104B Base Grants – Pilot Investigation of Variable Contaminant Loads in Fish

Contaminants such as mercury and polychlorinated biphenyls (PCBs) are typically quantified as measures of central tendency, i.e. averaged across all sampled fish of the same species within the same body of water. More recent studies suggest that individuals within a population do not all exhibit the same feeding and habitat residence patterns, therefore have varying risks to contaminant exposure and accumulation. If popular sport fish such as yellow perch, Perca flavescens, or black crappie, Pomoxis nigromaculatus, exhibit diet plasticity and specialize for pelagic or benthic habitats, then some groups of fish may pose a greater risk to consumers. Specifically, we hypothesize that diet plasticity and specialization in fish populations could lead to a bi-modal distribution of contaminant loads. Given that different contaminant exposure is likely to manifest through differential foraging strategies and habitat use, we will collect fish of each species within 3 different lakes in Northern Indiana to evaluate potential for relationships between the mercury and PCB loads of individual fish and their diet/habitat specialization. Understanding this relationship and the level of variation of contaminant loads within individual lakes could help federal and state agencies make informed decisions on fish consumption advisories.