Winter and spring movements of anadromous Arctic char: Linking behavior to environmental conditions through an Inuit-led telemetry study

At the end of the Inuit summer, anadromous Arctic char (Salvelinus alpinus) migrate toward Tasirjuarusik Lake (Kangirsuk, Nunavik, Quebec). They sustain subsistence fishing during the upstream migration. However, during the winter, local Inuit fishers have been unsuccessful in catching Arctic char in this lake, but catches do resume in late spring. The Kangirsuk hunters and fishers’ association, Uumajulirijikkut Kangirsumi, initiated a telemetry study to assess (1) if the Arctic char were overwintering in the lake and (2) if the fish behavior during winter and spring was linked to environmental characteristics (temperature, oxygen, or ice). Eight Arctic char were tagged with acoustic transmitters during their upstream migration, and passive receivers were deployed throughout the lake continuously for 2 years. Five of the tagged fish overwintered in the lake, where they remained inactive for approximately 8 months. The difficulty of catching them in winter is likely due to their low activity level combined with the large areas of littoral zones (selected habitat) in this lake. A significant increase in the activity level of the tagged Arctic char occurred simultaneously with the onset of snowmelt runoff until the complete mixing of the lake. Char left the lake at peak discharge, coinciding with the ice breakup at the lake outlet. The results of this collaborative research, led by the community with locally grounded questions, align with and complement the observations of fishers. Despite the limited number of tagged fish due to community concerns about animal well-being, the results illustrate different migration patterns within this population and shed light on the environmental triggers that lead to the resumption of char activity in spring.