13-18 



comparison of preoperational and operational study data. Condition 

 indices (Galtsoff , 1964) , based on a ratio of meat-weight to shell 

 cavity voliome were designed to provide an objective means of evaluating 

 oyster readiness for market. This study utilizes the condition index as 

 an additional parameter for evaluation of preoperational and ox-sera- 

 tional differences. In all instances dry weight-condition indices were 

 lower at Harbor Station than at Fort Hale and, in all but one instance 

 (1975) , condition indices at Harbor Station were lower than in the 

 oyster stock used for the study. That the difference between experi- 

 mental stations was a consistent pre- and post-operational phenomenon, 

 suggests that environmental conditions in the inner harbor are generally 

 less favorable to oysters. 



Mortality for 1974-1977 was found to be independent of station 

 but dependent on year, indicating that differing environmental condi- 

 tions at the two experimental sites (including any environmental modi- 

 fication due to the operation of New Haven Harbor Station) had no effect 

 on overall oyster mortality. Significantly higher mortality occurred in 

 1975 than in any other year tested at both sites and may have been 

 associated with low condition indices observed in the initial oyster 

 stock in 1975. High June and July mortalities give some indication that 

 the oysters purchased were not as healthy as in previous years , and thus 

 were less resistant to disease or predation. 



Yearly variation in mean net growth was highly significant; 

 between-station variation was not. At both stations, growth was great- 

 est in 1976 and least in 1977. Patterns of oyster growth by month at 

 Fort Hale and Harbor Station for the years 1973-1977 were not signifi- 

 cantly different from each other. Though there was significant vari- 

 ation in mean net growth between years 1973-1977, these results imply 

 that environmental conditions relevant to oyster growth were similar at 

 both stations during pre- and post-operational periods. 



The interpretation of these results leads to the conclusion 

 that no effect of the operation of New Haven Harbor Station could be 



