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Fisher

Photo of a Pacific fisher by the USFWS

Scientific name: Pekania pennanti

Status: Proposed Threatened

Listing: The west coast population of the fisher was accorded federal candidate status in April 2004. In 2013, USFWS initiated a status review to assess whether listing of the west coast distinct population segment of fisher was still warranted. On April 14, 2016, the USFWS issued its finding that the fisher does not require the protection of the Endangered Species Act.

The state of Oregon lists the fisher as a sensitive species in the critical category.  It is also listed as a protected non-game species.

In Oregon, the west coast distinct population includes the Oregon Cascades west to the coast.  

Potential Range Map

  • Historic Status and Current Trends

    Fishers, found only in North America, occur in the northern coniferous and the mixed forests of Canada and the northern United States. Their range extends from the mountainous areas in the southern Yukon and Labrador Provinces southward to central California and Wyoming, the Great Lakes and Appalachian regions, and New England.

    In Oregon, fishers occurred historically throughout the Coastal and Cascade mountains. Currently, the range of the fisher is severely reduced. Despite extensive surveys conducted in forested regions of Oregon, records dating from 1954 to 2001 show that the remaining populations of fishers are restricted to two separate and genetically isolated populations in southwestern Oregon; one in the northern Siskiyou Mountains and one in the southern Cascade Range. The population in the southern Cascades descended from reintroduced fishers that were translocated to Oregon from British Columbia and Minnesota.

    Description and Life History

    The fisher, a member of the weasel family (Mustelidae), has a long body, short legs and a long, bushy tail. The head is broad and flat with a sharp, pronounced muzzle. The ears are broad, rounded, and low. Fur color varies from light brown to dark blackish brown, although the face, neck, and shoulders may have a lighter grizzled gray appearance. Often there are irregular white patches on the chest and underside. Fur length ranges from 30 millimeters (about 1 inch) on the stomach and chest to 70 millimeters (about 2.75 inches) on the back. Adults range in length from 90 to 120 centimeters (about 2.5 to 4 feet). Males weigh 3 to 6 kilograms (about 7 to 13 pounds); females weight 1.5 to 2.5 kilograms (about 3 to 5.5 pounds). Large feet, with 5 toes on all 4 feet and retractable claws, enable fishers to rotate their hind paws almost 180 degrees, allowing them to run down trees head first like a squirrel. Central pads on the hind paws have circular patches of coarse hair which are associated with plantar glands. These glands produce a distinctive odor believed to be used for communication during reproduction. It is estimated that fishers live up to 10 years. They are solitary animals except during the breeding season (late February through April).

    Fishers are opportunistic predators that hunt exclusively in forested habitats where prey is abundant and vulnerable to capture. Their diverse diet includes birds, porcupines, snowshoe hare, squirrels, mice, shrews, voles, reptiles, insects, carrion, vegetation, and fruit. Their name is misleading since fishers do not actually catch fish. The name may have come from early European settlers who noted the fisher's similarity to the European polecat which was variously known as a fitchet or fitchew.

    Habitat

    Fishers are associated with forests having moderate to dense forest canopy and complex structure (for example, large amounts of coarse down wood, moderate shrub cover, dead trees and trees with decay elements, and a component of hardwood trees). The physical structure of this type of forest provides the fisher with reduced vulnerability to predation and an abundance of prey. The distribution of the fisher is likely limited by elevation and snow depth.

    Reasons for Decline

    The west coast population of the fisher is at risk mainly because of loss and fragmentation of habitat due to timber harvest, roads, urban development, recreation, and wildfires. Other threats include small population sizes and isolation, predation, and human-caused mortality from vehicle collisions, poaching, and incidental capture and injury.

    Conservation Measures

    Between 2008 and 2010, the National Park Service reintroduced nearly 100 fishers into Olympic National Park from populations in nearby British Columbia.  Fishers are also being reintroduced onto private timber company lands in the northern Sierra Nevada range of California in an effort to reestablish fisher into their historic range.

    We are encouraging state and federal agencies who are proposing activities within the historic range of the fisher to give consideration to the fisher during the environmental planning process, especially activities which alter or destroy mature and old growth forests, as well as other biologically complex forests.

    References and Links

    Aubry, K. B., Lewis, J. C. 2003. Extirpation and reintroduction of the fisher (Martes pennanti) in Oregon: implications for their conservation in the Pacific states. Biological Conservation 114 (1):79-90.

    Powell, R.A. and W.J. Zielinski. 1994. Fisher. In: Ruggiero, L. F, Aubry, K B, Buskirk, SW, Lyon L.J., and Zielinski, W. J. eds. American marten, fisher, lynx, and wolverine. Gen. Tech. Rep. RM-254. Fort Collins, CO. Rocky Mountain Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture; 184 p.

    U.S. Fish and Wildlife Service. 1996. Endangered and threatened wildlife and plants; 90-day finding for a petition of list the fisher in the western United States as threatened. FR 61:8016-8018.

    U.S. Fish and Wildlife Service. 2003. Endangered and threatened wildlife and plants; 90- day finding for a petition to list a distinct population segment of the fisher in its west coast range as endangered and to designate critical habitat. FR 68:41169-41174

    U.S. Fish and Wildlife Service. 2004. Endangered and Threatened Wildlife and Plants; 12-month Finding for a Petition to List the West Coast Distinct Population Segment of the Fisher (Martes pennanti). Portland,

    Washington Department of Fish and Wildlife Final Report 1998.

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