The concentrations of zinc, lead and cadmium in four species of fish from several lacustrine sites were determined. Cyprinids were found to have significantly higher levels of the three metals studied than perch, Perca fluviutilis. Whilst zinc thresholds may be species specific, levels of lead and cadmium vary both within species and sites. There is some evidence that lead and cadmium levels increase with age in roach, Rurilus rutilus. Additionally both cadmium and lead appear to accumulate in the heart, liver, kidney and brain as well as in the bone. Relatively high levels of lead and cadmium were recorded in the eyes of bream, Abruma brumis.

The feeding habits, rates of growth, fecundity and other aspects of the general biology of five-bearded rockling from the Severn Estuary and the Bristol Channel are reviewed for the period 1974/76. Additionally the changes in heavy metal accumulation during this time have been measured and an attempt has been made to relate them to the diet of the fish.

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