Research article

Winter is not coming: evaluating impacts of changing winter conditions on coregonine reproductive phenology

¹ Department of Biology, University of Vermont, Burlington, Vermont, USA
² Rubenstein Ecosystem Science Laboratory, University of Vermont, Burlington, Vermont, USA
³ Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
⁴ Institute of Polar Sciences, National Research Council, Venice, Italy
⁵ French National Research Institute for Agriculture, Food and the Environment (INRAE), University Savoie Mont Blanc, CARRTEL, Thonon-Les-Bains, France
⁶ United States Geological Survey, Great Lakes Science Center, Lake Superior Biological Station, Ashland, Wisconsin, USA
⁷ University of Innsbruck, Mondsee, Austria

^* Corresponding author: taylorstewart@utah.gov

Received: 21 January 2024
Accepted: 5 July 2024

Abstract

Fishes in northern latitude lakes are at risk from climate-induced warming because the seasonality in water temperature is degrading, which can change ecosystem properties and the phenology of life-history events. Temperature-dependent embryo development models were developed for a group of cold, stenothermic fishes (Salmonidae Coregoninae) to assess the potential impacts of climate-induced changes in water temperature on cisco (Coregonus artedi) from two populations in Lake Superior (Apostle Islands [USA] and Thunder Bay [Canada]) and one in Lake Ontario (USA), vendace (C. albula) in Lake Southern Konnevesi (Finland), and European whitefish (C. lavaretus) in lakes Southern Konnevesi, Constance (Germany), Geneva (France), and Annecy (France). Water temperatures for each study group were simulated and changes in reproductive phenology across historic (1900–2006) and three future climatic-warming scenarios (2007–2099) were investigated. Models predicted that increases in water temperatures are likely to cause delayed spawning, shorter embryo incubation durations, and earlier larval hatching. Relative changes increased as warming scenarios increased in severity and were higher for littoral as compared to pelagic populations. Our simulations demonstrated that slower cooling in the autumn and (or) more rapid warming in spring can translate into substantial changes in the reproductive phenology of coregonines among our study groups. We expect that the changes in reproductive phenology predicted by our models, in the absence of thermal or behavioral adaptation, will have negative implications for population sustainability.