ML061420123
| ML061420123 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/31/2005 |
| From: | Entergy Nuclear |
| To: | Office of Nuclear Reactor Regulation |
| ALICIA WILLIAMSON 301-415-1878 | |
| Shared Package | |
| ML061380814 | List:
|
| References | |
| Download: ML061420123 (54) | |
Text
I MARINE ECOLOGY STUDIES RELATED TO OPERATION OF PILGRIM STATION SEMI-ANNUAL REPORT No. 66 Report Period: JANUARY 2005 THROUGH JUNE 2005 Date of Issue: October 30, 2005 Compiled and Reviewed by:
Environmental Protection Group Entergy Nuclear -
Pilgrim Station Plymouth, Massachusetts 02360
TABLE OF CONTENTS SECTION
- 1.
INTRODUCTION
- 2.
SUMMARY
- 3.
MARINE BIOTA STUDIES 3.1 Marine Fisheries Monitorina Winter Flounder Area-Swept Estimate; AprilMay 2005
[Marine Research, Inc.]
3.2 Entrainment Monitoring Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station; January - June 2005 [Marine Research, Inc.]
3.3 Impingement Monitoring Impingement of Organisms at Pilgrim Nuclear Power Station; January - June 2005 [Marine Research, Inc.]
Pilgrim Station i
Entergy Nuclear
INTRODUCTION A.
Scope and Obiective This is the sixty-sixth (66) report, provided semi-annually, on the status and results of environmental surveillance and monitoring programs related to the operation of Pilgrim Nuclear Power Station (PNPS).
The monitoring efforts discussed in this report relate specifically to the Western Cape Cod Bay ecosystem with particular emphasis on the Rocky Point area. This report is submitted in accordance with the environmental monitoring and reporting requirements of the PNPS NPDES Permit from the U.S. Environmental Protection Agency (#MA0003557) and Massachusetts Department of Environmental Protection (#359).
The objectives of the Environmental Surveillance and Monitoring Program are to determine whether the operation of PNPS results in measurable effects on the marine ecology and to evaluate the significance of any observed effects. If an effect of significance is detected, steps are taken to correct or mitigate any potential impacts.
The efforts described in this report represent a continuation of monitoring conducted at PNPS in the past by Entergy (and before that, by Boston Edison Company). This program was submitted to U.S. EPA and MA DEP for review in December 2004 and was subsequently approved. Note that in March 2002, Entergy Nuclear Operations, Inc. became the operator of Pilgrim Station, although Entergy Nuclear Generation Co. is still the owner.
This change had virtually no effect on the Marine Environmental Monitoring Programs at PNPS or the personnel associated with them.
B.
Marine Biota Studies
- 1.
Marine Fisheries Monitoring Marine Fisheries studies in 2005 focused on winter flounder population parameters to develop an understanding of any PNPS impact on this indicator species. Population estimates and adult equivalency analyses are conducted on this key species to help assess the impact of PNPS entrainment.
Results of the marine fisheries monitoring during the reporting period are presented in Section 3.1. Winter flounder are studied by trawling techniques.
Entergy has conducted efforts to support fisheries enhancement in 2000 through 2004 and did so again in 2005. Winter flounder were spawned and reared in a hatchery Env / Mar-Ecol-66 Introduction Entergy Nuclear
from January to May, and then released near the Plymouth Harbor Yacht Club in mid-May 2005.
Field results to-date have been very favorable. As of late September, 220 tagged-fish have been recaptured.
Long-term survival experiments (pen studies) were conducted from June to October. Because this activity continued past June, it will be documented separately and included in our annual report.
- 2.
Benthic Monitorinq No benthic monitoring was performed during this period.
- 3.
Entrainment Monitoring PNPS has been monitoring entrainment of fish eggs and larvae, and lobster larvae in the plant's cooling water for more than twenty-five years (in 1973-1975 phytoplankton and zooplankton were also studied). Information generated through these studies has been utilized to make periodic modifications in the sampling program to more efficiently address the question of the effect of entrainment. These modifications have been developed by Marine Research, Inc. (MRI) in conjunction with Pilgrim environmental personnel, and reviewed and approved by U.S. EPA and MA DEP on the basis of the program results.
Plankton monitoring in 2005 emphasized consideration of ichthyoplankton entrainment and selected species adult equivalency analyses.
Results of the ichthyoplankton entrainment monitoring for this reporting period are discussed in Section 3.2.
- 4.
Impingement Monitoring The PNPS impingement monitoring and survival program identifies, quantifies and determines viability of the organisms carried onto the four intake traveling screens.
Marine Research, Inc. conducted impingement sampling with results reported to Entergy's Environmental Protection Dept.
Results of the impingement monitoring for this reporting period are discussed in Section 3.3.
Env / Mar-Ecol-66 Introduction Entergy Nuclear
C.
Station Operation History Monthly average capacity factors for the first half of 2005 are shown below. During this period, one thermal backwash for biofouling control was performed (June 28 t). PNPS was operated at or near full power during the first six months of 2005, with the exception of one planned shutdown. Beginning on April 18, and ending on May 13, 2005 (241/2 days), Pilgrim had a planned refueling outage (RFO-15). During this outage both circulating (condenser cooling) water pumps were secured for 18 days (April 20th to May 8E).
The monthly average amount of sea water used for plant cooling water as well as the average discharge water temperatures are also shown below.
Flow volume is given as percent of total possible discharge flow from both the circulating water and salt service water systems. The nominal capacities for these intake pumps are: 155,500 gafmin. for each circulating water pump [2] and 2500 gal/min. for each salt service water pump [5]. To estimate annual entrainment, the average flow value is assumed to be 320,335 gal/min.
(99% of maximum possible cooling water flow).
2005 CAPACITY DISCHARGE DISCHARGE MONTH FACTOR TEMP. (OF)
FLOW (%)
January 99.0 65.4 97.5 February 98.1 63.4 97.7 March 97.0 63.9 97.7 April 49.5 56.9 58.9 May 60.4 75.7 68.7 June 99.0 81.6 97.8 Env / Mar-Ecol-66 Introduction Entergy Nuclear
SUMMARY
Results of the January-June 2005 Environmental Surveillance and Monitoring Program at Pilgrim are highlighted below.
Section 3.1-Marine Fisheries Monitorina:
- 1.
Trawls for winter flounder stock assessment were performed for the eleventh consecutive year. The "area-swept" study consisted of 75 tows in northwestern Cape Cod Bay to estimate this species' population (instantaneous abundance).
- 2.
Winter flounder population size (instantaneous abundance) was estimated using an area/density approach, based on the area-swept densities over the entire study area.
- 3.
Adjusted estimates of winter flounder abundance in the study area for 2005 were 126,118 adults and 229,156 total winter flounder.
Section 3.2-Entrainment Monitoring:
- 1.
A total of 35 species of fish were represented in the January-June samples.
- 2.
Winter-early spring samples were dominated by the Atlantic cod and witch flounder egg group and American plaice eggs along with sand lance, rock gunnel and grubby larvae.
- 3.
Late spring-summer collections taken in May and June were dominated by labridae-Limanda, and Atlantic mackerel eggs along with radiated shanny, winter flounder, cunner and rockling larvae.
- 4.
A review of January-June 2005 egg and larval densities suggested that, in most cases, numbers were consistent with those recorded from 1981 through 2004. An exception was noted in the June labridae-Limanda eggs, which had a lower mean density than previous years.
- 5.
Fourteen (14) stage 1 and one (1) stage 2 lobster larvae were collected in entrainment samples for the January-June 2005 period.
Section 3.3-lmpingement Monitoring:
- 1.
In 202.2 collection hours, a total of 490 fish comprising 25 species were collected from January-June 2005, resulting in a mean impingement rate of 2.61 fish/hour.
Env / Mar-Ecol-66 Summary Entergy Nuclear
- 2.
Impingement rates ranged from 6.72 fish/hour in April to 0.05 fish/hour in June.
- 3.
Atlantic silversides (Menidia menidia), rainbow smelt (Osmerus mordax), pollock (Pollachius Wirens), winter flounder (Pseudopleuronectes americanus), Atlantic herring (Clupea harengus).
grubby (Myoxocephalus aenaeus),
and Atlantic menhaden (Brevoortia tyrannus) accounted for 56.6, 11.8, 6.7, 6.5, 4.9, 2.7, and 2.2%, respectively, of the six month total.
- 4.
From January to June 2005, 379 invertebrates representing 12 species were sampled yielding an impingement rate of 1.87 invertebrates per hour (Table 3). Sevenspine bay shrimp (Crangon septemspinosa) accounted for 68.3% of the six-month total.
Env / Mar-Ecol-66 Summary Entergy Nuclear
Pilgrim Nuclear Power Station Marine Ecology Studies Semi-Annual Report # 66 Section 3.1 Marine Fisheries Monitoring
WINTER FLOUNDER AREA-SWEPT ESTIMATE WESTERN CAPE COD BAY 2005 Submitted to Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station Plymouth, Massachusetts by Marine Research, Inc.
Falmouth, Massachusetts October 24, 2005 I i
Introduction Field studies around Pilgrim Nuclear Power Station (PNPS) have demonstrated the water withdrawal affects of plant operations, specifically the entrainment of fish eggs and larvae, and impingement of adult and juvenile fish and invertebrates. The environs around PNPS serve as spawning, nursery, and feeding grounds for winter flounder (Pseudopleuronectes amiricanus) and this species is valuable both commercially and recreationally. From 1995 through 1999 the Massachusetts Divisiqn of Marine Fisheries (MDMF) estimated the size of the winter flounder population in waters off Pilgipnm Station. This study has been continued by Marine Research, Inc. (MRI) since 2000' the 2005 work being presented here.
Methods and Materials The study area, sampling methodology, and analytical calculations were the same as those used in the Massachusetts Division of Fisheries studies conducted in 1999 and by Marine Research, Inc. (MRI) from 2000 through 2004. Consistent with the past four years, tow duration was 30 minutes and tows less than 20 minutes were not included in calculations. Eighty-four tows were planned for 2005 consistent with previ!ops years.
The sampling area extended from Humarock, Marshfield southeastward to the MaryAfnn buoy, Manomet, from nearshore (9.2 m MLW) out to the 36.6 m (SMW) depth contobur (Figure 1; Lawton et al. 2000).
Since there is spatial variation in winter flounder.-
abundance by depth (Lawton et al. 1995), stratified estimates of abundance were used to improve precision.
The 55-foot F/V Frances Elizabeth was contracted to sample winter flounder using a Yankee otter trawl with 18.3 m sweep and 14.6 m headrope with 15.2 cm stretch mesh body and a 7.6 cm square mesh cod end with a 4.5 cm mesh liner, it was fished with 12.8 m legs and 73.2 m ground cables. The trawl doors were steel measuring 1.8 m x 1.2 m and weighing 205 kg each.
Beginning and end latitude and longitude, start and end times, and boat speed were recorded during each tow.
Tow tracks were plotted with Nobeltec Visual Navigation Suite. All winter flounder were measured to the nearest centimeter total length (IL), sexed by assessing the reproductive state and maturity.
This included checking for the presence of ripe eggs or sperm and for the presence of ctenoid scales on the left (blind) side of the caudal peduncle. Ctenoid scales often occur on mature males.
Prior to being released all fish were examined for tags (MDMF tagging study 1994 to 1998; Lawton et al. 2000).
Winter flounder population size (instantaneous absolute abundance) was estimated using an area/density approach, based on the area-swept densities over the entire study area. Calculations were completed using the same procedures employed in 1999 by Lawton et al. (2000). Trawl gear efficiency was unknown and assumed to be 50% consistent with previous estimates. Density was determined by dividing the number 1
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7 I-L"_"
" i
- 1. "Area-Swept" sampling boundary, Northwest Cape Cod Bay.
of winter flounder per tow by the area of bottom covered. Bottom area was based on tow length and tow width. Tow length was taken from the tracks generated by the Nobeltec software. Tow width was estimated using the trawl doors' spread on the bottom. Spread was determined by measuring the between-wire width at the blocks and at six feet aft of the blocks and extrapolated to account for the wire out (usually 450 feet) yielding a typical door spread of 175 feet (54 meters).
Door spread was used because of the "herding" action caused by the sediment cloud generated by the doors and legs while towing (Somerton 2003, Somerton and Weinberg 2001, Lawton et al. 2000, Ramm and Ziao 1995, Dickson 1993a and Dickson 1993b). Catch per unit area was calculated for each tow. Computed estimates for adult winter flounder (Ž280 mm TL; Witherell and Burnett 1993) and for all sizes pooled were doubled to account for assumed catch 2
aieRsacIc 2
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efficiency. Density estimates were multiplied by total acreage (2.674 x 108 m2)' in the study area to calculate absolute abundance.
Results and Discussion In 2005, 4,206 winter flounder were taken in 75 tows completed between April 13 and May 4 yielding a mean catch of 56 fish per tow (catch per unit effort, CPUE). The CPUE for 2005 was lower than all previous years except for 1995 (Figure 2). The relative low abundance observed in 1995, 1996 and 1999 may be attributed to the use of a different fishing vessel with possibly different catch efficiencies (Figure 3).
Unadjusted estimates of winter flounder abundance in the study area for 2005 were 63,059 adults and 114,578 total winter flounder. These estimates were doubled to account for trawl efficiency which was assumed to be 50%; the adjusted numbers were 126,118 and 229,156, respectively (Table 1).
Winter flounder absolute abundance estimates for adults and total winter flounder were below average in 2005 based on the 1995 - 2004 time series, 42% and 41% of their respective means of 303,358 and 556,771.
Winter Flounder CPUE Spring 1995 - 2005 200 0
- 0 1995 1996 1997 1998 1999 2000 2001 2002 20C Year
.,'e.280 TL AII Flounder 03 2004 2005 Figure 2. CPUE for winter flounder caught in Western Cape Cod Bay, 1995-2005.
1 In 1995 and 1996 an acreage figure of 1.526 x 0' m2 was originally used. Beginning with 1997 this larger value was employed. The 1995 and 1996 estimates were corrected accordingly.
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Winter Flounder - Annual Abundance Estimates Spring 1995 - 2005
~1000 4800 0
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year MTotal Abundance -Eadult Abundancej Figure 3. Estimated annual abundance of winter flounder in Western Cape Cod Bay, 1995-2005.
Recent estimates of fishing mortality suggest that it is relatively low with an estimated exploitation rate of 12% in 2001 and 2002. The Gulf of Maine stock is not considered to be in an overfished state and overfishing is not believed to be taking place at the present time (NEFSC 2003, NEFSC 2005). The low 2005 area swept estimate is likely the result, at least in part, to the natural and fishing induced decline in the strong 1997 and 1998 year classes. A review of the NOAA Northeast Fisheries Science Center (NEFSC) spring abundance index has also shown a sharp drop in the Gulf of Maine stock from 2002 (3.7 kg per tow) to 2004 (1.1 kg per tow). The MDMF resource assessment time series for the northern flounder stock extending from the New Hampshire border to Cape Cod (Howe et al. 1994) has also dropped from 35.6 kg per tow in 2000 to 12.2 kg per tow in 2004 (Figure 4; NEFSC 2005). These data suggest that the decline observed in Western Cape Cod Bay is not local to the PNPS area.
It is important to note that the assumed trawl efficiency value of 50% almost certainly varies from year to year and was selected to be conservative. It is probably lower than 50% particularly for small fish which would result in higher population estimates than those presented. For example, Kuipers (1975) reported efficiency of 28%
for a beam trawl which is typically more efficient than an otter trawl. Harden-Jones et al.
(1977) cited in Gunderson (1993) used sonar to estimate that 44% of plaice positioned between the trawl doors were captured. Mearns and Allen (1978) reported efficiencies of 10 to 50% for a small otter trawl. Kjelson and Colby reported a range of efficiencies from 9 to 51%, Grosslien and Laurec (1982) efficiencies of 26 to 38%, and Walsh (1992) values that ranged from as low as 5% for small flounder to 75% for adults.
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Gulf of Maine Winter Flounder NEFSC Abundance Indicies 6
4 1979 1981 1983'19"85 1987'1989 1991 1993 1995 1997 1~999 2001'2003 2005 l
___ A_________
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I IX Figure 4. Northeast Fisheries Science Center (NEFSC) Gulf of Main and Massachusetts Division of Marine Fisheries (MDMF) northern stock spring abundance indices for winter flounder stocks, mean weight (kg) per tow, 1979-2005.
5s Marine Research, Inc.
The Coastal Lobster Investigations Project of the Massachusetts Division of Marine Fisheries maintains temperature monitors in the vicinity of Plymouth at three depth strata (40, 60 and 110 feet). These data along with surface water temperature from National Data Buoy Center Station 44013 (Boston Buoy; available at http://www.ndbc.noaa.gov/station-page.php?station=44013) were plotted from April 1 through May 15 for 2000 to 2005 (Figure 5). Included on these plots is the daily winter flounder catch per tow for each sampling day in Western Cape Cod Bay. These figures show that bottom water in 2005 was colder than the previous five years. From April 21 to 25 there was more than a 3° C drop in water temperature at the 40-foot, 60-foot and 1 10-foot monitors. Cool water temperatures in general and this decline in bottom water temperature may have delayed the inshore migration of mature winter flounder.
Length frequency data for 2005 exhibited a bimodal distribution (Figure 6). The majority of fish sampled were age 3 and 4 representing the 2002 and 2001 year classes, respectively (Witherell and Burnett 1993). The second mode was age 2 fish. As in previous years, due to the selectivity of the net and the 4.5 mm cod-end liner, the number of age 2 and younger fish was probably under sampled (Lawton et al. 2000).
6 Marine Research, Inc.
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8
Table 1. Estimated abundance (stratified by depth) of winter flounder in the study area (2.674 x108 m2 at MLW) with 95% confidence limits, Spring 1995-2005.
m 1995 Flounder 212,989 210,637 215,341
>280 mm TL All Flounder 444,850 437,438 452,261 1996 Flounder 316,986 314,365 319,607 2280 mm TL All Flounder 510,306 506,378 514,235 1997 Flounder 313,959 308,896 319,021
>280 mm TL All Flounder 882,889 887,834 887.945 1998 Flounder 264,812 242,779 286,825
>280 mm TL All Flounder 588,450 553,330 623,570 1999 Flounder 176,271 172,306 180,236
>280 mm TL All Flounder 367,908 360,826 374,989 2000 Flounder 464,176 450,222 478,126
>280 mm TL All Flounder 826,548 807,952 845,144 2001 Flounder 400,812 330,709 470,914
>280 mm TL All Flounder 559,713 471,109 648,316 2002 Flounder 476,263 429,430 523,096
Ž280 mm TL All Flounder 741,108 725,285 756,932 2003 Flounder 262,604 223,957 301,247
>280 mm IL All Flounder 398,528 387,156 409,898 2004 Flounder 157,532 154,555 160,509
>280 mm TL All Flounder 247,411 242,226 252,596 2005 Flounder 126,117 124,107 128,127
>280 mm TL All Flounder 229,156 226,144 232,169 9
Marine Research, Inc.
Literature Cited Dickson, W. 1993a. Estimation of the capture of trawl gear. I: Development of a theoretical model. Fisheries Research, 16:239-253.
Dickson, W. 1993b. Estimation of the capture efficiency of trawl gear. II. Testing a theoretical model. Fisheries Research, 16:255-272.
Grosslien, M.D. and A, Laurec. 1982. Bottom trawl surveys design, operation and analysis. FAO, CECAF/ECAF SERIES 81/22. 25p.
Gunderson, D.R. 1993. Surveys of Fisheries Resources. John Wiley & Sons, Inc. New York. 248 p.
Harden-Jones, F.R., A.R. Margetts, M. Greer Walker, and G.P. Arnold. 1977. The efficiency of the Garnton otter trawl determined by sector-scanning sonar and acoustic transponding tags. Tapp. P.-v. Reun. Cons. Int. Explor. Mer. 170:45-51.
Kjelson M.A. and D.R. Colby, 1978, The evaluation and use of gear efficiencies in the estimation of estuarine fish abundance. Estuarine Research. pp. 416-424.
Kuipers, B. 1975, On the efficiency of a two-meter beam trawl for juvenile plaice. Neth.
J. Sea Res. 9(1):69-85 Lawton, R.P. B.C. Kelly, V.J. Malkoski, and J. Chisholm. 1995. Final Report on Bottom Trawl Survey (1970-1982) and Impact Assessment of the Thermal Discharge from Pilgrim Station on Groundfish. Pilgrim Nuclear Power Station Marine Environmental Monitoring Program Report Series - Number 7. 56 pp.
Lawton, R.P., B.C. Kelly, J. Boardman, and M. Camisa. 2000. Annual Report on assessment and Mitigation of Impact of the Pilgrim Nuclear Power Station on Finfish Populations in Western Cape Cod Bay. Project Report No. 68 (Jan.-Dec.
1999). In: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-annual Report No. 55. Entergy Nuclear Generation Company, Plymouth, MA.
MRI (Marine Research, Inc.). 2001. Ichthyoplankton entrainment monitoring at Pilgrim Nuclear Power Station January-December 2000. In: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-annual Report No. 59. Entergy Nuclear Generation Company, Plymouth, MA.
NEFSC. 2003 Report of the 36th Northeast Regional Stock Assessment Workshop (36th SAW):Stock Assessment Review Committee (SARC) consensus summary of assessments. Ref. Doc 03-06. February 2003.
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NEFSC. 2005. Assessment of 19 Northeast Groundfish stocks through 2004. 2005 Groundfish Assessment Review Meeting (2005 GARM), Northeast Fisheries Science Center, Woods Hole, Massachusetts, 15-19 August 2005. Ref.Doc.05-13.
September 2005.
Mearns, AJ. and M.J. Allen. 1978. Use of Small Otter trawl in coastal biological surveys. EPA-600/3-78-083, 34p Ramm, D. C. and Y. Xiao. 1995. Herding in groundfish and effective pathwidth of trawls. Fisheries Research. 24:243-259.
Somerton, D. A. 2003. Bridle efficiency of a survey for flatfish: measuring the length of the bridles in contact with the bottom. Fisheries Research, 60: 273-279.
Somerton, D. A. and K. L. Weinberg. 2001. The effect of speed through the water on footrope contact of a survey trawl. Fisheries Research. 53:17-24.
Walsh.SJ. 1992. Size dependent selection at the footgear of a groundfish survey trawl.
North American Journal of Fisheries Management, 12:625-633.
Witherell, D.B., and J. Burnett. 1993. Growth and maturation of winter flounder, Pleuronectes americanus, in Massachusetts. Fishery Bulletin, U.S. 91:816-820.
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Pilgrim Nuclear Power Station Marine Ecology Studies Semi-Annual Report # 66 Section 3.2 Entrainment Monitoring
ICHTHYOPLANKTON ENTRAINMENT MONITORING AT PILGRIM NUCLEAR POWER STATION JANUARY - JUNE 2005 Submitted to Entergy Nuclear Generation Company Pilgrim Nuclear Power Station Plymouth, Massachusetts by Marine Research, Inc.
Falmouth, Massachusetts October 11, 2005
TABLE OF CONTENTS SECTION PAGE I
II III
SUMMARY
INTRODUCTION METHODS AND MATERIALS Monitoring Unusual Entrainment Values RESULTS LITERATURE CITED 2
1 2
3 IV 9
V 13 APPENDIX A*
APPENDIX B*
Densities of fish eggs and larvae per 100 m3 of water recorded in the PNPS discharge canal by species and date, January-June 2005.
Mean monthly densities and range per 100 m3 of water for the dominant species of fish eggs and larvae entrained at PNPS, January-June 1982-2005.
- Available upon request.
LIST OF FIGURES FIGURE 1
Aerial photograph of the entrainment sampling station in PNPS discharge canal.
6 i
LIST OF TABLES TABLE PAGE I
PNPS ichthyoplankton entrainment notification levels for 2005 by species category and month. See text for details.
7-8 2
Species of fish eggs (E) and larvae (L) obtained in ichthyo-plankton collections from the Pilgrim Nuclear Power Station discharge canal, January-June 2005.
14-15 3
Ichthyoplankton densities (number per 100 m3 of water) for each sampling occasion during months when notably high densities were recorded, January-June 2005.
16-17 ii
SECTION I
SUMMARY
Entrainment sampling at PNPS during the first half of 2005 was completed on five occasions during January and six in February. Sampling then occurred three times per week from March through June, except during the maintenance outage from April 18 to May 10, and on two storm occasions, March 11 and May 25.
A total of 35 species of fish were represented in the January - June samples. Winter-early spring samples were dominated by the Atlantic cod and witch-flounder egg group and American plaice eggs along with sand lance, grubby and rock gunnel larvae. Late spring-summer collections taken in May and June were dominated by labridae-Limanda and Atlantic mackerel eggs along with winter flounder, cunner, rockling, and radiated shanny larvae.
A review of January-June 2005 egg and larval densities suggested that, in most cases, numbers were consistent with those recorded from 1981 through 2004. An exception was noted in the June labridae-Linmanda eggs which had a lower monthly mean density than previous years.
Several unusually high densities were also recorded during the January-June 2005 period although they did not result in remarkable monthly mean densities relative to the PNPS time series.
Fourteen stage 1 and one stage 2 lobster larvae were found during the January-June 2005 entrainment sampling period. Previously, a total of 46 lobster larvae have been collected at PNPS dating back to 1974.
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SECTION II INTRODUCTION This progress report briefly summarizes results of ichthyoplankton entrainment sampling conducted at the Pilgrim Nuclear Power Station (PNPS) from January through June 2005 by Marine Research, Inc. (MRI) for Entergy Nuclear Generating Company under Contract No.
4500538686. A more detailed annual report covering all 2005 data will be prepared following the July-December monitoring period.
SECTION HI METHODS AND MATERIALS Monitoring Entrainment sampling at PNPS, begun in 1974, was originally completed twice per month during January and February, October-December; weekly during March through September; in triplicate at low tide. Following a PNPS fisheries monitoring review workshop in early 1994, the sampling regime was modified beginning April 1994. The revised program exchanged replication for improved temporal coverage. In January, February, and October through December during two alternate weeks each month single samples were taken on three separate occasions. Beginning with March and continuing through September single samples were taken three times every week. During autumn and winter months when sampling frequency was reduced, sampling was postponed during onshore storms due to heavy detrital loads. The delayed sample was taken during the subsequent week, six samples ultimately being taken each month.
To minimize costs, sampling was linked to the impingement monitoring program so that collections were made Monday morning, Wednesday afternoon, and Friday night regardless of tide (see Impingement Section). All sampling was completed with a 60-cm diameter plankton net streamed from rigging mounted approximately 30 meters from the headwall of the discharge canal (Figure 1). Standard mesh was 0.333-mm except from late March through late May when 2
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0.202-mm mesh was employed to improve retention of early-stage larval winter flounder (Pseudopleuronectes americanus). Sampling time in each case varied from 8 to 30 minutes depending on tide, higher tide requiring a longer interval due to lower discharge stream velocities. In most cases, a minimum quantity of 100 m3 of water was sampled although at astronomically high tides it proved difficult to collect this amount even with long sampling intervals since the net would not inflate in the low current velocity near high tide. Exact filtration volumes were calculated using a General Oceanics Model 2030R digital flowmeter mounted in the mouth of the net. Near times of high water a 2030 R2 rotor was employed to improve sensitivity at low velocities.
All samples were preserved in 10% Formalin-seawater solutions and returned to the laboratory for microscopic examination. A detailed description of the analytical procedures including developmental staging and a description of egg groupings appears in MRI (1988). As in past years, larval winter flounder were enumerated in four developmental stages as follows:
Stage 1 - from hatching until the yolk sac is fully absorbed (2.3-2.8 mm TL).
Stage 2 - from the end of stage 1 until a loop or coil forms in the gut (2.6-4 mm TL).
Stage 3 - from the end of stage 2 until the left eye migrates past the midline of the head during transformation (3.5-8 mm TL).-
Stage 4 - from the end of stage 3 onward (7.3-8.2 mm TL).
Similarly larval cunner (Tautogolabrus adspersus) were enumerated in three developmental stages:
Stage 1 - from hatching until the yolk sac is fully absorbed (1.6-2.6 mm TL).
Stage 2 - from the end of stage 1 until dorsal fin rays become visible (1.8-6.0 mm TL).
Stage 3 - from the end of stage 2 onward (6.5-14.0 mm TL).
Samples were examined in their entirety for larval American lobster (Homarus americanus). When collected these were staged following Herrick (1911).
Unusual Entrainment Values When the Cape Cod Bay ichthyoplankton study was completed in 1976, provisions were added to the entrainment monitoring program to identify unusually high densities of fish eggs and larvae. Once identified and, if requested by regulatory personnel, additional sampling could 3
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be conducted to monitor the temporal and/or spatial extent of the unusual occurrence. An offshore array of stations was established which could be used to determine whether circum-stances in the vicinity of Rocky Point, attributable to PNPS operation, were causing an abnormally large percentage of ichthyoplankton populations there to be entrained or, alternative-ly, whether high entrainment levels simply were a reflection of unusually high population levels in Cape Cod Bay. The effect attributable to any large entrainment event would clearly be greater if ichthyoplankton densities were particularly high only close to the PNPS shoreline. In past years when high densities were identified, regulatory personnel requested additional entrainment sampling, and the unusual density in most cases was found to be of short duration (<2 days).
With the change in 1994 to Monday, Wednesday, Friday sampling the temporal extent of any unusual density has been relatively easy to discern without additional sampling effort.
"Unusually abundant" was defined within monthly periods to deal with the large seasonal variation so readily apparent with ichthyoplankton and allowed tracking densities as each species' season progressed. On a month-by-month basis, for each of the numerically dominant species, all previous mean densities over three replicates (1974-1993; updated each year) were examined and tested for normality following logarithmic transformation. Single sample densities obtained from 1994-2004 were added to the pool within each month. Where data sets (for example, mackerel, Scomber scombrus eggs taken in June) fit the lognormal distribution, then "unusually large" was defined by the overall log mean density plus 2 or 2.58 standard deviations.' Log densities were back-transformed to make them easier to interpret thus providing geometric means. In cases where data sets did not fit the lognormal distribution (generally months when a species was frequently but not always absent, i.e., many zeros occurred), the mean and standard deviation was computed using the delta-distribution (see for example Pennington 1983, 1986, 1996, NUSCO 1993, Smith 1988). The same mean plus standard deviation guideline was applied.
The decision to rely on 2 standard deviations or 2.58 standard deviations was based on the relative importance of each species. The more critical criterion was applied to species of commercial, recreational, or biological interest, the less critical to the remaining species (i.e.,
'Normal distribution curve theory states that 2.5% of the measurements in a normally distributed population exceed the mean plus 1.96 standard deviations (= s, we rounded to 2 for simplicity), 2.5% lie below the mean minus 1.96 standard deviations. Stated another way 95% of the population lies within that range and 97.5% lies below the mean plus 1.96s. Likewise 0.5% of measurements exceed the mean plus 2.58s, 99% lie within range of the mean +/- 2.58s.
99.5% of all normally distributed values lie below a value equal to the mean + 2.58s.
4 Marine Research, Inc.
relatively greater densities were necessary to trigger notification). Species of commercial, recreational, or biological interest include Atlantic menhaden (Brevoortia tyrannus), Atlantic herring (Clupea harengus), Atlantic cod (Gadus morhua), tautog and cunner (the labrids; Tautoga onitisIl'autogolabrus adspersus), sand lance (Ammodytes sp.), Atlantic mackerel, windowpane (Scophthalmus aquosus), American plaice (Hippoglossoides platessoides), and winter flounder. Table 1 provides summary data for each species of egg and larva by month within these two categories showing the 2005 notification level.
A scan of Table 1 will indicate that, in cases where the long-term mean amounts to 1 or 2 eggs or larvae per 100 m3, the critical level is also quite small. This situation occurred during months when a given species was obviously uncommon and many zeros were present in the data set with an inherent small standard deviation. The external reference distribution methodology of Box et al. (1975) was also employed. This procedure relies on a dotplot of all previous densities for a species within month to produce a reference distribution. Densities exceeding either 97.5 or 99.5% of the reference set values were considered unusually high with this procedure.
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Figure 1. Aerial photograph of the entrainment sampling station in the PNPS discharge canal.
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Tablel. PNPS ichthyoplankton entrainment values for 2005 by species category and month used to determine unusually high densities. See text for details.
Densities per Long-term Mean +
Mean +
Previous High 100 m3 of water:
Mean' -
2 std.dev.
2.58 std.dev.
(Year)
January LARVAE Atlantic herring2 Sculpin Rock gunnel Sand lance2 February LARVAE Atlantic herring2 Sculpin Rock gunnel Sand lance2 March EGGS American plaice2 LARVAE Atlantic herring2 Sculpin Seasnails Rock gunnel Sand lance2 Winter flounder2 April EGGS American plaice2 LARVAE Atlantic herring2 Sculpin Seasnails Radiated shanny Rock gunnel Sand lance2 Winter flounder2 0.2 0.9 4.0-5 0.5 2
5 16 2
2 17 0.6 10.7 7
0.4 3
1 15 6
5 4
21 7
1 2
7 11 0.7 65 177 29 3
3 608 1
723 38.0 (1999) 9.7 (1999) 78.1 (2002) 337.0 (1996) 8.0 (2002) 183.1.(1998) 133.0 (1999) 372.9 (1995) 19.0 (1977) 28.5 (1997) 454.1 (1995) 14.4 (1980) 882.2 (1997) 708.0 (2002) 16.2 (1997) 70.3 (1978) 38.3 (1999) 386.2 (1985) 98.1 (1974) 59.6 (1974) 121.1 (1992) 2590.6 (1994) 198.3 (1994) 164 0.7 32 2
391 8
7 142 998 12 7
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Table 1 (continued).
Densities per 100 m 3 of water:
May EGGS Labrids2 Atlantic mackerel2 Windowpane 2 American plaice2 LARVAE Atlantic herring Fourbeard rockling Sculpin Seasnails Radiated shanny Sand lance2 Atlantic mackerel Winter flounder2 Long-term xffoanI Mean +
I QtA Aj'tI?
Mean +
Iq2 CtA A,-,
Previous High tvaarN
- v.L..
At O
.t V *
..'t OtU.u
% v.
A 36 18 9
2 0.7 4.1 3
7 7
37 2
9 3514 4031 147 15 34050.0 (1974) 19203.0 (1995) 319.0 (2000) 87.2 (2003) 1.1 8
4 208 236 10.5 (1975) 104.5 (1997) 78.3 (1997) 164.4 (1974) 266.9 (1998) 639.1 (1996) 377.6 (1998) 573.8 (1998) 59 4
123 June EGGS Atlantic menhaden2 Searobins Labrids2 Atlantic mackerel2 Windowpane2 American plaice 2 LARVAE Atlantic menhaden2 Fourbeard rockling Hake Cunner2 Radiated shanny Atlantic mackerel 2 Winter flounder2 14 2
958 63 27 1
6 9
0.3 54 7
91 10 22 3
21599 3515 261 3
10 799.7 (1998) 128.0 (1987) 37282.0 (1995) 8193.2 (1990) 355.5 (1998) 35.0 (1980) 495.9 (1981) 224.0 (1992) 50.6 (1998) 2215.6 (1998) 262.2 (1996) 2700.0 (1981) 813.5 (1998) 634 1
10 a87 155 106 8
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SECTION IV RESULTS Population densities per 100 m3 of water for each species listed by date, station, and replicate are presented for January-June 2005 in Appendix A (available upon request). The occurrence of eggs and larvae of each species by month appears in Table 2. Species occurring in egg groups, such as Paralichthys-Scophthalmus, were indicated as collected only if late-stage eggs were specifically identified and/or larvae were present in that month.
Ichthyoplankton entrained during January through April generally represent winter-early spring spawning fishes. Many of these species employ a reproductive strategy that relies on demersal, adhesive eggs not normally entrained. As a result, more species are typically represented by larvae than by eggs during the early portion of the year. Over both life stages the number of species represented in the catch increased from 6 in January to 17 in April. Egg collections in winter-early spring were numerically dominated by the Atlantic cod - witch-flounder egg group, and American plaice eggs. These species accounted for 83 and 8% of the total egg catch during the period, respectively. The cod - witch flounder egg group was entrained from January through April with monthly geometric mean densities of 2.1, 1.3, 0.7, and 1.3 eggs per 100 m3 of water, respectively. Atlantic cod was the prevalent species in this group from January through March based on the proportion of late-stage eggs. American plaice eggs were entrained in March and April with monthly geometric mean densities of 0.1 and 0.7 eggs per 100 m3 of water, respectively.
In the winter-early spring 13 species of larval fish were collected from the discharge canal. The sand lance, grubby (Myoxocephalus aenaeus) and rock gunnel (Pholis gunnellus) made up the majority of the larval fish collected from January to April, contributing 82, 9, and 5% of the total captured. Sand lance was the predominant larval species throughout the time period; they were most abundant during March and April, with monthly geometric mean densities of 36.4 and 27.1 larvae per 100 m3 of water. They comprised 87 and 80% of the total collected in March and April, respectively. Grubby had peak numbers in March with a monthly mean density of 9.8 per 100 m3, comprising 6.5% of all larvae collected. The rock gunnel peak density also occurred in March with a geometric mean density of 6.4 fish per 100 m3.
May and June (along with July) represents the late spring-summer ichthyoplankton season, typically the most active reproductive period among temperate fishes. The eggs of 16 9
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fish species were collected during this season. Of those collected labrid (tautog/cunner)-
yellowtail flounder (grouped together) and Atlantic mackerel eggs were the dominant species, comprising 74 and 17% of the total egg catch, respectively. Fourspot flounder-windowpane eggs (Paralicthys-Scophthalmus) were also found in abundance, making up an additional 3% of the late spring-summer eggs. Early and middle-stage tautog, cunner, and yellowtail flounder eggs were abundant in May and June with respective monthly mean densities of 24.9 and 159.3 eggs per 100 m3. Based on the proportion of late stage eggs most of the labrid-yellowtail eggs were assumed to be those of tautog or cunner. Geometric mean monthly densities for Atlantic mackerel were 5.9 and 16.2 eggs per 100 m3 for May and June, comprising 22 and 16% of the monthly total eggs collected, respectively. Fourspot flounder-windowpane monthly mean densities were 4.9 in May and 8.6 eggs per 100 m3 of water in June.
Larval collections in late spring-summer contained 25 species, with 13 collected in May and 20 collected in June. Winter flounder was the dominant species during this period, making up 50.5% of the total collected for May and June combined. Monthly geometric mean densities of winter flounder were 5.7 and 10.3 larvae per 100 m3 of water for May and June, respectively.
Cunner ranked second among numerical dominants during this period, making up 14% of all larvae collected. Cunner abundance was highest in June with a monthly mean density of 4.3 larvae per 100 m3 of water, accounting for 20% of that monthly total. Fourbeard rockling ranked third, accounting for 8% of the larvae collected during the spring-summer period. Abundance was highest in June with a monthly mean density of 3.7 larvae per 100 m3 of water. The fourth numerically dominant species was the radiated shanny (Ulvaria subbifurcata), accounting for 7%
of the larvae collected during May and June combined. Monthly mean densities were 1.3 and 2.0 larvae per 100 m3 of water, respectively.
Appendix B lists geometric mean monthly densities along with 95% confidence limits for each of the numerical dominants collected over the January-June period dating back to 1981.
Geometric means are reported because they more accurately reflect the true population mean when the distribution of sample values are skewed to the right as is commonly the case with plankton data. Generally low values obtained for both eggs and larvae during April-June 1984 and 1987, as well as May-June 1999 were shaded because low through-plant water volumes during those months probably affected densities of ichthyoplankton (MRI 1994). Entrainment data collected from 1975-1981 remain in an outdated computer format requiring conversion 10 Marine Research, Inc.
before geometric mean densities can be generated. These years were therefore excluded from comparison. Since densities of each ichthyoplankton species rise from and fall to zero over the course of each respective season, inter-year comparisons are most conveniently made within monthly periods. A general review of the data through the first six months of 2005 suggests that in most cases monthly mean densities were consistent with previous years. The following notable observations were made during the first half of the year (Table 3). These will be assessed in greater detail in the annual report particularly as they relate to the annual abundance indices.
For labridae-Limanda eggs June's monthly mean density was 159 eggs per 100 m3 of water, lower than previous densities in the PNPS time series which ranged from a high of 3,619 in 1989 to a low of 226 eggs per 100 m3 of water in 1994.
Atlantic herring larvae were collected at relatively high densities on three occasions in January, two occasions in April, and three occasions in May 2005 (Table 3). In all three months the previous high value was exceeded on one occasion. On March 25 Atlantic herring larvae reached a density of 31 larvae per 100 mi3 of water, exceeding the previous high of 29 larvae per 100 m3 of water observed in 1997. On April 15 the density of herring larvae reached 83 per 100 m3 of water exceeding the 1999 record high for the month of 38 larvae per 100 m3 of water. In May, the previous record of 11 larvae per 100 m3 of water observed in 1975 was exceeded on May 10, 2005 with a density of 15 larvae per 100 m3 of water.
Sand lance larvae were collected at relatively high densities on two occasions in March (Table 3). On March 25 a larval sand lance density of 2,242 larvae per 100 mi3 of water was observed, exceeding the previous high value of 708 larvae per 100 m3 of water observed in 2002.
Winter flounder larvae were observed at high densities on two occasions in June, the 3 rd and the 8th. On those dates larval densities of 138 and 256 larvae per 100 m3 of water exceeded 98% and 99% of previous June values, respectively.
Several other unusually high densities were recorded during the January - June 2005 period although they did not result in remarkable monthly mean densities relative to the PNPS time series (Table 3). These occurred for seasnail larvae (March), American plaice eggs (May), radiated shanny larvae (June), and cunner larvae (June). In the case of 11 Marine Research, Inc.
seasnail, plaice, and cunner these involved single observations suggesting that overall seasonal abundance was not likely to have been remarkably high.
Fourteen stage 1 and one stage 2 lobster larvae were found in the entrainment samples collected during the first half of 2005. This represents the highest number of lobster larvae collected during the January - June period. The second highest number collected (N =10) occurred in 2003. Previously, only 46 larvae were collected at PNPS in total dating back to 1974 including a more intensive lobster larvae sampling program in 1976. No direct relationship between prevailing winds or tide at the time of sampling and the number of entrained larval lobster is apparent. However, since night sampling was added in 1995, 94% of the lobster larvae captured were collected during the Friday evening sampling period,-representing 75% of the total larvae captured over the 32-year time period. The addition of a nighttime sample period has likely contributed to the increase in the observed number of lobster larvae entrained since adult female lobsters release larvae at night (Ennis 1975, Charmantier et al. 1991).
Additionally, Pilgrim Station established a protection zone around the plant extending seaward from the shorefront for a distance of approximately 1000 feet in October 2001. Within this zone no lobster harvesting is permitted, as a result there may be an increase in nearshore lobster reproductive activity and improvement in the success of larval release.
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SECTION V LITERATURE CITED Box, G.E.P., W.G. Hunter, and J.. Hunter. 1975. Statistics for Experimenters. John Wiley &
Sons, New York Charmantier, G., M. Charmantier-Daures, and D.E. Aiken. 1991. Metamorphosis in the lobster Homarus (Decapoda): a review. Journal of Crustacean Biology 11(4):481-495.
Ennis, G.P., P.W. Collins, and G. Dawe. 1975. Fisheries and population biology of lobsters (Homarus americanus) at Comfort Cove, Newfoundland. Can. Tech. Rep. Fish. Aquat.
Sci. 1116.
Herrick, F.H. 1911. Natural history of the American lobster. Bulletin of U.S. Bureau of Fisheries 29:149-408.
MRI (Marine Research, Inc.). 1988. Entrainment investigations and Cape Cod Bay Ichthyoplankton Studies, March-December 1987. llI.C.1-6-10. In: Marine Ecology Studies Related to Operation of Pilgrim Station, Semi-annual Report No. 31. Boston Edison Company.
1994. Ichthyoplankton Entrainment Monitoring at Pilgrim Nuclear Power Station January-December 1993. UI.C.I. In Marine Ecology Studies Related to Operation of Pilgrim Station. Semi-annual Report No. 43. Boston Edison Company.
NUSCO (Northeast Utilities Service Company). 1993. Monitoring the marine environment of Long Island Sound at Millstone Nuclear Power Station, Waterford CT. Annual Report Pennington, M. 1983. Efficient estimators of abundance for fish and plankton surveys.
Biometrics 39:281-286.
1986. Some statistical techniques for estimating abundance indices from trawl surveys.
Fishery Bulletin 84, no. 3: 519-525.
1996. Estimating the mean and variance from highly skewed marine data. Fishery Bulletin 94:498-505 Smith, Stephen J. Evaluating the efficiency of the delta-distribution mean estimator. Biometrics 44:485-493.
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Table 2: Species of fish eggs (E) and larvae (L) obtained in ichthyoplankton collections from the Pilgrim Nuclear Power Station Discharge canal, January-June, 2005.
Species January February March April May June American eel Atlantic menhaden Anchovy River Herring Atlantic herring Rainbow smelt Cusk Fourbeard rockling Atlantic cod Haddock Silver hake Atlantic tomcod Hake Silversides Northern pipefish Sea Raven Grubby Longhorn sculpin Shorthorn sculpin Seasnail Wrasses Tautog Cunner Radiated shanny Rock gunnel Wrymouth Sand lance Atlantic mackerel Anguilla rostrata Brevoortia tyrannus Anchoa spp.
Alosa spp.
Clupea harengus Osmerus mordax Brosme brosme Enchelyopus cimbrius Gadus morhua Melanogrammus aeglefinus Merluccius bilinearis Microgadus tomcod Urophycis spp.
Menidia spp.
Syngnathusfuscus Hemitripterus americanus Myoxocephalus aenaeus M. octodecemspinosus M. scorpius Liparis atlanticus Labridae Tautoga onitis Tautogolabrus adspersus Ulvaria subbifurcata Pholis gunnellus Crytacanthodes maculatus Ammodytes sp.
Scomber scombrus L
L EIL E
L E/L L
L L
L L
E/L L
L L
E E
E/L E/L E
E/L E
E E
L E
E/L E/L L
E/L L
E E
L L
L L
E L
L L
L L
L L
E L
L L
L L
L L
L L
L E
E L
L L
L L
L L
E/L EfL L
L L
L 14 Marine Research, Inc.
Table 2 (continued).
Species Butterfish Peprilus triacanthus Windowpane Scophthalmus aquosus Witch Flounder Glyptocephalus cynoglossus American plaice Hippoglossoides platessoides Winter flounder Pseudopleuronectes americanus Yellowtail flounder Limandaferruginea January February March April May June E
E/L E
E/L E
E E
E E
E E/IL E/L E/L E/L L
E/
E/L E/L 12 17 21 25 Number of species 6
8 15 Marine Research, Inc.
Table 3.
Ichthyoplankton densities (number per 100 m2 of water) for each sampling occasion during months when notably high densities were recorded, January - June, 2005. Densities marked by + were unusually high based on values in Table 1. Numbers in the last column indicate percent of all previous values during the month which were lower.
March Atlantic herring larvae 2
0.0 4
0.0 7
0.0 9
0.0 14 0.8 16 2.7
+
18 8.0
+
21 0.0 23 0.0 25 30.9
+
28 0.0 30 0.0 March 87 95 Sand lance larvae 2
2.3 4
0.0 7
5.2 9
1.7 14 35.6 16 32.5 18 77.6 21 37.7 23 51.0 25 2242.0 28 167.4 30 9.6 100
+
100
+
92 Previous high: 28.5 (1997)
Notice level: 2.0 Previous high: 708.0 (2002)
Notice level: 164.0 May Seasnail larvae 2
0.0 4
0.0 7
0.0 9
0.8 14 0.0 16 0.0 18 3.6 21 0.0 23 0.0 25 0.0 28 0.0 30 0.0 April Atlantic herring larvae 1
2.7 4
0.0 6
2.6 8
4.2
+
11 0.0 13 0.0 15 83.1
+
18 0.0 84 100
+
97 Previous high: 38.3 (1999)
Notice level: 3.0 Previous high: 14.4 (1980)
Notice level: 1.0 16 Marine Research, Inc.
Table 3 (continued).
May American plaice eggs 10 2.2 11 8.6 13 0.0 16 0.0 18 1.4 20 40.8
+
23 0.0 27 0.0 30 0.0 Mby Atlantic herring larvae 10 15.2
+
11 0.0 13 5.3
+
16 0.0 18 0.0 20 0.8 23 1.0 27 0.0 30 1.6
+
100 96 90 98 Previous high: 87.2 (2003)
Notice level: 15.0 Previous high: 10.5 (1975)
Notice level: 1.1 June Winter flounder larvae 1
2.9 3
137.8
+
6 62.8 8
256.4
+
10 103.7 13 27.1 15 0.0 17 23.5 20 2.4 22 0.6 24 46.2 27 0.0 29 2.2 June 98 99 Radiated shannv larvae 1
2.9
- 3.
1.0 6
3.1 8
1.9 10 21.7
+
13 45.0
+
15 0.0 17 4.6 20 0.0 22 0.0 24 000 27 0.6 29 0.0 91 95 Previous high: 813.5 (1998)
Notice level: 106.0 Previous high: 262.2 (1996)
Notice level: 10.0 17 Marine Research, Inc.
Table 3 (continued).
Cunner larvae June I
0.0 3
0.0 6
0.0 8
0.0 10 0.0 13 1.0 15 0.0 17 0.7 20 15.9 22 1.2 24 28.6 27 128.9
+
94 29 40.6 Previous high: 2215.6 (1998)
Notice level: 87.0 18 Marine Research, Inc.
APPENDIX A*. Densities of fish eggs and larvae per 100 m3 of water recorded in the PNPS discharge canal by species, date, and replicate, January-June 2005.
- Available by request.
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APPENDIX B*.
Geometric mean monthly densities and 95% confidence limits per 100 m3 of water for the dominant species of fish eggs and larvae entrained at PNPS, January-June 1981-2005.
Note the following:
When extra sampling series were required under the contingency sampling regime, results were included in calculating monthly mean densities.
Shaded columns for certain months in 1984, 1987, and 1999 delineate periods when sampling was conducted with only salt service water pumps in operation. Densities recorded at those times were probably biased low due to low through-plant water flow (MRI 1994).
- Available upon request.
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Pilgrim Nuclear Power Station Marine Ecology Studies Semi-Annual Report # 66 Section 3.3 Impingement Monitoring
IMPINGEMENT OF ORGANISMS on the INTAKE SCREENS at PILGRIM NUCLEAR POWER STATION JANUARY - JUNE 2005 Submitted to Entergy Nuclear Operations, Inc.
Pilgrim Nuclear Power Station-Plymouth, Massachusetts By Marine Research, Inc.
Falmouth, Massachusetts October 21, 2005
Summary This report describes the monitoring of impinged organisms at Pilgrim Station based on screen wash samples taken from January through June 2005. Three scheduled screen wash periods were monitored each week; however there was no sampling from April 17 to May 10, 2005 due to a scheduled refueling outage. Fish impingement rates averaged 2.61 fish/hour from January to June 2005. Mean monthly impingement rates ranged from 6.72 in April to 0.05 fish/hour in June. Atlantic silversides (Menidia menidia), rainbow smelt (Osmerus mordax),
pollock (Pollachius virens), winter flounder (Pseudopleuronectes americanus), Atlantic herring (Clupea harengus), grubby (Myoxocephalus aenaeus), and Atlantic menhaden (Brevoortia tyrannus) accounted for 56.6, 11.8, 6.7, 6.5, 4.9, 2.7, and 2.2%, respectively, of the six-month total.
Introduction Pilgrim Nuclear Power Station (PNPS) is located on the northwestern shore of Cape Cod Bay (Figure 1) with a capacity of 685 megawatts electric. The unit has two circulating water pumps with a capacity of approximately 345 cfs (cubic feet per second = 155,500 gallons per minute each) and five service water pumps (2,500 gallons per minute each) with a combined capacity of 23 cfs. Water is drawn under a skimmer wall, through vertical bar racks spaced approximately three inches on center, and finally through vertical traveling screens of 1/2i x 1/4 inch mesh (Figure 2). There are four vertical screens, two for each circulating water pump.
This report provides documentation of environmental monitoring and reporting requirements of NPDES Permit No. MA0003557 (USEPA) and No. 359 (MA DEP) at PNPS. It describes the monitoring of impinged organisms at Pilgrim Station based on screen wash samples taken from January through June 2005.
A discussion of the relationships among impingement values, environmental factors, and plant operation will be provided in the annual report.
1-
- Marzne Research, Inc.
k Narine Research, Inc.
Figure 1. Location of Pilgrim Nuclear Power Station.
Figure 2. Cross-section of intake structure at Pilgrim Nuclear Power Station.
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Methods and Materials Three scheduled screen wash periods were monitored each week from January to June 2005 although there was no sampling from April 18 to May 9, 2005 due to a scheduled refueling outage.
Since the main circulating water pumps were off, no impingement was expected.
Monitored screen washes included the 0830 wash on Monday, the 1630 wash on Wednesday, and the 0030 wash on Saturday morning. Each sampling period thus represented a separate, distinct eight-hour period. Prior to each sampling period, the time of the previous screen wash was obtained from a strip chart recorder located in the screen house to permit the current sampling interval to be calculated. Whenever the screens were static upon arrival, a 30-minute sample was collected and, whenever the screens were operating continuously when a biologist arrived, a 60-minute sample was obtained.
Spray nozzles directed at the screens washed impinged organisms and debris into a sluiceway which was sampled by inserting a collection basket made of 1/4-inch stainless steel mesh. All fish were identified and noted as being alive, dead, or injured. Fish that were determined to be alive were measured for total length (mm), and then released.
Those determined to be dead or injured were preserved and returned to the laboratory where weights (grams) and total lengths (mm) were recorded for up to 20 specimens of each species. Any impinged invertebrates were identified, measured, and representative specimens were returned to the laboratory where weights were recorded. The impingement rate was calculated by dividing the number of fish and invertebrates collected by the number of hours in the collection period.
Results and Discussion Fish In 202.2 collection hours, a total of 490 fish comprising 25 species were collected from January - June 2005 (Table 1, Figure 3). Mean monthly impingement ranged from 6.72 in April, when the plant was operational from April 1 to 16, to 0.05 fish/hour in June. Impingement rate was zero when the plant was off-line and no circulating seawater pumps were running from April 17 to May 9. Atlantic silversides (Menidia menidia), rainbow smelt (Osmerus mordax), pollock (Pollachius virens), winter flounder (Pseudopleuronectes americanus), Atlantic herring (Clupea harengus), grubby (Myoxocephalus aenaeus), and Atlantic menhaden (Brevoortia tyrannus) accounted for 56.6, 11.8, 6.7, 6.5, 4.9, 2.7, and 2.2%, respectively, of the six-month total. The highest numbers of Atlantic silversides were impinged in April when 48% of the January to June total of 277 fish was collected. Rainbow smelt were most numerous in February with 76% of the 6-month total (58 fish) collected. Both pollock and Atlantic herring were most abundant in May with 100 and 92% of their respective January-June totals of 33 and 24 fish. Winter flounder were most abundant in January and March (13 and 10 fish, respectively) accounting for 72% of the 6-month total of 32 fish sampled. Grubby were present in the collections from January through April. Atlantic menhaden were sampled primarily in January with 82% of the 11 fish collected over the January to June period.
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Pilgrim Nuclear Power Station Fish Impingement January - June 2005 Atlantic Silverside 56.5%
A 18 Remaining species 8.7%
\\Alantic menhaden 2.2%
\\
/ 7GGrbby
\\:
X _227%
Atlantic-herring 4.9%
Rainbow setWinter flounderf 11.8%
6 6.5%
n=490 fish Figure 3. Percent of total for numerically dominant species of fish impinged on the Pilgrim Nuclear Power Station intake screens, January to June 2005.
Total fish were impinged at a mean rate of 2.61 fish/hour from January through June 2005. The highest monthly impingement rate of 6.72 fish/hour was recorded in April which coincided with the high numbers of silversides collected. The mean monthly impingement rate over the first half of 2005 (2.61 fish/hour) was greater than the six-month mean for the 1980 to 2004 time series of 1.70 fish/hour (Figure 4, Table 2).
Invertebrates From January to June 2005, 379 invertebrates representing 12 species were sampled yielding an impingement rate of 1.87 invertebrates per hour (Table 3). Sevenspine bay shrimp (Crangon septemspinosa) accounted for 68.3% of the six-month total. Sevenspine bay shrimp were primarily impinged in March and April when 87% of the 259 animals was collected.
American lobster (Homarus americanus) and sand worms (Nereis spp) accounted for 11.2 and 10.6% of the 6-month catch, respectively. Lobsters were caught primarily in May when 97.7%
of the January to June total of 43 individuals was caught. Sand worms were present from January to April 2005, the peak occurring in February.
4 Marine Research, Inc.
Pilgrim Nuclear Power Station Fish Impingement Rates - January - June 1980-2005 20; ImPingment Rates (fish/hour) 15.__._._
5 Jan Feb Mar Apr May Jun 6 Month Mean I High/Low i Average 1980-2004 -2005 Figure 4. High/low average and grand mean monthly impingement rates for January to June 1980-2004 compared with January to June 2005 monthly mean rates at Pilgrim Nuclear Power Station, total fish.
5q Marine Research, Inc.
Table 1. Monthly totals for all fish collected at Pilgrim Station from the intake screens, January - June, 2005.
Species Jan Feb Mar Apr*
May*
Jun Total Percnt Atlantic Silverside Menidia nenidia Rainbow Smelt Osmerus nordax Pollock Pollachius virens Winter Flounder Pseudopleuronectes americanus Atlantic Herring Clupea harengus Grubby Myoxocephalus aenaeus Atlantic Menhaden Brevoortia tyrannus Cunner Tautogolabrus adspersus Threespine Stickleback Gasterosteus aculeatus Atlantic Cod Gadus norhua Blackspotted Stickleback Gasterosteus whearlandi Northern Pipefish Syngnathusfuscus Lumpfish Cyclopterus lumpus Rock Gunnel Pholis gunnellus Blueback Herring Alosa aestivalis Lttle Skate Leucoraja erinacea Alewife Alosa pseudoharengus Atlantic Tomcod Aficrogadus tomcod Mwnnsichog Fundulus heteroclitus Fourspine Stickleback Apeltes quadracus White Perch Morone americana Radiated Shanny Ulvaria subbifurcata Sand Lance Ammodytes sp.
Smallmouth Flounder Etropus microstomus Yellowtail Flounder Linandaferruginea 28 12 133 104 10 44 1
2 1
33 13 2
10 7
I I
22 3
1 5
4 9
2 2
1 2
2 5
1 4
1 I
2 3
2 1
3 277 58 33 32 24 13 11 7
6 5
3 3
3 3
2 1
1 1
1 1
1 1
I 1
56.5%
11.8%
6.7 6.5%
4.9%
2.7%
2.2%
1.4%
1.2%
1.0%
0.6%
0.6%
0.6 0.6%
0.4%
0.2%
0.2%
0.2%
0.2%
0.2%
0.2%
0.2%
0.2%
0.2%
2 1
1 1
1 1
I 1
I I
I I
0.2%
TotalFish 1
69 61 162 131 66 1
490 Total Collection Hours 23.48 45.84 60.26 19.50 33.67 19.42 202.17 Impingement Rate 2.94 1.33 2.69 6.72 1.96 0.05
- There was no sampling or seawater pumps running from April 18 to May 9, 2005. Impingement rates reported only represent the period when circulating seawater pumps were operational
Table 2. Monthly impingement rates (fish per hour) for all fish collected at Pilgrim Station from the Intake Screens, January - June, 1980-2005.
Year Jan Feb Mar Apr May Jun Mean 1980 0
0.14 0.57 0.13 0.14 0.21 0.20 1981 0.79 1.88 2.66 6.18 0.32 0.14 2.00 1982 0.25 0.25 2.41 0.74 1.15 1.15 0.99 1983 0.23 0.33 0.71 0.71 0.36 0.15 0.42 1984 0.21 0.18 0.12 0.04 0.06 0.01 0.10 1985 0.4 5.48 2.17 2.36 0.82 0.48 1.95 1986 0.1 0.8 0.63 0.29 0.3 0.97 0.52 1987 0.64 0.11 1.2 0
0.5 0.05 0.42 1988 0.33 0.11 1.13 0.27 0.13 0.04 0.34 1989 0.12 0.25 2
1.41 0.35 0.25 0.73 1990 0.61 1.11 0.44 0.47 0.48 0.1 0.54 1991 0.58 0.57 1.53 2.34 0.33 8.19 2.26 1992 1.30 1.13 1.69 0.75 0.49 0.05 0.90 1993 1.55 0.85 8.06 4.11 0.64 0.28 2.58 1994 1.93 0.73 3.35 10.63 1.00 0.43 3.01 1995 8.41 0.88 9.75 2.32 1.13 0.59 3.85 1996 1.19 0.58 7.00 11.15 2.51 0.22 3.78 1997 0.98 0.48 0.30 2.54 0.26 0.06 0.77 1998 2.42 3.24 5.22 4.19 0.44 0.10 2.60 1999 1.56 2.42 2.71 1.40 1.00 0.00 1.52 2000 3.01 1.98 9.06 17.58 0.47 0.12 5.37 2001 0.41 1.39 4.38 6.22 0.00 0.05 2.08 2002 1.05 2.05 2.36 1.78 0.09 0.05 1.23 2003 0.61 0.83 2.58 1.50 0.66 0.38 1.09 2004 0.68 0.91 4.57 11.91 2.14 0.04 3.37 average 1.17 1.15 3.06 3.64 0.63 0.56 1.70 2005 2.94 1.33 2.69 6.72 1.96 0.05 2.61
Table 3. Monthly totals for all invertebrates collected at Pilgrim Station from the intake screens, January - June, 2005.
Species Jan Feb Mar Apr May Jun Total Percent Sevenspine Bay Shrimp Crangon septemspinosa 27 6
121 105 259 68.3%
American Lobster Homarus amnericanus 42 1
43 11.3%
Nereis Nereis sp.
8 14 9
9 40 10.6%
Cancer Crabs Cancer spp.
2 2
1 2
5 7
19 5.0%
Blue Mussel Mytilus edulis 4
4 1.1%
Green Crabs Carcinus naenas 2
1 1
4 1.1%
Long-finned Squid Loligo pealii 3
3 0.8%
Starfish Asterias spp.
1 1
1 3
0.3%
Glyceridae Glyceridae 1
1 0.3%
Red-lined Worms Nephtys spp.
1 1
0.3%
Horseshoe Crab Limulus polyphemus 1
1 0.3%
Spider Crabs
'Libinia spp.
1 1
0 8%
Total 14 17 11 16 6
13 379 Total Collection Hours 23.48 45.84 60.26 19.50 33.67 19.42 202.17 Impingement Rate 0.60 0.37 0.18 0.82 0.18 0.67 1.87