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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 metabolites
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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