GN polar bear survey highlights benefits of non-invasive research methods: NTI
"Inuit have a problem with handling so many bears in such an invasive manner”
In the scientific world, researchers say most of what is known about polar bears was learned through handling and sampling the animals.
But Nunavut Tunngavik Inc. commended the Government of Nunavut this past week for what usng what it called a non-invasive approach to monitoring polar bears in western Hudson Bay.
NTI, which has spoken in support of that latest aerial survey, wants like to see the end of all invasive methods of research on animals like polar bears.
“Inuit are not against science — they want to know what’s going on,” said Gabriel Nirlungayuk, NTI’s director of wildlife. “But they don’t like invasive science.”
The recent survey of polar bears in the Davis Strait used “mark-recapture” methods, involving the tranquilizing of more than 1,800 polar bears with darts shot from helicopters, Nirlungayuk said.
Once the polar bears were immobilized, researchers on the ground took teeth and blood samples, attached ear tags, tattooed six-digit numbers into the bears’ lips and collared some females.
“When you’re looking at 1,800 bears, do you need to drug all 1,800 of them,” Nirlungayuk said. “At what minimum do you need to get a good sample? Inuit have a problem with handling so many bears in such an invasive manner.”
An 2008 study led by the University of Saskatchewan, which looked at Canadian grizzlies and American black bears, suggests that the handling of animals could affect them for weeks or more.
That study found that the majority of captured bears showed muscle injury, while bears that had been captured multiple times showed weight loss.
And the study found that in general bears moved less through their territory in the weeks following their capture.
But the GN’s latest polar bear count for the western Hudson Bay, conducted last August. used a hands-off method to collect its population estimates.
Flying in planes and helicopters at an altitude of 400 feet, surveyors covered 8,000 kilometres along the western Hudson Bay, relying on a method called “sight-resight distance sampling.”
The approach has two elements: the “distance sampling” refers to the number of wildlife spotted from the aircraft and the distance between the spotter and the animal, and then making corrections for missed animals
The “sight-resight” part involves two pairs of observers who work separately from each other in the aircraft, counting the wildlife they see from left to right without communicating with each other, and comparing their findings afterwards.
While this method has been used to conduct wildlife surveys all over the world for some time, the approach has only been used for a short time on Nunavut’s polar bears, said biologist Stephen Atkinson, who works with the GN.
The GN has been developing the method with researchers from the University of Minnesota since 2008.
And it works well on flat terrain, Atkinson said.
Sight-resight distance monitoring was conducted successfully in test surveys of the Foxe Basin polar bear population in 2009, he said, but worked less well in later surveys in the more mountainous Baffin Bay region.