Bioaccumulation and biomagnification of mercury in two warmwater fish communities

Total mercury concentrations were determined in two Connecticut lakes for s ix fish species representing a range of trophic levels -- largemouth bass ( Micropterus salmoides), chain pickerel (Esox niger), black crappie (Pomoxis nigromaculatus), bluegill (Lepomis macrochirus), smallmouth bass (M. dolom ieu), and yellow perch (Perca flavescens). Total mercury concentrations in all fishes increased with length and age. Slopes of log,, mercury concentra tion-age regressions, which were used to compare bioaccumulation rates, wer e different among species in both lakes. In both lakes, no difference in bi oaccumulation rate was found between top-level predators. Top-level predato rs and intermediate trophic level species (black crappie and yellow perch) accumulated mercury at a faster rate than bluegills. intermediate trophic l evel species had bioaccumulation rates comparable to top-level predators ov er the range of ages sampled. Differences in mercury concentrations between a top-level predator (largemouth bass) and intermediate trophic level spec ies decreased with age, while differences between largemouth bass and blueg ill increased with age.