Fish & Wildlife
пятница, марта 11, 2011
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 & 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."
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 & 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.