Canada is being forced to explain its polar bear policies to an international environmental watchdog.

The Commission on Environmental Co-operation, which is part of the North American Free Trade Agreement, has accepted a petition from a U.S.-based group that says Canada isn't following its own laws on protecting the bears.

In accepting the petition, the commission has found that the Center for Biological Diversity has registered a legitimate concern under the terms of the treaty.

"The commission found that we had a sufficient allegation and provided sufficient documentation of the violation that we can move forward in this process," Sarah Uhlemann, a lawyer with the center, said Friday.

The petition, filed in November 2011, alleges that Canadian officials ignored the most recent science on climate change and the loss of Arctic sea ice when they ruled last year against changing the status of the bear from "special concern" to "threatened," which would rule out hunting.

It also says that the Tory government had already broken its own laws by being more than three years late in filing a mandatory management plan for the Arctic predators. The petition concludes by suggesting that hunting quotas for the bears set by Inuit co-management boards are unsustainable for some populations.

Uhlemann said Canada's most recent scientific assessment of bear populations minimized the impact of ice loss. The bears use sea ice as a hunting platform for seals, their primary food.

"They really didn't address the effect of climate change, which is the biggest threat to this Arctic species."

The U.S. listed polar bears as threatened in 2008, leaning heavily on a 2007 study that predicted the loss of sea ice could reduce bear numbers by two-thirds by 2050.

"The (Canadian) analysis dismissed this study as preliminary," Uhlemann said.

"It's not. In 2010, the same study was published in Nature magazine, which is one of the world's pre-eminent scientific journals."

Polar bear expert Andrew Derocher at the University of Alberta said Canada's assessment downplayed the impact of sea ice.

"Every polar bear scientist in Canada knew it was a flawed report from the outset," he said.

"They were told it was flawed and they chose to ignore the advice. The only position that Canada can really take now would be to do a new status assessment."

Adam Sweet, a spokesman for Environment Canada, said federal scientists conduct regular polar bear research and the government is currently developing a management plan for the animals, as required by legislation. Responsibility for management is shared by provinces, territories and regional wildlife management boards and a request for a new assessment would also have to involve those groups.

"We will be delivering a clear and timely response that illustrates how Canada has effectively enforced the Species at Risk Act with regards to the listing of polar bear," Sweet said in an email.

The International Union for the Conservation of Nature, one of the world's largest scientific groups, has listed polar bears as "vulnerable," roughly equivalent to Canada's "threatened" status.

Bear numbers have always been controversial.

The union's Polar Bear Specialist Group says there are between 20,000 and 25,000 bears in the world in 19 different population groups. Eight of those groups are declining, three are stable and one is increasing. The fate of the other seven is unknown.

However, Inuit maintain bear numbers are healthy despite the roughly 500 that are hunted every year.

Earlier this week, the mayor of Hall Beach told northern media that bear sightings are a near-daily occurrence in his Nunavut hamlet and that hunters have already used up their quota. A Nunavut government survey this year suggested that bears in the western Hudson Bay region — thought to be one of the most endangered populations — were actually healthy, after which the territory nearly tripled the region's quota.

Environmentalists say sightings are increasing because the bears are hungry and are lured by the smell of human habitation. They point out Inuit act as guides for sport hunters and sell the bear hides.

Inuit say their traditional hunting way of life is becoming collateral damage in a debate that's really about climate change.

Canada has until Jan. 23 to respond to the commission. After that, the body must decide whether to start an investigation, known as a factual record.

It's not the first international attempt to shut down Canada's polar bear hunt.

In 2010, the Convention on International Trade in Endangered Species refused a request from the U.S. to list polar bear skins in the same banned category as elephant ivory. The group ruled that climate change, not hunting, was the real threat.

In October, the U.S. repeated its request. There has been no ruling yet.

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  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear plays with a bush on the tundra while waiting for the Hudson Bay to freeze 14 November 2007 outside Churchill, Manitoba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, to hunt for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear plays with a bush on the tundra while waiting for the Hudson Bay to freeze 14 November 2007 outside Churchill, Manitoba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, to hunt for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear plays with a bush on the tundra while waiting for the Hudson Bay to freeze 14 November 2007 outside Churchill, Manitoba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, to hunt for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear plays with a bush on the tundra while waiting for the Hudson Bay to freeze 14 November 2007 outside Churchill, Manitoba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, to hunt for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • Taiga

    Polar bear cub Taiga shakes water off her head as she plays in a pool Friday, Nov. 25, 2011 at Aquarium Park in Quebec City, Canada. (AP Photo/The Canadian Press, Jacques Boissinot)

  • Taiga

    A polar bear cub named Taiga plays in a pool Friday, Nov. 25, 2011, at Aquarium Park in Quebec City, Canada. Taiga was transferred from the Saint-Felicien zoo on Nov. 16, 2011 and will be officially introduced to the public in a few day.(AP Photo/The Canadian Press, Jacques Boissinot)

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear looks up as the sound of the camera catches his ear on the edge of Hudson Bay aheasd of the full freeze-over 14 November 2007 outside Churchill, Mantioba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, where they remain hunting for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • A Polar Bear walks on part of a frozen l

    A Polar Bear walks on part of a frozen lake migrating North 14 November 2007 as Hudson Bay freezes outside Churchill, Manitoba, Canada. Thousands of Polar Bears return to the Canadian icepack to hunt for seals every year at this time and remain on the frozen area until the spring thaw. AFP Photo/Paul J. Richards

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A mother Polar Bear and her cubs wait on the tundra for the Hudson Bay to freeze 14 November 2007 outside Churchill, Manitoba, Canada. Polar Bears return to Churchill, the Polar Bear capital of the world, to hunt for seals on the icepack every year at this time and remain on the icepack feeding on seals until the Spring thaw. AFP Photo/Paul J. Richards

  • A polar bear mother and her two cubs walk along the shore of Hudson Bay near Churchill, Man. in this Wednesday Nov. 7, 2007 photo. They're etched onto canadian coins, are part of Canada's national identity and lure tourists to the Arctic every year, but the majestic Canadian polar bear could pose a significant risk to northern communities if climate change continues to wreak havoc on its natural habitat. (AP Photo/The Canadian Press - Jonathan Hayward)

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear walks on the edge of Hudson Bay ahead of the full freeze-over 14 November 2007 outside Churchill, Mantioba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, where they remain hunting for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear walks on the frozen tundra on the edge of Hudson Bay waiting for the Hudson Bay to freeze-over 14 November 2007 outside Churchill, Mantioba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, where they remain hunting for seals on the icepack until the Spring thaw. AFP Photo/Paul J. Richards

  • A mother polar bear and her cubs sleep o

    A mother polar bear and her cubs sleep on the tundra on the edge of the Hudson Bay waiting for the bay to freeze over, 13 November 2007, outside Churchill, Mantioba, Canada. Polar bears return to Churchill, the polar bear capital of the world, to hunt for seals on the icepack every year at this time and remain on the icepack feeding on seals until the spring thaw. AFP PHOTO/Paul J. Richards

  • Polar Bears Begin Seal Hunting On Frozen Icepacks In Northern Canada

    A Polar Bear walks on the frozen tundra waiting for the Hudson Bay to freeze-over 14 November 2007 outside Churchill, Mantioba, Canada. Polar Bears return every year to Churchill, the Polar Bear capital of the world, to hunt for seals on the icepack where they remain until the Spring thaw. AFP Photo/Paul J. Richards

  • TO GO WITH STORY by Paul Richards, Canad

    TO GO WITH STORY by Paul Richards, Canada-climate-warming-wildlife-polarbears A mother Polar Bear rests on the frozen tundra with her cubs waiting for the Hudson Bay to freeze over 13 November 2007 outside Churchill, Mantioba, Canada. Polar bears in Canada's Hudson Bay area are battling for survival, as climate change reduces the time they can hunt for food, warn environmentalists and locals in Churchill, the self-proclaimed polar capital of the world. AFP Photo/Paul J. Richards