Seasonal variations in tissue metabolic capacities of yellow perch (Perca flavescens) from clean and metal-contaminated environments

This study examined seasonal variations in tissue metal contamination and physiological condition of yellow perch (Perca flavescens) from a clean lake (Halfway Lake) and a metal-contaminated environment (Whitson Lake) in spring, summer, and fall of 1999. Dietary metal content influenced liver metal concentrations, especially for cadmium. Fulton's condition factor (FCF), an indicator of recent feeding activity, was lower in Whitson fish except in summer, when higher FCF values corresponded with higher liver copper concentrations, presumably because of higher feeding rate. Tissue protein concentrations and indicators of biosynthetic capacities (nucleoside diphosphate kinase and RNA/DNA ratios) suggested lower biosynthesis in Whitson fish. Muscle aerobic and anaerobic capacities (using citrate synthase and lactate dehydrogenase as indicators, respectively) were consistently lower in Whitson fish, with maximal differences in summer. In contrast, although liver aerobic capacities were generally comparable among populations, anaerobic capacities were much higher in Whitson fish. Finally, gill sodium/potassium adenosinetriphosphatase (Na+/K+ ATPase) activity peaked in the spring in fish from both lakes, and higher activities were correlated with elevated gill copper concentrations. This study highlights the importance of seasonal variations in tissue metal concentrations and fish condition. This information is essential to evaluate the extent of impairment in condition faced by metal-contaminated wild fish.