The species composition and abundance of entrained zooplankton was 

 examined by WHOI for one annual cycle from 1970 to 1971 (Carpenter et 

 al. 1971a, 1971b). Day and night samples (0. 333-mm-mesh) were collected 

 biweekly at the Intake (Figure 1) with additional samples collected at 

 the Discharge and Quarry Cut as part of an entrainment mortality study. 

 Intake samples were collected from 1973 to June 1975 but only a portion 

 of these samples was processed. 



Entrainment survival studies emphasized copepods and included 

 comparison of copepod densities at the Intake and Quarry Cut, live-dead 

 counts, copepod sinking rates, and latent mortality (Carpenter et al. 

 1974b, 1975). The results indicated that approximately 70% of the 

 copepods entrained did not survive. The mortality was not immediate but 

 occurred up to five days after entrainment. After plant passage the 

 copepods sink and accumulate in the deeper waters of the Quarry and are 

 not returned to Long Island Sound. Mortality was attributed primarily 

 to mechanical damage with chlorination and increased temperature having 

 minimal affects. 



The effect of plant operation on the copepod population in waters 

 adjacent to Millstone was examined on five dates in 1971 and 1972 

 (Carpenter 1975). Two control stations and two stations in the effluent 

 mixing zone were sampled. 1 No detectable differences were found between 

 control and affected stations with five replicate tows per station. 

 Examination of the variability of copepod densities between replicates 

 showed that an average of 300 replicate tows at a station would be 

 necessary to detect a 5% change (Carpenter et al. 1974a). 



Zooplankton entrainment sampling procedure was changed in mid 1975 

 to increase the accuracy of entrainment estimates and has remained 



