Spatial and temporal harvest risk to polar bears in the Canadian Beaufort Sea

Abstract

Subsistence harvest in Arctic marine ecosystems is influenced by sea ice conditions affecting species distributions, abundance, and accessibility. We tracked 78 polar bears (Ursus maritimus) of different age, sex, and reproductive classes via satellite telemetry in the Canadian Beaufort Sea (2007-2014, n=71 258). We assessed vulnerability to harvest (no/low/medium/high) based on telemetry data overlap with density of historical harvest locations (1985-1987, n=121). All classes of polar bears were detected in historical harvest areas of low- to high-risk in greater proportion than expected from available area during the harvest period (January to ice break-up), and all but solitary adult females had >50% of locations in the risk areas. Subadult males were proportionally more often inside risk areas, yet were not observed in the high-risk areas. Other classes were observed <1% of the time in high-risk areas, yet still proportionally greater than expected from available area. Landfast ice has declined in the pre-melt (January-March) and end-of-harvest (June-July) seasons (1980-2021), with the rate of decline being greater in lower-risk areas (p≤0.05). With sea ice predicted to decline into the future, we suggest that polar bears in the Beaufort Sea may become more concentrated into areas of higher harvest risk.