used to test the hypothesis of independence of mortalities from 

 the stations (Table 10); the G-test statistics obtained: G=234.2, 

 v 2 0.005(4) = 14.860, p << 0.001 reject the hypothesis. 

 Therefore, the mortalities were associated with the stations 

 where the mussel populations were deployed. At the reference 

 station Rlr, the 45% mortality was significantly lower than that 

 of the LATr (52%) and the three populations, WLISc, 500MW and 

 WLISrN (71-73%) . In investigating the effects of stock and 

 location on growth and mortality in Mytilus edulis in Nova Scotia 

 waters, Dickie et al. (1984) reported that location was the major 

 factor -in determining growth, while stock influenced mortality. 

 Furthermore, the biomass and potential yield were determined 

 approximately equally by location and stock. In the present 

 study, because only one stock was used, the genetic effect was, 

 therefore, removed. Thus, the observed differences in mortality 

 (Table 10 and Fig. 10) and W/D ratio (potential yield) (Fig. 5) 

 were site-specific. 



Histopatholoaical Studies . Histological sections from the 

 reference and disposal site populations were examined by using 

 seven parameters: (1) the stage of gonadal development, (2) 

 staining and morphological characteristics of Leydig tissue, (3) 

 integrity of the intestinal epithelium, and intestinal content, 

 (4) integrity of the style sac epithelium and the presence of 

 crystalline style, (5) changes in plycate organ, (6) degree of 

 leucocytic infiltrations, as well as (7) prevalence of 

 parasitism. The first two parameters are indices of the mussel's 

 reproductive status, while parameters 3, 4, and 5 are indices of 

 feeding and excretion status. The degree of leucocytic 

 infiltrations, except during the post spawning resorption of 

 remanent ova, is an indicator of inflammation which could 

 identify overt histopathology. The last parameter is to assess 

 any tissue damage inflicted upon the host (mussels) by parasites; 

 this information is important in separating environmentally 

 induced histopathological manifestations from those caused by 

 parasitism. Whenever possible, the parameters were scored for 

 quantitative presentation and subject to proper statistical 

 treatment. 



For scoring the degree of reproductive conditions, the 

 gonads were categorized in five classes: castration, early 

 development, immature stage and spent. These stages are defined 

 as follows: 



a. Castration (C) : destruction or replacement of the 

 gonadal tissue by sporocysts of Proctoeces maculatus ; sex usually 

 undeterminable . 



b. Early development stage (E) : only germinal tissue 

 present; sex undifferentiated. 



