DNA helps rebuild fisher family tree

A few million years ago a very slender,

secretive, cat-like creature successfully claimed territory in

North America and lived in balance with other species.

Then, in a wink of time, the American

fisher became the most sought after furbearer of all time. In the

1800s, a trapper new to the Rocky Mountains could make a month’s

wages with the sale of one fisher pelt. During this time, Montana’s

native fishers were believed to have become extinct.

Fishers are of the mustelidae or weasel

family. They are dark brown to black, pointy faced, beady eyed and

sleek with a luxurious long, fluffy tail. However, few of us will

ever see one due to their solitary natures.

Fishers are specialists at hunting

porcupine, and also feed on snowshoe hare, other small mammals, and

on occasion insects, nuts, berries, mushrooms and even carrion.

A search for records of fishers trapped

or observed between 1930 and 1959 turned up nothing, said Ray

Vinkey, Montana Fish, Wildlife and Parks biologist in Philipsburg.

Officials concluded fishers were extirpated, that is they no longer

existed in Montana.”

That may sound like the end for

fishers, but in fact it was a new beginning.

Between 1959 and 1963, 78 fishers from

British Columbia and another 110 from Minnesota and Wisconsin were

released in various locations in Montana and Idaho to reestablish

the species, Vinkey said. In addition, from 1989 to 1991, 110

fisher from Minnesota and Wisconsin were introduced to the Cabinet

Mountains.

Vinkey’s graduate thesis completed in

2003 explored what happened to descendants of the 110 fisher

released in the Cabinet Mountains. At that time, Michael Schwartz,

with the Rocky Mountain Research Station in Missoula, was studying

fisher in central Idaho.

Looking back, this was the beginning of

a ground swell of interest in fisher, Vinkey said.

Vinkey found some, but not many, fisher

in the Cabinet Mountains. His work included DNA analysis of fisher

tissue samples supplied by Montana trappers and collaboration on a

research paper published in 2006. Trapping of the fisher continues

today with an annual quota of seven fisher.

Ray and his colleagues began to bring

in some fisher hair and tissue samples for DNA analysis that

contained a distinctive gene nonexistent in the source populations

provided to the Montana by British Columbia and mid-west states,

said Schwartz, now head of the DNA lab he helped establish at the

RMRS.

“We found fisher in north-central Idaho

exhibited this same gene,” he said.

The startling but logical conclusion

was that the gene came from native fishers, previously unknown to

exist.

The necessary proof that was needed

rested on locating a fisher from Montana or Idaho that lived well

before any introductions of fisher from other states. After a lot

of searching, Vinkey and Schwartz found a museum specimen at the

Harvard Museum of Comparative Zoology that was collected in 1896 in

the Northern Rockies. A DNA sample revealed the distinctive native

gene.

Today most native fishers are found

along the Idaho/Montana state line from Darby to Lookout Pass west

of St. Regis on the Montana Idaho border.

“Next we want to gather more precise

information about fisher, which we can do by using hair snares and

genetic analysis,” Vinkey said.

Today, a far-ranging, collaborative

study using DNA analysis to help estimate the distribution, number

and origin of fisher in Idaho and Montana is underway.

Collaborators include Montana Fish, Wildlife and Parks; Idaho Fish

and Game, Lolo National Forest and other national forests in Idaho

and Montana; the Coeur D’Alene Tribe; the Potlatch Lumber Company

in Idaho and others.