Effects of metals on the seasonal variations in the condition and metabolic capacities of yellow perch, Perca flavescens

by Audet, Debbie S.

Yellow perch (Percaflavescens)fkom Whitson and Halfivay iakes were studied to examine the effects of met& on the seasonal variations in fish tissue metal concentrations, condition and metabolic capacities. In each lake, fi@ yellow perch were captured with seine nets in May, August and October of 1999. The hepatosomatic index (HSI), Fulton's condition factor @CF)and visceral lipid index (VLI) were calculated for each fish captured. The seasonal scaIing coefficient of each population was also calculated. Twenty yellow perch per season per lake were m e r analyzed as follows. Liver and muscle water, protein and metal (Cu, Cd, Zn) contents were deterrnined. Metals were also rneasured in giIl filaments and stomach contents. Indicators of anaerobic capacity (lactate dehydrogenase), aerobic capacity (citrate synthase) and growth (nucleoside diphosphate kinase) were rneasured in muscle and liver tissues. Gill ~a'lK' ATPase and muscle RNAIDNA ratios (another indicator of growih) were also detennined. Whitson Lake fish, which are exposed to elevated environmental metal concentrations, had higher tissue metal concentrations and lower physiological condition, indicated by tissue protein contents and muscle enzyme activities and higher gill ~a+lK' ATPase activities (in spring only). These results suggest that fish living in metal-laden environments have a compensatory metabolic cost of survival.