Biophysical indicators and Indigenous and Local Knowledge reveal climatic and ecological shifts with implications for Arctic Char fisheries

Abstract

Managing Arctic marine resources to be resilient to environmental changes requires knowledge of how climate change is affecting marine food webs and fisheries. Changes to fishery resources will have major implications for coastal Indigenous communities whose livelihoods, health, and cultures are strongly connected to fisheries. Understanding these broad social-ecological changes requires a transdisciplinary approach bringing together contrasting and complementary disciplines and ways of knowing. Here, we examine climatic proxies, ecological, and fishery indicators (stable isotopes, fish condition, and lipid content), and interviews with Inuit fishers to assess how marine ecosystem changes have influenced Arctic Char (Salvelinus alpinus) ecology and fisheries over a 30-year time period (1987–2016) in the Kitikmeot region of the Canadian Arctic. Inuit fishers reported several observations of environmental changes, including longer ice-free seasons, warmer ocean temperatures, and the arrival of new marine species. Biophysical data revealed important changes toward earlier dates of ice breakup (>12 days in some areas) and a shift in isotopic niche reflecting a changing Arctic Char diet, with increased contribution of pelagic carbon and higher trophic level prey. Fish condition was improved in years with earlier ice breakup, as observed by both Inuit fishers and biophysical indicators, while lipid content increased through time, suggesting that longer ice-free seasons may have a positive effect on Arctic Char quality as reflected by both fish condition and lipid content. Long-term impacts of continuing climate change, however, such as the northward expansion of boreal species and increasing ocean temperatures, could have negative effects on fisheries (e.g., physiological impairment in fish if temperatures exceed their thermal range). Continuous community-based monitoring that directly informs fisheries management could help communities and managers adaptively, and sustainably, manage in the face of multiple interacting changes in Arctic marine systems.