Polar Bear Population in Western Hudson Bay Halved Due to Shrinking Sea Ice

A new study links climate-driven sea ice loss to reduced hunting time, energy deficits, and declining survival rates for polar bears and their cubs.

Researchers from the University of Toronto Scarborough developed a bioenergetic model to analyze the impact of shrinking sea ice on polar bear populations in Western Hudson Bay.
The polar bear population in this region has declined by 50% since the 1980s, with adult females losing an average of 39kg and cubs 26kg in body mass over the last 37 years.
Shorter hunting seasons caused by earlier sea ice melt and later freeze force polar bears to fast on land, leading to energy deficits that reduce reproduction and cub survival.
Mothers are producing less milk for their cubs, resulting in smaller litter sizes and lower cub survival rates during their first fasting period.
The study warns that similar population declines could occur in other regions as Arctic warming, occurring four times faster than the global average, continues to reduce sea ice.