Hudson Bay polar bears in sharp population decline

An exhaustive survey of the world’s most southerly polar bears has found a significant drop in their numbers that scientists fear could be climate change finally taking its toll on a population whose health has long been in decline.

“If this trend is real and if it continues, I think we happened to have caught it just as it started to go over a cliff,” said Martyn Obbard, lead author of the paper that appeared this week in the journal Arctic Science.

Obbard looked at the southern Hudson Bay population, a group of polar bears that live on the southeastern shores of Hudson Bay and into James Bay. His co-authors include scientists from the governments of Ontario, Quebec and Nunavut, as well as the United States.

The study found that the number of those bears has declined about 17 per cent in the past five years, from 943 to 780.

Disturbingly, the number of yearlings also fell. Aerial surveyors said 12 per cent of the population were yearlings in 2011; that number has fallen to five per cent.

“Many adult females may still be producing litters, but they may be less successful in raising cubs,” the paper says.

A series of studies over the past few years has previously documented concerns about these bears.

They were getting smaller and skinnier as sea ice in the bays shrank, researchers found. By 2012, the local bears were already spending on average 30 days longer on land than they did in 1980, depriving them of their critical, fat-rich diet of seals.