13-15 



Impacts 



A qualitative comparison of mean numbers of taxa indicated 

 that species richness did not change s\abstantiallY in the operational 

 period. A similar comparison of total numbers of organisms indicated an 

 operational decrease at Long Wharf which was attributable to a large 

 natural variation in Mya densities. Dominant fauna collected in pre- 

 operational samples were generally found at similar or increased den- 

 sities after plant operation had begun. Only Gemma gemma showed a 

 population change coincident with plant operation. A decline in popu- 

 lation density of Gemma at Sandy Point in May 1975 just prior to com- 

 mencement of operations in addition to a decline at Long Wharf in 

 October 1975, may indicate a harborvide decrease in Gemma populations 

 rather than a localized decrease related to station operation. 



Analysis of change by sampling period showed considerable 

 variability. Declines in species richness and densities were detected 

 in October 1976 samples at the inner harbor stations. Long Wharf and 

 East Shore, and were probably related to low levels of dissolved oxygen. 

 October reductions in species richness and organism density were not 

 observed in 1977, indicating that the die-off observed in 1976 was not a 

 regular summer phenomenon in New Haven Harbor. 



None of the fluctuations in distribution and abundance in New 

 Haven Harbor were suggestive of operational impact of New Haven Harbor 

 Station on intertidal assemblages. The dominant taxa collected in the 

 intertidal zone are opportunistic species which characteristically 

 utilize an unpredictable environment by virtue of their ability to 

 increase in density rapidly and to exist in dense populations. Unless 

 new severe stresses occur in the Harbor, it appears that intertidal 

 areas will continue to offer the same resources to tolerant colonists 

 and subsequent foragers and predators with little or no consequence from 

 operation of the New Haven Harbor Station. 



