University of Alberta researchers will no longer collar young polar bears, after a tracking collar was finally removed from a bear that gained notoriety a year ago for an image of its bloodied neck.

The photo, taken in Kaktovik, Alaska, led to worldwide concern for the bear's welfare. The male bear was collared years ago by U of A researchers studying polar bear movements within the southern Beaufort Sea. But as the bear grew, the collar did not fall off as it should have.

In a blog tracking sightings of the bear since March, the university confirmed it was captured on Aug. 22 in Alaska, close to a whale carcass. The bear was sedated and the collar was removed. The bear had "minor abrasions and localized skin irritation" as a result of the collar, the post said, but a veterinarian deemed the bear otherwise healthy.

The bear was released and there are no ongoing concerns about its well-being, biological sciences professor Andrew Derocher said.

The collar was placed on the bear "a number of years ago," when it was four years old, Derocher said. It was programmed to detach itself from the bear a year later.

The fact that the collar didn't come off was a technological failure. - Andrew Derocher, professor, University of Alberta

But the release mechanisms malfunctioned, and when the collar was finally removed it was found to have lost its transmission components so that only an inner band of material remained. Plastic washers were the only thing keeping the collar on the bear, as the aluminum nuts had fully corroded, Derocher said.

The manufacturer was notified of the defective collar.

"I suspected if this bear had pulled on this collar or another bear had pulled on it when they were wrestling or playing, it would have come off, but it just hadn't," Derocher said.

'I will not be collaring any young bears again'

Derocher said the bear was part of a joint study with U.S. wildlife officials tracking the movement of polar bears within the southern Beaufort Sea. The bears share territory between Alaska and Canada, Derocher said, and their population has declined by 25 to 50 per cent in recent years. Researchers were trying to learn how bears would move across the area in the event of an oil spill.

Putting tracking collars on bears is "pretty standard" across the five Arctic nations with polar bears, Derocher said. Between 700 to 1,000 polar bears have been collared in the circumpolar Arctic. Most are fully grown female bears. No bear has ever died as a result of being collared, he said.

But technological advances mean more ear tags are being used, Derocher said. The tags — about the size of a thumb — are also meant to fall off after a period of time.

"The technology has changed dramatically over the years," Derocher said. "We now have small ear-tag radios that we can use on bears like this to get the data that we need to manage the populations."

Derocher said the polar bear research program at the U of A is working toward less-invasive methods of monitoring the bears' movements over time.

"I will not be collaring any young bears again," he said. "The fact that the collar didn't come off was a technological failure. Of course, we don't expect our research animals to pay for that, but that's why we won't be doing it again."