Biologists say wolves on Prince of Wales Island have a high level of inbreeding. It’s not an emergency, but it’s something that game managers are keeping their eyes on.
It’s rare for a new wolf to find its way to Prince of Wales Island and breed with a member of the local population. About one new arrival is expected every five years, which equals roughly one generation of wolves.
That’s according to a 2019 study by researchers at the University of Montana. Tom Schumacher is the regional supervisor for Game Management Unit 2, the area that includes Prince of Wales Island. He mentioned the study at a recent meeting with local trappers.
“It’s very rare for wolves from outside unit 2 to emigrate and join the breeding population in Unit 2,” Schumacher said. “And you can actually calculate a rate from genetics. And the rate that (the university) students calculated was about one individual per wolf generation — wolf generation being four to five years. So that means every four to five years, one individual from outside unit 2 moves into unit 2 and breeds with other wolves here and produces offspring.”
By itself, inbreeding in wolves isn’t a huge problem. Schumacher said it’s expected on an island. The problem is what happens when it gets out of control: something called inbreeding depression. That could translate to things like infertility or deformities.
A wolf pack in Michigan at the Isle Royale National Park is suffering from inbreeding depression. And, according to the study of the Prince of Wales Island wolves, the two packs share about the same level of inbreeding.
“When closely related animals breed together, there’s a greater likelihood of passing on unfavorable traits, because both the mother and the father have those traits,” Schumacher explained. “And if both parents have them, they’re more likely to be expressed in the offspring.”
Schumacher said biologists have seen this happen elsewhere, and the study out of Montana is a “red flag” for Prince of Wales Island. But it isn’t time to sound the alarm yet.
“It’s not an emergency,” he said. “But it raised a flag and says, ‘You know, you really need to look at this.’ We currently have a much larger dataset to look at.”
That’s because, as of last fall, the state’s Department of Fish and Game estimated that there are around 268 wolves on the island. That’s higher than the target population of somewhere between 150 and 200 animals.
There are other packs in the region that stick together, too. Packs around the units containing Ketchikan, Petersburg and Kupreanof Island are also highly inbred. These areas are included in game management units 1A, 1B and 3.
Wolves that dominate the area around the Stikine River, the upper Lynn Canal and Glacier Bay also have close connections.
“But they’re less inbred, (they) appear to be better connected to wolves outside the region,” Schumacher said.
For now, management of the wolves will remain the same.
The wolf harvest for Prince of Wales Island starts on Nov. 15 and will last 31 days.