CHANGES IN THE BIOCHEMICAL-COMPOSITION OF A SUBTROPICAL BIVALVE, ARCA-ZEBRA, IN RESPONSE TO CONTAMINANT GRADIENTS IN BERMUDA

The biochemical composition of a subtropical bivalve, the turkey-wing mussel Arca zebra, was examined in specimens deployed along two contaminant gradients (Castle Harbour and Hamilton Harbour) in Bermuda. Pooled homogenized samples of the mussel were analysed for protein, ash, total lipid and lipid-class composition. The biochemical composition of A. zebra was similar to that observed in other bivalves that rely on glycogen as their primary energy substratum. Differences were noted in the lipid content and composition in mussels deployed in the two harbours. These differences suggest that Hamilton Harbour has higher food availability than Castle Harbour and so the A. zebra from Hamilton Harbour were in better physiological condition as indicated by higher lipid levels, primarily neutral lipids. The biochemical composition of the mussels provides no evidence that Castle Harbour is impacted by contaminants at a local dumpsite. Mussels deployed at Hamilton Harbour had increasing neutral lipid levels along an increasing contaminant gradient, a pattern observed previously in bivalves impacted by anthropogenic inputs to their environment. These changes may indicate impaired mobilization of free fatty acids from the neutral to polar lipid pools, or possible gonadal resorption following exposure to lipophilic contaminants. © 1990.