Endangered, threated gray wolf (Canis lupus)
The wolf population in Isle Royal National Park could go extinct in a few years, according to a recent study. Credit: John and Karen Hollingsworth, U.S. Fish and Wildlife Service. USFWS

Gray wolf populations in Michigan's Isle Royale National Park are at an all-time low and could go extinct within a few years, according to a recent study.

The Isle Royale wolf population peaked in 1979 when researchers counted 50 wolves, but the last count in 2012 included only nine wolves, according to a report released March 6 on the Isle Royale Research website.

The population is the lowest since the 1980s, when a disease outbreak reduced the number of wolves to 12. The population has fluctuated since 1979 and has been steadily declining since the 1990s. Researchers counted 24 wolves in Isle Royale National Park in 2009.

The wolves are at grave risk of extinction, John Vucetich, co-author of the report and a wildlife biologist at Michigan Technological University, in Houghton, Mich., told the Associated Press.

Researchers attributed the decline to a lack of females, which caused an increase of inbreeding and shrinkage of the gene pool. Only one female wolf remained in the latest count. A shortage of moose, the wolf's primary food source, also caused trouble for the population.

Hunting didn't play a role in the decrease, researchers said. Isle Royale is a federal wilderness area, protected from hunters.

It could be argued that this is the wolf's greatest refuge in the world, Rolf Peterson, co-author of the report and a wildlife biologist at Michigan Tech, told the AP. It's the only place they've never been killed by human beings.

Isle Royale is a small, isolated island unique because of the relationship between gray wolves and moose. Wolves are the only predator of the moose and the moose is almost the exclusive prey for wolves. Coupled with little human interaction, researchers are able to study predator-prey relationships unlike anywhere else, according to the report.

Moose first arrived on Isle Royale in the early 1900s and flourished, according to the report. No predators existed on the island until wolves crossed an ice bridge from Ontario, Canada to the island in the 1940s. Researchers began studying the populations in 1958.

The National Park Service shouldn't intervene to stop the wolf's decline, the report's authors wrote.

David Mech, a wolf expert with the U.S. Geological Survey, who wasn't involved in the study, told the AP that even with the small number of wolves, the population could last a decade and bring its numbers back up.

This is a really unique opportunity to see what they can do, he said. If there's any intervention, it destroys that potential.

But waiting until the current population dies out could make reintroducing wolves harder, Philip Hedrick, an Arizona State University conservation biologist not involved in the study, told the AP.

Having the wolf eliminated for some period of time may result in secondary effects that would make it difficult to re-establish a population, he said.

Gray wolves aren't endangered in the rest of the world, according to the National Wildlife Federation. The animal is found in a handful of spots in America, and is plentiful in Canada and parts of Asia.