Dietary habits and heavy metal concentrations in fish from the Severn estuary and Bristol Channel

Comparisons of the rates of growth, feeding habits and heavy metal levels of flounders from Barnstaple and Oldbury-on-Severn have shown that at all ages the fish from the North Devon coast are larger than those from the middle Severn estuary and that there are marked differences in diet. These differences in diet may contribute to the much higher zinc levels of the Barnstaple flounder samples.In the six other fish species which have been examined, there is a distinct correlation between the cadmium concentrations of the tissues and the proportion of crustaceans in the diet. Lead concentrations appear to follow a similar trend, but no relationship could be detected between diet and tissue zinc levels.