Polar bears west of Hudson Bay in Canada, in the southern tip of the Arctic, continue to die in large numbers, according to a new government study of the terrestrial carnivore. Female bears and their cubs encounter the greatest difficulties.

Researchers surveyed the western Hudson Bay region by air in 2021 and estimated there were 618 bears, up from 842 in 2016 when the population was last surveyed.

“The actual decline is much larger than I expected,” said Andrew Derocher, a University of Alberta biology professor who has studied Hudson Bay polar bears for nearly four years. decades. Derocher did not participate in the study.

Since the 1980s, the number of bears in the area has been reduced by almost 50%, according to the researchers’ findings. The ice, essential to their survival, is disappearing.

Polar bears depend on Arctic sea ice, the surface of which shrinks in the summer with warmer temperatures and re-forms during the long winter. They use it for hunting, perching near holes in the thick ice to spot seals – their favorite food – as they take to the air. But with the Arctic warming twice as fast as the rest of the world due to climate change, sea ice is breaking up earlier than usual and taking longer to freeze by the end of the year.

This has left many polar bears living in the Arctic with less ice to live, hunt and breed.

Researchers say the concentration of young, female cub deaths in western Hudson Bay is alarming.

“These are the types of bears that we always predicted would be affected by environmental change,” said lead author Stephen Atkinson, who has studied polar bears for more than 30 years.

Young cubs need energy to grow and cannot survive for long periods without enough food, and bear cubs suffer because they spend a lot of energy caring for and raising their cubs.

“It certainly raises feasibility issues,” Derocher said. “It is the engine of reproduction of the population.”

The reproductive capacity of polar bears west of Hudson Bay will decline, Atkinson explained, “because there are simply fewer young bears that will survive to become adults.”

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