Non-Steady State Mercury Bioaccumulation and Dynamics

This study explored Hg bioaccumulation with age in three Lake Huron lake trout populations, considering effects of growth and trophic dynamics. Hg concentrations and stable isotopes were measured in trout, smelt, round goby, zooplankton and zebra mussels. Trout populations demonstrated exponentially increasing Hg concentrations with age and revealed basin-specific accumulation patterns. High biomagnification Factor (BMF) correlated with low prey densities suggest that physiological and ecological factors regulating fish growth rates such as foraging efficiencies are important in regulating Hg bioaccumulation. Physiological processes affect Hg bioaccumulation, specifically elimination dynamics. Hg in liver, gonads, dorsal muscle, and remaining carcass in pre-spawn, spawning, and post-spawn yellow perch populations were investigated. Ratio of Hg in each tissue to whole-body Hg were different between male and female perch, as well as among pre-, during-, and post-spawning perch. Thus, changes in Hg tissue concentrations during spawning could result in high variability of Hg elimination rates