Bioaccumulation and Biomagnification of Mercury in Two Warmwater Fish Communities

Abstract

ABSTRACT Total mercury concentrations were determined in two Connecticut lakes for six 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. dolomieu), and yellow perch (Perca flavescens). Total mercury concentrations in all fishes increased with length and age. Slopes of log10 mercury concentration-age regressions, which were used to compare bioaccumulation rates, were different among species in both lakes. In both lakes, no difference in bioaccumulation rate was found between top-level predators. Top-level predators and intermediate trophic level species (black crappie and yellow perch) accumulated mercury at a faster rate than bluegills. Intermediate trophic level species had bioaccumulation rates comparable to top-level predators over the range of ages sampled. Differences in mercury concentrations between a top-level predator (largemouth bass) and intermediate trophic level species decreased with age, while differences between largemouth bass and bluegill increased with age.