Warming winters threaten peripheral Arctic charr populations of Europe

• Published in: Reviews in Fish Biology and Fisheries
• Main Authors: Kelly, Seán, Moore, Tadhg, de Eyto, Elvira, Dillane, Mary, Goulon, Chloé, Guillard, Jean, Lasne, Emilien, Mcginnity, Phil, Poole, Russell, Winfield, Ian, Woolway, R. Iestyn, Jennings, Eleanor
• Other Authors: CENTRE FOR FRESHWATER AND ENVIRONMENTAL STUDIES DUNDALK INSTITUTE OF TECHNOLOGY CO LOUTH IRELAND GBR, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Marine Institute Ireland, Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques (CARRTEL), Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Écologie et santé des écosystèmes (ESE), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), University College Cork (UCC), LAKE ECOSYSTEMS GROUP CENTRE FOR ECOLOGY AND HYDROLOGY LANCASTER GBR, European Centre for Space Applications and Telecommunications (ECSAT), Agence Spatiale Européenne = European Space Agency (ESA), Marine Institute Marine Research Programme by the Irish Government PBA/FS/16/02Marine Institute under the Marine Research Programme RESPI/FS/16/01WATExR project MINECO Swedish Research Council Formas Federal Ministry of Education & Research (BMBF) United States Environmental Protection Agency RCN IFD European Union (EU)690462
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Arctic charr; Biodiversity conservation; Climate reanalysis; General circulation model; Hydrodynamic modelling; Lake ecosystems; Winter limnology; [SDE]Environmental Sciences; Arctic; Winter Lake; Salvelinus alpinus
• Online Access: https://hal.inrae.fr/hal-02982057; https://hal.inrae.fr/hal-02982057/document; https://hal.inrae.fr/hal-02982057/file/s10584-020-02887-z.pdf; https://doi.org/10.1007/s10584-020-02887-z

International audience As the global climate warms, the fate of lacustrine fish is of huge concern, especially given their sensitivity as ectotherms to changes in water temperature. The Arctic charr (Salvelinus alpinus L.) is a salmonid with a Holarctic distribution, with peripheral populations persisting at temperate latitudes, where it is found only in sufficiently cold, deep lakes. Thus, warmer temperatures in these habitats particularly during early life stages could have catastrophic consequences on population dynamics. Here, we combined lake temperature observations, a 1-D hydrodynamic model, and a multi-decadal climate reanalysis to show coherence in warming winter water temperatures in four European charr lakes near the southernmost limit of the species’ distribution. Current maximum and mean winter temperatures are on average ~ 1 °C warmer compared to early the 1980s, and temperatures of 8.5 °C, adverse for high charr egg survival, have frequently been exceeded in recent winters. Simulations of winter lake temperatures toward century-end showed that these warming trends will continue, with further increases of 3–4 °C projected. An additional 324 total accumulated degree-days during winter is projected on average across lakes, which could impair egg quality and viability. We suggest that the perpetuating winter warming trends shown here will imperil the future status of these lakes as charr refugia and generally do not augur well for the fate of coldwater-adapted lake fish in a warming climate.