This document can be obtained for free from the Washington Department of Fish and Wildlife at this website:

http://www.wa.gov/wdfw/wlm/diversty/soc/status/fisher/fshrxsum.htm

This status report was prepared by the Washington Department of Fish and Wildlife, and was the basis for the current “endangered” status of the fisher under the Washington State endangered species act.

This document can be obtained for free from the Washington Department of Fish and Wildlife at this website:

http://www.wa.gov/wdfw/wlm/diversty/soc/status/fisher/fshrxsum.htm

Executive Summary (p. vii)

“Fishers historically occurred throughout much of the forested areas of Washington, though they were not particularly abundant. The fisher was over-trapped in the 19th and early 20th centuries. Trapping, predator and pest control programs, and loss and alteration of habitat combined to push the fisher to near extirpation. Despite protection from legal harvest for 64 years, the fisher has not recovered. The fisher population may have been kept from recovering by a combination of factors. These factors likely include: a reduction in quality and quantity of habitat due to development and logging; past predator and pest control programs; low inherent reproductive capacity of the species; and demographic and genetic effects of small population size.

Fisher biology is characterized by low population density and a low reproductive rate. They have large home ranges and generally avoid large openings, which suggests that viable populations would require large areas of relatively contiguous habitat. Throughout their range, fishers are generally associated with late-successional coniferous and mixed coniferous-deciduous forest. In western Washington, fishers may have been restricted by frequent soft snows or deep snow packs to elevations below 1800 m. Forests with high canopy closure, multiple canopies, shrubs, and that support a diverse prey base are most used. Large diameter trees, large snags, tree cavities, and logs are most often used for den and rest sites, and are an important component of suitable habitat.

Currently, the fisher is very rare in Washington. Infrequent sighting reports and incidental captures indicate that a small number may still be present. However, despite extensive surveys, no one has been able to confirm the existence of a population in the state. The lack of detections of fishers given the extensive carnivore surveys conducted since 1990, an average of less than four fisher sightings per year since 1980, and few incidental captures by trappers, all indicate that fishers are very rare in Washington and could become completely extirpated. We believe that any remaining fishers in Washington are unlikely to represent a viable population, and without a recovery program that includes reintroductions, the species is likely to be extirpated from the state.

For these reasons, the Department recommends that the fisher be listed as an endangered species in the state of Washington.”

Other noteworthy excerpts...

Distribution

"The fisher's range was reduced dramatically in the 1800s and early 1900s through overtrapping; alterations of forested habitats by logging, fire, and farming; and predator and pest control (Douglas and Strickland 1987, Powell 1993, Powell and Zielinski 1994). The combination of logging and trapping probably had the greatest impacts (Powell 1993)... Logging removed, altered, or fragmented most of the older forests used by the fisher (Powell 1993). Consequently, in the 1920s, 1930s and 1940s, many states and provinces closed fisher trapping seasons to protect remaining populations and allow the fisher to recover (Powell 1993). Legal protection and the regrowth of forests after 19th century farm abandonment allowed some populations in the Northeast to recover. Fishers were reintroduced in areas where trapping closures failed to allow fisher populations to recover (Berg 1982, Powell 1993, Strickland et al. 1982)." P. 2

Habitat Requirements

"Fishers use forests with a high percentage of canopy closure, abundant large woody debris, large snags and cavity trees, and understory vegetation (Buck et al. 1983, Arthur et al…). Good fisher habitat seems to have a high degree of diversity; multi-aged stands interspersed with small openings and containing wetland or riparian habitats which help support a diverse prey base may be ideal (Banci 1989). Coues (1877) and Seton (1929) noted that fishers seem to prefer forest near swamps, especially swamps in large timber. Riparian habitats are used extensively by fishers, especially as travel corridors and rest sites (Buck et al. 1983…)." Pp. 11-12

"Fishers tend to forage in coniferous forests when hunting for hares, and seek porcupines in hardwood and mixed forests. Powell (1994) hypothesized that fishers make brief but direct forays into hardwood stands to seek out porcupine dens so that little time is spent in this cover type. Standard use-versus-availability analyses may underestimate the importance of hardwood habitats because though the fisher spends little time there, the porcupines killed there may be an important food source (Powell 1994)." P. 12

"Maternal den trees are typically large. The smallest were reported by Paragi et al. (1996) in Maine, where den trees had a median dbh of 45cm …In California, Zielinski et al. (1995b) reported that mean dbh of den trees and snags was 98 cm…and Buck (1982) found a den in a 89 cm snag." P. 16
"Fishers use a variety of structures in live trees and snags for rest sites, including cavities, witches' brooms, mistletoe clumps, large lateral branches, squirrel and woodrat nests, stick nests, and forks. Large diameter trees are used most often (Table 3…). Fishers also use hollow logs, stumps, log and brush piles, root wads, ground and snow burrows, rock outcrops, and dense understory vegetation at rest sites (Buuck 1982…)." P. 16

Population Dynamics

"Where trapping of fishers for fur is permitted, it is typically the largest source of fisher mortality (Douglas and Strickland 1987). Fishers may also be killed by vehicles, predation, fighting, disease, infections, starvation, poisoning, accidents, and debilitation form porcupine quills (Strickland and Douglas 1984…)." P 18

Population Status

"By 1938, fishers on the Olympic Peninsula were largely restricted to the "wild and roadless portions of the Olympic Mountains" (Scheffer 1938)." P. 22
In Washington "sighting and trapping reports give no indication of recovery in recent decades. Most information on furbearing mammal populations is obtained through trapping data; but fisher seasons were closed in most of the western states before harvest records were kept." P. 22

"The fisher is, by all indications, extremely rare in Washington. These indicators include incidental captures in traps, sighting reports, and systematic surveys. This supports the premise that fishers have never recovered from over-trapping in the 1800s and early 1900s." p. 22

"Fishers are relatively easy to trap, and where they are present they occasionally get caught in traps set for other species, especially bobcat, marten, and coyote." P. 23

Habitat Status

"Short rotations can prevent the formation of large-diameter needed to produce cavity trees, snags, and logs that fishers use for dens sites (Cline et al. 1980, Mannan et al. 1980). Although young stands may support relatively high numbers of snowshoe hares, young managed forest supports lower numbers of some fisher prey, including squirrels and forest-floor small mammals (Buchanan et al. 1990…)." P. 27

Conservation Status

"The fisher is classified as a Protected Species and as a state Candidate species in Washington. Fisher trapping has been prohibited since 1933. The species was identifies by the Washington Department of Wildlife (WDFW) as a "species of concern" in 1978, and was considered a sensitive species by WDFW from 1985-1991. In 1991, a change in regulations established the status of "Sensitive" and outlined the procedure for adding species to that list. The species became a Candidate for listing as Sensitive, Threatened, or Endangered in 1991." P. 29

Conclusions and Recommendations

"The fisher was over-trapped in the 19th, and early 20th centuries. Trapping, indiscriminate poisoning during predator and pest control programs, and loss and alteration of habitat probably combined to push the fisher close to extirpation. Despite being protected from commercial harvest for 64 years, the fisher has not recovered. We believe that remaining fishers in Washington are unlikely to represent a viable population, and without recovery activities, the species is likely to be extirpated from the state. For these reasons the Department recommends that the fisher be listed as an endangered species in the state of Washington." P. 36