Arctic char enter the marine environment before annual ice breakup in the high Arctic

Lars J. Hammer, University of New Hampshire Durham
Nigel E. Hussey, University of Windsor
Marianne Marcoux, Fisheries and Oceans Canada
Harri Pettitt-Wade, University of Windsor
Kevin Hedges, Fisheries and Oceans Canada
Ross Tallman, Fisheries and Oceans Canada
Nathan B. Furey, University of New Hampshire Durham


Mobile consumers often match their movements to short-term resource pulses. In the Arctic, seasonal ice breakup facilitates an ephemeral productivity pulse exploited by marine consumers. The migration of anadromous Arctic char (Salvelinus alpinus) to marine waters occurs around the beginning of ice breakup, but the precise timing of movement is equivocal and current evidence is conflicting. To investigate the migratory timing of Arctic char, 34 individuals were tagged with acoustic telemetry transmitters within Tremblay Sound, Nunavut, Canada in two successive years. All tagged fish entered the marine environment before the coastal ice-off date (mean ± SE: 7.56 ± 0.56 days). Further movement metrics revealed that char utilized much of the sound before the ice-off date, with only slightly higher mean home ranges (0.3 km2 larger) and residency indices (by ~ 0.05) during the period following the ice-off date than prior. Such entry and use of marine waters prior to ice breakup may impart energetic benefits to early migrants, maximizing exploitation of the short, anticipated pulse of productivity. The current study provides a unique example of resource tracking that could confer heightened fitness to a marine consumer in the rapidly warming high Arctic.