mm CL. The mean CL of berried females during 1986 (78.0 mm) and 1987 (76.5 mm) and the proportions 

 of sublegal size berried females caught in 1986 (75%) and 1987 (90%) confirmed the small size at first 

 sexual maturity of females in the Millstone area. 



I_x)bsters that were near molting comprised 3.2% and 3.0% of the 1986 and 1987 total catches, respectively, 

 which were within the range of values reported during 2-unit operations. Growth per molt averaged 13.3% 

 in 1986-87 compared to 13.9% from 1978-85. The percentage of lobsters missing one or both claws (culls) 

 in 1986 (10.6%) and 1987 (10.3%) was lower than the average percentage culled in previous years (range 

 10.6%- 15.5%) due to the implementation of the escape vent regulation in 1984. 



The numbers of lobsters tagged in 1986 (5,698) and 1987 (5,680) were within the range of annual values 

 for lobsters tagged in pre-operational studies. Recapture rates for 1986 (21.0%) and 1987 (23.9%) were 

 also similar to pre-operational values (range 15.9''/o-23.9%). Lobstcrmen recaptured 20.2% of our tagged 

 lobsters in 1986 and 17.8% in 1987. Lobster movements were localized, since 94% and 97% of all 

 commercial recaptures were made within 8 km of Millstone Point during 1986 and 1987, respectively. 

 Several lobsters moved outside LIS and were caught in waters off RI and MA; three lobsters moved 

 offshore during 1986-87, where they were caught in deep water canyons on the edge of the continental shelf. 



Ix)bster larvae densities (number per 1000 m ) in entrainment samples were higher in 1986 (0.88) and 

 1987 (0.63) when compared to 1984-85 (0.42-0.43). The estimate of total lobster larvae entrainment, based 

 on sample density and total MNPS cooling water demand, was also higher in 1986 (548,635) and 1987 

 (304,694) when compared to 1984-85 (79,511-138,820). Ix)bster larvae survival was 6.5% and 3.8% in 



1986 and 1987, respectively. More stage IV larve were collected in 1986 compared to 1984, 1985, and 



1987 when greater numbers of stage I larvae were collected. 



The estimated numbers of lobster impinged at Unit 2 during 1986 and 1987 were 676 and 825, respectively, 

 these values were within the range of values reported in previous years (261-1220). Fish return systems 

 at Units 1 and 3 improved overall survival of impinged lobsters. Based on impingement of all organisms 

 at Unit 2 since 1972, a request made by NUSCO to discontinue impingement monitoring at Unit 2 was 

 accepted by the CT DEP in December 1987. 



There is no evidence to date that MNPS has significantly affected the local lobster population. The 

 displacement of lobsters in .lordan Cove due to scouring of sediments in the discharge area was temporary 

 and related to the intial period of simultaneous 3-unit operation. Impacts on larval lobsters entrained 

 tlirough the MNPS cooling water systems will not be apparent in the adult population until 4-5 years 

 when they grow to a size vulnerable to capture in our traps. 



Winter Flounder Studies 



The life history and population dynamics of the winter flounder {Pse.udopkuronectes americanus) have 

 been intensively studied since 1973 due to its importance to the sport and commercial fisheries of Con- 

 necticut. Because of the localized nature of winter flounder stocks, the population closest to MNPS, 

 which spawns in the Niantic River, has received most of our attention. 



Indices of abundance estimates are available from 1976 through 1987 for the adults spawning in the Niantic 

 River. These include a Jolly composite abundance index and median trawl CPUE, both computed from 

 data collected during annual mark and recapture surveys. The 1987 .Jolly index showed a slight increase 

 over the 12-year low value found in 1986, but abundance remained low in comparison to earlier years. 



Monitoring Studies, 1986-1987 



