evidence: Since the start of the continuous satellite record in 1979, Arctic sea ice has declined in all seasons, particularly in summer. However, sea ice has not declined the same way in all places, and polar bear populations have experienced different fates in different parts of the Arctic. In October 2019, the International Union for Conservation of Nature/Species Survival Commission-Polar Bear Specialist Group (IUCN/SSC-PBSG) released an assessment of 19 polar bear subpopulations across the Arctic. The subpopulations are divided based on management needs and what biologists know about the movement and genetics of the bears. Although the researchers could not determine population health everywhere, they found declines in four subpopulations, stability in five, and an increase in two. Although the study found a relationship between sea ice conditions and polar bear health, that relationship was not necessarily straightforward. In Hudson Bay, for example, female bear survival correlated strongly with sea ice conditions, but male survival correlated primarily with subsistence-hunting pressure from humans. Other factors could complicate the ice-bear relationship, such as the width of the continental shelf, the preferred habitat of seals (polar bears' main food source). In places where the continental shelf is narrow, such as the Beaufort Sea, poor sea ice conditions could exacerbate polar bears' difficulties in catching prey. Still, the study found greater population declines in areas with a higher number of reduced-ice days, such as the Beaufort Sea.