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Capturing bears for research can cause significant harm: study

The Canadian Press
Article online since August 19th 2008, 0:00

Wildlife biologists are sometimes harming the animals they study with commonly used research methods, says a new paper already causing heated debate in the scientific community.

Bears that are captured, examined and then released are left with lingering muscle damage and long-term weight loss that increases with the number of times they are caught, said Marc Cattet, a University of Saskatchewan biologist and veterinarian who is the lead author of the paper in the August edition of the Journal of Mammalogy.

"It's been a common misconception that the capture and handling of animals has short-term effects on animals but is unlikely to have any long-term effects," he said Tuesday.

Cattet used data from two different bear research projects - one in Alberta on grizzlies and one in North Carolina on black bears. Both projects used padded leg-hold snares, barrel traps and helicopter darting to capture bears and collect data on their health and movements.

Cattet and fellow researchers used that data to analyze the bears' blood for enzymes that are released by muscle damage during extreme exertion, struggle and stress.

About 70 per cent of the grizzlies captured by snares had higher than normal levels of such enzymes - in some cases up to 12 times higher. Levels were also high in nearly one in five of grizzlies darted from helicopters and in 14 per cent caught in barrel traps.

Black bears also had high muscle-damage enzyme levels in about two-thirds of those caught in snares and one-third of those trapped in barrels.

"We'd be damned sore if we were subjected to those kinds of procedures and if we had these levels of enzymes," Cattet said.

Stiff and sore, the bears move around their territory less. The study shows grizzly movement dropped almost in half and black bears roamed 25 per cent less, with the effects lasting for up to five weeks.

That disruption seems to have long-lasting consequences. The weight of a nine-year-old grizzly captured three times averaged 14 per cent lower than normal, an effect that increases with the number of captures.

Recapture is a common research method. About a third of the grizzlies in the study had been recaptured up to eight times.

The effects of weight loss may linger into the next generation. Research in polar bears suggests underweight sows deliver underweight cubs.

Although Cattet's research focused on bears, there's no reason to believe the findings wouldn't apply to other mammals commonly studied through capture and release, such as caribou, he said.

"We're all mammals. We're all built of the same materials. We function in the same way. It's a no-brainer."

Cattet points out that not only does capture-and-release harm animals, it distorts data scientists are in the field to collect.

"There's a good chance that what you're doing may actually affect your results."

However, capture-and-release is a standard and necessary study method because it's the only way to get certain information. It's deeply engrained in wildlife biology and Cattet said he's already experienced resistance to his conclusions.

"There will be people that will embrace it," he said. "On the other end of the spectrum, I think there's going to be some hostility, too.

"For some people, it's going to be perceived that this paper is a direct affront to their way of life and it's not going to be received well. I know from discussions over the past three to five years some people just don't want to hear it."

Even getting his paper published was a struggle, he said.

"In the review process there were some individuals that just didn't want it published."
Northern aboriginals have also raised concerns about wildlife research practices.

Last December, Nunavut Tunngavik Inc. - the group that oversees the Nunavut land claim - passed a unanimous resolution calling on the federal and territorial governments to stop all wildlife research that involves excessive handling of wildlife.

Response by Jessica Teel

Great article to share, thanks Brenden. This confirms what I have always suspected - that capturing animals for research negatively impacts the animal. This article doesn't mention the practice of extracting teeth from captured bears, which - duh, how could that not effect your feeding habits. It seems that in so many cases research is merely to satisfy human curiosity - and so much research never, ever helps the animal and is motivated by scientists wanting to gather data and publish papers on it. Given that any data that does not fit into game and fish policies is disregarded, you are left with damaged bears and only research that supports the status quo which means keep enough animals alive so we have some to shoot for fun. I for many years have thought that capture and relocation of "problem" bears contributes to the likelihood of bear aggression towards humans. I saw this play out in a fatal mauling in Canmore, Canada when I lived there. A benign bear that did not harm humans in close range was relocated twice, and then he mauled a jogger. Before the relocation he was not aggressive towards humans in the area.

The years of Denali wolf studies often had fatal consequences -so much so that their data had a statistical column devoted to fatalities caused as a result of darting the wolves. I hope researchers take seriously what this article has to say.

-Jessica Teel


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