may be reflecting increased scour during 3-unit operations. The infaunal community in 1987' exhibited 

 significant increases in the abundances of the amphipods, Ampelisca spp., Le.ptoc.heirus pinguis and Uniciola 

 irrorata. These organisms were among the dominants at this station prior to the power plant-induced 

 shifts observed following Unit 3 intake construction. Their return is believed indicative of the continued 

 recovery of this community. 



Power plant-related impacts on subtidal communities during the first year of 3-unit operation appeared to 

 be a response to scouring (at EF and IN and the transport and deposition of this sediment into JC. 

 Infaunal habitats immediately beneath the Unit 3 discharge (and extending seaward approximately 100 

 m) have been eliminated due to scouring by the 3-unit discharge; however, given the limited size of this 

 area, loss of this infaunal habitat would not significantly alter ecosystem functioning in the greater Millstone 

 area. At .IC, the deposition of sediments apparently from the discharge area would be expected as a 

 temporary change. Infaunal changes related to this siltation should also be temporary and cause no 

 detectable changes in the ecology of the Millstone area. If however, the sedimentary changes are the result 

 of some plant-induced change in the sedimentation patterns in .IC or the infaunal shifts were a response 

 to temperature, then more widespread and ecologically significant changes in local infaunal communities 

 might occur. Given limited operational history, impacts due to temperature could not be identified 

 separately from those which occurred in response to sediment changes. 



Lobster Population Dynamics 



The lobster population in the Millstone Point area was sampled from May through October during 1986 

 and 1987 using wire pots set at three stations. The carapace length, sex, presence of eggs, missing claws 

 and molt stage was recorded for each lobster to quantify population characteristics. I,obsters > 55 mm 

 carapace length were tagged and released where they were caught to monitor growth and movement. 

 Studies were also conducted on adult lobsters caught on the intake traveling screens (impingement) and 

 on larval lobsters drawn through the plants cooling water system (entrainment). All these studies were 

 designed to assess the impacts of 3-unit operation on the local lobster population. 



Total catch per unit effort (CPUE; #lobstcrs/# pots hauled) during 1986 and 1987 was 1.70 and 1.72, 

 respectively, and within the range of values reported during 2-unit operations (0.85-2.10). I^gal CPUE 

 was lower during 1986 and 1987 (0.097, 0.089) when compared to previous years' results and has significantly 

 declined since 1978. The lower CPUE of legal-sized lobsters may be related to fishing pressure which has 

 increased in Long Island Sound since 1978. A 50% decline in catch at .lordan Cove occurred from August 

 to September 1986 and was related to 3-unit operations. Sediments in the discharge area were scoured 

 and subsequently deposited in Jordan Cove, where lobster habitats were buried by sediments. This decline 

 in catch was only temporary, since catches in October 1986 and throughout 1987 at .lordan Cove were 

 normal and indicated that sediments had stabilized and lobsters had returned to the affected area. Similar 

 impacts associated with the disruption of lobster habitat were observed in previous years following dredging 

 in the vicinity of the intake structures. 



The mean size of lobsters caught during 3-unit operation was 70.1 mm in 1986 and 70.2 mm in 1987. 

 These values were smaller than those reported in previous years (range 70.7-71.8 mm) due to the lower 

 CPUE of legal-sized lobsters during 1986-87. Male to female sex ratios during 1986 and 1987 were 1.0:0.87 

 and 1.0:0.88, respectively, and within the range of values reported during 2-unit studies. The Twotree 

 station continued to yield a higher proportion of females than the other two nearshore stations, a trend 

 consistent since the study began. Female size at sexual maturity was similar during 2- and 3-unit operations; 

 females began to mature between 50 and 55 mm CI, and all females were mature at sizes greater than 95 



Executive Summary 



