Recent increases of animal mass mortality events have coincided with substantial changes in global climate. Yet, tractable approaches that predict how climate change will accentuate occurrences of these ecological catastrophes remain nascent. We compiled one of the most comprehensive datasets of lentic fish mortality events, thermal tolerances of affected families, and 1.2 million air and water temperature profiles across 8891 north temperate lakes in North America. Temperature extremes within and across lakes were strongly associated with the three most frequent cause types (infectious agents, summerkills, winterkills). Thermal tolerances mediated the lethality of direct thermal stress, but mortalities of warm- and cold-water fishes occurred at similar temperature deviations. Water and air temperature-based models accurately predicted contemporary summerkills and suggested ~ 6- to 34-fold increases, respectively, in their frequency by 2100. These models forecast and contextualize impending ecosystem changes in an increasingly volatile world.
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The authors thank all individuals that helped document mortality events; three anonymous reviewers for helpful comments that improved the manuscript; A. Till for developing the original analytical framework; and E. Edmonson, H. Crisp, T. J. Bartley, and U.S. Fish and Wildlife Service for contributing taxa silhouettes to PhyloPic. SPT was supported in part by the NSF (GRFP 1842401). AMS was supported by NSF DEB 1748945. ALR was supported by the Peter B. Moyle & California Trout Endowment for Coldwater Fish Conservation and by the California Agricultural Experimental Station of the University of California Davis, grant number CA‐D‐WFB‐2467‐H. SBF was supported by NSF DEB 1856415. NBDP was supported by the Minnesota Agricultural Experimental Station and the USDA‐NIFA state project MIN‐41‐019.
© 2022 The Authors. Limnology and Oceanography Letters published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography.