Declining muskrats in the delta: Low water levels and otters may be a cause, biologist says

When Dougie Joe of Inuvik, N.W.T., was growing up, his aunts, uncles and mother always told him to watch carefully as he cleaned out his hunted muskrats.

"Like watch for pus on the liver, and theremay be tumours in the stomachs or the guts. To watch for when they're going to start decline in numbers," said Joe.

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Today, Joe says that it's been 15 years sincehe first started seeing a "steep decline" in muskrats, without the population rebounding.

"The main thing we've been hearing over and over for several years now is that the muskrats are really depleted," said Chanda Brietzke, a biologist from the University of Victoria researching muskrats in the territory's Mackenzie Delta region.

Since 2013, she's made several tripsto the delta to conduct aerial and ground surveys,live trapping and collecting muskrat carcasses for examination.

Brietzke's interviews with local trappers have revealed a perplexing situation that'sleaving even longtime trappers confused.

"They've declined, and we don't know why they're declining. Something is happening," said Danny C. Gordon of Aklavik to Brietzke.

"The last number of years, it's disappeared. Like you know. Just gone, like. I don't see muskrat, there's nothing," Fred Koe, a Gwich'in trapper from Fort McPherson, told Brietzke.

Why it matters

"It matters to people because muskrats have been and continue to be an important part of living that lifestyle out on the land, and they're an important food for many people," said Brietzke.

"I'm a trapper. I grew up in a bush, and frankly I just love being out there," said Joe who works with Brietzke as a traditional knowledge advisor, guiding her to locations where muskrats are usually found.

"That's what I grew up doing, so [it's] kind of a really important fur-bearing animal to me."

"People love muskrat. I love muskrat," said Brietzke. "They wish they could be harvesting more, they wish they could be on the land, but the muskrats aren't there."

Theories from otters to low water levels

Environmental change is one theory.

"A lot of those lakes where my dad used to trap, I go to them nowadays, a lot of them are still good but other ones are totally drained out," said Joe.

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Brietzke said water levels in many lakes are declining, which may affect the population.

She also said thatother animal populations have increased, such as beavers and otters.

"As far as otters go, they're really, really voracious predators of the muskrat. So as their populations increase, we'd expect that they are probably taking out a lot of muskrat," she said.

Brietzke said it's still too early for any concrete answers, though she hopes to present some results from her research in January.

"We still haven't answered the question of 'What's going on?' so we're just continuing to kind of get at that from as many angles as we can."