9-4 



relativoly little if any effect of New Haven Harbor Station operation but 

 wliere water quality and food availability would be generally similar. 



The study was modified in May 1973. Oysters were purchased 

 from New Haven Harbor instead of Marion, Massachusetts, where they 

 previously had been obtained. Also, because of high oyster mortalities 

 (up to 50% per month) not typical of the other two sites. Long Wharf was 

 abandoned as a study site. More importantly, the program was revised to 

 define the condition of the oysters, in addition to documenting changes 

 in length. Condition index (CI) , based on the relationship between the 

 weight of the oyster meat to the volume of the shell cavity, is used as 

 a measure of the quality of the meat but cannot be applied directly to 

 growth (Galtsoff , 1964) . 



The operation of a generating station could potentially affect 

 oyster growth and condition in New Haven Harbor by altering certain physical,| 

 chemical and biological parameters. The primary parameters that could 

 be affected are temperature, dissolved oxygen, turbidity and food supply. 

 Rather than design a series of experiments to determine the separate and 

 combined effects of changes in these parameters on oyster biology, this 

 study focused on the overall properties of oyster growth and mortality. 

 By performing in situ experimental measurements of growth and mortality 

 parameters, it was possible to formulate and test specific hypotheses 

 that are directly applicable to the determination of the potential 

 impact of the operation of New Haven Harbor Station on the growth and 

 survival capabilities of oyster populations in the harbor. 



Three hypotheses were developed with respect to these ob- 

 jectives and statistically tested to determine if any postoperational 

 effects could be delineated and attributed to the activity of New Haven 

 Harbor station. These hypotheses were: 1) mortality differs by station 

 or by year; 2) net change in length (growth) varies by station or by 

 year and 3) seasonal growth patterns differ at the two stations. It was 

 possible to test only a corollary hypothesis of 3) namely: length 

 changes at the two experimental stations occur in the same time periods 



