laboratory (Wardle, 1972). In the last two samples, February 1980 

 and June 1980, reference plaice were sampled very rapidly a^ter capture 

 and their blood glucose values represent the normal unstressed values. 

 Plaice from the Abers were stressed by capture and showed a hyper- 

 glycemic response, suggesting some recovery of physiological function 

 with time. These data show some of the difficulties in using blood 

 glucose concentration as an index of stress in fish. If blood samples 

 cannot be taken immediately after the fish are captured, capture- induced 

 responses may obscure any due to pollution. 



Liver glycogen concentrations in fish from the last two collections 

 were highly variable (Table 21). Because of extremely large standard 

 deviations, no patterns could be discerned. 



Total cholesterol and high density lipoprotein (HDL) cholesterol 

 concentrations in the blood of plaice were measured in sampels from the 

 last two collecting trips (Table 22). The general trend was for total 

 cholesterol to be elevated and HDL cholesterol concentration to be 

 depressed in fish from the two oil-contaminated Abers. Several of these 

 differences were statistically significant. As a result, HDL cholesterol 

 as percent of total cholesterol was lower in plaice from Aber Benoit and 

 Aber Wrac'h than in plaice from the reference station at lie Tudy. 



Concentration of liver-free ascorbic acid was measured in plaice 

 from all five sampling trips (Table 23). In all but the February 1980 

 sample, liver ascorbate concentrations in plaice from oil-contaminated 

 Aber Benoit and Aber Wrac'h were substantially lower than concentrations 

 in livers of plaice from reference stations. In four cases, the differ- 

 ence was statistically significant. In the February collection, the 

 pattern was reversed. Reference fish contained hepatic ascorbate concen- 

 trations significantly lower than concentrations in livers of fish from 

 the two Abers. At this time, all the reference fish were gravid females 

 ready to spawn. Only a few of the fish from the Abers were in this condi- 

 tion. It is highly likely that the extreme depletion of liver ascorbate 

 reserves in the reference fish is the result of ascorbate mobilization 

 for gonadal maturation and ovogenesis. These gravid reference fish also 

 had relatively low hepatic glycogen reserves (Table 21) . 



Adductor muscle-free amino acid profiles and concentrations were 

 measured in oysters from the first three collecting trips (Tables 24-26). 

 Total free amino acid concentrations were always lower in adductor muscles 

 of oysters from oil-contaminated Aber Benoit and Aber Wrac'h than in 

 adductors of oysters from reference stations. This difference cannot 

 be attributed to differences in seawater salinity between Aber and 

 reference stations, since all stations had salinities in the 30-34 o/oo 



307 



