Growth and mercury accumulation in yearling yellow perch,Perca flavescens,in the Ottawa River,Ontario

Synopsis Diet, growth, energy content and mercury concentrations of yearling yellow perch,Perca favescens, were determined from June 1974 through May 1975. Benthic invertebrates predominated in the diet throughout the summer with zooplankton important in June and fish in August and September. Ash, lipid, protein and energy content of the yearling yellow perch increased through the summer reaching maximal values in August, 1974. Fish collected May 15, 1975 has reduced ash, lipid., protein and energy content with an increased moisture content. Both protein and lipid were catabolized during overwintering. Seasonal variation in organic mercury concentration was not significant (p>0.05). Inorganic mercury decreased significantly (p0.05) in September, 1974 and May, 1975 samples, reflecting changes in diet and the shorter biological half-life of inorganic mercury. The pollutant bioaccumulation model of Norstrom et al. (1976) adequately described the observed accumulation of organic mercury in young perch from June through September 1974, but either underestimated uptake or overestimated clearance for the period October 1974–May 1975.