Wolf-sterilization helped herd swell
by CHUCK TOBIN in the Whitehorse Star
A wolf-sterilization program said to have been pioneered in the Yukon is
continuing to evolve, says territorial government biologist Michele
Oakley.
The program now involves the testing of a contraceptive vaccine which is
much quicker and much less disruptive for the wolves, she said. But it is
still too early to say with any certainty about the success of the
vaccine.
“We still rely on surgeries,” said the Kluane regional biologist, who does
the surgeries herself, as she is also a qualified wildlife veterinarian.
The sterilization program developed in the Yukon is being cited as a key
contributor to the growing success in the recovery of the Fortymile
caribou herd, which has more than doubled in size over the last seven
years to an estimated 46,000 animals.
The Fortymile herd was the centre of attention last week when it began
migrating east across the Yukon River north of Dawson City – for the first
time in 50 years.
The sterilization program is based on reducing wolf-pack sizes by
sterilizing the dominant male or female, or both, and then killing or relocating pups
and subordinate adults.
The intent is to reduce the amount of predation on caribou and moose, as
there would only be two mouths to feed instead of six or seven – or up to
16 in one case, while the dominant pair maintains its traditional hunting
territory.
Oakley said while there was some early sterilization work done in
Minnesota, the program was really pioneered in the Yukon by biologists
Rick Farnell and Bob Hayes, and field technician Al Baer.
“There is not doubt it works,” Oakley said in a recent interview. “It has
turned the Fortymile herd around, and its turning around the Aishihik
herd.”
Oakley called the work by Farnell, Hayes and Baer “ground-breaking.”
“Definitely, the people here that did this in the ’90s were the first
ones; they were real pioneers to get this going.”
Since the days of the early 1990s and the Yukon’s controversial
wolf-control program, it’s estimated the Aishihik caribou herd has more
than doubled from 600 or 700 to 1,600 animals.
And the current calf survival rate of 30 calves for every 100 cows is
keeping the herd growing. There has also been a significant increase in
the moose population, though rough estimates of calf survival over the
last three years showed numbers fewer than what is necessary for
population growth, said wildlife technician Lorne Larocque.
Larocque said it’s not wolf predation that is restraining growth, but the
spring-time weather.
The effects of the cold, wet and often snowy months of May can be seen
right through the caribou, moose and sheep populations, he said.
Larocque said it looks like the moose, however, are being hit a little
harder than the other populations.
“I think these guys like some warmer weather and green when they drop
their calves but they have not been getting it.”
But the wolf control program is continuing to achieve the desired effect,
and it’s gaining attention from other jurisdictions, Oakley said. British
Columbia, she said, is right now taking a look at it.
Oakley said if the contraceptive vaccine is proven to work, it will be a
significant advance to the program because all it requires is a poke with
needle, rather than tranquilizing the wolf and performing surgeries.
While the necessary surgery on males can be done in the field in about 15
minutes, the required surgery to sterlize the dominant female is more
complex, and requires bringing the female into a facility where the work
can be done.
There has not been any lethal control of wolves in the Aishihik area since
1997, other than regular trapping, but Oakley is continuing to maintain
the sterilization work.
One of the concerns from the outset of the program was whether a dominant
pair could defend its traditional territory against encroachment by other
wolves.
But in both the Yukon and Alaska, the dominant pairs are maintaining their
traditional territories.
And not only that, said Oakley, but it appears they’re living longer, and
that may be because they don’t have any offspring to care for; no pups to
hunt and provide for.
“It’s the DINK principle,” she chuckled. “Double income, and no kids.
“It’s hard on a female that has a litter, and nurses it and still looks
after themselves.”
In Alaska, the wolf-control program involved the relocation of over 100
wolves from 15 packs that occupied critical habitat of the Fortymile herd.
The largest pack was made up of 16 wolves. Of the 15 packs, 13 sterilized
pairs are still together and maintaining their traditional territories.
It was once believed that the Fortymile herd numbered 500,000 caribou, and
the range extended from central Alaska to Lake Laberge.
Its numbers fell to a low of about 5,000 animals by 1975, and
over-harvesting by hunters with easy access to the herd’s range was said to be a key
factor.
If everything remains equal, biologists on both sides of the border
believe the herd can again double to more than 90,000 animals within the
next decade.
While it’s not uncommon to have pockets of the herd numbering in the
thousands to wander into the Yukon, they have never traversed in the numbers that
have forced them across the Yukon River in 40 years.
Gerry Couture is a senior veteran member of the Yukon Fish and Wildlife
Management Board. He believes Yukoners must come to know and appreciate
the growing success in recovering the Fortymile caribou herd.
The return of the herd, said Couture, will have a remarkable and
immeasurable
impact on the Yukon’s central ecosystem, where it once played the dominant
role.
As the herd grows, it’s probably time for Yukoners to begin having the
discussions about how to manage it while it winters in the Yukon, and
management includes what harvest levels should be implemented.
Under an agreement between Alaska and the Yukon, a harvest level is
established based on the herd’s growth.
Under that formula, for instance, the allowable harvest on the Yukon side
for this year would have been 300-plus animals, though the Yukon
government continues to keep the harvest closed for non-aboriginal
resident hunters. And the Tr’ondek Hwech’in First Nation has asked its
membership to not hunt the herd.
“They are here now, and we have to do the things to make sure they keep
coming back.”
Couture said if everything remains equal, the herd could actually hit
80,000 to 90,000 strong in five years.
We are at the point, he said, where Yukoners need to ask themselves at
what point do we start hunting the herd, and to what extent should it be
reduced when and if a harvest begins?
“It’s time for us to start thinking about it.”