Data and code from: Marine migrations and trophic niche use of Arctic charr in southwest Greenland fjords with contrasting influxes from glacial runoff

Le résumé fourni par la source

Arctic charr is a partially migratory salmonid often undertaking annual marine migrations for feeding. As migration is an adaptive life-history trait, climate-driven environmental changes can alter selective pressures shaping movement behavior. To assess climate-related influences on migratory patterns and trophic niche use, we combined acoustic telemetry, otoliths, and stable isotope analysis to study populations in two Southwestern Greenland fjords differing in glacial runoff: Igaliku and Ikersuaq. Anadromous charr in Igaliku used the full fjord, traveling up to 21 km from their home river, while those in the more glacially influenced Ikersuaq remained nearshore with shorter movements (9km). Despite similar marine feeding duration (48 vs. 54 days), Igaliku fish exhibited lower marine feeding intensity. Arctic charr in Igaliku experienced warmer (8.2 ºC) conditions than those in Ikersuaq (5.8 ºC), with estuaries (Igaliku 8.2 ºC; Ikersuaq 7.6 ºC) consistently as warm or warmer than marine areas in both systems. Findings suggest Arctic charr is constrained by fjords with high glacial runoff and may shift to more open waters, thereby altering diet, growth rates and life-history strategies under future climate change scenarios.

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