13-13 



ments where achievement of a dynamic equilibrium is prevented by rapid 

 and unpredictable environmental changes. Faunal density was marked by 

 annual summer minima and fall recovery with the result that most dense 

 populations were recorded in late fall/early winter. The "August effect" 

 of reduced summer density appears to be associated with three combined 

 factors of sufficient depth to allow dissolved oxygen diminution at the 

 bottom, an organic-rich silt-clay substratum, and location in the inner 

 harbor. This combination of factors, in conjunction with the other 

 environmental stresses in the harbor, appear to be responsible for mass 

 mortalities during peak stress periods in August. 



Numerical classification analyses identified four station 

 clusters in the harbor; two resembled community types that have been 

 identified from other east coast estuaries. Stations in the inner 

 harbor, due to their more variable fauna, did not cluster well, and only 

 one group of three similar stations was identified. Two sediment- 

 controlled commxonity types were recognized from the Morris Cove samples. 



The combined data sets show New Haven inner harbor to be a 

 highly-stressed area characterized by variable and unpredictable bio- 

 logical parameters. The various pollutant sources in and around the 

 harbor combine to severely limit standing stocks of benthic macrofauna, 

 as reflected by low diversity values. The impacts associated with the 

 inner harbor appear to decrease with increasing distance from their 

 source as shown by the similarities noted between the fauna of Morris 

 Cove and that of Clinton Harbor, a relatively pristine Long Island Sound 

 estuary. 



Impacts 



No significant differences in subtidal benthic species rich- 

 ness or faunal density were observed between preoperational and oper- 

 ational years. Morris Cove contained more species in greater abundance 

 than the inner harbor during both preoperational and operational periods. 



