By Andrew Krueger, Forum News Service

ISLE ROYALE, Mich.. -- Researchers say it appears just three wolves remain on Isle Royale, down from nine a year ago and the fewest reported on the Lake Superior island since scientists started studying the population nearly 60 years ago.

Newsletter signup for email alerts

Michigan Technological University scientists released the results of their 57th annual winter survey on Friday -- the longest-running predator-prey study in the world. There have long been questions about the long-term survival of the island national park's wolf population, but the latest figures were "beyond my most pessimistic predictions" going into the survey, said researcher Rolf Peterson, a professor at Michigan Tech and co-leader of the study.

"There's now so few wolves left that they're virtually doomed," he said.

Peterson, who has worked on the study for more than 40 years, said researchers know one radio-collared wolf died last year on the island. As for the other five wolves that were there in 2014 but not this winter, they were not radio-collared -- so there's no way to know for sure what happened. Some may have died, and others may have crossed an ice bridge to the mainland late in the winter of 2013-14, after that season's survey was done.

The identity of the remaining wolves won't be verified until genetic testing is completed this year, but Peterson said researchers suspect they're an adult male and female about 4 to 5 years old -- nearing the end of the average lifespan of a wolf in the wild.

The third wolf appears to be a pup, perhaps 9 months old, and researchers said it shows signs of genetic defects -- perhaps an abnormal spine. Inbreeding among the small, isolated wolf population on Isle Royale -- and potential resulting physical deformities -- has been a concern for years.

That has prompted calls in past years by some observers -- including Peterson and study co-leader John Vucetich, an associate professor at Michigan Tech -- to consider a "genetic rescue" for the island's wolves by bringing in new wolves from outside the park.

A year ago park leaders opted against an emergency genetic rescue of wolves, saying they would instead conduct a long-term environmental review of the park's diminished wolf population.

Isle Royale National Park Superintendent Phyllis Green said Friday that plans for the review continue to move forward, and the results of the most winter recent survey won't affect that process. A decision to step in and alter the course of nature in the park isn't one to be taken lightly, she said.

Green said a review will look at the entire island ecosystem --  including but not limited to wolves -- and consider existing rules and regulations for the national park. There also needs to be an examination of whether a genetic rescue or other possible intervention would have a chance of succeeding, she said.

"To the best of our ability, we have to try to think through all the different scenarios that could play out," she said. Park staff and researchers need to identify the "best path forward" before moving ahead.

There's still apparently a breeding pair of wolves on the island, Green noted, and there's still a chance that outside wolves could wander over on their own across an ice bridge in winter from the North Shore of Lake Superior. Two wolves did just that in February, researchers said previously, though they stayed only a few days before returning to the mainland.

But even if park officials suddenly decided to allow outside wolves to be brought to the island,  Vucetich said in a news release Friday that with just three wolves left "there is now a good chance that it is too late to conduct genetic rescue."

Wolves are relatively new to the island, having crossed the ice in 1949. Their numbers reached a high of 50 in 1980.

The island's moose population, meanwhile, has grown steadily in recent years -- an average 22 percent increase in each of the past four years. About 1,250 moose now roam the island, up significantly from a low of 385 in 2007 but far from the peak of near 2,500 in the 1990s.

The wolves remaining on the island apparently killed just one moose last winter, researchers said -- the lowest number on record for the study.

Peterson said that if wolves are taken out of the equation, the moose population may grow to the point that it harms plant life on the island -- and then crashes, as it did in the 1990s.

"The study of what's left will continue," Peterson said of his research efforts. "But the wolves, I expect, won't last long. ... The future (on Isle Royale) would seem to be one without wolves, and moose without any predator to hold them in check. ...

"It's very sad that we've gotten to this point," he said. "It didn't have to be this way."