Examination of Direct and Indirect Effects of Legacy Industrial Pollution On Organ Growth in Wild Yellow Perch (Perca flavescens)
To identify new bioindicators of legacy industrial pollution in aquatic ecosystems, I investigated the effects of chronic pollution on organ growth in fish. Specifically, I examined which organs are most sensitive to pollution and whether these changes were prompted by the indirect effects of impoverished food webs resulting from chronic pollution or the direct toxic effects of pollutants on cell proliferation. I measured relative organ size, trophic position, and hepatic cyp1a1 gene expression in wild yellow perch from impacted and reference sites across the Detroit River and Lake St. Clair. Overall, sites with higher levels of contaminants exhibited increased cyp1a1 expression, food web disruption, lower relative brain size, and higher relative liver size. However, the effects of pollution on organ growth were best explained by disruption of foraging ecology rather than direct toxic effects of contaminant exposure due to significant associations between organ size and trophic position, but not cyp1a1 expression.