9-6 



tray was therefore moved to a less accessible dolphin offshore from the 

 Fort Hale pier and restocked with a new sample in September 1971. In 

 May 1972 all remaining oysters at all stations were discarded and 

 replaced with new specimens, also from the Marion, Massachusetts, area. 

 The experiment was then continued until April 1973. 



1974 - 1977 



Starting in 1973 a bushel of oysters was purchased from 

 Long Island Oyster Farms in New Haven, in May or June of each sampling 

 year. About 200 oysters of various lengths were selected and divided by 

 a random sampling technique into three portions. One hundred and fifty 

 were numbered with identification tags, measured and 75 each placed in 

 trays at Harbor Station and Fort Hale. Fifty oysters were returned to 

 the laboratory to serve as initial controls . The following measurements 

 were taken: shell length, total volume (by displacement) and air weight 

 of intact oyster, volume and dry weight of shells, volume and wet and 

 dry weight of meat. The condition index (CI) was calculated by dividing 

 oyster meat weight by the shell cavity volume (total oyster volume minus 

 the volume of shells) and multiplying the quotient by 100 (Galtsoff , 

 1964) . Oyster lengths were measured at the beginning and end of the 

 experiment in 1974 and monthly during the experiment in 1975-1977. 

 Harbor Station and Fort Hale oysters were sacrificed at the end of each 

 experimental year and subjected to the same volume and weight measure- 

 ments (Table 9-1) . 



Hypothesis Testing 



The data acquired by these methods were used each year to make 

 statistical comparisons between stations and to test the validity of the 

 three summary hypotheses as here described. Hypothesis (1) mortality 

 differs by station or by year, was tested with a series of 3-way 

 Otosts (Sokal and Rohlf, 1969). Factors were a) stations, b) years 



1 



