The effects of aquatic contaminants and environmental stressors on the composition of fishes: concealed implications to beneficial nutrient profiles.

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Nearly one-fifth of the global population relies on fish to supply about 20% of their annual food intake by weight. The quality and availability of fish is being affected by global fishing pressures, rapidly changing environmental conditions associated with global climate change, and human-caused water pollution. Fish consumption guidelines must therefore weigh eating beneficial nutrients, such as healthy omega-3 fats, proteins, and vital micronutrients, against the detrimental effects of contaminants of common concern such as mercury, oil-derived chemicals, industrial chemicals, and pesticides within fish. However, little information is available regarding how climate-change related environmental changes and these types of aquatic contaminants interact to change how fish grow - and the essential dietary nutrition they provide as food. My research will address the central question of "How are climate change and contaminants in the aquatic environment changing the nutrition of our food?", with the long-term objective of understanding the mechanisms behind how both these factors are affecting species diversity and distribution, growth and development, and the ultimate nutrient composition of fishes. This research will involve: 1) Field sampling in regional watersheds using environmental DNA (eDNA) to determine the diversity of animal species present and collect information about the environmental conditions associated with local fish species of interest (e.g., walleye, perch). Comparing the population characteristics from different locations along the Assiniboine River and related tributaries to the environmental conditions and contaminants levels present within them will provide an understanding of the challenges fish are facing, and the local species that are the most vulnerable to them. 2) The use of laboratory experiments on a model fish species (e.g., zebrafish) to assess the effects of climate change such as temperature, salt levels, and acidity, as well as exposure to contaminants on the fat metabolism of these fish, specifically on how they effect the presence of nutritionally beneficial omega-3 unsaturated fatty acids. 3) The use of semi-natural environments to examine how those same climate change and contaminant exposures affect the nutrient profiles of local fish species, while also assessing them under the natural fluctuations and conditions of the environment in which they originated. This will validate lab results in the context of real-world conditions and help to determine which local species exhibit the most resilience to these changes and may play an expanding role as important food species in the future. The results of this research will help us understand how multiple factors in our rapidly changing environment are collectively affecting how fish live and grow, and to answer the poignant question, "Will the wild fish we eat in the future be as nutritious as they are now?"