Grant: Discovery Grants Program - Individual

Lakes and rivers provide many ecosystem services that are critical to the cultural, spiritual, nutritional, and economic well-being of remote northern communities, especially Indigenous communities. Eating fish harvested from natural waters contributes to food security and reflects traditional culture in many northern regions, but fish can also be a source of mercury to people. Mercury (Hg) is a potent neurotoxin, and can cause health problems if concentrations are high enough. After Hg is released into the atmosphere by natural (e.g, volcanoes) or human (e.g., artisanal gold mining) activities, it can travel long distances and end up deposited in remote Arctic systems. Mercury can then be taken up into aquatic food chains and build up in fish and other animals. Most people are primarily exposed to Hg by eating fish, and Indigenous peoples in the Arctic are exposed to more food-derived Hg than other populations due to their reliance on wild-harvested foods. To facilitate development of safe guidance for consumption and climate change adaptation plans, it is important to understand how and why Hg levels in fish vary among ecosystems, and how changes to the land (e.g., resource development, permafrost thaw) affect downstream water quality, fish ecology, lake ecology, and ultimately fish Hg. Permafrost thaw and other disturbances are changing land-water connections in many northern watersheds, and changes in water temperature and other environmental factors are affecting how fish move, feed, and grow; these changes will affect fish Hg. In the next five years, my research group will study how the type of energy (land-based or lake-based) that supports lake food webs affects fish growth rates and mercury levels. We will also investigate how seasonal movements and use of different habitats by fish affects their Hg levels. We will use a number of different tracers and tools - including stable isotope ratios, fatty acids, and otoliths (fish ear bones) - to conduct this research. Results will be used to refine consumption guidance for people so that benefits of eating fish can be maximized. Communities in the Dehcho region of the Northwest Territories will get more information on the safest and healthiest sources of fish. Inuit communities in Nunavut that rely on Arctic Char as a food source will be better able to predict how climate change will affect fish Hg levels. Overall, understanding how catchment, lake, and fish factors interact to drive fish Hg levels will allow us to more accurately predict how ongoing environmental change will affect safety and security of critically important fisheries in the Canadian North.