e.g., the hypoxia of bottom waters prevalent in the region during 

 the summer. 



Gonadal development of Mytilus edulis under normal 

 conditions is the result of interactions of environmental 

 factors, especially temperature, salinity, light and food, as 

 well as endogenous factors such as the influence of parasitism. 

 In the present study, the reproductive activity may also have 

 been affected in mussels living on and near dredged material 

 disposal sites by the changing physical and chemical conditions 

 of the environments. 



The relatively high proportion of immature gonads observed 

 at WLISrN (19%) and WLISc (27%) (Table 11) suggest that the 

 reproductive development of the mussels is location-specific and 

 reflect differences in the depth at which the mussels were held, 

 availability of food, disposal, and other associated local 

 environmental parameters. Bayne et al. (197 8) demonstrated that 

 when mussels were experimentally exposed to temperature and food 

 ration stresses, they produced smaller and fewer eggs than 

 unstressed controls. Also the ripe gametes of the stressed 

 animals occupied a smaller proportion of the mantle tissue than 

 that of the controls. In this study, temperature probably did 

 not play an important role in determining the gonadal 

 development. According to Reid et al. (1979) , the bottom 

 temperatures of WLIS and Fishers Island Sound in September 1972 

 were 18" - 20° C and 16" - 18° C, respectively. During the 

 winter, the bottom temperatures were rather uniform throughout 

 Long Island Sound and varied within a narrow limit of 4° - 6° C. 



The reduced proportion of mature mussels at WLISrN and WLISc 

 implies a concomitant reduction of areas occupied by female 

 germinal follicles in the mantle. This view is generally 

 supported by qualitative observations of the histological slides 

 which show diminution of female germinal follicles. Quantitative 

 studies conducted by Arimoto and Feng (1983b) revealed that the 

 New Haven disposal site mussel population had significantly 

 smaller ova (1880 + 140 n 2 ) than the New Haven reference mussel 

 population (1520 + 140 n 2 ) (p<0.01). 



The reduction of areas occupied by the gametic follicles or 

 of ovum size could also be induced by the food ration stress and 

 the infection caused by Proctoeces maculatus . While it is 

 difficult to conduct food rationing experiments in the field, it 

 is possible to determine whether the mussels were feeding and 

 carrying out normal extracellular digestion by examining the 

 presence of crystalline styles and intestinal content in the 

 histological slides. There were no discernible or at best 

 marginal significant differences among the four mussel 

 populations as far as feeding was concerned (Table 13, G=2.966, 

 p>0.5). Moreover, at WLISc and 500MW where the depth is greater 

 than 3 meters, diatom tests were readily identifiable in the 



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