Tracking collars could affect the health of Nunavik caribou

Laval University biologists put a collar on a captured caribou in Northern Quebec in February 2013. (PHOTO COURTESY OF CARIBOU UNGAVA)

Tracking Arctic animals is no easy task — not even for the most skilled hunter.

For researchers based in southern universities and research facilities, it’s often radio transmitters embedded into collars, backpacks or ear tags that are used to study those animals’ habitat use, behaviour and survival.

But recent research by the Quebec program Caribou Ungava has found that collar weight may reduce survival among migratory caribou females — such as those found in Nunavik’s vulnerable George River and Leaf River herds.

“In the last two decades or so, most of the work on caribou has been done by satellite, because of their isolated location,” said Steeve Côté, a biology professor at Laval University and director of its Caribou Ungava research centre.

“Basically, the animal wears a collar that we can program to monitor its location every few minutes,” he said. “Some technology even allows us to reprogram from anywhere in the world.”

VHF collars, which have been used for several decades, emit radio pulses that allow operators to determine their location.

Satellite collars first emerged in the mid-1980s; the Quebec government was among the first to start using them in 1986 as part of a large caribou monitoring program in northern Quebec and Labrador.

Newer models include GPS-satellite-linked systems, which provide regular position updates accurate to about 30 feet.

But more advanced technology has generally required a heavier battery pack to function.

Researchers with Caribou Ungava studied the survival of female caribou with the George and Leaf Rivers herds fitted with 514-gram VHF collars, compared to the same type of caribou fitted with 1.63 kilogram (3.5 pound) satellite collars — more than three times heavier than the VHF technology.

Researchers looked at data gathered in the early 1990s, as well as in 2000.

During the study period, adult females from the George River herd equipped with the lighter VHF collars had a significantly higher survival rate than adult females equipped with heavier satellite collars.

Females with VHF collars had an average survival rate of 87 per cent while females with satellite collars had an average survival of 73 per cent.

The annual survival of adult females from the Leaf River herd was very high, although it did not differ depending on collar type.

“Everyone using any type of device should make sure it’s not interfering with the welfare of the animal,” Côté said.

“The problem is, you can only monitor the animals who are wearing collars, not the others.”

Previous studies have concluded that the acceptable weight of any sort of collar or tagging device is about three per cent of the animal’s body weight.

But Caribou Ungava’s findings are particularly important given the vulnerability of both George and Leaf River herds, whose populations have been on the decline over the last decade.

There are two messages that emerge from this, and other studies, Côté said.

“One thing it indicates that we should respect not having heavy collars — the technology is available,” he said.

Côté noted that since about 2000, caribou from the George River and Leaf River herds are no longer fitted with heavy collars. Modern satellite collars can weigh less than 500 grams.

“The second message is to reconsider all those studies we rely on from the 1980s and 1990s,” Côté said. “We still use this data a lot but we should be aware now that there might be impacts on survival.

“Everyone should look at the impacts of this data in their study. Otherwise, you’re not measuring the reality.”

Lighter tracking collars generally limit the amount of data researchers are able to gather, he said.

“But in the end, data is better if it’s unbiased,” he said. “And if we find an impact, we should be responsible for (negating) it.”

Radio transmitters: A heavy burden on migrating caribou? was presented to the ArcticNet conference in Halifax last winter.

The study, led by Laval University student Alexandre Rasiulis, falls under Caribou Ungava, a joint research program of the Quebec government, Laval University and the University of Sherbrooke.