8-36 



Catch-data collected during the survey indicate that Squilla 

 occurs in relatively low abundances; however, because of the burrowing 

 nature of mantis shrimp, otter trawls cannot be expected to provide a 

 reliable estimate of Squilla abundance. Benthic grabs are also in- 

 effective since mantis shrimp can move deej) into their burrows away from 

 the area sampled by the grab. Gosner (1971) gives account of a lysio- 

 squillid which went undetected on the south shore of Cape Cod, an area 

 of frequent ecological investigations, until 1958. Caldwell and Dingle 

 (1976) indicate that although Squilla are numerous enough in some waters 

 to be a major predator, they are not collected in high abundances because 

 of their burrowing behavior. It is likely that Squilla are much more 

 abundant in New Haven Harbor than catch data indicate and that they may 

 contribute more significantly to ecosystem dynamics in the harbor than 

 has heretofore been assumed. 



ANALYSIS OF IMPACT 



Epibenthic organisms may be directly affected by power plants 

 in three major ways: 1) by contact with elevated temperatures associated 

 with the thermal discharge plume, as well as sudden cooling of waters 

 influenced by the plume whenever the plant shuts down; 2) by entrainment 

 of eggs and larvae in the water passing through the power plant's cool- 

 ing system; and 3) by impingement of organisms on the cooling-system 

 intake screens. In this section, the possible effects on the epibenthic 

 community of these three modes of impact are discussed and related to 

 the situation observed in New Haven Harbor, and an analysis of impact of 

 the Harbor Station on the epibenthos is presented based on data collected 

 prior to and during operation of the New Haven Harbor Station. 



The effects on estuarine organisms of elevated temperatures 

 from power plant thermal effluents are well documented (Talmage and 

 Coutant, 1978). A discussion and literature review of the tolerances 

 and responses of marine invertebrates to natural and artificial temper- 

 ature regimes has been presented by Kinne (1970) . The effects of elevated 

 temperature on most organisms appears to be greatest during the reproduc- 



