OTTAWA - Canada must consider that different groupings of polar bears face vastly different threats as it decides whether or not to list the species as a threatened, the World Wildlife Federation says.
Dr. Peter Ewens, director of species conservation with the World Wildlife Fund Canada, said the current science which has led Canada to list the bears only as a species of concern is based on an analysis of all the bears and some of them are not currently at risk.
"It's not top notch science," Ewens said of the analysis conducted by the Committee on the Status of Endangered Wildlife in Canada.
Canada has 13 different subpopulations of polar bears and some of them are facing a far greater threat to survival than others, including the bears in Manitoba.
The WWF considers five of the 13 groups to be declining in population. Five are stable and the others don't have enough data for that to be determined.
There are an estimated 15,000 bears that make either a permanent or temporary home in Canada.
The United States classified the polar bear as a threatened species for the first time Wednesday. Canada's Environment Minister John Baird is expected to decide whether to follow suit this August, when he receives a completed scientific review of the bears' plight.
"I'm waiting to get the detailed information on all 13 sub-populations," said Baird.
Manitoba stepped up in February to list the species as threatened within Manitoba legislation. That designation added further protection to the bear's denning areas, which are mostly in Manitoba.
Manitoba's bears, which are shared with Nunavut, are part of the Western Hudson Bay grouping, and are one of three groupings of Canada's bears the WWF considers to be at very high risk of declining population.
Between 1984 and 2006, the Western Hudson Bay bear population dropped more than 20 per cent, and now stands at about 935. Scientists have also noted the bears are lighter and weaker than they have ever been.
"There has been a decline in the weight and body condition in every age group except that largest males," said Bill Watkins, wildlife biologist with Manitoba Conservation The Churchill bears summer in Manitoba and spend winters out hunting on the ice in Hudson Bay. But with climate change hiking temperatures in the arctic the ice in the bay is breaking up three weeks earlier each spring, cutting into the bear's hunting time.
When they are on mainland, the bears do not eat, instead living off their fat stores. Watkins said when they have three weeks less to eat, and three weeks longer to fast, it's no wonder the bears are found to be at least 10 kilograms lighter for every week extra they spend on mainland.
They lose about one kilogram for every day they don't eat.
It is affecting reproduction, with fewer triplet or twin cubs produced, and higher mortality rates among cubs.
And Watkins says, if three weeks earlier for the ice break up isn't disastrous, "what happens if hits four weeks or five weeks?" "There will come a point where the bears can't survive the fasting period on shore," he said.
mia.rabson@freepress.mb.ca
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