collected belonged to the family Gammarldae, and were principally 

 Cammarus lawrencianus . 



At Millstone, gammarids were found in greater abundances inshore 

 (EN) , and in night collections (Table 4) . While ganunarids were most 

 abundant in late spring and summer, the harmonic regression R^ values 

 (< 0.30) reflected the high variability of gammarid abundances. Peak 

 densities varied orders of magnitude from a low of approximately 45/m~ 

 in early September 1980 to a high of over 3,800/m^ in early June of 

 1977. Mean annual densities ranged from 0.25/m^ (NB) in 1976 to 91/m- 

 (EN) in 1977 (Table 3). 



CONCLUSIONS 



Twelve years of marine monitoring studies at MNPS suggest that 

 plant operation has had a negligible effect on zooplankton. The 

 fluctuations in abundance observed in the Millstone studies have been 

 within the expected range of natural variability and were similar to 

 other studies in and near LIS (NAI 1976; LILCO 1983; Turner 1982). 

 Harmonic regression models and the associated mean residuals (Figs. 2 - 

 17) developed for selected zooplankton species have indicated stable, 

 recurring annual patterns in abundance. 



Although entrainment by coastal power plants can result in 

 zooplankton mortality (Carpenter et al. 1974; Lauer et al. 1974; Cannon 

 et al. 1977), the absence of significant changes in the local 

 zooplankton community is not unexpected, since such a small percentage 

 of the community is directly influenced by power plant operation 

 (Capuzzo 1980). In addition, the wide geographic range (Deevey 1948; 

 Riley and Conover 1956; Faber 1966; LILCo 1983), high reproductive 

 capability (Jeffries 1962; Corkett and McLaren 1969; McLaren et al. 

 1969; Katona 1970; Corkett and Zillioux 1975; Dagg 1978) and compensatory 

 mechanisms (Heinle 1966, 1970) characteristic of zooplankton communities, 

 further serve to mitigate any localized power plant impacts. 



Once Unit 3 becomes operational (1986), the combined 3-unit operation 

 will entrain about 4% of the average volume of the Nlantic Bay tidal 

 exchange (NUSCo 1976). This percentage is small considering that 



19 



