Date of Award

2012

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Biological Sciences

First Advisor

Trevor E. Pitcher

Second Advisor

Daniel Heath

Keywords

Biological sciences, Health and environmental sciences, Polychlorinated biphenyls, Fishes, Great lakes, Contaminants, Female reproductive traits

Rights

CC BY-NC-ND 4.0

Abstract

The ability to withstand a range of environmental contaminants has been documented in numerous taxa. Until recently, the field of ecotoxicology has focused, in part, on identifying adaptive traits of populations exposed to contaminants, with little emphasis on understanding mechanisms underlying individual-level variation in these traits. An emerging field, termed evolutionary toxicology, expands the scope of ecotoxicology by investigating such mechanisms and discussing their evolutionary implications. My thesis blends the fields of ecotoxicology and evolutionary toxicology by investigating novel avenues and addressing novel questions in these fields that remain to be explored, as discussed in my review article. To do this, I first used an ecotoxicological approach and identified associations between female reproductive traits and inorganic environmental contaminants in brown bullhead ( Ameiurus nebulosus ) in the Lower Great Lakes Region. I further used an experimental approach to support the hypothesis that acclimation is one possible mechanism underlying these associations. Next, I used an evolutionary toxicological approach to examine male primary and secondary sexual traits under sexual selection in wild populations of both Chinook salmon ( Onchorhynchus tshawytscha ) and Coho salmon (Oncorhynchus kisutch ) with regards to individual measures of polychlorinated biphenyls (PCBs). I found that for Chinook salmon, PCB concentrations best describe variation in primary and secondary sexual traits in males with low 11-KT concentrations. This result highlights potential physiological mechanisms associated with PCBs that can explain variation in traits under sexual selection. It also supports the hypothesis that PCBs may have implications for the expression of sexually selected traits and suggests that future research focus on possible implications of this on mating success and ultimately sexual selection. No significant associations were identified between PCBs and sexual traits in Coho salmon, potentially due to a number of sampling limitations. Overall, my thesis examines the bridge between ecotoxiolcogy and evolutionary toxicology and discusses how this novel research can be applied to management practices, such as habitat restoration

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