Fisher

The Fisher (Martes pennanti) is a member of the WEASEL family, with a typically pointed face and rounded ears. The long and slender body of the fisher has a dense, dark brown to black fur coat with grizzled brown patterns around the shoulders and back, and a bushy tail. Females have finer, more lustrous fur than males. Legs are strong and short; paws have 5 digits. Body length ranges from 51 to 63 cm; tail, 33-38 cm. The male (2.7-5.4 kg) is almost twice as large as the female (1.4-3.2 kg). Fishers usually meander through the forest, or run in a typical 2 x 2 pattern where 2 sets of tracks, one slightly ahead of the other, is followed by another set of 2, and so on.

Distribution and Habitat
The fisher is found in boreal and temperate FORESTS of the Canadian provinces and territories, except Newfoundland and Prince Edward Island, north to latitude 60º. It prefers landscapes of mature and old coniferous and mixed-coniferous-deciduous forests interspersed with younger stands.

Food Habits
Fishers feed mainly on snowshoe hares, squirrels and small mammals. They are known for their ability to prey on porcupines.

Reproduction
Fishers are generally solitary except during mating season (March-April); they are polygamous. The gestation period is about 350 days because of delayed implantation of the fertilized egg in the uterus. Maternal dens are usually found in cavities of deciduous trees. Young (1-3) are born in March.

They are sexually mature by 1 year of age, but effective breeding may not occur before 2 years of age. Their life expectancy is about 10 years.

Conservation
Across Canada the fisher is classified as a furbearer, and is harvested over 65% of its range. Most populations are stable or increasing. In British Columbia, the fisher is a blue-listed species (ie, of special concern). Fisher populations are vulnerable to habitat loss through logging, fire, oil and natural gas exploration, and urban encroachment.

See also FUR TRAPPING.

Author GILBERT PROULX

Suggested Reading
Roger A. Powell, The Fisher: Life History, Ecology, and Behavior (1980, 2nd edition 1993); Daniel J. Harrison, Angela K. Fuller and Gilbert Proulx, editors, Martens and Fisher (Martes) in Human-altered Landscapes: An International Perspective (2004).

Links to Other Sites
Canadian Biodiversity Website
A great information source for all budding biologists. Learn about biodiversity theory, natural history, and conservation issues. From McGill’s Redpath Museum.