Inuit Skills, DNA Analysis Inform New Polar Bear Tracking Method

Biologists Peter V.C. de Groot and Peter Boag say their method of integrating the traditional knowledge of Inuit hunters with state-of-the-art genetic DNA analysis is cheaper and much easier on the bears than the current tracking practice, in which they are spotted from helicopters, tranquilized and marked.

"The data from current aerial monitoring methods may be becoming less accurate with increased sea ice changes caused by global warming, and we need a more sensitive tool to monitor Canada's bear populations," says Dr. de Groot.

"This method, along with others being evaluated, should allow us to annually survey all of the country's polar bears, non-intrusively, with Inuit involvement, at a fraction of the current cost," he said.

The Queen's researchers are using a multi-phased approach to create a clearer picture of the polar bear population.

Polar bear hair is caught in traps and the number and sex of the animal is determined using DNA markers. (Photo by Peter V.C. de Groot)

First, a number of "hair traps," fenced enclosures baited with meat, will be set up about 15 kilometers (nine miles) apart across a 600 kilometer (370 mile) area.

Bits of hair left behind by the bears as they attempt to reach the meat are sent to Dr. Boag's lab, where the number and sex of the animals are determined using DNA markers.

At the same time, samples of bear feces are collected and genetically screened by collaborators at the Laboratory of Wildlife Diseases at the San Diego Zoo for the presence of disease-causing agents that may infect polar bears.

Polar bear footprints provide the other two elements of Dr. de Groot's tracking method.

As a testament to the strength of the Inuit ability to identify a bear's sex, age and size from its prints in the snow, some of the region's top hunters are allowing the reliability and accuracy of their diagnoses to be evaluated.

The hunters' assessments, complemented by an analysis of digital images of the footprints, will be combined with the results of the genetic data to map the bear population's age and sex distribution, diet, movement and mating patterns.

The Queen's team has received up to $500,000 from the federal Ministry of Indian and Northern Affairs to refurbish and upgrade research cabins in the McClintock Channel, west of Baffin Island, in prime polar bear habitat.

Polar bear feasting on a whale carcass, Baffin Island, Canada. (Photo by D.W. Baker)

The funding for this project is part of the Canadian government's integrated Northern Strategy that focuses on exercising Canada's Arctic sovereignty, protecting the North's environmental heritage, promoting social and economic development, and improving northern governance.

Local laborers will be employed to haul building materials hundreds of kilometers by skidoo, and set up the cabins. Coupled with ongoing polar bear surveys in which local residents set up the sampling stations and analyze tracks, this work is expected to provide an economic boost for the communities involved.

When the refurbished huts – each equipped with wind turbines, generators, heaters and 15 beds – are not being used for research, Inuit hunters may be able to bring in eco-tourists by skidoo to observe the bears in their natural habitat.

Polar bears across the Arctic are imperiled due to overharvesting and climate change, experts report. In McClintock Channel, 284 bears were counted in 2000.

The number of McClintock Channel polar bears is currently down by over 60 percent of historic levels due only to overharvesting, according to Andrew Derocher, Chair of the IUCN Species Survival Commission's Polar Bear Specialist Group.

Dr. Derocher is a polar bear scientist with the University of Alberta in Edmonton, Canada. "Some populations recovered as harvests were controlled, but have since declined due to climate-related effects," he says. "In Western Hudson Bay, previously sustainable harvests cannot be maintained as the reproductive and survival rates have declined due to changes in the sea ice."

"We can control harvests through management and these efforts are underway for several of the over-harvested populations," said Dr. Derocher. "So far, I have not seen any movement on serious consideration of reducing greenhouse gases in North America, or other countries with few exceptions. Climate warming is not under control and I do not see the management changes coming to effect the needed changes in climate change emissions."

There are currently 19 populations of polar bears in the Arctic - in Canada, Alaska, Russia, Norway and Greenland. Thirteen of these populations live wholly or partially in Canada, from the Ontario coast of Hudson Bay north to Ellesmere Island, Nunavut, and from the northern Yukon in the west to Labrador in the east.

Because population estimates are costly to obtain in the Arctic, census data is scarce for some polar bear populations. The current overall estimate is of 20,000 to 25,000 wild polar bears, with about 15,000 living in Canada.

Copyright Environment News Service (ENS) 2009. All rights reserved.