When exposed to petroleum, marine molluscs and teleost fish readily 

 accumulate hydrocarbons in their tissues (Neff et al. , 1976b; Varanasi 

 and Malins, 1977; Neff and Anderson, 1981). Molluscs tend to release 

 accumulated hydrocarbons relatively slowly when concentrations in the 

 ambient medium are reduced. However, under similar conditions, teleost 

 fish release hydrocarbons very rapidly. Differences in hydrocarbon 

 release rate by molluscs and fish can be attributed to differences in 

 ability to convert hydrocarbons to polar more readily excreted metabo- 

 lites by the cytochrome P-450 mixed function oxygenase system and related 

 pollutant-metabolizing enzyme systems (Varanasi and Malins, 1977; Neff, 

 1979). In the present investigation, aliphatic and aromatic hydrocarbons 

 were analyzed in oysters and plaice from oiled and reference stations to 

 assess patterns of hydrocarbon accumulation and release and to allow for 

 correlations between levels of hydrocarbon contamination of animals and 

 histopathological/biochemical responses. 



MATERIALS AND METHODS 



Oysters Crassostrea gigas were collected for biochemical analysis 

 on the first three sampling trips. Sampling sites were as described 

 earlier in the section on oyster histopathology. Oysters were shucked 

 and a sample of hemolymph was collected immediately from the heart or 

 the adductor muscle and stored frozen until analyzed. Adductor muscle 

 was also sampled and stored at -60°C until analyzed. 



Plaice Pleuroneotes platessa were collected by otter trawl from 

 oil-contaminated Aber Benoit and Aber Wrac'h. Reference stations for 

 plaice samples were as follows: December 1978, Baie de Douarnenez; 

 April 1979, Loc Tudy; August 1979, February 1980, June 1980, He Tudy. 

 Fish from the Baie de Douarnenez and Loc Tudy were collected by otter 

 or beam trawl. Fish from He Tudy were captured by net at the sluice 

 gate of the CNEXO mariculture pond and held in large circular holding 

 tanks with flowing seawater until sampled. 



Samples were taken as soon as possible after capture and while the 

 fish were still alive. Tissue samples included blood, muscle and liver. 

 Blood samples were centrifuged to remove red blood cells. Serum, 

 muscle, and liver were frozen immediately in liquid nitrogen and kept 

 frozen at -60° until analyzed. 



Samples from 5-10 animals from each station and each trip were 

 analyzed biochemically. Blood glucose and liver glycogen were measured 

 with a Yellow Springs Instruments automatic glucose analyzer, Model 23A. 



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