f 0.1T'. 0.7 0.3 1988: 0.2 0.7 1.3 !!h1.63 1.1 1.0 1989 0.0 0.3 0.9 s ji0.9j 0.6 0.5 Mean 0.1 0.4 0.9 (0[$Nj 0.8 0.6 Pooted soecies - 1987 39.2 27.9 72.2 R$JM 34.7 40.1 1988 27.2 13.2 54.5 $35i35f 8.9 28.2 1989 62.7 23.6' 102.1 (6$43 3 9.4 53.8 Mean 43.0 21.6 76.3 17.7 40.7 " [42[5] Shaded colum is date f rom surveillance station.
- 6. Underwater Finfish Observations For the purpose of analyzing the underwater observational data
~
we have classified 1989 as a low operational year. Relatively little waste heat was discharged; however, there were one or two circulating water pumps in operation during the study period. During the early part of the 1989 dive study, project divers . noted very dense carpets of kelp, Laminaria spp. , and blue mussels- l across the bottom of the discharge canal. Further, as noted in llj 1988 (Lawton et al.1989), patches of Irish moss were also observed . in the discharge area. As Pilgrim Station began ascending towards l 32 Il
I full operational status in 1989, thermal load increased and both the algae and mussels in the discharge suffered high mortality. By
-July, the kelp was detached from rocks in the canal, and 4.he bottom was piled high with mussel shell stock. At this time, divers observed numbers of starfish and crabs in the discharge. From
~
August through October, the dominant species of algae in the canal was Enteromorcha spp. . Patches of Irish moss still occurred in the .g_ 5 discharge area, however, only at the mouth of the canal. Pooled finfish distribution (Figure 14) was similar to that for most of the previous years, with the majority of fish (58%) Pooied rintien oietribution found in the discharge area. ro ((*"*'L,, ,,,,,, ,,,, I 7 The percentage of fish found in j - the control area-in 1989 (36%) 7 was similar to 1987.
- _ ]ls 1; $ sjz _
9 if.'t Only 6% of f 4 4
"' {j '
l _ $3
-the fish observed in 1989 no-_ f
*~
- g _
g j f, j,,;'g n occurred in the stunted zone; j .'j[f Q
] ;,,
I..
- I .the index was 3.8 fish / dive for o.mmm . ...
8oo eoe eoo eoe 8oe eoc T
?
, , , 83,c g_ this area. Total number of fish Figure 14. nistribution of finfish observed E sighted was 800, which
~
approached the number recorded as in 1987 (883). Overall species diversity (11 species) and composition were similar to that of recent years; however, striped bass and bluefish were observed in greater numbers in 1989. Cunner Cunner was again the dominant species at 66% of the total sightings. Local abundance, however, remains depressed. Project 33 I
y _ gill net records also point to cunner Distribution - a reduction in local abundance ro ; of cunner. The 1989 CPUE for "' B 7 so-f _
- 2 cunner in the gill net was the _
& _ ;,x h
]
~
lowest recorded in 18 years of 40- - Jl -
;$ $s
?
j
}; ~ j M-
!{2{2 ;g M gy h[
sampling. Cunner were found at ro.
!'d is ff p Th gg hh
?$
all stations in -1989, with 'o' O I $d W [i $ highest numbers in the control soc soc H i J so6 soc so6 s66 so6 n4 p a r l; in. in. i.a i.u iur i.u in. - area (Figure 35). A comparison Figure 15. Distribution of cunner observed by divers off Pilgrim Station, 1983 1989. lg j. with previous years revealed similar spatial distributions in 1984 and 1987 (outage years).
..1 Tautqg i
Tautog sightings increased Tautog Distribution i markedly from 1988, and were at **' too '.".."*".."*"".."e*"."..*,.". g"i the second highest level [ $ sj j
- 2 recorded for the study. A y slight increase in tautog catch 5~
I$ P 4
.o. m ,p? x 4 -
2 also was . n.oted in project ao- @ [. p- j - ro- 73 p r
- 2:
g ,, ; gill-net sampling. As has been io. [pa !) L - L j the case (Figure 16), o . . . - N!' 'c 6 b ... tautog soc soc soc soc soc soc soc in. in. in. . . . in, su. .. were found primarily in the Figure 16. ofstribution of tautos observed by divers off Pilgelm Station, 1983 1989. discharge area. To date, no definitive relationship has been confirmed between tautog and plant output (mean seasonal MDC) . Recruitment obviously influences local abundance. I 34
'I Strioed Bass Striped bass ranked third in our observations. Over the last .I- few years, bass have not been observed in any abundance in the discharge area. None were sighted by project divers in 1988.
Undoubtedly, the presence of a stronger discharge current attendant Q with resur.ption of operation of Pilgrim Station in 1989 provided the attraction.to the discharge area. Another extremely popular 1 5 gamefish (also attracted to moving water), the bluefish, was observed by divers in 1989; the last sightings were in 1983.
- 7. Soortfishina
~
Angling effort and resultant sportfish catches at the Pilgrim Station Shorefront recreation area increased somewhat in 1989 from the previous nadir of 1988. A steady decline in fishing occurred from 1986 through 1988 which was clearly linked to the extended' station outage. Angling trips were up by 25% from 1988, while the total catch doubled from about 100 to 200 fish. During the 1989 fishing season (April ;iovember) at the Shorefront, Pilgrim Station was in a power ascension program as it was' returning to full operating capacity. Discharge current and
- I. waste. heat were variable, with mean monthly thermal capacity ranging from 4.6 --66.0%. There were times when only one of the two circulating seawater pumps (155,000 GPM each) was operated ,
with concomitant reduction in the volume of water discharged. When operational, Pilgrim Station's thermal discharge is a continuously flowing, artificially created current, containing a thermal component that has been found to attract and concentrate certain game fishes (Lawton et al. 1987) Power plant generation 35 I
has been interrupted by numerous outages that have negatively impacted sportfishing at the Shorefront area. The absence of a L strong thermal discharge current has resulted in marked reductions - of bluefish and striped bass catches in the outfall area'. At the time of a plant outage during most of September and October 1975, only 14 adult bluefish were caught at Pilgrim Shorefront' as compared to over 500 in 1973 and 700 in 1974 for-the same months, when a strong thermal current was present. An estimated 1,000 bluefish and 150+ striped bass were.taken by angling off the power plant in 1983 and 2200 bluefish and almost 400 bass in 1985, years of high reactor power level (> 80% thermal capacity and two pumps in operation). Conversely, with the absence of waste heat and a c marked reduction in flow of water through the discharge _ canal' during the fishing seasons of 1984 and 1986-1988 (outage periods), the pooled catches of both species fell to about 150 fish in total for all 4 fishing sonsons. : During the July and August creel survey of 1989, the catch of bass and bluefish, although relatively low, showed a slight upswing from the previous three years, with a total of 71 fish landed. ~It is noteworthy that divers sighted both species in the discharge area for the first time since 1986. Aggregations of up to 30 bass and 15 bluefish were observed in the discharge current (both circulating seawater pumps were operating at the time). Nevertheless, because bluefish and striped bass hold the interest of the more avid anglers, it is natural that when fishing success for these species declined over the three years of the most recent ,
-outage, angler interest and visits to the Shorefront declined in 36
I 1989. This also was a limiting factor to the catches-of. bass and bluefish in 1989.
,I: It is concluded that the operation of Pilgrim Station together with its shorefront' access have positively affected sportfishing in the Pilgrim area via the attraction the thermal discharge current.
has for game fish, concentrating them at a point source within casting distance from shore. On the negative side, the attraction
'I- of forage and game species to the warm current increases the potential for stress and fish kills via heat and cold shock, or gas' supersaturation, which have occurred in the past.
I 4 I I I I I I I I I 37 I
I IV. IMPACT PERSPECTIVE-A' summary of the major findings of impact of Pilgrim Nuclear Power Station on fisheries resou'rces in the inshore sector of western Cape Cod Bay,-focusing.on the immediate area around the - power plant, is presented - by study in Table 4 . The summary highlights salient points; for more detailed discussions of : investigative area refer to the individual sections of this report. . There are commercially important lobster and groundfish - fisheries as well as intensive recreational hook-and'-line and lobster fisheries in Western Cape Cod Bay. The living and
. nonliving components of the environment govern many reactions of the' species populations comprising the marine community life. The assessment of environmental impact of Pilgrim Station on the area's fisheries' resources necessitates measuring many parameters that- -
' influence the occurrence, distribution, abundance, and size composition of target species. Monitoring data collected to date off the power' plant reveal local biotic changes and environmental disruptions;-however, these have been localized or occasional in occurrence.
As Pilgrim Station has operated overall at an average of 46% of its output capacity, we most likely have not experienced plant . impact to its fullest. Impact assessment at the past level of plant output may not be valid for a long-term, higher operational level that.is expected in the future. I l 38 Il
U' h 4 lable St A surmary of lepect essessewnt by attdy of Pilgele huclear yI; Power $tstion (PkP5) on martrie fisherles' resources in western Cape Cod Boy. j nve s t l ast t on Imart of pup 1 191M 1969 C oment s I Glitenet stu# Curwr evidently ettrected to totative etmadence of twwwr . The isplications of j the thernet ef fluent. Significant in the area of the therest attraction are twofold; positive terrelation to PNPs ' discharge down in 1984 to sport fishersen th6s sperationet thermal leading. A tmost (outage year) eruf down le bener bist, tut core 40% of the verf sbilley in setch rate further in 1965 (high output versely thle concentrates
, I: can to espl6into by verletion in plant ' teed',
capacity), suggesting a recent decline in local fish In e high rist ares with the potentist for stock else. CPUE f rom 1986+ overfishing, thermet 1969 destined overett. stress, gas kn4ble disease, ord esposure to chemicett.
.I_ there is e cymstionable relattenship Rotative abindance of teutog I
Samu es above. bat.,een CPui f or i.uiog .,d Pues .versti aning ihe out.ge d=ctined operet tonet output. and remained low In 1969, 1
- I.
8Cuga observations sterorting data that ewwwr ere Increased twwwr sightings in W6th te thernet ef fluent . ( e attracted to the plant discharge the control tone in 1984/1967; 1961) there was en smarent
/ : curr ent , in the discharge in 1983, 1965, shif t in d6stribution of
. 1986 and tredaced current), twiner away from the dis' Somewhat more swwwr seen in ' charge toernaded) sone end the controt eres in 1989. toward the sentrot tone.
Concentrattens of striped bass in only 2 of the years since 1979, As basa exhibit a prefere
. the vicinity of PNP $ tinked to the bluefish end bees were not once for moving water, f
eeoting water discharge. alehted by divers in the such as PNPS ef fluent, environs of PwPS- 1984/1986, their absence f rom the tait were seen in 1965 end 1989 d6ving area in 1964 and 1986 la l In emelt schools f requenting emetently rotated to the the discharge ares. Only a low discharge flow daring the few base were seen in 1906 67, outage.
~
Cree 4 survey With the plant operating, the Over 1,000 bluefish ord 150e Power Plant lies had e lI3 - outf all et twPs has proven to be an attractive feederyg grotnf concen-striped bass were cought by engters at PUPS in 1983; ord positive ef f ect en the sport fishing of f Recty trating sportf tsh for en estended - ' 2,200 bluefish eeul atsest 400 Pointt however, the at trac-perled of time in e location close bass in 1965; no bass erus only . tion of game fish to the to shore. e smett raster of bluefish discharge increases the t
= I, wre caught in 1984 Catches were entremely low 1986 1958 potential for overfishing e tocat eleck ord for fish daring the plant eutege but tills wie high tenswroture showed a slight tsiewing in and ges swerseturstion, e 1969 es the plant increased 8tuefishing was pretenged Its operationst status, into moventwr 1985 by the presence of the hotaveter discharge.
~
lieut selte stutty Intek
- eedeyment with its breaka telne catches -In the Intehe theresone f 6nfish residing ,
water craf dre sged thennet amears increased in 1964 and 1965, in the Intehe, espectatty in
- to be a haven for fishes in en tml were down in 1956, the visinity of the intake otherwise open coastet region, back to in 1947, but down in screen wett, ere athlect . ,
1986 and 1969. to plant entrapment. layingement eruf thernet backwesh effects. trawl shafy Winter fleuwser may evold the A blemdat distritmation of Autum trerufs (plots) of I' lmedtete area of the dice charge canal daring operatlan. flourder relative atzsulance was fourd at the surveltlance station in 1984 that was not f oind f or 1961 1985, 1985 1968 in 1966 61, CPut in the relative stasidence for winter flourvler were dif forent at ref erence versus survell' lance altes from 1961 1985 (operational eeers) but were t discharge eres enceeded that sletter 1964/1984 1969 In t et the refererte location. In 1965, we fourd CPut to 1966 4 1969, CPUt was slightly be correlated (4) et higher at the reference station, ref erence and discherge areas. I, Concentreting in the cherviet of Catch per ef fort f or winter Seasotial bottom treet estch the intake ese>ayment are flousJer dromed markedly in rates f or w6nter floursive winter flowder. 1984 erd l985 et both the were consistently highest in ref eience and discharge the intake ees>ayment in spring s t a t ions . CPut stabillsed or semer and felt. l (n 1986 erd 196 8, declining this is e tuon to recree-l sem=what in 1988 arul 1989. t ionat fisherewn at PNPS I' .
$noref ront .
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' 1ebte $1 (cont,) ..
Inyes t t as t 4 on 1einect af P1's W83
- 1999 t mwwnt s trovt stJfy (sent.)
the intake et Puet, en ettered A topperison of 1963 to 1964 This situotton has the ' envirement, hoe therectaristles . Is rust omticebte because potentlet for tweetive -! (relatively sheltered habitat with - routine treet tre was not cere ' lopect, for it increases t rect end eiget tover) eAlch emer. ducted in the intene in 196L susceptibility to -! ently ettreet jwentle fish, Itowever, tagering the ispingement end therent including winter flounder. 1he catches in the Inteke vf th backwesh ef fects, tergest ruewr of smett winte* the other sites sogled f rom flewuter was in the intake. 19th*1987 we ford that s@ stentietty larger rueers of .. , smetter winter flomder were in the intake chemet in spring and/or swewr; in 1968 fett, = 1
' Lobster potatetch study . -i
+ \
there may be e comeetten tetween tetch rate of toget tobster A elentficant megettve il' PsPS coeting water discherge end destined overett in the study - correletten (P 3 0.05) was toget toboter esteh rate in the eree in 1964 frem the 1963 f ound for ennuet thernet discharge pree, tent end oss the towest vetue tapacity eM toget tobster - 'q . for the 15 year studys catch este In the igeeted , increasing egeln in 1985 by eres for W31983,1965. '. obout 1000, in 1966, CPUE was the highest of the entire survey but dromed in 1967 to y a levet identitet to 1984. An : upswing ecturred in 1968-69, l Olssolved get in August 1965, Purt was operating ho Ge0 incidents etnerved in Get s@ersaturetten resulted .
' onelysis eM et er near 100% tepetity; water 1983. In 1984, PUPS had no in several noteworthy incleents get tmAste iftldents temperatures la the discherpe were thermet tegonent to induce of CBD in fish ee PUPS. Morteiltles - -)
disease (Geo) es high as 30.$ C and dissolved Gs0. This was etso the case of 43,000 and 5,000 sett eenheden incidents et PNPt. peses were supersatursted luf trogen 'f rom 19661988, occurred in the discherge in 1973 and
+ orgon esturation levels ranged 1975, respectively. Striped outlet frem 112119%), An estimated 600 schooting in the discharge were I silversidee eM 300 juvenite own- of fileted in tote 1975. 680 can i heden were af flicted with CaC in severely stress or ktlt toutright er i the discharge canet; fish were through increased susceptibility to '
stressed, but sortality, which was disease or predetton) fish residing i likely, vos # vat evidenced. residing in the heated discharge.
=*
_' I g 1 l I 1 1 i
- i i
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l.- .. V. CONCLUSIONS Lobster - Commercial Fisherv
- 1. The commercial catch rate of legal lobster (182.6 mm carapace length) in the discharge (surveillance) area in 1989-increased 21% to 0.41/ trap-haul, while legal catch rate in the control area-increased 36% to 0.34.-
- 2. Annual legal' catch rates in the. discharge area, which had declined from 1983-1988 (from 0.47 in 1983 to 0.34 in 1988), and in the control area, which have increased over the last three years, have not mirrored the fluctuating annual commercial catch I. rates in western Cape Cod Bay.
- 3. Annual catch rates in the impact area may be negatively affected by plant operational status.
Lobster - Research Study
.I- 1. The research lobster trap study has been conducted for four years under conditions of reduced environmental stress from the power plant. Waste heat released into the receiving waters was reduced, and at times there was little or no effluent current, whereas at other times one of the two circulating water pumps was operated. The proper pairing of a potentially impacted / treatment site with non-impacted / reference sites is imperative when assessing stress during plant operation, and has been studied during this period.
- 2. We identified two parameters -catch rate and size composition -
I that offer promise for assessing impact of the waste-heat discharge current from Pilgrim Station on the local lobster g 41 I
![ I population. Size composition data of legal lobster at the two reference areas can be pooled and tested.against size distribution data of legals in the discharge area when the plant resumes full operation. Regarding catch rate, we used the ; prestress outage period at the plant to establish a baseline relationship, in the form of a ratic, of catch rates in the surveillance area to that at the reference locations (mean of ] the two areas) . We will test these against operational data, yet i to be collected. Inshore Groundfish ' 1.. Annual trawl catch / effort data of the three dominant groundfish
- winter flounder, little skate, and windowpane - were compared l from 1982 through 1989 (included four outage years) l between Station 1--(reference-location in Warren Cove) and Station 3 (Discharge area) to assess plant impact; there was no indication of a plant discharge effect on the distribution of these species.
- 2. Winter flounder relative abundance was higher at.the Intake I' (Station 6) than at other stations in spring; abundance declined ~
l- slightly in summer and peaked in fall. 1'
- 3. There was additional confirmation that the Intake is a seasonal .
haven for small winter flounder $22 cm. Pelaaic and Benthi-Delaaic Fishes l .~ 1. The catch rate of pollock dropped substantially from 1988; catch - rate was the lowest recorded since 1976 for this species. Atlantic herring abundance greatly decreased in 1989. Overall u I L u s, l.
I cunner abundance for le period 1984-1989 exhibited a marked decline. I 2. A significant positive correlation (r =0.627; P < 0.05) was found when cunner CPUE and seasonal MDC were tested. Regrecsion analysis of cunner catch rate on seasonal plant capacity yielded a highly significant F ratio (Fs = 10.36; P s 0.01) . Thirty-nine percent of the variability in cunner CPUE can be exclained by variations in MDC.
- 3. Because cunner are attracted to the discharge, they are at risk from potential near-field effects, e.g. thermal stress and chlorine toxicity.
Shore-zone Fishes
- 1. The Pilgrim Intake, a man-made embayment, is a microcosm of a naturally formed bay and has proven to be a haven for shore-zone fish in an otherwise open coastal region.
- 2. No correlations of haul seine catch and plant operation have been detected.
- 3. Fish concentrations in the Intake, especially in proximity to the intake screen wall, are subject to mechanical and thermal backwash effects of power plant operation.
Underwater Pinfish Observations
- 1. Project divers observed high mortality of kelp and blue mussels in the discharge canal as PNPS operation increased.
- 2. Observed fish were most often found in the discharge (58%) area; 36% were found in the control zone and 6% in the stunted zone.
Species diversity and composition were similar to recent years, except that both striped bass and bluefish were sighted in 1989. 43 LI
- 3. Cunner abundance remained nearly the same as in 1988; they were most often found in the control area. Tautog ranked second, and were found in the discharge area. Striped bass were third, and were found exclusively in the discharge area. '
Soortfishina
- 1. Angling activity (fishing effort) and resultant sportfish catches at the Pilgrim Station Shorefront recreation area increased somewhat in 1989 from the previous nadir of 1988.
- 2. Poor fishing in the past has been clearly linked to station outages, i.e. the absence of a strong thermal current with its positive taxis for many fish.
- 3. The concentration of fish in the thermal discharge current increases the potential for stress and fish kills via thermal stress, cold shock, chemical influences, or gas supersaturation.
I I-g! I I ; I; I 44 I'i I'
'I VI. ACKNOWLEDGMENTS We acknowledge the contributions of numerous staff members of the Division of Marine Fisheries (DMF), who assisted in various phases of data collection, computer programming, and data analysis, ' especially Theresa Ritchot, Neil Churchill, Steve cadrin, and Dan McKiernan. We thank Chris Kyranos, commercial lobsterman, for allowing us to sample his lobster catches, and Raymond Dand and Robert Ellenberger, Boston Edison (BEco) public relations' personnel, for gathering sportfish data at the Shorefront area. Also greatly appreciated is the work of Kim Trotto of DMF for word-processing sections of this report. Finally, we thank Robert D. Anderson, BEco Senior Marine Fisheries Biologist, W. Leigh Bridges, Assistant Director of Research for DMF, and the Pilgrim Administrative-Technical Committee for overseeing the entire study program. I I I I E I I e g I
_ _ = , . . . . I VII. LITERATURE CITED I Auster, P. J. 1985. Factors affecting catch of American lobster, Homarus americanus in baited traps. NOAA National Undersea Research; University of Connecticut, Groton, CT.46 p. Boston Edison Company. 1980. Benthic map overlays and assessment of benthic monitoring programs, Vol. 2. Nuclear Engineering
- Dept., Environmental Sciences Group. Boston Edison Company, Boston, MA, USA. 25 p.
Boston Edison Company. 1989. Mrine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 33. Boston, MA. Bridges, W. L., and R. D. Anderson. 1984. A brief survey of Pilgrim Nuclear Power Plant effects upon the marine aquatic environment, p. 263-271. ID: J.D. Davis and D. Merriman (editors), observations on the ecology and biology of western Cape Cod Bay, Massachusetts, Springer-Verlag, Berlin, FRG, 289 p. Campbell, A. 1983. Growth of tagged lobsters (Homarus americanus) off Port Maitland, Nova Scotia, 1948-80. g Canadian Technical Report of Fisheries and Aquatic Sciences, 3 No. 1232. 10 p. . Conover, D.O., and M.R. Ross. 1982. Patterns in seasonal abundance, growth, and biomass of the Atlantic silverside, Menid.ia menidia, in a New England estuary. Estuaries 5(4): 275-286. Estrella, B. T. 1985. Massachusetts coastal commercial trap sampling program May-November 1984. Mass. Div. Marine Fish., g Boston, MA. 58 p. 3 Estrella, B. T., and D. J. Mckiernan. 1986. Massachusetts coastal commercial lobster trap sampling program. May-November, 1985. Commonwealth of Massachusetts Dept. of Fisheries, Wildlife, and Environmental Law Enforcement. Division of Marine Fisheries. 74 p. Green, J. M. 1974. A local mass winter kill of cunners in Newfoundland. Can. Field Nat. 88:96-97. Green, J. M. 1975. Restricted movements and homing of the cunner, Tautocolabrus adsoersus (Walbaum) (Pisces: Labridee). Can. J. Zool. 53: 1427-1431. o g I i
I Kelly, B. C., V. J. Malkoski, S.J. Correia, R.P. Lawton, M. Borgatti, and B. Hollister. 1988. Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station I on marine fisheries resources No. S6mioAnnual Report No. 31.
- 44. ID: Marine Ecology Studies Related to Operation of Pilgrim Station.
Boston Edison Compcny, Braintree, MA. Keser, M., D. F. Landers, Jr., and J.D. Morris. 1983. Population Maracteristics of the American lobster, Homarus americanus, I in castern Long Island Sound, Connecticut. NOAA Technical Report, NMFS SSRF-770, 7 p. I Lawton, R. P., P. Brady, C. Sheehan, M. Borgatti, and V. Malkoski. 1983. A comparison of power plant impingement with other types of sampling gear to survey finfish off Pilgrim Nuclear Power Station. ID: Marine Ecology Studies I Related to Operation of Pilgrim Station. Semi-Annual Report No. 21. Boston Edison Company, Boston, MA. 9 p. I Lawton, R. P., G. Luders, M. Kaplan, P. Brady, C. Sheehan, W. Sides, E. Kouloheras, M. Borgatti, and V. Malkoski. The commercial lobster pot-catch fishery in the Plymouth 1984. I vicinity, Western Cape Cod Bay, p. 131-150. 10: J.D. Davis and D. Merriman (editors), Observations on the ecology and biology of western Cape Cod Bay, Massachusetts, Springer-Verlag, Berlin, FRG. 289 p. Lawton, R.P., P. Brady, C. Sheehan, W. Sides, E. Kouloheras, M. Borgatti, and V. Malkoski. 1984. Growth and movement of I tagged lobsters released in western Cape Cod Bay, 1970-1977, p. 119-129. In: J.D. Davis and D. Merriman (editors), observations on the ecology and biology of western Cape Cod Bay, Massachusetts, Springer-Verlag, I Berlin., FRG. 289 p. Lawton, R.P., C. Sheehan, V. Malkoski, S. Correia, and M. Borgatti. 1985. Annual report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine fishery resources of western Cape Cod Bay, Project Report No. 38 I (Ja n . -Dec . 1984). In: Marine Ecology Studies Related to operation of Pilgrim Station, Semi-Annual Report No. 25. Boston Edison Company, Braintree, MA. Lawton, R. P., V. J. Malkoski, S. J. Correia, J. B. O'Gorman, and M. R. Borgatti. 1986. Annual Report on monitoring to assess impact of Pilgrim Nuclear Power Station on marine I fisheries resources of western Cape Cod Bay. Project Report No. 40 (Jan.-Dec. 1985). ID: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-Annual Report. 27. Boston Edison Company, Braintree, MA. 47
.I I I _-
~ ,L-- __ e a -+ ,.4 l
Lawton, R.P., V. Malkoski, S. Correia, B. Kelly, C. Sheehan, M. Borgatti, and P. Brady. 1987. Final report on marine recreational fishing at the Pilgrim Station shorefront: 1973-1975, 1983-1986. Pilgrim Nuclear Power Station Marine , Environmental Program Report Series No. 3 Boston Edison ' Company 53 p. Lawton, R.P., B.C. Kelly, V.J. Malkoski, and M. Borgatti. 1988. W Annual report on monitoring to assess impact of The Pilgrim Nuclear Power Station on marine fisheries resources of g. western Cape Cod Bay (ImDact on Fisheries Resources). Project Report No. 44 (January-December, 1987). Summary g) Report No. 20 (Volume 2 of 2). In: Marine Ecology Studies i Rela ted to the Operation of Pilgrim Station, semi-annual i Reptit No. 31. Boston Edison Company, Boston, MA, USA. i i Lawton, R.P., B.C. Kelly, V.J. Malkoski, and M. Borgatti. 1989. Annual report on monitoring to assess impact of The Pilgrim Ei 3 Nuclear Power Station on marine fisheries resources of ; western Cape Cod Bay (Imoact on Fisheries Resourrag). g i Project Report No. 46 (January-December, 1988 ) . (Volume 2 gj of 2). ID: Marine Ecology Studies Related to the Operation ; of Pilgrim Station, semi-annual Report No. 33. Boston Edison Company, Boston, MA, USA. Lund, W.A., Jr., and G.C. Maltezos. 1970. Movements and migrations of the bluefish (Pomatomus saltatrix) tagged in i waters of New York ared southern New England. Transactions of the American Fisheries Society 4: 719-725. Lyman, H. 1974. Successful Bluefishing. International Marine Publishing Company. Camden, Maine. 112 p. Olla, B. L., A. J. Bejda, and A. D. Martin. 1975. Activity, movements, and feeding behavior of the cunner, Tautocolabrus adsoersus, and comparison of food habits with young tautog, Tautoaa onitis, off Long Island, New York. Fishery - Bulletin. 73(4): 895-900. Sokal, R.R., and F. J. Rohlf. 1969. Biometry: The principles and practice of statistics in biological research. W. H. Freeman and Company, San Francisco. 776 p. j' Thomas, J. M., and P. Van Voris, 1986. Statistical approaches for quantitatively assessing ecological impact and risks. E 3 Proceedings: Risk Assessment in Aquatic Ecology. pp. 2-63 to 2-81. Woolner, F., and H. Lyman. 1983. Striped Bass Fishing. Nick ' Lyon Books, Winchester Press. 192 p. I I L l
.s
1 I FINAL SEMIANNUAL REPORT Number 35 (volume 1 of 2) I to BOSTON EDISON COMPANY I I I BENTHIC ALGAL AND FAUNAL MONITORING AT THE PILGRIM NUCLEAR POWER STATION (CHARACTERIZATION OF BENTHIC COMMUNITIES) January - December 1989 I I by Nancy A. Padell and Robert E. Hillaan I g April 4, 1990 BATTELLE MEMORIAL INSTITUTE Duxbury Operations I 397 Washington Street Duxbury, Massachusetts 02332 I
. I'
I I TABLE OF CONTENTS Page EXECUTIVE
SUMMARY
........................................ 1 I N TR O D*J C T I O N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 M2THODS.................................................. 3 OUANTITATIVE ALGAL AND FAUNAL SAMPLING.............. 3 I Benthic Samp11ng............................... Sampling Techniques............................ 3 3 QUALITATIVE TRANSECT SURVEY......................... 6 LABORATORY ANALYSIS................................. 13 rsunal Processing.............................. 13 nigal Processing............................... 14 DATA ANALYSIS....................................... 16 Analytical Techniques.......................... 17 I RESULTS.................................................. 21 I FAUNAL MONITORING................................... Systematics.................................... Species Richness............................... 21 21 21 I Faunal Density....................... ......... Species Dominance.............................. Species Diversity.............................. 23 25 29 Measures of Similarity......................... 31 ALGAL MONITORING.................................... 44 Algal Community Description.................... 45 I Algal Community Overlap........................ Algal Biomass.................................. Chondrus/Phyllophora Colonization Index Study.. 45 46 54 I QUALITATIVE TRANSECT SURVEY......................... March 1989 Transect Survey..................... June 1989 Transect Survey...................... 56 56 59 I September 1989 Transect Survey................. December 1989 Transect Survey........ ..... .. 59 61 HIGHLIGHTS OF haS'LTS.................................... 63 FAUNAL MONITORING.. ................................ 63 ALGAL MONITORING......... .......................... 63 QUALITATIVE TRANSECT SURVEY......................... 64 ACKNOWLEDGMENTS.......................................... 64 LITERATURE CITED......................................... 65 I ii
t LIST OF TABLES Page- , Table 1. The Algal Species Used in the Quantitative ' Community Analyses............................ 15 i Table 2. Faunal Species Richness for March and September 1989................................ 22 Table 3. Faunal Densities at the Effluent, Manomet Point, and Rocky Point Stations in March and September 1989...................... 24 Table 4. Rank Order of Abundances for the 15 Most Abundant Faunal Taxa in Samples Collected in March and September 1989...................... 26 Table 5. Diversity Values for Each Station Sampled in March and September 1989...................... 30 Table 6. Species Groups Identified by Inverse Cluster Analysis of March and September 1989 Data..... 39 Table 7. Average Dry Weight Biomass per Replicate (g/m ) i of Macroalgae at Effluent, Manomet Point, and Rocky Point Subtidal (10 ft MLW) Stations in March 1989.................................... a 50 g ! Table 8. Average Dry Weight Biomass per Replicate (g/m ) of Macroalgae at Effluent, Manomet Point, and Rocky Point Subtidal (10 ft MLW) Stations in ' September 1989................................ 51 Table 9. Colonization Index values for Chondrus crispus and Phyllophora spp, at the Manomet Point, Rocky Point, and Effluent Subtidal (10 ft MLW) g Stations in March and September 1989,......... E5 g I I' I I' I m I I'
I LIST Or FIGURES rigure 1. Location of the Rocky Point, Effluent, r.nd Manomet Point Subtidal (10 ft MLW) Stations... 4 rigure 2. Rock Substratum Airlift Sampling Apparatus.... 7 rigure 3. Location of the Qualitative Transect Surveys.. 9 .I rigure 4. Underwater Writing Tablet Used by Divers During the Qualitative Transect surveys....... 11 rigure 5. Dendrogram Showing Results of Cluster Analysis of Data Using Bray-Curtis similarity and Group Average Sorting............................... 33 Figure 6. Dendrogram Showing Results of Cluster Analysis of Data Using Normalized Expected Species I Shared (NESS) Similarity and Group Average Sorting....................................... 34 I rigure 7. Dendrogram Showing Heaults of Cluster Analysis of Combined March and September 1989 Data Using Bray-Curtis Similarity and Group Average . Sorting....................................... 36 Figure 8. Dendrogram Showing Results of Cluster Analysis of Combined March and September 1989 Data I Using NESS Similarity and Group Average Sorting....................................... 37 I rigure 9. Dendrogram Showing Results of Cluster Analysis of 50 Numerically Dominant Species From March and September 1989 Saaples Using Dray-curtis Similarity and Group Average Sorting.......... 38 Figure 10. Constancy Diagram for Specice Groups and Replicate Groups in 1989...................... 42 Figure 11. Tidelity Diagram for Species Groups and Replicate Groups in 1989...................... 43 Figure 12. Algal Community overlap (Jaccard's Coefficient of Community) and Number of Species Shared Between Replicate Pairs at the Manomet Point, I Rocky Point, and Effluent Subtidal Stations (10 ft MLW), March 1989....................... 47 I rigure 13. Algal Community Overlap (Jaccard's Coefficient of Community) and Number of Species Shared Between Replicate Pairs at the Manomet Point, Rocky Point, and Effluents Subtidal Stations
.I (10 ft MLW), September 1989...................
iv 48 I. .
I LIST OF FIGURES (Continued) I Figure 14. March 1989 Qualitative Transect Survey of the PNPS Acute Impact Zone off the Discharge Canal 57 Figure 15. June 1989 Qualitative Transect Survey of the PNPS Acute Impact Zone off the Discharge Catial 58 Figure 16. September 1989 Qualitative Transect Survey of the PNPS Acute Impact Zone off the Dischar Canal.....................................ge
.... 60 Figure 17. December 1989 Qualitative Transect Survey of j the PNPS Acute Impact Zone off the Dischar Canal.....................................ge
.... 62 LIST OF PLATES i
Plate 1. Aerial View of the Rocky Point and Effluent Quantitative Sampling Stations................ 5 Plate 2. Aerial View of the Manomet Point Quantitative Sampling Station....................'.......... 5 I! I Il ; I I: I , I V I i
I EXECUTIVE
SUMMARY
I This report presents the results of the 1969 benthic monitoring surveys at the Pilgrim Nuclear Power Station (PNPS). I The surveys are part of a long-term monitoring effort by Boston Edison Company (BECO) to assess the impact of the thermal effluent on the inshore benthic community Volume 1 of this report characterizes the benthic environment and its seasonal changes in 1989. i.-thods and procedures follow guidelines established by the Pilgrim Administrative TeC V.ical Committee (PATC) and adopted by BECO as modified in 1981. Methods and procedures are described in Volume 1 of this report. - The habitats and their algal and faunal communities found 1 at the Manomet Point, Rocky Point, and Ef flue; t subtidal stations are typical of shallow, exposed areas in western Cape J Cod Day. The rocky substrata characteristic of all three statiuns are covered with dense macroalgal communities typically dominated by Chondrus crispus and Phy11ophora spp. This algal turf has created a habitat suitable for diverse faunal communities. In past years, faunal species at all three I sampling stations have numbered from 50 to more than 100, and total faunal densities have ranged from 10 to 10 6 individuals 4 per square meter. In 1989 as in 1988, faunal communities were l dominated by the blue mussel, Mytilus edulis. Major results of the 1989 sampling were the substantial but unexplained decrease ; in Mytilus edulis in the fall at the Rocky Point and Manomet i Point sites, the reappearance of a dark red alga, believed to be the warm-water alga Gracilaria tikvahiae, at the Effluent in September and December, and the reappearance of a demarcated denuded zone at the Effluent station. i l' i 3 1
3 r q ; ; :.:;.;3. g g:.[.}3.}_,:. : = ? a q;;G ;;; ;;}~;.;: y;;; 2:7;;l7ly ;;3 1 I INTRODUCTION I This report presents, in a condensed format, the results of (1) the March and September 1989 benthic quantitative g surveys and (2) the March, June, Septemb9r, and December 1989 5 transect surveys performed at the Pilgrim Nuclear Power Station (PNPS) under Doston Edison Company Purchase Order #66229. Detailed technical information is available from Battelle, upon request, through Boston Edison Company. The report is separated into two volumes. Volume 1 characterizes the benthic environment and its seasonal changes in 1989; Volume 2 discusses the impact of the PNPS operations on the benthic communities, based on the observations described in Volume 1 and compared to earlier observations (1983 to 1988). This format makes the results accessible to readers who are more interested in overall results than in technical details. The Pilgrim Nuclear Power Station is located on the northwest shore of Cape cod Bay, 8 km (5 mi) southeast of Plymouth Harbor, Massachusetts. The quantitative algal and faunal data in this report were derived from field samplings in g March and September 1989. Qualitative transect dPta were 3 collected on March 28, June 19, September 28, and December 15, 1989. Data discussed in this report were collected following an outage that began in April 1986 and continued through February 1989. During the reporting period, on average, two circulating water pumps were operating. I I-I 2 II 8'
I I METHODS - I The methods and procedures follow guidelines established by the Pilgrim Administrative Technical Committee (PATC) and I adopted by Boston Edison Company as modified in 1981. and procedures, including modifications made Methods in subsequent years, are described below. QUANTITATIVE ALGAL AND FAUNAL SAMPLING
- g. Benthic Sampling -
.m . The quantitative studies measure and compare benthic community parameters at three stations (rigure 1, Plate 1, and Plate 2): a surveillance station located nearly 120 m offshore from the mouth of the discharge canal (Effluent station), and two reference stations located 0.25 nmi northwest (Rocky Point) and 2 nmi southeast (Manomet Point) of the Effluent station.
Quantitative benthic samples were collected at mean low water l (MLW = 10 feet) on March 28 and September 28, 1989 at all three stations . Precise station locations are determined by visual bearings by using specific structures located on the shore ~and by lowering a lead line overboard to find the MLW depth. The l ( Rocky Point station is located by lining up the PNPS red and white off-gas stack with the siren tower. The Effluent station I is identified as the center line between the two discharge jetties. The Manomet' Point station is located by lining up the outermost street lamp pole with the double-crossed pole behind I- it (both poles are located along the southern bank of Manomet Point). Sampling Techniques All sampling was performed by a team of SCUBA divers who used a Battelle research vessel as their base of operations. 3 L LI
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O SUBTIDAL (10 ft MLW) STATIONS. 4 5.- . 1 ( . - . . - - . - .- - - . _ _ _ . - . . - - - - . . _ _ - - _ . - - - - - - - - - . - - - - . - - - - - - - - - ~ - . - - , - - n ~ - - - -
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g ,., ' e .I ' PLATE 1. AERIAL VIEW OF TH.S ROCKY POINT AND EFFLUENT l j ouxNTITarzvr sAnenINo sTArroNs. I l I e
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l I lI I e'^1e 2. ^e 1^' v'e or r>>e SAMPLING STATION.
~~o er eo 1 oux 1 ^r>ve I 5 I
I sampling equipment consisted of an airlift sampling apparatus I and a metal pipe-frame quadrat measuring 0.33 m on a side (rigure 2). The quadrat ensured that a uniform surface area of 2 0.1089 m was consistently sampled from each rock. A standard SCUBA tank supplied the suction necessary to operate the airlift device. The sample collection procedure is as t'ollows. At each station, the divers descend with the sampling equipment and randomly select large, flat-surfaced rocks or boulders for sampling. (Small rocks with less than twice the surface area of the quadrat are not sampled because of their susceptibility ; to movement or dislodgment during storms and because they may ' have an unstable resident community.) The quadrat is placed on g a rock by a diver who positions the airlift device a few inches B above t'.ie rock. Using a sharp-bladed tool (such as a paint scraper), a second diver scrapes the area within the quadrat. The loosened algae and resident fauna are carried by suction up through the airlif t into a Nitex bag (0.5-mm mesh) attached at ' the opposite end. When the area within the quadrat has been l scraped clean, the Nitex bag is removed, sealed, and placed j into a large nylon mesh catch bag. Five replicate samples are i taken by this procedure at each station, and taken to the vessel. g 3 i on board the vessel, the sealed Nitex bags are placed in a bucket containing seawater. While the vessel travels to the next sampling station, the contents of each Nitex bag are transferred to a pre-labeled individual 1-gal plastic jar I containing 10 percent formalin and 100 g of borax (a buffering ! agent that prevents softening of calcified shells). After the ; entire sample is transferred, the jar is filled with seawater. 4 OUALITATIVE TRANSECT SURVEY Qualitative transect surveys were made along the axis of the discharge canal on March 28, June 19, September 28, and December 15, 1989. This phase of the study maps the lat' e ral 6
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FIGURE 2. ROCK SUBSTRATUM AIRLIFT SAMPLING APPARATUS. 7 I
I and offshore extent of denuded and stunted algal zones directly I offshore from the PNPS discharge canal (rigure 3). Because of the complexity of this procedure, the methods and procedures followed during the qualitative transect surveys are presented g below in the sequential order of events. W I. Laving out Transect Line A. Equipment e Base line, 1.92-cm nylon, approximately 35 m long e Two dive flags e Transect line, 1-cm nylon, with lead weights and distance marks every 10 m, 100 m long e Anchor (Danforth) for seaward end of transect line e Marking buoy plus line attached to end of transect
?
line e- Diver-safety line, attached from buoy to research vessel ! B. Procedure ai g,
- 1. The research vessel and crew approach the effluent canal. Two crew members transport the base line onto the jetty. The vessel maneuvers approximately 90 m offshore of the effluent canal and sets an anchor with an attached marking buoy, the vessel waits outside the effluent canal while the base line is fastened to an g eyebolt on the north jetty. The free end is carried 3 across the effluent canal via the top of the barrier net or the canal bridge. This end is attached to an a eyebolt on the south jetty. The base line is drawn- g-tight and tied off, crossing perpendicular to the effluent canal. This line provides a point of attachment for the transect line from the center of the _E-effluent canal. A dive flag is attached to the canal B bridge.
- 2. The vessel maneuvers into the effluent canal, picks '
up the crew members, and approaches the base line. The ! transect line is attached by snaphook to the center - point of the base line. The vessel maneuvers seaward parallel to .the effluent canal while a crew member feeds out the transect line. Sufficient tension is 8 I 8,
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Anchor & une N I I FIGURE 3. LOCATION OF Tile QUALITATIVE TRANSECT SURVEYS. 9 I
I, maintained to keep the transect line straight and in , the center of the effluent canal. The transect line is i fed out until the.end anchor and attached marking buoy , are reached. The buoy line is cleated off and engine power is used to stretch the transect line tight and align it along the center line of the effluent canal. When the transect line is straight and centered, it is lowered to the bottom with the buoy line, and the marking buoy is released.
- 3. The vessel is positioned near the seaward end of the transect line and anchored. A diver safety line is rigged from the marking buoy to the vessel to facilitate diver access to the transect line. The safety line is kept sufficiently clack to avoid lifting the transect line. A dive flag is secured te the a vessel.
E II. The Transect Survey , A. Equipment e one white underwater writing tablet and pencil 3 (Figure 4) E The tablet is used to record measurements and observations, for each 10-m interval. Thg compass course (310 for the northwest zone; 130 for the southeast zone) for each measurement angle is written on the tablet. e Dacron measuring line (30 m long) wound on a plastic reel Line distances are marked with orange fluorescent paint and duct tape for each 5-m interval. e Nylon mesh catch bag , e Two magnetic diving compt. ses B. Personnel ' Two divers are required and each has specific duties. e Div&x No. 1. Serves as the. dive leader; carries g writing tablet, measures algal transition zones, 3 makes general observations, and signals for transfer of the measuring line.
- j. e Diver No. 2. Reels out measuring line perpendicular L to the transect line, then remains stationed just L
10 I I
I I I I Stunted Denuded U Stunted Denuded k To... To. N To... To... 10 10 20 20 I 30 30 Ce 40 40 11 1/ 2 I in. 50 60 50 60 "" 70 70 80 60 90 90 .R E South " North
,, Course 130 Course 310*
8 - in. I I FIGURE 4. UNDERWATER WRITING TABLET USED BY DIVERS DURING THE QUALITATIVE TRANSECT SURVEYS. I-11
I ll ; beyond stunted zone with reel in hand. On signal, Diver 1 transfers measuring line to successive 10-m a marks, g C. Procedure
- 1. Divers Nos. 1 and 2 descend the buoy line co the seaward end of the transect line. Divers swim along IP the transect line toward effluent canal and note 3 changes in Chondrus crispus density and condition.
Several passes are made by Diver No. I to identify the 3 transitional zones between normal, stunted, and denuded growth. These zones are based on the distribution of Chondrus and are defined as follows: e Normal Zone: Chondrus are density, height, and frond g development typical for the local natural 3 environment, e Stunted zone: Chondrus is found on the upper surfaces of the rocks but is noticeably inferior in height, density, and frond development to normal Chondrus growth. - e Denuded Zone: Chondrus-occurs only as stunted plants restricted to the sides and crevices of rocks. No g Chondrus is found on the upper surfaces of rocks in g this area, except where the microtopography of the rock surfaces creates small protected areas.
- 2. Diver No. I records the distance from the base line '
where the denuded and stunted zones intersect the transect line. Measurement is made to the nearest , meter by interpolation between the 10-m marks. '
- 3. Diver No. 2 takes position at the first mark shoreward of a transition zone and attaches the measuring line to the transect line. DgverNo. 2 swims from that point on a course of 310 , unwinding the measuring line. This establishes a line of measurement E perpendicular to the transect line. Diver No. 2 stops 5 just beyond the stunted / normal transition zone.
- 4. Diver No. I checks the compass bearing of the measuring line and corrects the position, if required.
Diver No. 1 then swims along the measuring line from the transect line point of attachment to the distal end. Several passes are made back and forth to clearly . define transition zones, once the transition zone is defined, the distance (to the nearest meter) _ is measured and recorded on the tablet. g Diver No. I then g communicates his perception of the stunted / normal transition zone to Diver No. 2 for a second opinion. 12 E.
I I If there is a discrepancy, additional observations are made to clearly delineate the transition zone.
- 5. Diver No. 1 swims back along the measuring line toward the transect line and records general I observations assemblages.
regarding the floral and faunal
- 6. Diver No. 1 signals for transfer of the measuring line by tugging on the line. Diver No. 2 then moves I- the line shoreward to the next 10-m mark.
I [The 10-m procedure from steps 2-6 is repeated until each distance surveyed.) from the base line is measured and
- 7. Upon reaching the north jetty, Diver No. I records the distance of the submerged jetty ends from the base line. These data help serve to calibrate the transect line position for mean high water (MHW).
- 8. Diver No. 1 swims inside the effluent canal toward I the base characteristics.
line and records the algal growth
- 9. Diver No. .2 measures the transition zones on the I southeastern side of the transect line.
and observations are taken by Diver No. 1. previous procedures are repeated along successive 10-m Measurements The I marks seaward. Diver No. 2 swims a magnetic course of 130 to position the measuring line at each interval.
- 10. When all measurements- and observations are completed, the divers ascend and return to the vessel.
- 11. The crew retrieves the transect line and the base line.
- 12. At the laboratory, the field notes are incorporated into a field report and submitted to the Project Manager.
LABORATORY ANALYSIS Faunsl Processing The algal and faunal components of each replicate sample are separated in the laboratory by washing and removing (by using forceps) the organisms from the algae onto a 0.5-mm mesh screen. The fauna are preserved in 70 percent ethanol, and the 13
=__ . __ _____
algae are returned to a 10 percent formalin in seawater solution. Each faunal sample is divided into a 0.25 percent aliquot and a 0.75 percent aliquot by using a rolsom splitter prior to sorting. A solution g of Rose Bengal stain is added to each 3 faunal aliquot. The 0.25 percent aliquot from each replicate is processed and the 0.75 percent aliquot is archived. In 1989, ' the fauna were- analyzed by Ocean's Taxonomic Services; organisms were identified to the lowest possible taxon by using research-quality stereomicroscopes and compound microscopes. Identifications were verified by a Battelle taxonomist familiar with taxa found during thir, program. Bryozoans, colonial hydroids, or spirorbid worms were not identified or enumerated becuse they are attached epifauna on the algae and their presence in the faunal fraction is an underestimate of their abundance. These epifauna were noted during the' algal processing. Algal Processing The entire algal component of each replicate sample is examined, using both stereomicroscopes and compound microscopes, to determine the presence or absence of 37 indicator species (Table 1). The indicator species were chosen .in September 1978 from 'a list of the several hundred algal species recorded from the PNPS study sites ducing 1974-1978. Selected species include members of three major algal families and are representative of a variety of habitats. The indicator species include all dominant macroalgal species within the study area, the majority of the macrophytic species, and the most common epiphytic species. Although the indicator species constitute only a small fraction of the total number of species inhabiting the study area, they comprise by far the most substcntial part or the algal community as measured by both percent cover and biomass. Also recorded are algal species present in addition to the 37 indicator species and 14 l'
E I TABLE 1. ALGAL SPECIES USED IN THE QUANTITATIVE COMMUNITY ANALYSES. SPECIES ARE (TAXON, 1982) UNLESS NOTED OTHERWISE.[NDICATOR SPECIES CHLOROPHYTA (green algae) I Bryopsis plumosa b Enteromorpha flexuosa I Chaetomorpha linum Phizoclonium riparium C_ . melagonium Ulva lactuca Cladophora spp. juv.a PHAEOPHYTA (brown algae) Chordaria flagelliformis b Laminaria digitata I Desmarestia aculeata D. v, iridis b L. saccharina Sphacelaria cirrosa RHODOPHYTA (red algae) Ahnfeltia plicata Phycodrys rubens Antithamnion americanum Phyllophora truncata Bangia spp. juv.",D P. pseudoceranoides Bonnemaisonia hamifera P. traillii Plumaria elegans b I Caliophyllis cristata Ceramium rubrum Polyides rotundus Chondrus crispus Polysiphonia elongata b _Corallina officinalis P. fibrillosa Cystoclonium purpureum P. harveyi Gracilaria tikvahiae b . nigrescent Gymnogongrus crenulatus b P, . urceolata l Membranoptera alata Rhodomela confervoides b Palmaria palmata Spermothamnion repens
- This species was not originally designated an indicator species.
This species was not found in the 1989 data. L 15 LI
j l similarities and differences between each replicate sample. A voucher collection of permanent slide mounts has been created. The slides include reproductive structures and other taxonomic characters. The Chondrus crispus and Phyllophora spp. fractions of each replicete sample are examined to assess the degree of algal and faunal colonization of the host species. The algal colonizers include epiphytic species such as Spermothamnion - repens, Ceramium rubrum, _Cystoclonium purpureum, and Polysiphonia spp.; the faunal colonizers are primarily the encrusting hydrozoans, bryozoans, spirorbid worms, and blue ' mussel s. pat (Mytilus edulis). Each Chondrus and Phyllophora replicate fraction is compared with a set of four reference samples t. hat are ranked according to increasing levels of algal and faanal colonization. Each fraction is assigned the numerical value of the reference sample to which it is most similar. Separate algal and faunal colonization indices are determined for the Chondrus and Phyllophora populations of each station by summing the valt.es assigned to the five replicate samples. Dry weight biomass of each sample is determined for four g* 5 separate algal fractions: Chondrus crispus, Phyllophora spp., epiphytic algal species, and the remaining benthic species. Total algal biomass is also determined. Each fraction is weighed on a Mettler balance after drying for 72 h in a 0 standard drying oven set at 70 C. DATA ANALYSIS Data analysis is performed at Battelle on a Digital Equipment Corporation VAX computer system. All species are coded onto npecifically designed project data sheets as the samples are processed. Data are entered twice into separate files, and a VAX Utility Differences program is run to compare the two files for discrepancies. Any differences are verified against the original coding sheets and corrected. 16 I.
I I Analytical software consists of a suite of statistical developed I programs data. In specifically for the analysis of benthic addition to a variety of data management and modification programs, these programs include primarily PRARE1 and CMPHNW. PRARE1 summarizes the data for each sample, calculates a variety of diversity-related indices, and generates a rarefaction curve. CMPHNW is a multivariate classification package that contains a wide variety of user-specified options for implementing similarity indices and clustering strategies. CMPHNW allows both normal and inverse I analyses to be performed. Analytical Techniques Rank Order of Abundance I The individual species comprising the fauna at each I station down to are rank ordered for each replicate from most abundant the least dominant forms. The contribution of each
- g species to the overall total percent of the fauna is denoted by 3 a decreasing cumulative percentage, starting with the most dominant species and ending with the most rare. To obtain the rank order for each station, basic statistical analyses, including calculation of means and extrapolation to an abundance per square meter are performed on each replicate sample, rollowing this organization of the data, it is I possible or to determine if species composition changes with time with locality. Since some species may be more sensitive to stress than are others, knowledge of the biological characteristics of an individual dominant species is essential.
Diversity Measures Shannon-Wiener diversity (H') and evenness (J') values (Levinton, 1982) are calculated for samples collected during both spring and fall samplings. Juveniles and indeterminate 17 1 I
i I individuals (damaged specimens that could not be identified.to I species) are excluded from these calculations. A jackknife proceduro - for determining species richness is : used, in . combination with pooled species data in' order to evaluate the contributions of rare species to the communities. g[ W This jackknife procedure fo??ows methods developed by Heltshe and Forrester (1983). This procedure takes into account the fact that finite random samples of a population are not a true representation of a population. The jackknife estimate of species richness ~ is a function of the number of so called t "uniq w rpecies present at each station, " unique" being defined as those species present in one and only one replicate j at a station.- The jackknife estimate of species richness (5) ! is expressed as l i l S - S +-[(n - 1)/n] k , ; where S represents the pooled species numbers at each station, . n- is the number of replicates, and k is the number of unique j species. The variance of estimated species richness (var (S)] is ' also calculated. This parameter measures the spatial distribution of unique species, i.e., that occur in only one replicate from a station.
' Similarity Measures E'
The most direct measure I. of faunal similarity between samples is the number of species in common. The concept of species shared is biologically meaningful and can be readily i visualized in terms of species distribution. Similarity analyses are performed by using two measures: (1) NESS - (Normalized Expected Species Shared)(Grassle and Smith, 1976), and (2) Bray-Curtis (Boesch, 1977). NESS is based on the expected number of species shared between random samples of size m, drawn from a population. NESS is more sensitive to 18 I
I rare species in the populations to be compared, etsv-cortis I values- are (inverse) by calculated using- the for replicates (normal) and nf r p e a '. e s numbers of individuals fo.rai. Wese measures are used to elucidate community patterns tur (1) I normal cluster analysis, where all replicate samples are compared for species present in each replicate, and (2) inverse cluster analysis, where the co-occurrence of the top 50 numerically' dominant species at all three stations are compared. Nodal analysis Nodal analyses were performed using the results of the Bray-Curtis similarity analyses. Nodal analysis is a method for relating the groupings resulting from normal cluster analysis (by replicate) and inverse analysis (by species) to enhance the interpretation of the resulting patterns (Boesch, 1977). The method proceeds by using two-way tables that show replicate groups on a vertical axis and species groups on a measures constancy and I horizontal axis. This technique fidelity. Constancy is defined as a measure of the frequency (number of occurrences) of a group of species in each group of replicate, samples. The constancy index (Cg3) is expressed as C 13 - a 33/(n ng 3) , where actual number of occurrences of members of a) g species group is the i in replicate group j, ny represents the entities in species group i, and n represents the entities in 3 replicate group j. I Fidelity is an indicator of the degree to which species are exclusively associated with the replicates in a particular seasonal site group. ridelity is an expression of the 19 I
IL constancy- of.' species in a-replicate group as compared to the constancy- over all replicates. Thus, the fidelity of species-group i in replicate group.j is expressed as
-F g3 = la g3 n))/(n) agg) ,
using-the same' terms as in the constancy.-index. I I I I I I I I I I g; I I 20
'I RESULTS I- PAUNAt. MONITORING Systematics During this program, a total of 483 invertebrate species has been observed in the studi area. In 1989, 11 previously unreported taxa were added to the list of benthic invertebrates recorded at PNPS. These taxa included five arthropods. (Heteromysis formosa, Decapoda zoea, Gammarellus spp., Brachyura zoea, and Brachyura spp. juvenile), three molluses (Mitrella spp. juvenile, Nassarius .spp. juvenile, and Cerastoderma .spp.), two polychaete annelids (Aglaophamus spp. and Flabelligera spp.), and one echinoderm (Strongylocentrotus spp. juvenile). _I Species Richness number of invertebrate species found (i.e., species-I The richness) at each station in March and . September 1989 is presented in Table 2. During the March sampling, the number of species found at the Effluent station (56) ranked between Manomet Point (58) and Rocky Point (55). When compared to the March 1988 data, the number of species collected at the reference statieno decreased, but the number of species at the Effluent increosed. By September, the number of species found at the Effluent station remained the same, and the station still ranked between~ I: Manomet Point (55) and Rocky Point (61). Values at both the Effluent and reference stations were less than those seen in September 1988. To assess the rare species that might be present at the stations but were not found because of the small total area sampled at each station (0.5445 m2), a jackknife estimate was calculated (Heltshe and Forrester, 1983). The highest 21
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l El TABLE 2. FAUNAL SPECIES RICHNESS FOR MARCH AND SEPTEMBER 1989 Number of. Species Rich.iess Variance I" Station / Month Species (S) ($)(195% CI) [ var (8)] Effluent Harch 56 69.6 ( 16.69) 36.16 i September' 56 64.0 (s. 3.51) 1.60 Manomet Point March 58 66.0 ( 4.97) 3.20 t September 55 65.4 ( 8.31) 8.96 ;' Rocky Point i Harch 55 00.6 ( 5.66) 4.16 September 61 69.0 ( 10.53) 14.40 - a CI: Confidence interval. i I I-3" I I I 22 I E. 1
I I estimated species richness (S) was in March at the Effluent station,-but by September Rocky Point had the highest estimated species richness (Table 2 ) .. In 1989, the estimated species richness did'not differ significant1y among stations, indicated by the overlapping 95 percent confidence intervals.
'The variance of the estimated species richness [ var (S))
is a measure of the spatial distribution of species that occurs in only one replicate from a station; these species are I referred that all to as unique specieu. unique species are concentrated in a small area at High var (S) values indicate that station; low var (%) values indicate that the unique species are distributed randomly over the area sampled. High var (S) values were found only at the Effluent station in March, whereas the values at the reference stations were very low. By September, these values had dropped at the Effluent station but increased at the reference stations, indicating that the communities at the three stations had become more similar-in distribution of unique species. Faunal Density Benthic macrofaunal relative abundances (individuals /m2) were calculated for total taxa, including juveniles and damaged specimens that could not be identified to species (indeterminates), for both sampling periods (Table 3). In March, mean density at the Effluent was less than one-quarter found at the Manomet Point and Rocky Point stations. I of By that September, however, the mean density at the Effluent had mean
-increased by 346 percent and was greater than the densities at the reference stations. Unlike 1988, when densities increased at all stations from spring to fall, the Rocky Point and Manomet Point mean densities had decreased by 52 and 16 percent, respectively, in 1989. This decrease et the reference stations is due primarily to substantial and I 23 g
I I I TABLE 3. PAUNAL DENSITIES AT THE EFFLUENT, MANOMET POINT, AND ROCKY POINT l GTATIONS IN MARCH AND SEPTEMBER 1989 W Mean Number of NumberofIgdiv." NumberofIgdiv." Individuals" per per m per a Replicate (Mytilus included) (Mytilus excluded) Mar Sep Mar Sep Mar Sep Effluent 6,029 26,894 55,363 246,961 17,172 79,440 - Manomet Point 28,374 23,799 260,551- 218,540 31,699 92,617 Rocky Point' 34,973 16,866 321,148 154,876 59,807 70,285 e I I I
. I I
I I I I 24 I l
.a
I I unexplained decreases in the number of Mytilus edulis collected I at these sites. Most of the increase in faunal density at the Effluent could be directly attributed to increases in other species as well as in Mytilus edulis. When Mytilus was excluded from the calculations, the total abundance of all other organisms showed an increase ranging from 175 to 363 percent from spring to fall at all stations (Table 3). The increase was most pronounced at the Effluent station, where abundances excluding Mytilus rose 2 7 from 17,172 individuals /m in the spring to 79,440 2 individuals /m in the fall. Species Dominance The 15 numerically dominant species at each station were determined by using the mean number of individuals per replicate (Table 4). For this analysis, the juveniles and I indeterminates determined. were excluded because the species could not be The dominant species at all stations during both sampling periods was Mytilus edulis, which accounted for over I 62 percent of the collected fauna, dominant taxa at the three stations were arthropods (amphipods, Most of the remaining isopods, decapods, caprellids, etc.) as has been found at these rocky subtidel locations in the past. During March, eight of the 15 dominant species at Manomet Point and nine of the 15 dominant species at Rocky Point were I also species found at the Effluent. in common, with the The two reference stations had 10 two dominant species (Mytilus edulis and Lacuna vincta) being identical in rank at each station. These two species were also the two dominant species at the Effluent. The four dominant species at Rocky Point and at the Effluent were identical in rank. In March, the 15 dominant species contributed approximately 97 percent of the total identifiable fauna at the Effluent, 99 percent at Manomet Point, and 98 percent at Rocky Point. I 25 I
s TABLE 4. -RANK ORDER OF' ABUNDANCE FOR THE 15 DOMINANT SPECIES IN SAMPLES COLLECTED IN MARCH AND SEPTEMBER 1989 l W fteen percent of station masber per Identified
. species Replicate r:me Mhacu 1989
{ f Effluent ateftilus edulis (Bivalve) 4159.2 75.80
*1.acuna vincta (Gastropod) 407.2 7.42 -
*1schyrocerus anguipes (Amphipod)- 188.8 3.44 .
'Jassa talcata (Amphtpodt 136.0 2.48
*corophaum bonelli.(Amphipod) 87.2 1.59
'Pontogeneia 2nerais (Asphipod) 68.8 1.25
*1dotea phosphorea (1sopod) 58.4 1.06
*Dexamine thea (Amphipod) 39.2 0.71
*ca111opiu G oviseulus (Amphipod) 38.4 0.70 Phyllodoce maculata (Polychaetel 28.0 0.51 Pequrus acastanustDecapod) 26.4 0.48 Proboloides holmesi (Amphipod) 21.6 0.39 Pagurum longtearpus (Decapod) 21.6 0.39 onoba aculous tGastropod) 17.6 0.32
_ cancer arroratus (Decapod) 16.0 0.29 Total of 15 spectos $314.4 96.83 Pennining reuna - 41 species 172.0 3.17 Up Total Fauna - 56 species $487.2 100.0 Stenamet Point'
*Mytilus edulis (Bivalve)
- Lacuna vincta (Gastropod)
*Hiatella arctica (Bivalve) 24901.6 846.4 191.2 90.64 3.08 0.70 I.
- *Ischyrocerus anguipe a ( Amphipod) 168.0 0.61
*Jassa talcata (Amphspod) 122.4 0.45 .-
*onobs aculeus (Gastropod) 114.4 0.42
*corophtum bonelli (Amphipod) 112.0 0.41 Hiatella striata (Bivalve) 100.8 0.37
*Margarttee helacinus (Gastropod) 96.0 0.35
, *Plousyntes giaber tAmphipod) _
86.4 0.31 Naineras quadracuspida (polychate) 68.0 0.31
*Desamine g (Amphtpod) 65.6 0.24 strongylocentrotus droebachiensis -
(Echinocerm) 64.0 0.23 -
*Pontooeneta inermis (Amphipod) 60.0 0.22 -
Nerets pelagica (Folychacto) 56.0 0.20 Total of 15 species 27052.8 98.54 Remaining rauna - 43 species 421.6 1,46 Total rauna - 58 species 27474.4 100.00 Rocky Point
*Mytilus edulis (Bivalve) 28460.0 85.29
- Lacuna vincta (Gastropod) 1645.6 4.93
*Ischyrocerus enoutpea tAmphipod) 187.2 2.36
'Jassa falcata (Amphipod) 404.8 1.21
*Margarttes helicinus (Gastropod) 320.0 0.96
*Haatolla arctica.tStvalve) 169.6 0.51 A1vania pseuccareolate (Gastropod) 162.4 0.49 Anomia atmplex tBavalve) 146.4 0.44 Idotea pnospnorea (Isopod) 117.6 0.35
*coropnium acutum (Amphipod) 103.2 0.31
*onoba aculeus (Gastropod) 98.4 0.29
*Pleusvmtes glaber (Amphipod) 96.8 0.29
*corophium bonetit (Amphipod) 93.6 0.28 Proboloides holmest (Amphipod) 92.0 0.27
*Pontogeneta snermis (Amphipod) 79.2 0.24 Total of .15 species 32776.8 98.22 Remaining reuna - 40 species 593.6 1.78 Total Fauna - 55 species 33370.4 100.00 26
TABLE 4. RANK ORDER OF ABUNDANCE FOR THE 15 DOMINANT ~ SPECIES IN SAMPLES COLLECTED IN MARCH AND SEPTEMBER 1989 (Continued) I pesen percent of
- station mmeier per identified
- speel.. seplicate reune survupant 1989
-Etfluent
'Myttius edu11e (Divalvel 18242.4 13.74
*Janea laicata (Amphiped! 1310.4 5.30
*taeuna vincto toestropod) 867.2 3.51 crertdule fornicate toestrep w 675.2 2.73 l ~
*benamine h (Amphipod) 552.8 2.23 corophium ocutum ( Aghtpodt 453.6 1.83 aceropnium innelli ( Amphipod) 453.6 1.83 .
I *1 dotes g ep ares (Isopod)
*Pontogeneta inerate (Amphipod)
*1echyrocerus enquipes (Anhipod!
Plaueystee 91 ster 4 Amphipod) 400.0 336.8 276.8 272.8 ' 1.62 1.36 1.13 1.10
'calltopium laeviseulus (Ampnipod) 123.2 0.50 Hiate!!n arettea tenvalvel 109.6 0.44
, capre11e penantle (Capre111d) 104.8 0.42 capresta lineerte (Capre111d) 84.s 0.34 Total of 15 species 24264.0 98.07
- i. RomaOting reune - 41 species Total ;.dentified reuna - 56 apoctea 475.2 24739.2 1.93 100.00 steneemt Point
'Mytilus adults (Divalvel 13713.6 62.40
*t.acuna vnneta (Gastropod) 2320.0 10.56
'Jassa fenceta (Aghtpod) 1578.4 7.18
*corophium bone!!i (Amphipod) 1424.0. 6.48
*tionantne thea (Amphipod) 590.4 2.69 coropntum eeutum (Amphipod) 356.0 1.62 Capfella ponentle (Captellid) -260.8 1.19 Callioptua Amevneculus ( Appatipod) 214.4 0.98
*Pleueystes gnaber (Amphipod! 156.0 0.71 I *Hietente erettee (Divolve)
*Pentegeneie snormis ( AppMood)
*msigerates heiteanue f eetropod) caprella linearse tcapretild) 152.8 152.8 151.2-116.0' 0.70 0.70 0.69 O.53
*onobe seuleue toastropod) 112.0 0.51
. *1schyrocerue anguipes tAmphipod).. 110.4 0.50 Total of 15 opecies 21409.6 97.44 Itensining rauna - 40 species 566.4 2.56
; Total identitled reuna - 55 species 21976.0 100.00 W mactly Point
*Mytitus edulin (nivolvel 9212.8 63.79
. *Jassa rateata (Amphtpod) 664.8 4J0 Immemine 3 tAmphipod) 660.0 4.57
*tacuna vincts (Gastropod) 597.6 4.14
*corophium bonelli (Amphipedt 400.0' 2.17
*Margarttee hettelnue toastropodt 303.2 2.10
*cotophium acutum (Amphipoil) 264.0 1.83 I, *Pleueymtes ghaber (Amphiped) crepictuta turniente (Castropod)
*onoma seuleun toestropod) 246.4 240.0 200.8 1.11 1.66 1.39
*Htatella arettea (nivalve) 113.6 1.20
*Pontogeneta snormis (Amphipodt 160.8 1.11 capre11a penantta (capre111dl 158.4 1.10 83schyrocerus anguapee (Amphipod) 139.1 0.96 capronta linearts scaprellid) 133.4 0.96 Total of 15 opectee 13560.0 93.89 Pemaining rauna - 46 species 883.2 6.11 Total Identified Fauna -- 61 species 14443.2 100.00 I
- Dominant taxa common to both March and September samples.
27 I
In September, the Effluent and Manomet Point stations shared 13 of the 15 dominant species. The Effluent and Rocky Point stations shared 13 of the 15 species and the two reference stations had 14 species in common. The five most .
- o. abundant species were the same at the reference stations, although the rankings differed. Four of these five were among the five most abundant spec 2es at the' Effluent. During the j fall, the 15 dominant species contributed approximately 98 percent of the total identified fauna at the Effluent station, and 97 and 94 percent at Manomet Point and Rocky-Point, respectively. No polychaetes or echinoderms were among the 15 dominant species during the fall sampling period. -
Both similarities and seasonal changes at the three stations were evident when the dominant species for each sampling period were compared. Mytilus was numerically dominant at all stations during both sampling periods, with- ! abundances increasing considerably from March to September at the Effluent, but decreasing by about 45 and 68 percent at Manomet Point and Rocky Point, respectively. Other species found at-all stations during both sampling periods included one g gastropod (Lacuna vincta) and four amphipods (Ischyrocerus W , anguipes, Jassa falcata, Corophium bonelli, and Pontogeneia inermis). At the Effluent station, nine species that'were dominant-in March remained dominant in the fall. A noticeable change at the Effluent involved three decapods, one polychaete, one amphipod, and one gastropod, that had been dominant species in the -spring but were not dominant in the fall (Table 4). Molluscs increased in abundance at the Effluent from spring to g fall,. and Crepidula fornicata and Hiatella arctica, absent in 5 March, ranked fourth. and thirteenth, respectively, in September. Of the nine dominant species common during both spring and fall, all increased in abundance in the fall; two amphipods increased more than tenfold. The molluscs represented four of the 15 dominant species in the fall and decreased from 84-to 80 percent of the total fauna in spring and fall. 28 I
I At Manomet Point, 11 species were dominant in both spring and fall collections. One echinoderm, two polychaetes, and one Il mollusc (iiiatella striata, rarely collected in spring samples) were dominant in the spring but were not dominant in the fall.
; At. Manomet Point, only eight of the 11 dominant species found in common during both samplings increased in abundance from spring to fall. The molluscs represented five of the 15 most abundant -species during the fall, and decreased from 96 to-75 percent of the total fauna from March to September.
At Rocky Point, 11 of the 15 dominant species were present g in both March and September. Seven of these 11 species 5- increased in abundance from spring to fall. Two molluscs, one isopod, and one amphipod were dominant in the spring-but not in the fall. Molluscs accounted for six of the 15 dominant-species in the fall, and decreased from 93 to /4 percent of the total fauna from March to September. Species Diversity Species diversity is a measure of the species richness-I combined species with the (evenness). distribution of population size of each In general, low-evenness values indicate e,ommunity. is dominated by one or a few species
-~
that .a (Levinton, 1982). Communities with high diversity are normally not stressed. Shannon-Wiener diversity (11') and evenness (J') values (Levinton, 1982) were calculated for samples collected I in March and September 1989 (Table 5). indeterminate individuals were excluded from the calculations. Juvenile and Before 1989, the lowest diversity was found at the I Effluent diversity during was both found campling at the periods. Effluent In 1989, the lowest only in September. In March, the Effluent had the highest diversity and Manomet Point had the lowest diversity. The highest diversity for the year
~
was found at Rocky Point in September. From March to September 1989, diversity increased at all stations. I 29 J I
I 1: TABLE 5. DIVERSITY VALUES FOR EACH STATION SAMPLED IN MARCH AND SEPTEMBER 1989- I5 March 1989- September 1989 . Mytilus Mytilus Mytilus Mytilus Included Excluded Included Excluded Station- H' J' ,H' J' H' J' B' J' _ Effluent '1.73 0.30 '3.82 0.66 1.85 0.32 3.87 0.67 Hanomet Point 0.83 0.14 4.02 0.69 2.24 0.39 3.41 0.59 Rocky Point 1.15 0.20. 3.69 0.64 2.53 0.43 4.39 0.74 H' Shannon-Viener diversity. I j J's Evenness. 1 I 1 B. I I I 30 I ;
- 5. - ,
a__-___.___-__--_--------______.
I y To facilitate comparisons with data from previous years, Mytilus edulis was excluded from 1989 statistical analyses owing to the species' high abundance relative to the abundances of all-other reported species. Statistical analysis excluding
;g& Mytilus resulted in higher diversity and evennero values at all stations during both' samplings. However, diversity and evenness values at the Effluent were intermediate between those seen at the reference stations, and the highest values were found at Manomet Point in March and at Rocky Point .in September.
Measures of Similarity
- Similarity analysis followed by cluster analysis (Boesch, 1977) was used to answer the following questions about the structure of the benthic communities present at the three stations sampled in 1989:
e' Does the benthic community at the Effluent station differ from the benthic community at each reference station? e Do seasonal changes of .the benthic community at the Effluent station differ I. from those at the reference stations?
.
- If there are differences in. species composition and/or seasonality, which species cause these differences?
To answer these. questions, similarity analyses were performed by using two measures: Bray-Curtis (Boesch, 1977) and the Normalized Expected Species Shared (NESS) (Grassle and Smith, 1976). These measures were used to elucidate community L patterns .for (1) normal cluster analysis, where all replicate
- samples taken in 1989 were compared for the species present in each replicate, and (2) inverse cluster analysis, where the co-occurrence of the top 50 numerically dominant species identified in the 1989 samples was compared.
I 31
o l I Normal Analysis The results of the Bray-Curtis similarity analysis for the spring samples are shown in rigure 5(A). The group of Effluent g station replicates cluster together at the 0.65 similarity B~ level and are similar to the group of replicates-from the reference stations at the 0.30 similarity level. In other words, they are more dissimilar than similar. The replicates at the two reference stations were very similar to each other and did not form distinct station groups. By the fall, the replicates did not cluster into distinct station groups [ Figure 5(B)). The analysis resulted in a . dendrogram that showed greater similarities among replicates . collected at different stations than among the replicates collected at the same station. Much of the sample similarity could be attributed to the dominance of the mussel Mytilus edulis. To minimize this influence, NESS, a similarity measure that is more sensitive to rare species, was used (Figure 6). The dendrograms for March and September were somewhat similar, in that the replicate g' samples at the Effluent form discrete clusters. In March, all W replicates of the reference stations, except. MP3, cluster together at the 0.82 similarity level and.all replicates from the Effluent cluster together at the 0.79 similarity level. The group of Effluent station replicates is similar to the . group of replicates at the reference stations at about the 0.70 level indicating that the reference stations are more similar to each other than they are to the Effluent group. - In September, different pattern is seen. The Manomet a g Point replicate group (plus RP3) and the Rocky Point replicate E group (four replicates) each clusters at about the 0.91 similarity level. All Effluent replicates cluster together at the 0.95 similarity level and are more similar to Manomet Point replicates (and RP3) than to the remaining Rocky Point replicates, indicating that the Effluent station has become more similar to Manomet Point (and RP3) than to Rocky Point. 32
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l 8 i . W . t0 I I REPLICATE MP1 MP2 MP4 MP3 MPS RP3 eft (F2 EF3 EF4 EF5 RP1 RP5 RP2 RP4 - FIGURE 6. DENDROGRAM SIIOWING RESULTS OF CLUSTER ANALYSIS OF DATA, USING NORMALIZED EXPECTED SPECIES SIIARED (NESS) SIMILARITY AND GROUP AVERAGE SORTING. (A) MARCII 19 89. (B) SEPTEMBER 1989. ' 34 I I
I The Bray-Curtis cluster analysis of the combined spring I and fall data patterns (rigure 7). was performed to examine the data for seasonal The replicates did not cluster into clear groups,. which would have indicated strong seasonal differences I in species -composition at each station. from different samplings clustered together. Instead, replicates For example, Manomet Point replicate 2 collected in September was more similar ~ to one Rocky Point and two Manomet Point replicates collected in March than it was to the other replicates collected in September. When NESS is applied to the combined data sets, less I' emphasis is placed on the Mytilus populations, and a seasonal pattern- emerges (rigure 8). In the spring, the Effluent replicates cluster separately from the group.containing the two reference stations. In the fall, however, though still forming a distinct cluster group, the replicates are more similar to the reference station replicates than they were in the spring, an indication of increasing homogeneity throughout the area. Inverse Analysis The combined spring and fall 1989 data were analyzed by inverse clustering to investigate faunal patterns underlying the . seasonal variations seen in Figures 7 and 8. The top 50
. numerically dominant species were used, producing the dendrogram shown in Figure 9.
- Thirteen species groups were identified as a result of this analysis (Table 6). Group 1 contains 29 species, including 14 arthropods, 10 molluscs, 3 polychaetes, and 2 g.
g echinoderms. Twenty-two species of Group 1 were among the top 15 dominants of at least one station in either spring or fall 1989 (Table 4). Pourteen of the 22 were among the top 15 dominants during both spring and fall. Group 2 contains two species of arthropods. Both species were among the top 15 dominants of at least one station in 1989. Group 3 contains two polychaetes and one ech-inoderm. 35
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s i I TABLE 6.- SPECIES GROUPS IDENTIFIED BY 'lNVERSE CLUSTER ANALYSIS OF MARCH AND SEPTEMBER 1989 DATA Group 1 -Group 5 Idotea phosphorca Motopella arigusta gi Corophium acutum Anomia aculeata gl Corophium bonelli Nicolea rostericola De/. amine thea Onchidoris aspera Fleusymtes glaber I~. Pontogeneia inermis Group 6 Hiatella arctica Ischyrocerus angulpes Hodiolus mediolus I Jassa falcata-Lacuna vincta Onoba aculeus Group 7 Alvania pseudoareolata I Hargarites-helicinus calliopius:laevisculus Caprella penantis Phyllodoce maculata Caprella linearis Group 8 Crepidula fornicata
.I-- -
Amphithoe rubricata Eualus pusiolus Caprella nr. septentrionalis
-Mitrella lunata Group 9 ' I'- flarmothoe imbricata Cerastoderma pinnulatum Dodecaceria sp. A.
Pholoe minula IL ProboloTdes holmesi Group 10 o Strongylocentrotus droebachiensis Harmothoe extenuata
-Hiatella strinta
.Nercis:pelagica Group 11 Ophiopholls aculeata g_ Anemia simplex Asterias forbesi
-g:-
Mytilus edulis Group 12 Group 2
=;
Idotea balthica cancer irroratus Pagurus acadianus Group 13 Group 3- Pagurus longicarpus g Amphipholis squamata
-- g - Cirratulus cirratus Caulleriella bioculata Group 4 Naineris quadricuspida Capite[la capitata I. Asabellides oculata I 39
None of these species was dominant at any of the stations sampled. Group 4 includes three polychaetes, one of which,
.Naineris quadricuspida, was among the top 15 dominants at Manomet Point in the spring.
Group 5 includes two molluscs, one polychaete, and one _ amphipod. None of these species was among the top 15 dominants at any station in 1989. Group 6 contains two molluscs, one of which, Alvania pseudoareolata, was among the top 15 dominants at Rocky Point in March. Group 7 comprises one polycheete, Phyllodoce maculata, which was among the top 15 dominants at the Effluent'in March. i The remaining groups contain one species eacht Groups P, 12, and 13 each contained one arthropod species; Groups 9 and 10 each contained one polychaete species; and Group 11 l contained one echinoderm species. The arthropod in Group 13, I Pagurus longicarpus, was among the top 15 dominants in March at the Effluent. Nodal Analysis Nodal analysis is a method for relating the groupings l resulting frem the normal cluster analysis (by replicate) and
- inverse analysis (by species) to enhance the interpretation of I the resulting patterns (Boesch, 1977). Two measures, constancy l and fidelity, are.used.
Constancy is a measure of the frequency of a group of -l species in each group of replicate samples. The highest l possible value is 1.0, indicating that all species within a -] species group occurred in all replicates within a replicate , group. The lowest possible value is 0, which indicates that no . 1 species within a species group occurred in any of the ! replicates within a replicate group. Constancy is a tool used i to look for differences in species composition at different stations. When the same stations are reoccupied at different times, constancy may be used to identify temporal changes. 1 i- 1 40 E
4 I ridelity is an indicator of the degree to which species are exclusively associated with the replicates in a particular seasonal site group, ridelity values range between 0 (where all species within a species group are evenly distributed over all replicates) and >3 (where all species within a species group occur 'in only one replicate). ridelity is a tool for examining the spatial differences in the species composition at a group of stations. When the same stations are reoccupied at different times, fidelity may be used to indicate the degree to
- which the-species are limited to each collecting season.
Results of the nodal analysis are presented in constancy and fidelity diagrams (rigures 10 and 11, respectively). Each diagram is composed of a species group dendrogram across the top, a site group dendrogram to the left, and a resulting-matrix. The species group dendrogram divides the 50 dominant species into 13 species groups (Table 6). The site group dendrogram, based on only those 50 species, generated five site-groups corresponding to the Effluent and reference stations during each . sampling period. The central part of the diagram I is with a matrix that shows-the intersection of each species-group _ each site group. The value at each intersection is indicated by the shading; and the width of each field of the matrix depends on the number of species or replicate samples constituting _the group. Figure 10 is the constancy diagram of the 13 species groups (Table 6) for the five seasonal site groups. Species group 1 shows high to very high constancy at all stations during both spring and fall. This result is expected because this group includes most of the species that were among the 15 I~ dominant species at all stations during both seasons. The organisms in species group 2 show a definite seasonal preference. In spring, constancy was low to very low at the reference stations and very high at the Effluent. By fall, however, constancy was very high at all stations, indicating that all species of this group occurred regularly in all replicates. 41 i
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Ii.. Species group 3 shows very low to very high-constancy in I the spring'at all stations. By fall, this species group shows moderate constancy at all stations. Species group 4 shows low to very high constancy in the g spring at all stations. By fall, species group 4 shows high W constancy at all stations. Species- group 5 shows moderate to very high constancy at all stations .in the spring. By fall, this group shows low constancy at all stations. Species group 6 shows low to very high constancy at all stations. By fall, this group shows low constancy at all stations. , Species groups 7 through 13 represent a-single species each. Only Phyllodoce maculata (species group 7) and Pagurus
, longicarpus (species group 13) are dominants at any site, and they are dominant only at the Effluent. .
In. general,. fidelity values for the 13 species groups at , the five seasonal sites range from low to very low (Figure 11), indicating an overall suite of species that is found throughout the region and are- not restricted to any particular-site or season. The exceptions are species group 5 which shows a moderate preference for the reference stations (except MP2 and MP3) in the spring; species groups 6 and 10 which show a high to moderate preference, respectively, for one Effluent seasonal site group (one replicate); and species group 13 which shows a high preference for one Effluent seasonal site group (four replicates) in the spring. ALGAL MONITORING The habitats and associated algal and faunal communities , found at the Manomet Point, Rocky Point, and Effluent subtidal stations are typical of shallow, exposed areas in western Cape Cod Bay and have been well documented by Grocki (1984) and Davis and McGrath (1984). The rocky substrata characteristic of all three stations are covered with dense macroalgal 44 L l I
- I communities typically dcminated by two species, Chondrus crispus and Phyllophora spp. Table 1 includes the species identified in the 1989 samples: 37 indicator species (Boston Edison Co., _1988a) and two additional species.
;I.
Algal Community Description The rock and cobble substrata found at Manomet Point, Rocky Point, and the Effluent stations were moderately colonized by red macroalgae during 1989. Biomass of Chondrus crispus was highest at the Effluent in March and September. I- Phyllophora spp. biomass was highest at Rocky Point in March and at the Effluent i n. September. The highest biomass of
.I.
benthic- species other than Chondrus and Phyllophora (remaining benthic species) was at the Effluent in March and September. The highest mean biomass of epiphytic algae was found at Rocky Point in March and at the EfU uent in September. The primary hosts for epiphytes were Chor.drus, Phyllophora, and Polyides rotundus. Red algae (Rhodophyta)' such as Spermothamnion
.g- repens, Phycodrys rubens, Cystoclonium purpureum, Callophyllis W cristata, Membranoptera alata, Rhodomela confervoides, and ceramium rubrum' were the most commonly observed. The warm water -indicator, Gracilaria tikvahiae, was not identified in any 1989 sample, but was observed within the denuded zone from 10 to 30 m along the transect line during the September and-December 1989 transect surveys.
I Algal Community Overlap Community overlap was calculated for March and September 1989 data; Jaccard's coefficient of community (Grieg-Smith, L 1964) was- used to measure the similarity in algal composition among the Effluent, Manomet Point, and Rocky Point stations. By using species occurrence, this coefficient mathematically evaluates the similarity between two replicates or stations, and it is not influenced by differences in abundance. 45
^
I , i Occurrence reccrds of the 30 algal species, including the indicator species (Table 1), were used for community overlap calculations. Results of community overlap comparisons between replicate g samples for each station for March and Sept.cmber 1989 are 3 presented in matrix form in rigures 12 and 13. In March, - community overlap was generally higher between the two reference stations (82 percent) than between ei'.her the Manomet Point or the Rocky Point stations and the Eff*4uent station (77 and 81 percent, respectively). In September, the same pattern was seen. Community overlap was higher between the reference stations (87 percent) than between Manomet Point and the ; Effluent (85 perceri t and Rocky Point and the Effluent (74 i percent). This indicates that in both March and September the algal communities at the two reference stations were more similar to each other than either was to the Effluent. U overall, the similarity of all three stations was high (>77 percent in March, >74 percent in September). From spring , to fall, the similarity of the algal community at the Effluent i to that at the Manomet Point ststion increased, but the -I similarity of the Effluent to the Rocky Point station - decreased. Replicate percent overlap ranges for the Effluent were narrower in September than in March, indicating the , replicates at this station were more aimilar to each other in September than in March. This was also the case at Rocky Point. However, at Manomet Point, the percent overlap ranges were narrower in March than in September.
, Algal Biomass Algal biomass usually shows a very regular seasonal pattern at all three stations, biomass values being low in spring and high in fall (Boston Edison Co., 1987a). In 1986, ,
and to a lesser extent in 1987, the pattern was atypical. In 1988, the typical pcttern was reinstated except at the Manomet where algal biomass decreased slightly in the Point station, 46 I-
E E E .E E E E E E - E E E E 1 2 3 4 5 1 2 3 4 5 1 11 11 14 12 1 15 14 15 14 , 2 73.3 11 11 11 sanaber et 2 33.3 14 13 14 samuIs e of Species W ies 3 61.1 73.6 12 12 shared 3 73.7 87.5 14 14 Shored 4 70.0 57.9 57.1 14 4 75.0 68.4 77.8 14 5 60.0 64.7 63.2 63.6 5 58.3 66.7 64.7 69.9 ,, i Percent Overlap Potteet overley PNEDET Poistr ST7tT10It atJCIF rO11rr STRFlest ?
- - smn-,
1 2 3 4 5 sammber of C - ity Squecies Shoemd e tap 1 15 14' 14 15 temmesec of Statices Peir < 2 85.2 15 15 16 species , SAnsted 8tnecept Point - Ekschy Point 22 81.5 3 73.7 75.0 15 18 h Point - afflemet 29 76.9 4 73.7 75.0 71.4 16 moety Point - afft et 21 so.s a 5 75.0 76.2 90.0 72.7 reecent Oveel. , EFFIEEIrr STRFIm FIGURE 12. ALGAL COMMUNITY OVERLAP (JACCARD'S COEFFICIENT OF COMMUNITY) AND NUMBER OF SPECIES SHARED BETWEEN REPLICATE PAIRS AT THE MANOMET POINT, ROCKY POINT, AND , EFFLUENT SUBTIDAL STATIONS (10 ft MLW) IN MARCH 1989.
, r , e- --.- % .e . .~. .g , . , = ~ - - s, ,r .--,, , s=-.w-
1 2 3 4 5 1 2 3 4 5 19 17 18 19 17 2 1 17 17 18 17 18 19 tamber of 16 shedser of 2 106.9 species
- 2 94.4 16 17 Species 17 17 Sher ==9 SItered 3 89.5 99.5 85.9 90.0 19 19 3
94.7 94.7 94.4 19 4 1 4 90.0 85.0 95.0 19 5 95.9 95.e 85.9 99.9 5 73.9 69.6 es.e 82.6 Peteemt overlap Percent overlap DDCET POfirr STftTTON telwwET 73YNT STRfleer N FETWEEN STRTIout2 1 2 3 4 5 W et %%iT SF*czes shemt o.,,3. , 20 21 21 21 1 Stetica Fair 21 21 21 Species 2 87.0
" ~ N NEd M 87.8 87.5 91.3 23 21 3
"*-*1* 23 85.2 4 so.e se.o 92.e 22 W **'* - S'f1 =
- 2e 7e.1 5 se.o e7.5 so.s s t .'S eercent overtop trrimwr starson FIGURE 13. ALGAL COMMUNITY OVERLAP (JACCARD'S COEFFICIENT OF COMMUNITY) AND ROCKYNUMBER POINT, Of*
SPECIES SHARED BETNEEN REPLICATE PAIRS AT THE MANOMET POINT, AND EFFLUENT SUBTIDAL STATIONS (10 ft MLW), SEPTENBER 1989. M M M M M M M M M M M M M M mm g g g.
I fall. In 1989, the typical pattern was seen at the Effluent I and Manomet Point stations, whereas biomass at Rocky Point decreased from spring to fall.
)
Chondrus crispus biomass values were calculated for the Effluent, Manomet Point, and Rocky Point in March and September 1989 (Tables 7 and 8, respectively). In March 1989, the mean replicate value for Chondrus biomass was essentially the same at Manomet Point and Rocky Point (20.91 and 19.48 g/m 2, respectively) but was higher at the Effluent (34.85 g/m 2 ). The ange of replicate biomass was greatest at the Effluent (3.30 91.98 g/m2) and smallest at Rocky Point (6.70 to 34.06 I to g/m2). Chondrus made up 27 percent of the total algal biomass at the Effluent, 39 percent at Manomet Point, and 10 percent at Rocky Point sti.tions. In September 1989, the highest mean Chondrus biomass. per replicate was observed at the Effluent (85.28 g/m2) followed by those at Manomet Point (82.51 g/m ) and Rocky Point (80.44 2 g/m ). The mean Chondrus biomass at the Effluent was six percent higher than at Rocky Point. The greatest range of ! '*P * *** ***' "*" ' ""d """ **' " '"t (25.25 to 178.83 E 2 W g/m ); the lowest range was found at Rocky Point (57.19 to 2 110.71 g/m ). Chondrus made up 32 percent of the total algal biomass at the Effluent, followed by 57 percent at Rocky Point and Manomet Point. The typical seasonal increase of Chondrus l biomass from spring to fall occurred at all stations. Mean values of Phy11ophora spp, biomass measured in March I and September 1989 are shown in Tables 7 and 8, respectively. In March, the mean Phyllophora 2 biomass per replicate was highest at Rocky Point (87.59 g/m ) and lowest at Manomet Point (22.75 g/m 2 ). Mean biomass per replicate at the Effluent (40.87 g/m2) ranked between those at the reference stations. This value is 53 percent lower than that at Rocky Point and 80 percent higher than that at Manomet Point. The range of replicate biomass was greatest at Rocky Point (40.94 to 157.35 2 2 g/m ) and smallest at Manomet Point (2.48 to 47.37 g/m ), Phyllophora comprised 32 percent of the total algal biomass at 49 I
TABLE 7. DRY WEIGHT BIORASS VALUES (g/m ) FOR Chondrus crispus, Phyllophora spp., EPIPHYTES, THE REMAINING BENTHIC SPECIES, AND TOTAL ALGAL SIOMASS FOR MAROMET POINT, ROCKY POINT, AND EFFLUENT SUBTIDAL (10 ft MLW) STATIONS FOR MARCH 1989 diendrus crispone Egrigssytic species rosyliophora spp. li.;y Sumthic species Total Alget staticeq/Deplicate Siemess Percenst Sie w s Pertmut Siemmes Fortset Siemess Pettoet Biemess W Point 1 6.98 8.67 47.37 58.84 19,09 23.71 7.07 8.78 84.51 2 4.31 39.11 3.86 35.03 1.93 17.51 8.92 8.35 11.02 3 2.11 27.85 2.48 31.79 1.74 22.31 1.47 18.85 7.80 4 39.47 49.54 30.84 38.71 4.59 5.76 4.77 5.99 79.6 7 5 51.68 57.39 29.19 32.42 5.23 5.81 3.95 4.39 90.05 4 2 20.91 38.86 22. F5 42.28 6.52 12.12 3.64 6.76 53.81 pocky Point
$ 1 2
23.04 13.13 10.00 3.39 67.56 157.35 29.33 40.64 3.67 2.02 1.59 0.52 136.05 214.72 59.07 55.45 230.32 38?.22 3 20.47 19.24 62.42 58.67 2.66 2.50 20.84 19.59 106.39 4 34.06 16.32 109.70 52.57 2.94 1.41 61.96 29.69 208.66 5 6.7c 10.47 40.94 63.99 0.46 0.72 15.88 24.82 63.98 2 19.48 9.77 87.59 43.95 2.35 1.28 89.89 45.19 159.31 Efflesant 1 10.28 12.93 22.77 28.64 29.65 37.30 16.80 21.13 79.50 2 16.25 27.36 21.94 36.94 14.87 25.00 6.33 18.66 59.39 3 52.42 29.24 32.14 29.08 39.47 22.02 35.25 19.66 179.29 4 3.30 2.77 31.49 26.43 40.67 34.13 43.70 36.67 119.16 5 91.98 45.58 76.01 37.67 21.21 10.51 12.58 6.23 201.79 I 34.85 27.26 40.87 31.97 29.17 22.82 27.93 17.94 127.82 i: Nan biomass. lE
- W W W W W W W W W W W W 'M M M M M TABLE 8. DRY WEIGHT BIOMASS VALUES (g/m ) FOR CBONDRUS CRISPUS, PHYLLOPHORA SPP., EPIPBYTES, THE REMAINING BENTHIC SPECIES, AND TOTAL ALGAL BIOMASS FOR MANOMET POINT, ROCKT POINT, AND EFFLUENT SUBTIDAL (10 ft MLW) STATIONS FOR SEPTEMBER 1989 diendrus crispes 99sy11 W e spy. tamminang epiperytic species apetitie Species Tetal Al p 1 Station /pppliente Bacenss Percent Bae m s Porteset Basenss Fetteunt Baemess Fettent Diesess W Feint 1 61.60 55.41 - - 10.28 9.25 39.30 35.35 111.18 2 25.25 38.14 - - 7.53 81.37 33.42 50.68 66.20 3 88.13 64.73 8.45 6.21 4.13 3.03 35.44 26.03 136 15 4 58.75 56.78 4.50 4.35 4.87 4.71 35.35 34.16 103.47 5 178.83 59.30 68.67 22.77 10.56 3.50 43.52 14.43 301.58 i 82.51 57.41 16.32 11.36 7.47 5.20 37.41 26.03 143.72 Pocky Feint 1 61.60 47.29 38.46 29.53 18.45 14.16 11.75 9.02 130.26 tri 2 90.24 59.29 31.12 20.45 8.54 5.61 22.30 14.65 152.20
"" 3 110.71 64.53 18.91 11.02 11.11 4.48 30.84 17.98 171.57 4 82.44 68.55 9.09 7.56 9.18 7.63 19.55 16.26 120.26 5 57.19 42.96 32.41 24.35 26.53 1Y.93 16.99 12.76 133.12 I 89.44 56.86 26.00 18.38 14.76 10.43 20.29 14.34 141.48 stif le=et 1 138.71 71.54 24.51 12.64 5.88 3.03 24.79 12. 79 193.89 2 14.05 4.80 138.80 47.44 43.15 14.75 96.58 33.01 292.58
- 3 78.58 29.32 117.23 43.75 50.31 18.77 21.85 8.15 267.97 4 142.29 40.30 152.57 43.21 5.05 1.43 53.15 15.05 153.06 5 52.79 23.91 124.21 56.26 21.30 9.65 22.49 10.19 220.73 i 85.28 32.10 111.46 41.96 25.14 9.46 43.77 16.48 265.64 i
- fasen biomess.
-~ , - - . - - - , . . , _ .
r-I the Effluent, whereas the algal biomass at the Manomet Point and Rocky Point reference stations included 42 and 44 percent Phy11ophora,.respectively. ! In September, the highest mean Phy11ophora biomass per replicate was found at the Effluent (111.46 g/m2 ) and the lowest values were found at Manomet Point (16.32 g/m2) because only three Manomet Point replicates contained Phy11ophora. The mean replicate biomass at Rocky Point ranked intermediate 2 (26.00 g/m ). The mean biomass value at the Effluent was 329 percent higher than at Rocky Point, and 583 percent higher than at Manomet Point. The greatest range of replicate biomass was i observed at the Effluent (24.51 to 152.57 g/m 2 ), and the smallest range was calculated for Rocky Point (9.09 to 38.46 2 g/m ). Phy11ophora made up 42 percent of the total algal biomass at the Effluent, il percent at Manomet Point, and 18 percent at Rocky Point. A typical seasonal increase of ,Phy11ophora biomass from i spring to fall occurred only at the Effluent, whereas a decline was noted at Rocky Point and Manomet Point. The seasonal variations of Ph ilophora were not similar to those observed g for Chondrus. W i The algal biomass category designated nemaining Benthic Species com, prises of all bonthic algae, excluding Chondrus crispus, Phy11ophora spp., Laminaria spp., and algal epiphytes. benthic species were Chaetomorpha spp. at all
~
Important stations during both samplings, Phycodrys rubens at the reference stations in March and at the Effluent in September, ; and Polyides rotundus at the Effluent station in March and at l all stations in September. g Tables 7 and 8 also present mean replicate biomass values 3 for the remaining benthic species (RBS). The highest mean RBS . biomass was found at the Effluent in March and September (29.17 . 2 and 25.14 g/m , respectively). The lowest mean RBS biomass was 2 noted at Rocky Point (2.35 g/m ) in March and at Manomet Point (7.47 g/m ) in September. The mean RBS biomass ranked intermediate at Manomet Point (6.52 g/m2) in March and at Rocky 52
- 5. , -
Point (14.76 g/m ) in September. The range of replicate I biomass 2 g/m ) and was greatest at the Effluent in March (14.87 to 40.67 September (5.05 to 50.31 g/m 2); the smallest range was observed in Rocky Point samples in March (0.46 to 3.67 I g/m ) 2 g/m ). and in Manomet Point samples in September (4.13 to 10.56 The mean RBS comprised 23 percent of the total algal biomass at the Effluent in March and 9 percent in September. The total algal biomass at Manomet Point included 12 percent RBS in March and 5 percent in September. In March at Rocky Point, the RBS made up 1 percent of the total algal biomass; in I September, it comprised 10 percent of the total. Tables 7 and 8 present mean replicate biomass vulues of epiphytic algae. As during most of the previous studies, Phy11ophora spp. exhibited a higher degree of epiphytic colonization than did Chondrus crispus. It has been hypothesized that the higher biomass of epiphytes associated with Phy11ophora was due to the sturdier morphology of this I species (Boston Edison Co., 1986). In March 1989, the mean biomass values were highest at Rocky Point (89.89 g/m 2 ); in September, the were I g/m2). Point in The highest values at the Effluent (43.77 lowest mean biomass values were found at Manomet March (3.64 g/m 2) and at Rocky Point in September (20.29 g/m 2 ). In March, epiphytic algal biomass at the Effluent was 75 percent lower than that at Rocky Point and about 530 percent greater than that at Manomet Point. In September, epiphytic algal biomass at the Effluent was 17 percent higher than that at Manomet Point and 116 percent higher than that at Rocky Point. Epiphytic algae at the l Effluent made up 18 percent of the total algal biomass in March and 16 percent in September. The contribution of epiphytic algae to the total algal biomass at Manomet Point and Rocky l Point was 7 and 45 percent, respectively, in March and 26 and 14 percent, respectively, in September. Epiphyte biomass increased from spring to fall at the Manomet Point and Effluent stations and decreased at Rocky Point. 53 I
I' l Mean values for total algal biomass in March and September Il i 1989 are shown in Tables 7 and 8, respectively. In March, total algal biomass was greatest at Rocky Point, and in September values at the Effluent were the greatest of the three ; stations. In March, total algal biomass at the Effluent was j 138 percent greater than that at Manomet Point and 36 percent l lower than at Rocky Point; in September, total algal biomass at ' the Effluent was 85 to 88 percent greater than that at Manomet Point and Rocky Point, respectively. Total algal biomass increased considerably from spring to fall at the Effluent and Manomet Point stations. At Rocky Point, however, biomass decreased 29 percent from spring to fall, bringing the total algal biomass value at Rocky Point to a lower value than any measured since 1963. g m Chondrus/Phyllophora Colonization Index Study Colonization values are determined for the primary host species (Chondrus and Phyllophora) and are a qualitative measure of the degree of algal epiphytes and invertebrate species present on the host species. Colonization index values are the summations of colonization values-for algal and faunal g colonizers. Details of the procedure are the same as presented E in Semi-Annual Report No. 30 (Boston Edison Co., 1987b). Excluding the September Manomet Point data, data from 1989 (Table' 9) continue to indicate that Phyllophora spp was more heavily colonized by epiphytes than was Chondrus. This observation has been typical during most of the past samplings and, as no t t's earlier, is probably due to the denser frond development of Phyllophora spp, as compared with Chondrus. Generally, colonization of Phyllophora spp. was lowest at , Manomet Point and highest at the Effluent. In March, P_hyllophora colonization was highest at Rocky Point and approximately equal at the Manomet Point and Effluent stations. In September, Phyllophora colonization was highest at the Effluent and lowest at Manomet Point. 54 I
I g TABLE 9. COLONIZATION INDEK VALUES FOR Chondrus crispus AND P'iy11ophora spp. FOR THE MANOMET POIlff, ROCKY POItff, AND EFFLUENT SUBTIDAL (10 f t MLV) I STATIONS POR KARCH AND SEPTEMBER 1989 E Manomet Point Rocky Point Effluent B Mar Sep Mar Sep Mar Sep Chondrus crispus Algal Colonization 5 6 5 8 5 10 Faunal Colonization 5 5 5 5 5 14 Total 10 11 10 13 10 18
~
Phy11ophora spp. Algal Colonization 9 4 15 10 10 15 Faunal colonization 5 4 12 5 5 20 I Total 14 8 27 15 15 35 I I I I I . I I I ss
I I OUALITATIVE TRANSECT STUDY Qualitative transect surveys of acute nearfield impact g zones were initiated in January 1980 and have been conducted E quarterly since 1982. Four surveys of the area were performed during 1989 (March 28, June 19, September 28, and December 15), bringing the number of surveys conducted to 36. Results of surveys conducted from 1980 through 1983 were summarized in Semi-Annual Report No. 22 to Boston Edison Company (Boston Edison Co., 1983). A detailed discussion of the March and June 1989 surveys can be found in Semi-Annual Report No. 34 (Boston Edison Co., 1989b). These results will be summarized here along with new data from the September 'and December 1989 surveys. The denuded zone has been defined as being essentially devoid of Chondrus crispus, whereas the stunted zone was defined as having Chondrus of decreased size and density when compared with conditions considered normal for this species. However, because of the increasing recolonization of the denuded and stunted zones during the outage of PNPS, it became ! increasingly difficult to define these zones. The border between the stunted and denuded zones was no longer clear because of recolonization by Chondrus h resulting in patchy, thin growth in the formerly denuded zone. In 1989, boundaries could not be detected in March and June (Figures 14 and 15). As in late 1987 and 1988, no measurements of the size of the stunted and denuded zones were made. However, in September and December 1989, boundaries of the denuded zone were detected and area E measurements were made (approximately 1382 m 2 in September and W 2 1235 m in December). March 1989 I ; Figure 14 illustrates the results of the divers' observations immediately offshore from PNPS on March 28, 1989. 56 I
.. . . . ~ - . . ~ - . . . . . . - . . . . . . . . - - - - . - - . . . . -
March 28,1989 93 I
- 80 s,\
I r S ( -
- 70 1
Sparse ' Bou6 der 4 Chondrus i
- 60 g \
g Sparse Chondrus, Fucus, Fucus derninant d k and Laminaria growth
- 60 I -
- 40 I Chondrus, Fucus, and Laminaria present l
- 00 .
1
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eSubrnerged Jetty
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Effluent Canal i e i I i i I 30 20 10 0 10 20 30 - Meters Nortnal . .. . Chondrus P Patchy / Sparse r Qhondrus
..t Denuded Chandrus I Growth M Zone J Growth FIGURE 14. MARCII 1989 QUALITATIVE TRANSECT SURVEY OF T!!E PNPS ACUTE IMPACT ZONE OFF Ti1E DISCIIARGE CANAL.
57
i l I; i Meters
"" 90 June 19.1989 1
J Il, 3
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" 60 Nortnal Chondrus growth l W
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Effluent Canal ' ! n i I I I 1 30 20 to 0 10 20 30 Meters m - Norrnal Chandrus Patchy / Sparse Chondrus Denude:1 Chondrus s d Growth Zone Growth FIGURE 15. JUNE 1989 QUALITATIVE TRANSECT SURVEY OF T!!E PNPS ACUTE IMPACT ZONE OFF Tile DISCIIARGE CANAL. l W-58 l
A large boulder that is nearly exposed at mean low water and used as a landmark by both the Battelle and Division of Marine risheries dive teams is plotted in the figure. The boulder serves as a visual fix for the proper placement of the transect I line and ensures consistency over the series of observations. Sparse Chondrus crispus growth was observed throughout the area that has historically been described as denuded of this species. Some rocks in the survey area were nearly denuded of chondrus and other algal growth. Transitions frori denuded areas to areas of stunted or normal Chondrus growth were not clear and no reliable area measurements could be made. Other genera, Laminaria and rucus, were also found throughout the survey area. June 1989 E Based on the divers' observations on June 19, 1989, no denuded or stunted zones could be defined along the 80-m transect line (rigure 15). However, a denuded area was observed 30 m offshore along the transect center line and I adjacent to the end of the north jetty. Although sparse Chondrus growth was observed throughout the survey area north of the transect line, growth became thinner as the line progressed offshore. Chondrus growth was normal south of the tiansect line throughout the survey area. rucus and Laminaria were prevalent throughout the survey area. I September 1989 I return Divers' of the observations denuded zone. on September 28, 1989 revealed a Doundaries were defined (rigure 2
- 16) and area measurements (approximately 1382 m ) of the zone could be made. Sparse Chondrus growth was observed north of the transect line and moderate growth was noted south of the transect line outside the boundaries of the denuded zone.
Chondrus growth was normal beyond 90 m. The term sparse has 59
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I 'I been substituted for the term stunted because, although chondrus that were observed were I apparently was not prevalent, normal, plants rueus was present within the denuded zone, however Laminaria was not observed within the boundaries of the survey area. A dark red alga, believed to be Gracilaria tikvahiae, was observed from the 10- to 30-m mark of the transect line, although no specimens were found in the samples. December 1989 Although scattered Chondrus growth was observed throughout I the survey area, a denuded zone was also apparent during the December 15, 1989 survey (rigure 17). The configuration of the denuded zone was similar to that observed during the September 1989 survey. However, the area (approximately 1235 m2) of the denuded zone was somewhat reduced relative to the previous survey. The denuded zone was practically devoid of all macroalgal species, although scattered clusters of Chondrus and rucus were observed within the zone. In addition, many rocks the denuded zone were densely covered with the coralline I in alga, Corallina officinalis. Tucus was present in the denuded zone, however, no Laminaria was observed within the boundaries of the survey area. As in September, sparse Chondrus growth was observed north of the transect line and moderate growth was noted south of the transect line outside the boundaries of the denuded zone. A dark red alga, believed to be Gracilaria tikvahiae, was observed during the survey from the 10- to 30-m mark along the transect line, although no specimens were found in the samples. I I I I 61 I
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i I HIGHLIGHTS OF RESULTS I FAUNAL MONITORING I 1. For 1989, intermediate September. species richness at the Effluent between the reference stations in March and During March and September, was , none of the stations could be distinguished by species composition.
- 2. raunal densities were lowest at the Effluent station in March. Densities increased dramatically at the Effluent I and decreased at the reference stations from March to September, when the highest density was found at the Effluent. Much of the increase was due to the mussel Mytilus edulis.
- 3. Mytilus edulis was the most abundant species at all stations during both seasons in 1989. All stations had #
I. similar dominant species during both March and September, but there was a substantial decline in Mytilus edulis abundance at the reference stations from March to September.
- 4. Species diversity was highest in March and lowest in '
I September at the Effluent station. The mussel Mytilus edulis constituted a large percentage of the total fauna at each site. When Mytilus was removed from the the diversity increased at the Effluent and I analysis, Rocky Point stations and decreased at Manomet Point from March and September. I 5. Similarity was high between the samples taken at the Manomet Point and Rocky Point reference stations in March. In September, similarity was high between samples taken at the Effluent and Manomet Point stations.
- 6. Seasonality in community structure was detectable at all t
stations. However, the significance of seasonality was t muted by high abundances of a few species during both sampling periods. ALGAL MONITORING
- 1. In March, community overlap was highest between the two I reference stations and lowest between Manomet Point and the Effluent station. In September, community overlap was highest between both reference stations and lowest between Rocky Point and the Effluent station.
l
- 2. Total algal biomass for 1989 increased dramatically from spring to fall at Manomet Point and the Effluent. A slight decline was observed at Rocky Point.
I 63 I
I
- 3. Colonization index values were generally lower for both algal and faunal epiphytes in March than in September, excluding epiphytic growth on Phyllophora spp, at the Manomet Point. and Rocky Point. Due to its denser frond development, Phyllophora spp. was more heavily colonized by epiphytes than was Chondrus.
- 4. A dark red alga, believed to be the warm-water alga Gracilaria tikvahiae, returned to the effluent area in September and December.
QUALITATIVE TRANSECT SURVEY No clear boundaries separating denuded, stunted, and normal zones could be defined in March and June and no reliable measurements could be made. However, in September and December boundaries of the denuded zone ! were detected and area measurements were made. 1 I ACKNOWLEDGMENTS Batte11e's Project Manager for the algal and faunal investigations in 1989 was Dr. Robert E. Hillman. Faunal and algal identifications were performed by Mr. Russell Winchell of Ocean's Taxonomic S e r v e,;e s . Faunal identifications were verified by Ms. Nancy Padell. Field sampling was coordinated by .g Mr. Robert Williams and Mr. John Williams- of Cosper B Environmental . Services, Inc. The field team included Mr. Robert Williams of Science Applications International Corporation, Inc., Mr. John Williams, Mr. Kurt Buchholz, Ms. Linda Langeland, and Ms. Nancy Padell. Ms. Ellen Baptiste ran the statistical programs. Ms. Heather Trulli and Ms. Barbara Greene also participated in this project. VAX is a registered trademark of Digital Equipment Corporation. I I' 64 I
I LITERATURE CITED I Boesch, D.F. ecological 1977. Application of numerical classification in investigations of water pollution. Department of Commerce, NTIS PB-269 604. EPA-60013-77-033. U.S. 114 pp. Boston Edison Co. 1980. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 16. I Boston, MA. Boston Edison Co. 1983. Marine ecology studies related to I' operation of Pilgrim Station. Boston, MA. Semi-Annual Report No. 22. Boston Edison Co. 1986. I Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 27. Boston, MA. e I Boston Edison Co. 1987a. Marine ecology studies related to operation of Pilgrim Station. Boston, MA. Semi-Annual Report No. 29. Boston Edison Co. 1987b. Marine ecology studies relat9d to operation of Pilgrim Station. Semi-Annual Report No. 30. boston, MA. Boston Edison Co. 1988a. Marine ecology studies related to operation of Pilgrim Static.n. Semi-Annual Report No. 31. Boston, MA. Boston Edison Co. 1988b. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 32. Boston, MA. B-- Boston Edison Co. 1989a. Marine ecology studies related to I operation of Pilgrim Station. Semi-Annual Report No. 33. Boston, MA. Boston Edison Co. L I Boston, MA. 1989b. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 34. Davis, J.D., and R.A. McGrath. 1984. Some aspects of nearshore benthic macrofauna in western Cape Cod Bay. In: J.D. Davis and D. Merriman (eds.). Observations on thi Ecology and l Biology of Western Cape Cod Bay, Massachusetts. , 3 Springer-Verlag, New York, NY. 228 pp. 65 I
c Grassle, J.P., and W.L. Smith. 1976. A similarity measure I , sensitive to the contribution of rare species and its use in investigation of variation in marine benthic communities. Oecologia 25:13-22. Grieg-Smith, P. 1964. Quantitative Plant Ecology. 2nd ed. ! Butterworths, Washington. 256 pp. > Grocki, W. 1984. Some aspects of nearshore benthic macrofauna , in western Cape Cod Bay. In: J.D. Davis and D. Merriman (eds.). Observations on the Ecology and Biology of Western Cape Cod Bay, Massachusetts. Springer-Verlag, New York, NY. 228 pp. Heltshe, J.P., and N.E. Torrester. 1983. Estimating species richness using the jackknife procedure. Biometrics 39:1-11. Levinton, J.S. 1982. Marine Ecology. 525 pp. Prentice-Hall a Inc., Englewood Cliffs, NJ. g Taxon. 1982. Benthic studies in the vicinity of Pilgrim Station. 3: Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 19. I I' I 1 I I I I 66 I o 1 I
5 FINAL SEMIANNUAL REPORT Number 35 ' (Volume 2 of 2) to BOSTON EDISON COMPANY I I BENTHIC ALGAL AND FAUNAL MONITORING AT THE I PILGRIM NUCLEAR POWER STATION (IMPACT ON BENTHIC COMMUNITIES) January - December 1989 I by Nancy A. Padell and Robert E. Hillman I I April 4, 1990 I BATTELLE MEMORIAL INSTITUTE Duxbury Operations 397 Washington Street Duxbury, Massachusetts 02332 I (617) 934-0571 I - . . .. ..
I i i FINAL j SEMIANNUAL REPORT Number 35 (Volume 2 of 2) ' I BOSTON EDISON COMPANY to ; I I > I BENTHIC ALGAL AND FAUNAL' MONITORING AT THE PILGRIM NUCLEAR POWER STATION i I (IMPACT ON BENTHIC COMMUNITIES) January - December 1989 L i LI .I 'r Nancy A. Padell and Robert E. Hillman LI : I r April 4, 1990 I ; I BATTELLE MEMORIAL INSTITUTE Duxbury Operations I 397 washington Street L. Duxbury, Massachusetts 02332 (617) 934-0571 . 4 e-e - -m v-'- ew+ e-te--- - . - e.- I
I TABLE OF CONTENTS Page EXECUTIVE
SUMMARY
....................................... 1 INTRODUCTION............................................ 2 METHODS................................................. 4 BACKGROUND.............................................. 7 QUANTITATIVE FAUNAL COMMUNITY MONITORING................. 10 SPECIES RICHNESS................................... 10 FAUNAL DENSITY..................................... 12 SPECIES DOMINANCE.................................. 14 SPECIES DIVERSITY.................................. 15 SIMILARITY AMONG STATIONS.......................... 15 DISCUSSION--FAUNAL MONITORING...................... 18 QUANTITATIVE ALGAL COMMUNITY MONITORING................. 21 ALGAL COMMUNITY DESCRIPTIONS....................... 21 ALGAL COMMUNITY OVERLAP............................ 21 ALGAL BIOMASS...................................... 23 DISCUSSION--ALGAL MONITORING... ................... 26 QUALITATIVE TRANSECT SURVEYS............................ 26 EFFECTS PERSPECTIVE..................................... 32 HIGHLIGHTS OF RESULTS................................... 35 QUANTITATIVE FAUNAL MONITORING..................... 35 QUANTITATIVE ALGAL COMMUNITY MONITORING............ 35 QUALITATIVE TRANSECT SURVEYS....................... 36 LITERATURE CITED........................................ 37 I I ii I
i LIST OF TABLES I Table 1. Algal Community Overlap in Percent between ' Stations for the Period 1983-1989............ 22 Table 2. Summary of Impacts of PNPS on Benthic Communities.................................. 33 LIST OF FIGURES ! Figure 1. Location of Roc.ky Point, Effluent, and Manomet Point Subtidal (10 ft MLW) Stations . 5 I. Figure 2. Monthly PNPS Capacity Factor (Bars) and Circulating Pump Activity (Dotted Line) Plotted for the Period 1983 through 1989..... 8 Figure 3. Species Richness for the Period April 1983 through September 1989 Plotted with the Monthly PNPS Capacity Factor (MDC)........... 11 Figure 4. Faunal Densities (m ) for the Period April 1983 through September 1989 Plotted with the E. Monthly PNPS Capacity Factor................. 13 g' Figure 5. Shannon-Wiener Diversity (H') for Data Excluding Mytilus edulis Plotted with the Monthly PNPS Capacity Factor (MDC)........... 16 , Figure 6. Dendrograms Showing Results of Cluster g Analysis of March and September 1989 Data by 3 ' ' Using Bray-Curtis and Group Average Sorting.. 17 rigure 7. Seasonal Fluctuations in Total Mean Chondrus Biomass at the Manomet Point, Rocky Point, and Effluent Stations during Spring and Fall Sampling Periods for the Collections between April 1983 and September 1989 Plotted with the Monthly PNPS Capacity Factor (MDC)....... 24 Figure 8. Seasonal Fluctuations in Total Mean Phyllophora Biomass at the Manomet Point, Rocky Point, and Effluent Stations during Spring and Fall Sampling Periods for the - Collections between April 1983 and September 1989 Plotted with the Monthly PNPS Capacity Factor (MDC)................................. 25 iii I.
I LIST OF FIGURES (Continued) rigure 9. Seasonal Fluctuations in Total Mean Algal Biomass at the Manomet Point, Rocky Point, I and Effluent Stations during Spring and Fall Sampling Periods for the Collections between April 1983 and September 1989 Plotted with the Monthly PNPS Capacity Factor (MDC)....... 27 Figure 10. Area of Denuded and Stunted Zones in the vicinity of the PNPS Effluent Canal Plotted with the Monthly PNPS Capacity Factor (MDC).. 29 rigure 11. Results of Qualitative Transect Surveys of I the PNPS Acute Impact Zone off the Dischar Canal.....................................ge
... 31 LIST OF PLATES I Plate 1. Effluent Plume Exiting the PNPS Cooling Water Discharge Cana1.............................. 2 Plate 2.
I Diver with Underwater Writing Tablet Preparing to Enter Water..................... 6 I I I I I I I iv ! I 1
a I !
, I l EXECUTIVE
SUMMARY
I This volume of Semiannual Report No. 35 summarizes impact 1 findings for the Pilgrim Nuclear Power Station (PNPS) benthic
-monitoring program from 1983 through 1989. Methods and procedures follow guidelines established by the Pilgrim Administrative Technical Committee (PATC) and adopted by Boston Edison Company (BECO) as modified in 1981.
The PNPS cooling system has affected benthic communities at the mouth of the discharge canal by warming ambient waters and increasing current velocities sufficiently to cause benthic I- scouring, resulting in a denuded area immediately off the discharge canal and a region of stunted algal growth surrounding the denuded area. The PNPS outage, which began in April 1986, ended during this reporting period in March 1989. Therefore, the circulating water pump usage was higher this year than l during the 3-year outage. Two circulating water (CW) pumps operated most of the time, and the annual maximum dependable capacity (MDC) factor was approximately 29 percent for 1989. Prior to 1989, in response to the prolonged PNPS outage, I both the, algal and f aunal cotamunities at the Ef fluent station had recovered from the securino and thermal effects of the discharge. Recolonization by the red macroalga Chondrus crispus l had occurred in the formerly stunted and denuded areas of the acute impact zone. An increase in faunal species richness and densities accompanied this increase in algal growth. Major results of the analysis of the 1989 sampling data l I indicated that the faunal communities were again dominated by the blue mussel, Mytilus y1ulis, as they were in 1988; there was
. a substantial but unexplair.ed decrease in Mytilus in the fall at the Rocky Point and Manonet Point sites; there was an apparent return of the warm-water alga Gracilaria tikvahiae to the l Effluent in September and December; and there was a reappearance of a. demarcated denuded zone at the Effluent site.
I
. _ _ _ _ - _ _ - .- -...-~ . - - - - . . - - . _ . - - . - _ - . _ - .-. . -
I , INTRODUCTION I Pilgrim Nuclear Power Station (PNPS) is a base-loaded, . nuclear-powered electrical generating unit designed to produce ; 655 MW of energy under full operational conditions. Water ! withdrawn from Cape Cod Bay is used to remove heat from the condensers. g The cooling water returns to Cape Cod Bay via a 3 discharge canal designed to dissipate heat through rapid mixing ' and dilution. At full operational capacity, the two circulating water pumps produce a combined flow of approximately 20 m3 per second. Plate 1 shows the plume created as the effluent leaves the discharge canal. ff.yl
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k & & W ya &}&N2 y PLATE 1. EFFLUENT PLUME EXITING THE PNPS COOLING WATER DISCHARGE CANAL. THE EFFLUENT PLUME PRESENTS TWO l W SOURCES OF POTENTIAL IMPACT ON BENTHIC COMMUNITIES: INCREASED TEMPERATURES AND INCREASED CURRENT VELOCITIES RESULTING IN BENTHIC SCOURING. g g The cooling system at PNPS may impact the benthic communities at I the mouth of the discharge canal in two ways: (1) by warming the I 2
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'I 1 l' ambient waters and (2) by- increasing current velocities sufficiently to cause benthic scouring.
The modified benthic monitoring program being conducted near PNPS began in 1981. The program objectives are to identify I and assess the significance of impacts associated with PNPS operations on the nearshore benthic communities. Introduction of an environmental stress has the potential to affect benthic community. members because of their limited ability to move away from disturbances. Significant changes in benthic community parameters may, therefore, be correlated with the source of the I disturbance. This volume of Semiannual Report Number 35 summarizes 1 l l impact findings in relation to the benthic monitoring program ) under Boston Edison Company ourchase Order No . - 66229. It discusses overall data trendt, presented in Volume 1 and in i previous reports (since 1983) to summarize the-effects that PNPS operations have on benthic communities. l I I I I I , 3 g I 3 I:
l METHODS The present benthic mcnitoring program uses quantitative and qualitative methods to determine the presence and magnitude ; of impacts associated with the Pilgrim Nuclear Power Station i (PNPS). Methods and procedures follow guidelines established g by the Pilgrim Administrative Technical Committee (PATC) and E-adopted by Boston Edison Company (BECO), as modified in 1981. Methods are fully described in Semi-Annual Report No. 35, volume 1 (Boston Edison Co., 1990). The quantitative studies measure and compare ' benthic community parameters at three stations (Figure-1): a surveillance station located nearly 120 m offshore from the mouth of the discharge canal (Effluent station), and two reference stations located 0.25 nmi northwest - (Rocky Point) and 2 nmi southeast (Manomet Point) of the Effluent station. Manomet Point, because of its distance from the source of stress, is likely to experience a less severe effect. from.PNPS than that experienced closer to the discharge > canal,- which is monitored by qualitative transect surveys. Data collected from'the three stations are compared for spatial (reference versus surveillance) and temporal (differences in seasonal trends and among years) variability. _ Differences between g; the Effluent and reference stations are then examined a for indications of an impact from PNPS at the Effluent station. The acutely impacted area immediately offshore of the canal (0 to 90 m from the submerged ends of the canal) is monitored through quarterly qualitative diver surveys (Plate 2) to measure the extent of algal stunting and denudation caused by the thermal effluent. These observations focus on the red macroalga, Chondrus crispus, a species prevalent in western Cape Cod Bay and commercially harvested in the PNPS area Divers swim along a measured transect line, noting the E W boundaries of the denuded, stunted, and normal Chondrus zones of the acute impact area. Variations in zone size are recorded to determine the area extent affected by PNPS operations. 4
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I BACKGROUND I PNPS operational conditions from 1983 to 1989 provide an I opportunity water discharge to assess (1) the degree of impact of the cooling to the benthic com.aunities and (2) the length of community recovery time if the effect of the discharge was removed. Figure 2 presents the annual maximum dependable capacity (MDC) factor and circulating water pump operation for PNPS since 1983. The MDC is a measure of reactor output that. approximates thermal loading to the marine environment. A maximum MDC value of 100 percent represents the highest allowable change in ambient temperature for discharge to Cape Cod Bay (32'r AT). I The cumulative capacity factor from 1973 to 1989 was 45.3 percent. During this period, power output varied greatly. In 1983, PNPS was productive, with an annual MDC of 80.3 percent. The' following year (1984) PNPS was offline, yielding an annual-MDC .of only 0.1 percent. The 1984 cutage resulted in reduced scouring in an area immediately off the discharge canal; partial circulating water flow occurred during most of the. year I- ' and no -flow occurred from late March to mid-August 1984. The extremely low MDC in 1984 was followed by a-record high in 1985 (84.4 percent). The erratic pattern of PNPS output continued in 1986, with an annual MDC of 17.5 percent. Outages began on March 7, 1986, and since mid-April 1986 the station was offline i through February 1989. Two circulating water pumps-operated through February 1986; only one pump was online from March 1986 through February 1987. Except for a few occasions, no circulating pumps were operating from mid-rebruary through I; early September 1987. From September through December 1987, one pump was online. During 1988, only one circulating water pump, at most, was in operation at any one time (Marine Biocontrol Corporation, 1988). As a result of this low circulating water pump activity, reduced current generation occurred at the Effluent station in 1988. In March 1989 the outage ended with the E ,
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2 1 . m a a. j i g35 g I 5gI I 3 5 1 1 1 5 4 l8 s 5 5 5 g5 I Is agaaaa 3 gsE 5I agaa sa ag g 1/83 7/83 1/84 7/84 1/85 7/85 1/86 . 7/86 1/87 7/87 1/88 7/88 U89 7/89 V90 -! Sanpling Period FIGURE 2. MONTHLY PNPS CAPACITY FACTOR (BARS) AND CIRCULATING PUMP ACTIVITY (DOTTED LINE) PLOTTED FOR~THE PERIOD-1983 THROUGH 1989. f
~
~
_ _ =. ._ _ _ . _ . .. __ .-. _. _ _ _ _ _ . -. . . _ . _ . _ _ ._ . . _ . _
1 i commercial generation of electricity. Two circulating water pumps operated most of the time, and the annual MDC was 28.9 percent. Monthly MDC values greater than 50 percent occurred I in August,. September, November, and December. From. 1983, the situation at PNPS has presented a valuable opportunity to compare the results from two peak operational years (1983 and 1985) with results from about 4 years of potential environmental recovery (1984 and 1986 through February 1989). The continuing PNPS outage that began in April 1986 was of particular interest during this reporting period. Because the outage lasted through February 1989, benthic community recovery in response to the reduced current and lack of thermal effluent might be expected to continue well into I 1989. The recovery response is similar to the responses noted in 1985 following the 1984 outage. These 1984/1985 responses [ were summarized in Semi-Annual Report No. 27 (Boston Edison Co., 1986) and included e A change in the relative rankings of the Effluent and reference stations in terms of species ' the Effluent station typically ranked I! richness;
-third prior to the 1984 outage, but recovered to rank second by March 1985.
e Species diversity values at the Effluent station that were more similar to diversity at the reference stations than would typically occur if I e PNPS were operating. A lagged recovery of the effluent acute impact zone, resulting in macroalgal growth within the
>I previously denuded Chondrus zones.
e The presence and absence of several species of I. ' algae Laminaria (most notably Gracilaria tikvahiae and spp.) considered indicators of warm-water (G. tikvahiae) and cold-water I ~ (Laminaria spp ) habitats, in response to the presence and absence of thermal effluent from PNPS. I I E:
I OUANTITATIVE FAUNAL COMr.JNITY MONITG'MNG Il SPECIES RICHNESS Ur.til 1985, species richness (or number of species) at all-three stations had varied seasonally, with low values in spring g, followed by high values in fall-(rigure 3). In addition, the 3' Effluent station showed depressed species richness when compared to the reference stations. Consistently lower species richness at the Effluent was assumed to be directly associated with PNPS thermal elevations. However, the Effluent station may also be affected by circulating water pump activity and ' outside influences (i.e., weather). These activities could decrease algal cover and, g therefore, habitat for the fauna, W thereby increasing faunal vulnerability to storms. As discussed in Semi-Annual Report No. 27 (Boston Edison Co . , - 1986),- 1985 Effluent data indicated a lagged recovery response to the 1984 PNPS refueling outage. In 1986, species L richness increased at the Effluent when no thermal effluent was discharged from PNPS. : l In 1987, species richness at all three stations increased l from . March to September, with the Effluent having the lowest number of species each sampling period (rigure 3). These l l results, observed during the continuing _ outage, resemble the observations made until 1985 when'PNPS was operating. In 1987, the benthic community at the Effluent apparently still had not fully recovered from the effects of the thermal effluent discharged from 1985 through early 1986 (Boston Edison Co., 1988a). During either season in 1988, there were no statistically significant differences between stations in regard to the , number of species. In March 1988, species richness was lowest at the Effluent, yet'a greater number of species was found than in March 1987. By September 1988, species richness at the Effluent had changed considerably, the number of species 10 I 5
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4/83 10/8 3 J/84 9/84 3/85 9/85 3/86 9/86, 3/87. 9/87 3/88 9/88 3/89 9/8912/89 SarTting Period FIGURE 3. SPECIES RICHNESS FOR'THE PERIOD APRIL 1983 THROUGH SEPTEMBER 1989 PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC). 1
I increased to a level similar to'that'found at the reference I stations. In March-1989, the number of species found at the Effluent ranked between the reference stations. When compared.to March 1988, the number of species collected at the Effluent increased, yet the number of species at the reference stations I g decreased. In September 1989, the number of species found'at B the Effluent remained the same and it still ranked between the. . reference stations, values at all stations were.less than those seen in September 19.88. Species richness at the reference stations has remained-relatively constant since September 1987. Species richness values found' at the Effluent station have risen steadily from- . March 1987 to September 1988. Although the values decreased somewhat in March 1989, they are similar to the values seen at the reference stations. This suggests that recovery at the - Effluent during the prolonged outage tended to make that station. indistinguishable from-the reference stations in terms of species richness. FAUNAL DENSITY Figure 4(A) shows total faunal densities (number of ?
*"e'.viduals per square meter) from 1983 through 1989 at all three. stations. As reported in previous years, no seasonal - -
pattern was apparent at any station. In addition, there'was no consistent relationship between densities at any two stations. In-50 percent of the sampling periods, lower densities occurred at the Effluent than at the reference stations, and the
-reference stations changed in their relative ranking to each.
other, occasionally, however, faunal densities at the Effluent g were greater than at one or both reference stations. 5 In. 1989, there was an increase in faunal density from spring to fall at the Effluent station ((Figure 4(B)]. A decrease in faunal density at the reference stations was due to a substantial but unexplained decrease in Mytilus edulis. When 12 8
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. Sarmling Period M Effluent @ Manomet Point C Rocky Point ---
onth PNPS FIGURE 4. FAUNAL DENSITIES (m ) FOR Tile PERIOD APRIL 1983 g TIIROUGII SEPTEMBER 1989 PLOTTED WITl! THE MONTHLY PNPS
.g CAPACITY FACTOR. (A) TOTAL FAUNA. (B) Mytilus edulis.
13 8
I-Mytilus numbers- were excluded from the data, the abundance of I all-remaining fauna (pooled data) increased from spring to fall at all stations. This increase was most pronounced at the Effluent. The contribution of Mytilus (Figure 4(B)} to total faunal ; density at all stations has varied greatly throughout this monitoring program. Relatively high densities occurred in fall l 1984 at all stations, in spring 1986 at the Effluent station, and during the spring and fall of 1988 and 1989 at all. stations. Except for those peaks, densities have been relatively low since September 1985. - Empirically, there has not appeared to be a direct j relationship between variations in faunal density among g stations and PNPS operations (Figure 4(A) and 4(D}}. Total 5 faunal densities at the Effluent station during the three high-capacity years (1983 and 1985) differ in value and seasonal variation. In addition, total faunal density differs-considerably- during the two outage periods in 1984 and early' 1986 through early 1989. The 1989 faunal density data (Figure 4(A)] suggest that the Effluent station was still- g recovering, at least through September, as'a response to the W outage. g 3: l SPECIES DOMINANCE ( Fifteen- faunal species have dominated (by generally >80 percent of total abundance; >93 in 1989) at all three stations throughout the program, regardless of season or year. Rankings of .the 15' dominants vary, but species composition has been g.: fairly consistent at all stations. Therefore, faunal species W dominance has not been noticeably affected by PNPS operations, _ In March and September 1989, Mytilus edulis was the most abundant species, comprising 62 to 91 percent of the fauna at each station. Mytilus edulis numbers increased considerably from March to September at the Effluent. The reference I I
I 5: stations, however, each experienced a substantial but unexplained decrease of Mytilus from March to September. SPECIES DIVERSITY Species diversity is a measure of the number of species I present community. (species For richness) and their relative abundance in.a consistency with previous reports, Mytilus
. edulis counts were excluded from the 1989 data calculations.
A seasonal pattern of low faunal diversity in spring by
~
followed high diversity in fall has been observed at all stations from 1983 to 1989 (rigure 5). Generally, the Effluent station shows a lower diversity than do the reference stations.
- I' In 1989, the. Effluent showed a slight increase in diversity from spring to fall and was ranked between the reference stations during both sampling periods.
; SIMILARITY AMONG STATIONS The results of 1989 cluster analyses discussed in volume 1 show that. the faunal community (species composition) at the
~
Effluent differed from those at the reference stations only in E spring. In March, only the. replicates at the Effluent clustered together into a distinct station group, yet similarity was greatest among replicates at the reference stations (Figure 6(A)). By fall, partly because of the abundance of Mytilus edulis, the replicates did not cluster into distinct station groups [ Figure 6(B)]. Similarity was greater among replicates at- different stations than between replicates from the same station. Prior to 1989, the difference between stations was
;g: much more distinct. The increasing similarity between the 3 Effluent and reference stations suggests benthic community recovery at the Effluent station is related to the recently ended PNPS outage.
Seasonality in community structure was found at all stations in 1989. The effects, however, were muted due in part B:
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- f I 6 9/85 3/86 9/86 3/87 9/87' 3/88 9/88 3/89 9/8912/89 4/83 10/83 3/84 9/84 3/85 Sampling Period FIGURE 5. SHANNON-WIENER DIVERSITY (H') FOR DATA EXCLUDING Mytilus edulis PLOTTED WITH THE MONTHLY PNPS' CAPACITY FACTOR (MDC).
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. .. ... .. .. .. .. i FIGURE 6. DENDROGRAM SilOWING RESULTS OF CLUSTER ANALYSIS OF DATA USING BRAY-CURTIS SIMILARITY AND GROUP AVERAGE SORTING. A. MARCH 1989, B. SEPTEMBER 1989.
17 I ,
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to the abundance of Mytilus. Similarity analyses of combined I spring and fall data indicated strong. seasonal differences at the Effluent station; the reference stations showed fewer j seasonal differences. Results of additional 1989 faunal analyses indicate ~I differences among stations and seasonal fluctuations can be '! related to certain groups of species. Generally, the major differences among the faunal communities at the Effluent and ! reference stations were in the composition and density of subdominant species, which play a marked role in influencing ! overall community structure. i DISCUSSION--FAUNAL MONITORING - [ The results of 1989 faunal community analyses indicate l that, by the end of the sampling year, only minor differences -l existed among the Effluent station and the reference stations. Species richness at the Effluent ranked intermediate between the reference stations, but the similarity analysis showed that similarity among the Effluent and reference stations was high. ; Prom March 1987 until September 1988, . 'I species richness increased steadily at the about Effluent station but has remained g the same at the reference stations since September 1987. 5 In 1989, species richness at all stations declined from what it was in September 1988, yet the Effluent was no longer lowest in < terms of species richness. Differences in faunal densities among stations have not , appeared empirically to be related to PNPS operations. In ! addition, the species that comprise the majority (generally >80 - percent) of the total fauna at all stations differ only in I their relative. rank. Seasonal trends in faunal diversity covary at the three stations and in the past have indicated depressed diversity at the Effluent as compared with the reference stations. During the 1989 sampling period, diversity at the Eifluent was not depressed; the Effluent ranked i 18 I I
g intermediate between the reference stations during spring and fall. Logan and Maurer (1975) have hypothesized that faunal communities I "noninteractive, in the mouths of thermal effluent canals are in a pioneer state,' characterized by- high diversity, low species numbers, and low population-densities caused by sporadic and severe environmental changes, such as variations' in temperature or turbidity. Results of this benthic monitoring program indiccte that faunal communities at the Effluent station are somewhat different from those described by Logan and Maurer, possibly because the station is not locsted in the mouth of the discharge canal. Although species richness is typically depressed at the Effluent I station, diversity is also typically depressed and faunal density is not always the lowest of the three stations. The' Effluent community is one that is believed to be characteristic of a stressed environment. Logan and Maurer (1975) state that the occurrence of high diversity in the path of a thermal effluent is caused probably I by recolonization environmental change following (i.e., sporadic periods of- severe decreased temperatures caused by storms, extreme tides, or plant shutdown). Data from this
.II benthic monitoring study, therefore, suggest that although there has been an effect of the PNPS discharge at the Effluent station, conditions at the station were relatively stable for prolonged periods of time, resulting in sustained low diversity compared with the reference stations. This stability was maintained until 1984, when PNPS experienced a long shutdown.
Under " normal" conditions, I PNPS operating faunal communities at the Effluent station experience different annual temperature variations from those experienced at the reference
.5 stations (i.e., higher temperatures in the summer and winter owing to thermal loading), resulting in the seasonal differences in the community parameters discussed earlier.
These annual variations were compounded by the extreme maxima and minima of PNPS operation from 1983 through 1986, creating I
- p. -
I environmental variability at the Effluent station on a different scale from what would be expected under continuous operation. As has been noted (Boston Edison Co., 1987b), the impact of PNPS at the Effluent station is on the rarer, more : transitional species rather than on the dominant species. Although the effect of PNPS at the Effluent station is not g extreme under normal- operating conditions, erratic PNPS 5 operation between 1983 and 1986 created prolonged thermal ..; variations from high power output (maximum impact), followed by no power output (maximum recovery) and variations in discharge ' current flow from . full flow (mar.imum impact) to no flow (minimum impact). Those fluctuations resulted in environmental impacts at the Effluent station that were less consistent than those seen before 1984, explaining variations in the relative ranking of the stations for several of the parameters measured during this program. Enlightened assessments of future effects , under a wide variety of discharge conditions can be made when comparisons of faunal communities during the-relatively stable
~
pre-1984 ' operational phase are made with the variable communities during the 1984 to 1986 erratic operations and the increasing community similarity among_all stations since the beginning- of the long outage in early 1986 through February g 1989. -B I. I I I I' I 20 I>'
QUANTITATIVE ALGAL COMMUNITY MONITORING I ALGAL COMMUNITY DESCRIPTIONS The algal community at the Effluent station is dominated by the red algae, Chondrus crispus and Phyllophora spp., species that also dominate the reference _ stations. However,. one indication of .the effect of PNPS on the Effluent station algal community, unlike the effect on the faunal community, has been the presence of several less abundant species that are-absent f. rom the reference stations. The most significant of these is the red macroalga Gracilaria tikvahiae. I an indicator of Gracilaria tikvahiae, considered' warm-water habitats, was not found in 1989 quantitative samples but was observed-during the September and December qualitative transect surveys off the discharge canal. (The identification: of this alga could not be confirmed because no specimens were collected by the field team, and the alga was not found in any replicate from the Effluent.) This species occurred regularly I at the Ef fluent station during norn.al operational years when a thermal effluent- was discharged. In 1986, a drastic decrease g- of G, tikvahiae was observed, and the disappearance of'this 5' species from 1987 to September-1989 was clearly related to the continuing PNPS outage (lack of thermal effluent). A similar decrease in abundance of this species at the Effluent occurred
-in response to the 1984 outage'(Boston Edison Co., 1986).
EL ALGAL COMMUNITY OVERLAP 8-g Table 1 presents algal community overlap values among 5 stations (i.e., the number of species shared by a given pair of stations) since 1983. The tendency has been for the two reference stations to be more similar to each other (higher overlap values) than to the Effluent station. I 21
^ "' - -
s f e
, h, TABLE 1. ALGAL COMMUNITY OVERLAP IN PERCENT AMONG STATIONS FOR.THE PERIOD ~1983-1989
'1963 1984 1985 1986 '1987 1988 1989 Apr oct me sep mr sep mr sp mr say me see -mr sep
~
MP vs. RP 81.0 77.8 76.0 84.0 88.0 65.5 90.9 84.0 77.2 80.8 88.9 82.8 81.5 ,87.8 MP vs. LY 85.2 67.9 68.0 71.1 77.0 73.1 T5.9 70.4 66.7 80.0 '81.5 89.7 76.9 85.2 , i RP vs. ty 81.0 .73.0 70.4 71.0. 75.0 88.9 80.8 77.8 70.8 76.0 82.5 85.7 80.0 7t.1 N N MP = mnomet Point RP e Rocky Point EF = EffIuent i i l r
.. t l
i
.- _. - - - _- - .-= .-. - . = . , - - ~ .. . .. . _ - _ _ = _ - _ _ _ = _ = . - _ _ _ _ - _ _ - _ ..- - - .
I During 1983-1988 (Table 1) and in September 1989, the ' I . overlap values for versus Rocky Point, the various station pairs (Manomet Point Manomet Point.versus Effluent, and Rocky Point'versus Effluent) were not very.different, suggesting that i all stations. were becoming similar in terms- of species composition, and indicating a relatively uniform algal species distribution among all stations. In March (Boston Edison Co.,
'1989b) and September 1989, the reference stations.were more i similar (greater overlap) in species composihion to each other than either reference station was to the Effluent station.
I overall, the similarity among all three stations was hight >77 percent in spring and >74 percent in fall. As suggested last year (Boston Edison Co., 1989a), these
. species overlap variations are not only influenced by PNPS operations, but are also part of naturally occurring,-long-term variations in Cape Cod Bay. Moreover, the outage that lasted L almost 3 years did not cause any marked changes in the dominant algal species composition, indicating that effects of PNPS operations on species composition were minimal.
l L ~ ALGAL BIOMASS s In ' general, 1989 algal biomass followed the same seasonal pattern seen since 1983 (except for 1986). Increases in Chondrus crispus- biomass at all stations, especially at the l Effluent, were seen from' March to September (Figure 7). In ;
. March 1989, Chondrus biomass values-at the reference stations were the lowest recorded between 1983-and 1989.
In contrast to the increase in Chondrus biomass from I' - spring to fall, Phyllophora spp. biomass decreased at the Rocky Point and Manomet Point stations and increased sharply at the Effluent (Figure 8). The decrease at Manomet Point has continued since September 1985 and, by September 1989, mean biomass at Manomet Point was at its lowest in the time period from 1983 to 1989. p 23 i,
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- s a a s a a e a s s 9/85 3/87 9/87 3/88 9/88 3/89 9/8912/89 4/83 10/8 3 3/84 9/84 3/85 3/86 9/86 Sarmling Period FIGURE 7. SEASONAL FLUCTUATIONS IN. TOTAL MEAN Chondrus BIOMASS AT THE MANOMET POINT, ROCKY POINT, AND EFFLUENT STATIONS DURING SPRING AND FALL SAMPLING PERIODS FOR THE COLLECTIONS:BETWEEN APRIL.1983 AND SEPTEMBER 1989 PLOTTED.WITH THE MONTHLY PNPS CAPACITY ~ FACTOR (MDC).
m M .' . .M-M M M W. M M -W M M M M M m m 'm
~ 100 500~ Phyttophora e- Rocky Point 3- Manomet Point O
9 l s, e. ... .... Et fluent - l \. oo - ucc 400 - l l
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o o n. n n o n n i i i i . i a. n. i > s i i i 4/83 3/84 10/8 3 9/84 3/85. 9/85 3/86 9/86 3/87 9/87 3/88 9/08 3/89 9/89 12189 Sampling Period I FIGURE 8. SEASONAL FLUCTUATIONS IN TOTAL MEAN Phyllophora BIOMASS AT THE MANS) MET POINT, ROCKY POINT, AND EFFLUENT STATIONS DURING SPRING AND FALL SAMPLING PERIODS FOR THE COLLECTIONS BETWEEN APRIL 11983 AND SEPTEMBER 1989' PLOTTED WITH THE' MONTHLY PNPS CAPACITY. FACTOR (MDC). __ .u - _ _ _ .. _ . . __. _ _ -- . .s.. _ - . ~ . _._ _ .__ _ _.
( From 3 spring to fall 1989, total algal biomass increased at the Effluent and Manomet Point stations and decreased at Rocky Point (Figure 9). All total algal biomass values were
.less than any recorded since-1983, with the exception.of the .
total algal biomass at Rocky Point in March 1987. DISCUSSION--ALGAL MONITORING Although the PNPS outage ended in early 1989, the Effluent ' station still showed evidence of recovery, at least through September. In March and September, similarity measurements ' (Jaccard's coefficient of community) indicated only a slightly greater degree 'of similarity between the reference stations then shown by a comparison of the reference stations with the g, W , 1 Effluent station. - i During this program, the algal community at the Effluent station experienced disturbances affecting species composition rather than overall abundance (biomass). Biomass values for j the major algal categories failed to show any patterns, either ' among stations or over time, that would indicate a significant effect of PNPS at the Effluent (Figures 7 - 9). The impact of PNPS on the Effluent algal community is reflected in the presence or absence of several less dcminant species, probably g 3 because there are more opportunities available for new species to. colonize the Effluent than the reference stations. For example, the outage accounted for the absence (since 1987) of the warm-water alga, Gracilaria tikvahiae, until its apparent reappearance in September and December 1989. The variation in less dominant species is considered less severe than might be expected if the Effluent station were closer to the areas of acute impact (i.e., near the mouth of the discharge canal). I QUALITATIVE TRANSECT SURVEYS A lagged recovery response to the 1984 PNPS outage within I the acute impact zone was reported in Semi-Annual Report No. 27 26 E. .
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10/8 3 9/84 3/85 9/86 3/87 9/87 3/88 9/88 3/89 9/8912/89 Sanpting Period FIGURE 9. SEASONAL FLUCTUATIONS IN TOTAL MEAN ALGAL BIOMASS AT THE'MANOMET POINT, ROCKY POINT, AND EFFLUENT STATIONS DURING SPRING AND FALL: SAMPLING' PERIODS FOR THE COLLECTIONS BETWEEN APRIL 1983 AND SEPTEMBER 1989 PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC).
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I I
'l (Boston' Edison C o'. , 1986). Evidence of this lagged recovery !
included a decrease that began in mid-1984 and continued through- mid-1985 in the size of the total impact area. rigure .
.10 presents results of the qualitative transect surveys from '1983 through 1989. The total acute impact area-is-plotted with !
the extent of the denuded. zone and the monthly MDC factor. The stunted- zone is represented by the difference between the _; denuded and total acute impact zones. Between December 1984 _ and December 1985, the total impacted area (denuded and stunted zones combined) was the smallest recorded between 1983 and 1 1986, indicating a lagged recovery of this area in response to the lack of thermal effluent in 1984. This phenomenon reversed i itself under normal PNPS operating conditions, and between September and December 1985 showed a lagged increase of the -j acute impact zone size. These results etinfirmed a lagged period g of about 6 - 9 months between the causal factor (cessation or
-WM resumption of thermal effluent' discharge) and associated response (decrease or increase of the acute impact zone size).
]
From 1987, increased recolonization of the denuded and l stunted zones by Chondrus crispus has made zone boundaries - difficult to distinguish (no measurements could be made from June 1987 through June 1989). As in summer 1984, the . considerable decrease of the denuded area of the acute impact ] zone from December 1986 to June 1987'was mostly the result of l the shutdown of the circulating water pumps fc r late March to ! early September (Boston Edison Co., 1988a). App rently, water current. scouring is a greater stress to algal colonization than , increased water temperature. Scouring denudes the substratum, whereas temperature results in stunted growth. The increase of the denuded area of the acute impact-zone in September and December 1987 can be related to the resumption of circulating q water pump operation in September, confirming this assumption. - , In 1988, the circulating water pump activity was low, resulting in little thermal loading and discharge current. Results of the 1988 transect survey showed increased recolonization of the formerly denuded and stunted zones by 28
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~I oo, sS ,S a o, s ,E e o, s ,5 m o,-s ., e o, s e o, s o, 1985 -1986 1987 1988 1989 1983 1984 FIGURE 10. AREA OF DENUDED AND STUNTED' ZONES IN THE VICINITY OF THE PNPS EFFLUENT CANAL PLOTTED WITH THE MONTHLY PNPS CAPACITY FACTOR (MDC).-NO AREA-MEASUREMENTS WERE MADE IN' SEPTEMBER AND DECEMBER 1907, 1988, AND MARCH AND JUNE-1989 BECAUSE OF LACK OF DEFINITIVE DEMARCATIONS OF DENUDED AND STUNTED ZONES.
I chondrus in response to the continuing cutage. Divers were I unable to detect boundaries of these zones and no area measurements could be made. In March and June 1989, divers were again unable to detect -boundaries .of the denuded or stunted zones and no area i measurements could be made (Figure 11). In September and _ December, ! presumably in response to increased PNPS operations ; and the resultant scouring of the acute impact zone, boundaries of the denuded zone could again be detected, and area measurements were made. During the 1987 qualitative transect surveys, Laminaria . spp., an indicator of cold-water habitats, was observed in'the acute impact zone and cited as an indication of recovery of the ! area during the power outage. In 1988, the continued presence '! of Laminaria in the acute impact zone remained an important I indicator of the lack of a thermal component of the discharge'. ( .In March and June 1989, Fucus and Laminaria were prevalent ' throughout the survey area. By September and December, Fucus was present within the denuded zone, however, Laminaria was not ; observed w'. thin the boundaries of the survey area, indicating -presence of r thermal discharge. : 11, Il 1: ,
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.I l
I j I; EFFECTS PERSPECTIVE An overview of benthic community response to PNPS operations between 1983 and 1989 is presented in Table 2. The g power outage that began in early April 1986 and ended during W the 1989 report period resulted in a lagged recovery of benthic 4 communities at the Effluent station off the mouth of the discharge canal. During 1987, the recovery was most obvious in the macroalgal assemblages of the acute impact zone, the zone that included an area completely denuded by the scouring effect of the discharge, and an area of algal growth stunted by the g thermal component of the discharge. W In late 1987 and in 1988, the faunal and macroalgal g assemblages continued to recover at the Effluent station. 3 Recolonization by Chondrus crispus occurred to the point where the stunted and denuded zones could no longer be distinguished from the surrounding typical growth areas. The recovery in the acute impact zone is the response most directly related to PNPS operations. An increase in faunal species richness and , densities at the Effluent station accompanied the increased g macroalgal coverage. IN By the fall of 1989, a denuded zone returned to the acute impact zone as a result of increased scouring due to PNPS operations. The warm-water alga, Gracilaria tikvahiae, appeared to have returned to the survey area, and Laminaria, a was not observed in the survey area, indicating the presence of a thermal effluent. g overall, the full impact pot?ntial. of PNPS hat not yet been observed because the mean operating rate of the plant has g been only about 45 percent to date. W I I. 32 I
M E NM O E E TABLE 2.
SUMMARY
OF IMPACTS OF FNPS ON BENTHIC COMMUNITIES. st=dr rurs W 9acerter Effects 1983-19e9 n - -ee Quantitative species itffloset station remks last relative afflueet station ranked seceof im Outages <tering 1984 end 1996 thrwegh early raamal Richness to reference stations, bedicating stords 1985 and first in sameda and 1999 requited is increeses tre species studies ingmet from Pers eneling unter september 1986. Spacies ricanoes - cirheems solens at the aff1wwet staties. disdnerge. declined free spring to fell 1995. Fluctuating poser output abstabilised afflueet station remkod Inst is conditione and pretee9ed piewer state, 1987 and 1998. Effismet statiam intreekseing use species at Effloont. l remked interendiste in fuerth and Species riciasses in 1987 was few, September 1999. apparently because of circuleting ust c pussy actieity. Species richsess has bene been rising steadily sisco Meech 1987. d l Approachisq welmaa s**e at reference stations im Septeueer 1988 e 4 in 1909. I Density tee detectable pattern overall. se damage in response to minisamm molative resdrs and <> gree of differsete (1994, 190 W ) er ammisese (1983, between the reference and Ef fleest , 1995) output. stations beve boom ascensistent over the yeets of this stud F, indicating abs ore of a detectable effect ce resunet j d duesities at the Efflueet statiosa. i species Os-eemat species reistively coastamt ca=rasitious of deeinant species et Fiftese species beve th,=imated att 3 Dominance in occurrence et ett three stations, all stations unaffected free 1983 tu statices throughest program, regardless exhibiting no impact free Pers. 1989. of sements and year. In 1989, caust h able , increase in partiles oestis ebserved at I the af flommt. Sudystantist f ut monpleined j
<4ecrease free spring to fall at the ;
referesco stations. species meteresco stations exhibit higher as s19aiticant diseges in ranks of notatively stable diversity vetees et Diversity species diversity them the affluent diversity among stations as a result the af flemet station indicat e stable statice, imilcoting difference ese of fluctuating poser free 1993 to ceeditions (i.e., sustained differenrol to purs operations. 1989. with regard to this peremet.c. ! I L
, , --. ,, w , c + - - . _ . - - , ,: . . _ , , _ ~ , - _ _ _ . - . _ _ - - - _ _ _ - - _ _ - _ _ - _ _ _ _ . _ , _
s TABLE 2.
SUMMARY
OF IMPACTS OF PNPS ON BENTHIC COMMUNITIES (Continued) .
Study FWS comp ment Paramptoe Effects 1983-1989 cements Onantitative paresures of soference stations aero simiter to soferomee statices centimisad to Cleef.or amelysee reinforce c ontention Faemm1 Similarity one emother themt to the Efflemet emitibit hiM similarity with ces that effect M pqrS is en es tatmeimmat Studies station, indicatisq impact from FWPS smother them with Efflemet staties, species et the Efflemet. 14 9 gad recovery (continued) eperations. even during periods of high poteetfel of faammel cohties evi
scriptieres habitats beve Isocomo established at indicator species 1sypothasis. faquant c-4 ties, ere distinguistisette Studies the Efflemet station, indicating Gracilerie tikeshine and Imminarie free referomee stations t'y stenhainant .
impact from FWPS operatices. spp. both respond to maximum and eru6ers of the ceumomities. [
t.a minimmse output of FWrs. 95 C.
D tikvahime present from I N 1999. G. tikweblee romppeered in y Saptember emed Deceu6er 1989. I community Greater cc M ty everlap between no siysificant change le typical e - ity everlap indientes a rotatively overlap reference stations than between respense to WWPS ested f rom 1983 to stable impact et the Efflueet regeiring Effleast and reference stations, 1986. Sicco felt 1987 overlap perleds greater then 12 mmwths for indicating impact from PWPS between Efflemet and refereJce recovery. Overlap increese im September operations. statiemns increased. In genrch and 19e7 may indicate bagimmine recovery.
Smytember 1999 overlap uns hiqinest asew ery eviehet in 1998. AltheeWe the '
betw=en the two reference stations. estage ame>d in early 1989. recovery still
' evidesst.
Algal We patterm evi< bust in terms of Algal biemmes tenffected by 1994 and Alget biomass cateysties, representing Bicusss re?stive alget biomass among all 1986-40 este p . Biemess e clined esmimmat siget wa s, en met three statices. substantially since 1988. eshis+it a detectable ispect frem FWPS.
I pantitative Acute Damecho and stinted afgel semes taggad recovery at the ef flueet acute A 1399.d response is logical gives the Treesect Impect Zone created by effleset discharge. impact somse in respense to outages destructive motore of the *Ilscherge in Santvey in 1994 and 1996-88. Saees !!!- these memes. Scaering couned by defined after June 1987. Ds senos circulating meter pummps inses geceter detected in 1998. A duovedad mene effect them eleveted water temperatores in toeppmered in September and D=cember theathd etee of acute impe t sena. i 1989.
I I HIGHLIGHTS OF RESULTS QUANTITATIVE FAUNAL MON 1rORING ,
- 1. For 1989, species richness at the Effluent station ranked '
intermediate between the reference stations in March and September. This indicates that, as a result of the recent power outage, the Effluent station had become relatively
>I, similar,. in terms of species composition, to the reference '
stations.
- 2. In 1988 and 1989, faunal densities were lowest at the Effluent station in March and highest at the Effluent in
- September. Densities decreased at the reference stations from March to September, 1989. Results from 1983 through 1989 do not empirically indicate a direct relationship between PNPS operations and faunal densities.
- 3. Species composition of the top 15 dominants has been similar at all stations and fairly consistent since 1983.
Dominant species were not measurably affected by PNPS and I showed no response to the previous outage in 1989. March and September, Mytilus edulis was numerically In dominant at all stations, comprising over 60 percent of the fauna. From March to September, 1989, there was a substantial but unexplained decline in Mytilus edulis abundance at the reference stations.
- 4. Species diversity has typically been lowe t at the Effluent station since 1983. In 1989, diversity was the highest in March and the. lowest in September at the Effluent station.
When Mytilus edulis was excluded from the analysis, the
- I- Effluent ranked intermediate between the reference stations indicating the increased presence of less dominant species.
- 5. Similarity was high between the reference stations in March 1989, and by September the similar.ity was high between the Effluent and Manomet Point stations, due partly to the I abundance of Mytilus edulis. From 1983 to 1986, similarity between the reference stations was much higher than between the Effluent and reference stations. The partial recovery I of the Effluent fauna indicated by the similarity measure in 1989 may be a response to the previous outage at PNPS.
QUANTITATIVE ALGAL COMMUNITY MONITORING
- 1. Algal communities were similar among all stations in 1989.
The warm-water alga, Gracilaria tikvahiae, was believed to I have been observed at the Effluent station during the September and December transect surveys. During normal operational years, Gracilaria tikvahiae was regularly observed. However, this species was absent from 1987 i
Ii i (after a decline in 1986) through September 1989 owing to II 1 lack of thermal effluent from PNPS. El
- 2. From 1963 to 1987, the number of algal species shared g, l (overlap) between the reference stations was slightly l higher than between the Effluent and reference stations. In fall 1988, due to recolonization at the Effluent station as a result of the prolonged outage, algal assemblages at the reference stations were more similar to the Effluent station assemblages than to each other.
E.i I In 1989, overlap Rl was highest between the two reference stations once again. *'
- 3. Algal biomass generally showed the same seasonal pattern observed since 1983-(except for 1986); biomass was low in spring and high in fall only at Manomet Point and the l Effluent station. A slight decline was observed at Rocky .
l Point. QUALITATIVE TRANSECT SURVEYS The size of the denuded area of the acute impact zone is mainly influenced by the circulating water pump operation. In 1989, circulating water pump activity was high, resulting in current ge7eration. Recovery of the algal community appeared to continue even though the outage ended in early 1989. Recolonization of Chondrus crispus during g the previous outage resulted in a disappearance of the 3 formerly stunted and denuded zones in March and June; clear boundaries were not detected. In September and December, the denuded zone reappeared and area measurements however, I were made. I I Il 1 Il 1! i 36 5>
=;
, I I LITERATURE CITED Boston Edison Co. 1986. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 27. Boston, MA. Boston Edison Co. 1987a. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 29. Boston, MA. Boston Edison Co. 1987b. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 30. I Boston, MA. Boston Edison Co. 1988a. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 31. I Boston, MA. Bcston Edison Co. 1988b. Marine ecology studies related to operation of Pilgrim Station. Semi-Annual Report No. 32. B Boston, MA. I Boston Edison Co. 1989a. Marine ecology studies related to Operation of Pilgrim Station. Semi-Annual Report No. 33. Boston, MA. Boston Edison Co. 1989b. Marine ecology-studies related to operation of Pilgrim Station. Semi-Annual Report No. 34. Boston, MA. Logan, D.T., and D. Maurer. 1975. Diversity of marine invertebrates in a thermal effluent. J. Water Poll. Con. Fed. 47(3):515-523. Marine Biocontrol Corporation. 1988. Pilgrim Station Chlorine and Biofouling Monitoring Program, Monthly' Status Report,
.I December 1988, submitted to Boston Edison. Boston, MA.
I
.I I
I I
, 37
. . . ~ - - _ . . - . . . _ . - - . - -. -- - . - . - . - ~ . _
I I ICHTHYOPLANKTON E11TRAINMENT MONITORING , AT PILGRIM NUCLEAR POWER STATION I, JANUARY-DECEMBER 1989 Volume 1 of 2 [ (Results) I L Submitted to Boston Edison Company Boston, Massachusetts lI t t l' ' l by l Marine Research, Inc. l i Falmouth, Massachusetts l' April 4, 1990 - I eI n I I g
I I TABLE OF CONTENTS SECTION M .I I EXECUTIVE
SUMMARY
1 II INTRODUCTION 2 III METHODS AND MATERIALS 3 IV RESULTS AND DISCUSSION 7 A. Ichthyoplankton Entrained - 1989 .7 B. Multi-year Ichthyoplankton Comparisons 16 C. Lobster Larvae Entrained 27 v HIGHLIGHTS 29 I APPENDICES A and B (available upon request) I I . I I I I I I . I
Ii LIST OF FIGURES uom mac , 1 Entrainment sampling station in PNPS discharge ) canal. 4 2 Location of entrainment contingency plan samp-ling stations, C-1 through C-13, 6 3 Dominant species of fish eggs and larvae found in PHPS ichthyoplankton samples by season. Per- > cent of total and summed monthly means for all i species are also shown. 8 ; 4 Hean monthly densities per 100 m8 of water in 3' the PNPS discharge canal for the eight numer- g ,' ically dominant egg species and total eggs, 1989 (dashed line). Solid lines encompassing shaded area show high and low values over the 1975-1988 period. 18 5 Mean monthly densities per 100 m8 of water in the PNPS discharge canal for the eleven numeri-l u cally dominant larval species and total larvae, 1989 (dashed lino). Solid lines encompassing 3 shaded area shos high and low values over the 1975-1988 period. 22 3 LIST OF TABLES TABLE BGE 1 Species of fish eggs (E) and larvae (L) ob-tained in ichthyop3ankton collections from the Pilgrim Nulcear Power Station discharge canal, January-December 1989, 30 2 Species of fish eggs (E) and larvae (L) col-lected in the PNPS discharge canal, 1975-1989. 33 LIST OF APPENDICES APPENDIX A* Densities of fish eggs and larvae per 100 m8 of I water recorded in the PNPS discharge canal by ; species, date, and replicate, January-December ' 1989. B* Mean monthly densities and range per 100 m8 of water for the dominant species of fish eggs and larvae entrained at PNPS, January-December 1975- " 1989.
*Available upon request.
il l I: I,
SECTION I EXECUTIVE
SUMMARY
I ! Ichthyoplankton sampling was completed twice per month in .
.I January, February, October-December, and weekly from March through l September. Over the course of the year both circulating water system pumps were in service during 24 of the 41 sampling occasions (59%); one pump was operating during the remaining periods. -
Numerical dominants among the 40 species represented in the 1989 collections included sculpins, rock gunnel, Atlantic mackerel, labrids, fourbeard rockling, hakes, and windowpane. Comparisons between 1989 monthly mean densities per 100 m8 of water and those recorded over the 1975-1988 period suggest that Atlantic cod eggs and winter flounder larvae were uncommon in 1989. I Record high numbers of rockling, hake, mackerel, menhaden, and windowpane eggs were recorded. No larval lobsters were obtained in 1989, the previous one being found in 1982. I l I l l I 1
I SECTION II INTRODUCTLQH This report summarizes results of ichthyoplankton entrainment sampling conducted at the . Pilgrim Nuclear Power Station (PNPS) discharge canal on a regular basis from January through December 1989. Work was carried out by Marine Research, Inc. (MRI) for Boston Edison Company (BECo) under Purchase Order No. 66231 in ' compliance with environmental monitoring and reporting requirements of the PNPS NPDES permit (U.S. Environmental Protection Agency and Massachusetts Division of Water Pollution Control). In an effort to condense the volume of material presented in these reports, details of interest to some readers may have been omitted. Any l questions or requests for additional information may be directed to Marine Research, Inc., Falmouth, Massachusetts, through BECo. I I' I 9 I 2 I
I SECTION III METHODS AND MATERIALS Entrainment sampling at PNPS was completed twice per month during January, February, October, November, December, and weekly March-September. Samples were collected in triplicate from rigging mounted approximately 30 meters from the headwall of the discharge , canal (Figure 1) at low tide during daylight hours. A 0.333-mm mesh, 60-cm diameter plankton net affixed to this rigging was I streamed in the canal for 8 to 12 minutes depending on the abundance of plankton and detritus. In each case, a minimum of 100 l m8 of water was sampled. Exact filtration volumes were calculated ' using a General Oceanics Model 2030R digital flowmeter mounted in the mouth of the net. I PNPS was in the process of returning to full power during 1989 I following an extended outage which began in April 1986.. The. operation of the two circulating water system (CWS) pumps varied during the year with at least one CWS pump operating during each ichthyoplankton collection period. Over the course of the year both pumps were in service during 24 of the 41 sampling occa01ons (59%). All samples were preserved in 10% Formalin-seawater solutions and returned to the laboratory for microscopic analysis. A detailed description of the analytical procedures may be found in MRI (1988).*
- Marine Research, Inc. 1988. . Ichthyoplankton Entrainment Monitor-ing at Pilgrim Nuclear Power Station January-December 1987.
III.C.1-6-10. In: Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-annual Report No. 31. Boston Edison Company. 3
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I : When the Cape Cod Bay ichthyoplankton study was completed in 1976, a contingency sampling plan was added to the entrainment monitoring program. This plan was designed to be implemented if eggs or larvae of any dominant species proved to be " unusually
.I abundant" in the PNPS discharge samples. The goal of this sampling plan was to determine whether circumstances in the vicinity of Rocky Point, attributable to PNPS operation, were causing an abnormally large percentage of ichthyoplankton populations there to be entrained or, alternatively, whether high entrainment levels simply were a reflection of unusually high population levels in Cape Cod Bay. " 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 month from 1975 through 1988.
The contingency sampling plan consists of taking additional sets of triplicates from the PNPS discharge on subsequent dates to monitor the temporal extent of the unusual density. An optional offshore sampling regime was also established to study the spatial i distribution of the species in question. The of fshore contingency ! program consists of single, oblique tows at each of 13 stations (Figure 2) on both rising and falling tides for a total of 26 samples. Any contingency sampling requires authorization from l Boston Edison Company. 'I I .I -- --
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I SECTION IV RESULTS AND DISCUSSION I A. Ichthvoplankton Entrained - 1989
.I Population densities per 100 m8 of water ' each species listed by date, station, and replicate are presented for 1989 in Appendix A (available upon request). Table 1 lists all species i represented in the 1989 collections, indicates the months eggs and/or larvae of each species were found and, for the more common species, the months of peak abundance.
Ichthyoplankton collections are summarized below within the three primary spawning seasons observed in Cape Cod Bay winter-early spring, late spring-early summer, and late summer-autumn. Figure 3 shows the dominant species of eggs and larvae within each I season for 1989. I Winter-early sprina spawners (December-Aor11) l The beginning of this spawning season is sampled at the j end of the calendar year. In, December 1989 collections ; contained only a single species of egg and a single species of larva. Atlantic cod (Gadus morhua) contributed the eggs ! I. with a monthly mean density of 2 per 100 m8 of water. I l l Atlantic herring (Clupon harengus harengus) accounted for the ; larvae with but a single specimen being found (mean = 0.1 per 100 m8). The number of species represented in the earlier ! collections was two in January, then increasing to five in ; 7
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I ; February, 15 in March, and 13 in April. Eggs were relatively uncommon throughout the period since species contributing most l to entrainment during these months spawn demersal, adhesive eggs which are not generally subject to entrainment. Among 13 sampling periods f rom January through April, eggs were )
- present on seven occasions. Eggs first appeared on the second date in February (16th) consisting of a single demersal longhorn sculpin egg (Myoxocephalus octodecenspinosus; mean density = 0.3 per 100 m8 of water). Four species were .
represented by eggs in March - winter flounder (Pseudo-pleuronectes americanus), American plaice (Hiopoalossoides platessoides), Atlantic cod, and rainbow smelt (osmerus mordax). Monthly.mean densities were 0.2 per 100 m' of water for flounder, 0.1 per 100 m8 for each of the other species. April egg collections contained five species - yellowtail flounder (LIA *erruginen), American plaice, fourbeard rockling (Encholyop, ~ imbrius), Winter flounder, and Atlantic cod. Monthly mean densities per 100 m8 of water were 2.7, 1.5, 0.9, 0.8, 0.7, respectively. It is important to note that, because winter flounder eggs are demersal and adhesive, their densities in the PNPS discharge canal should not be considered representative of densities in the waters around Rocky Point. Those collected were probably dislodged from the bottom by currents or perhaps other fish. The same is true for rainbow smelt which spawn demersal, adhesive eggs in fresh water.
I 1
)
Numbers of species represented by larvae generally increased ]
- with time during the winter-early spring period; two species were found in January, four in February, 11 in March, and 10
! in April. aunnelius), Numerical dominants included rock gunnel (Pholis sculpin (Myoxocephalus spp.), and seasnail I (Liparis - atlanticus) . Rock gunnel densities averaged 0.1 l larvae per 100 m8 of water in January while accounting for 49% ! of the catch, increasing to 11.6 per 100 28 in February (79% of total) and 61.0 per 100 m8 in March (47% of total). Rock l l l gunnel densities then declined somewhat in April to 11.1 per l l 100 m8 (21% of total). Sculpin first appeared in February l with a monthly mean density of 2.0 per 100 m8 accounting for 13% of the total larval catch. Their numbers increased in i March to an average density of 60.6 per 10 m8, then dropped l to 26.8 per 100 m8 in April; they represented 47 and 50% of I1j I all larvae during those two months respectively. Over the l seasonal period as a whole, grubby (Myoxoccohalus aenaeus) were most nunerous among the three species of larval sculpin, ] shorthorn sculpin (H. scorolus) ranked second, and longhorn i sculpin third; overall a ratio of 40:18:1 was obtained for the three respective species. Larval seasnail, like the rock I gunnel, first appeared in February (monthly mean = 1.2 per 100 l m2 of water) averaged 0.8 per 100 m2 in March, and increased to 7.5 larvae per 100 m2 in April. The gulf snailfish (Liparis coheni) contributed all the Liparis spp. in February, l the majority of them in March. They were absent in April, i 12 1
i giving way to the seasnail', L. atlanticus. Over the period as a whole a ratio of 3.7 seasnail to i gulf snailfish was obtained. I Late spring-early summer (Mav-July) A total of 23 species were represented in May, 24 were represented in June, and 18 were represented in July. Among these, 12 species were represented by eggs in May and June, 13 in July. Numerically dominant eggs included Atlantic I mackerel (Scomber scombrus), the labrids, and windowpane l (Scophthalmus aquosus, grouped with uncommon Paralichthys oblongua eggs). Mackerel accounted for 75% of the May egg total, 17% of the June egg total, and 1% of the July egg total. Labrids (including the labrid-Limanda group) accounted for 17% of total in May, 78% in June, and 88% in July. Corresponding figures for windowpane were 0.4, 2, and 5%, respectively. Mean monthly densities in May, June, and July l respectively were 5584,1013, and 11 per 100 m8 for mackerel; l 1295, 4581, and 770 per 100 m8 for Inbrids; and 33, 137, and
.g u 45 per 100 m8 for windowpane.
Larval collections contained 19 species in May, 22 species in June, and 12 species in July. R6Liated shanny (Ulvaria subbifurcata), seasnails, Atlantic mackerel, cunner (Tautoco-1Abr.ua adspersus), and fourbeard rockling were numerically dominant. Radiated shanny accounted for 37% of the May larval catch with a monthly mean density of 20 per 100 m8 declining ! , 13 l ! \
I to 1% of the June total with a mean of 4 per 100 2 8}}