Consequences of changing climate and geomorphology for bioenergetics of juvenile sockeye salmon in a shallow Alaskan lake |
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| Authors: | Jennifer R Griffiths Daniel E Schindler |
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| Institution: | School of Aquatic and Fishery Sciences, University of Washington, Box 355020, Seattle, WA, USA |
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| Abstract: | Abstract – In high northern latitudes, a wide range of geomorphic processes associated with fluvial, glacial and permafrost activity may interact with climate change to produce unexpected changes in lake thermal regimes with attendant effects on ecological processes. We coupled output from a hydrodynamics model of lake thermal structure to a bioenergetics model to assess how alternative scenarios of climate change, geomorphic evolution and habitat restoration in a shallow Alaskan lake may affect juvenile sockeye salmon bioenergetics and growth. In particular, we evaluated the metabolic costs of different thermal regimes and the potential for changes in consumption to offset those costs. Increased water temperatures associated with future climate increased metabolic costs which were partially offset if fish were able to maintain feeding rates, expressed as a constant proportion of maximum consumption. In this lake, water levels have declined substantially in the last 50 years. Simulated restored lake level had negligible effects on lake temperature and thus on sockeye salmon growth when compared to current conditions. Maintaining lake connectivity to inlet tributaries (cooling lake temperature) was crucial in reducing sockeye salmon metabolic costs particularly with further drops in lake level and climate warming. While considerable research is focused on predicting future thermal and geomorphic conditions in aquatic ecosystems, these processes are rarely considered together, especially for lakes. Understanding the biological responses to geomorphic–climate interactions will be required for developing scenarios for coping with ecosystem responses to global change and evaluating restoration alternatives, especially in high‐latitude systems that support economically and culturally important fisheries. |
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| Keywords: | climate change geomorphic evolution bioenergetics sockeye salmon fisheries |
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