Scientists pleased with results of aerial polar bear survey

The Government of Nunavut may use aerial surveys to count polar bears instead of more intrusive techniques of counting populations which require the drugging and handling of the animals. (PHOTO BY JANE GEORGE)

The numbers aren’t in, but the first impressions of a population survey of the polar bears of Foxe Basin are promising.

Not only did researchers count a lot of bears, but they did it by an aerial survey, a method which may replace the standard mark-and-recapture method so unpopular with Inuit in the communities.

“We need to address the concerns that Inuit have and that’s what we’re trying to do,” said Drikus Gissing, director of wildlife for the Nunavut’s department of Environment.

The flat terrain of Foxe Basin meant that a reasonably accurate count could be done by air, without tranquilizing and handling the bears, Gissing explained.

The Department of Environment carried out aerial surveys in Foxe Basin in 2009 and 2010 after a 2008 pilot study, all in September when the bears are easily found along the coastlines.

“There’s never really been a population survey of Foxe Basin,” Gissing said.

The department did the survey twice by air so researchers could compare the results from two years and see if the method could produce reliable data.

“There’s a lot of resistance in the scientific field to aerial surveys,” Gissing said.

What the surveys uncovered was hopeful – islands spotted with high concentrations of bears, with over a thousand in total spotted in each aerial survey, potentially indicating a stable or increasing population.

“A lot of the females had two or three cubs,” said Gissing.

But a straight aerial survey is not as reliable as mark-and-recapture, when researchers shoot bears with tranquilizers, tag them, and then return every year for three years to mark more and count the proportion of bears with older tags.

Such research has always met with opposition from Inuit who object to the stress which the bears experience when they are drugged and handled. Inuit also fear the health impacts of eating meat from a bear that had been drugged.

If an aerial survey gives a population estimate of 1,000 to 2,000 bears, a mark-recapture study would have a narrower range of numbers such as 1,500 to 1,800.

That means that when the Department of Environment makes its recommendations on a hunting quota for the Foxe Basin bears, it will be lower than it would have been if the survey had been conducted by the mark-recapture method.

“That’s going to be a challenge selling that,” Gissing admitted. “But that’s what they need to accept as well. If they want us to not handle bears, they will have to accept a more conservative TAH [total allowable harvest].”

Also, aerial surveys won’t help researchers estimate population growth the way mark-recapture can.

Aerial surveys are needed every five years instead of three consecutive seasons of mark-recapture every 15 years, which would be the ideal schedule, Gissing explained.

As it stands now, Nunavut is way behind on its surveys of the different polar bear populations, especially for the populations of the Gulf of Boothia, McClintock Channel and Lancaster Sound.

And Inuit often complain that scientists are using out-of-date field studies when coming up with new population estimates.

Most recently, hunters and Inuit organizations criticized the Government of Nunavut when it slashed polar bear quotas in Western Hudson Bay and Baffin Bay.

For that reason, the polar bears in those two regions will get full-scale population surveys in 2011, although the methods to be used haven’t been set yet.

The department did carry out an aerial survey pilot project on the Western Hudson Bay population in September 2010, but researchers are more concerned about the data’s reliability.

Polar bears in the summer are known to dig dens in riverbanks within the tree line when it is too hot, evading the eyes of airborne watchers.

On the other hand, aerial survey data there can be measured against the mountains of ecological data that federal scientists based in Churchill, Manitoba have been colleting for decades.

As for Baffin Bay, the rugged terrain may make a September aerial survey ineffective.

Gissing said the department is considering doing an aerial survey in the spring while the bears are out on the sea ice, but unreliable weather conditions could interfere at that time of year.

The department did a limited aerial survey pilot around Qikiqtarjuaq last spring, and the data is still under analysis to see if the method holds up to scientific scrutiny.