Martes pennanti

The Fisher is a forest-loving predator that eats anything it can catch, usually small-to-medium-sized rodents, rabbits, hares, and birds. It also eats carrion. Fishers are among the few predators able to kill Porcupines. They do it by biting the face, where there are no quills, until the animal is too weak to prevent being rolled over and attacked in the soft underbelly. Fishers are active by day or night. They tend to be solitary and defend territories. They were once hunted for their lustrous, chocolate-brown fur, and the range of this species has been reduced greatly in the United States. They are still hunted in some places, but some states and provinces of Canada list the fisher as endangered, and the population has recovered from extreme lows in the last century.

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Mammal Species of the World
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Fishers are found only in North America, from the Sierra Nevada of California to the Appalachians of West Virginia and Virginia. They range along the Sierra Nevada to their southernmost extent and south along the Appalachian mountain chain. They do not occur in the prairie or southern regions of the United States. Populations have declined in the southern parts of their range in recent history.

Biogeographic Regions: nearctic (Native )

More info for the terms: cover, natural

According to reviews, the fisher occurs from southern Yukon and southwestern Northwest Territories southeast through British Columbia and possibly extreme southeastern Alaska, Alberta, Saskatchewan, Manitoba, Ontario, southern Quebec, and New Brunswick to Nova Scotia. Its distribution extends south through several forested areas of the northeastern United States including Maine, New Hampshire, Vermont, northern New York, Pennsylvania, western Massachusetts, the upper peninsula of Michigan, and northern Wisconsin and Minnesota. There is also a population in West Virginia. In the western United States, fisher populations are known to occur in western Montana, the Idaho panhandle [94,96,97], the southern Sierra Nevada of California, the Klamath and Siskiyou mountains of northwestern California and extreme southwestern Oregon, and the southern Cascade Range of southwestern Oregon [14,136]. The fisher may be extirpated from Washington [14,118]. For more detailed summaries of the fisher's historic and current distribution, see these sources: [94,96,97]. For a map of the fisher's current and historic distribution, search the National Museum of Natural History's Mammal Species of the World website for fisher.

The following lists are speculative. They are based on distribution information reported no earlier than 1993 and the habitat characteristics and species composition of communities fishers are known to occupy. There is not conclusive evidence that fishers occur in all the habitat types listed, and some community types may have been omitted, especially in areas where fishers have not been recently documented. In addition, the following cover types provide habitat of varying quality for fishers. See Preferred Habitat for more detail.

(key to state/province abbreviations)
UNITED STATES AK CA CT ID ME MA MI MN MT NH NY PA OR VT WI WY WV
CANADA AB BC MB NB NT NS ON QC SK YT

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This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):

BLM PHYSIOGRAPHIC REGIONS [25]:

1 Northern Pacific Border

2 Cascade Mountains

4 Sierra Mountains

8 Northern Rocky Mountains

Fishers range from Quebec, the Maritime Provinces, and New England west across boreal Canada to southeastern Alaska, south in the western mountains to Utah, Wyoming, Idaho, and California, and formerly south to Illinois, Indiana, Tennessee, and North Carolina. Large range in northern North America; extirpation from southern portion of range, due mainly to habitat loss, has been counteracted by recent natural and human-aided range expansions in the eastern U.S.; adequate population data are unavailable for much of the range, but the species currently is regarded as secure.

Fishers are found only in North America, from the Sierra Nevada of California to the Appalachians of West Virginia and Virginia. They range along the Sierra Nevada to their southernmost extent and south along the Appalachian mountain chain. They do not occur in the prairie or southern regions of the United States. Populations have declined in the southern parts of their range in recent history.

Biogeographic Regions: nearctic (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Fishers range from Quebec, the Maritime Provinces, and New England west across boreal Canada to southeastern Alaska, south in the western mountains to Utah, Wyoming, Idaho, and California, and formerly south to Illinois, Indiana, Tennessee, and North Carolina. Recently the species has expanded its range in the eastern United States, and it has been reintroduced in areas from which it was extirpated, including West Virginia, with some of the latter individuals wandering into Virginia (Handley 1991). The species is relatively abundant in the eastern provinces of Canada, with low populations in British Columbia (USFWS, Federal Register, 1 March 1996).

Male fishers are, on average, larger than females, with a body length of 900 to 1200 mm and a body weight of 3500 to 5000 grams. Females range from 750 to 950 mm in length and 2000 to 2500 grams in weight. Tail length of males is between 370 and 410 mm and tail length of females is between 310 and 360 mm. Their coats range from medium to dark brown, with gold to silver hair tips on their head and shoulders, and with black legs and tail. They may also have a cream chest patch of variable size and shape. Fur color and pattern varies among individuals, sexes and seasons. Fishers have five toes on their feet, and their claws can be drawn up into the paws, like a cat's.

Range mass: 2000 to 5000 g.

Range length: 750 to 1200 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Males fishers are, on average, larger than females, with a body length of 900 to 1200 mm and a body weight of 3500 to 5000 grams. Females range from 750 to 950 mm in length and 2000 to 2500 grams in weight. Tail length of males is between 370 and 410 mm and tail length of females is between 310 and 360 mm. Their coats range from medium to dark brown, with gold to silver hoariness on their head and shoulders, and with black legs and tail. They may also have a cream chest patch of variable size and shape. Fur color and pattern varies among individuals, sexes and seasons. Fishers have five toes on their feet, and their claws are retractable.

Range mass: 2000 to 5000 g.

Range length: 750 to 1200 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: male larger

Length: 103 cm

Weight: 8200 grams

Sexual Dimorphism: Males are larger than females.

Length:
Range: 900-1,200 mm males; 750-950 mm females

Weight:
Average: 3,500 g males; 2,000-2,500 g females

Fishers prefer coniferous forests, but they are also found in mixed and deciduous forests. They prefer habitats with thick canopies. They also prefer habitats with many hollow trees for dens. Trees typically found in fisher habitats include spruce, fir, white cedar and some hardwoods. Also, as would be expected, their habitat preference reflects that of their favored prey species.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: taiga ; forest ; mountains

More info for the terms: cover, density, hardwood, presence, selection, shrubs, succession

Fishers are associated with areas of high cover and structural complexity (see Cover Requirements) in large tracts (see Landscape/scale effects) of mature and old-growth forests. Other site characteristics that can be important include presence of nearby water, slope, elevation, and snow characteristics.

Much of the information regarding fisher habitat is based on occurrence of fishers compared to availability. It is important to note that preference does not necessarily equate to superior habitat [30]. As a measure of preference, time spent in available habitat assumes that individuals have equal access to available habitats, which is unlikely (review by [35]). In addition, Powell [95] describes the case where foraging techniques for various prey have different efficiencies, resulting in relatively less time spent in the habitat of the prey associated with the more efficient foraging technique.

Fishers generally avoid early and/or prefer late successional stages, but in some cases they use fairly young forests extensively. For example, in predominantly grand fir (Abies grandis) and subalpine fir (Abies lasiocarpa) forests of north-central Idaho, stands subjectively categorized as pole-sapling age or younger were rarely used in summer or winter. In summer, mature forest and old-growth were preferred, but in winter young grand fir forests were preferred [65]. In Douglas-fir, lodgepole pine, and hybrid white spruce forests of south-central British Columbia, early seral stands (<10 years) were used by transient fishers significantly (P<0.05) less than expected, and young (41-80 years) forests were used more than expected based on availability in the landscape [128]. In northwestern California, fishers were associated with old-growth Douglas-fir forest [106]. However, use of varying succession classes by fishers in conifer stands of northwestern Montana was in accordance with availability [108].

In some locations, fishers prefer areas near water. In a relatively hot and dry California study area comprised primarily of Sierra mixed conifer, ponderosa pine (Pinus ponderosa), red fir (Abies magnifica), and montane hardwood habitats, there were significantly (P<0.05) more resting sites (51.9%) than random sites (27.8%) within 330 feet (100 m) of water [137]. In coniferous forests of north-central Idaho, several factors demonstrated the fisher's preference for riparian areas. Summer fisher locations were significantly (P<0.0001) closer (223 feet (68.0 m)) to water than random sites (400 feet (121.9 m)). In addition, fishers preferred grand fir/arrowleaf ragwort (Abies grandis/Senecio triangularis) riparian habitat in both summer and winter [65]. Similarly, fisher rest sites in northwestern Connecticut occurred in forest wetland habitat significantly (P<0.05) more often than expected (17%) in both winter (39%) and summer (29%) [68].

In some areas, fishers prefer comparatively steep slopes. In a mixed-wood forest of central Alberta, the average slope of fisher locations (5.8°) was significantly (P=0.002) greater than the average slope of random locations (1.9°) [17]. The average slope at resting sites (49.8%) in 2 California study areas, one predominantly comprised of Douglas-fir, white fir (Abies concolor), Oregon white oak (Quercus garryana), and tanoak (Lithocarpus densiflorus) stands and the other primarily Sierran mixed conifer, ponderosa pine, red fir, and montane hardwoods habitats, was significantly (P<0.05) steeper than random sites (42.6%) [137]. In coniferous forests of north-central Idaho, level slopes and benches were used (38%) much less than expected based on availability (71%) [65].

Fishers occur in a wide range of elevations, but generally prefer relatively low-elevation sites. In Maine, fishers were studied in an area that ranged from 0 to 1,210 feet (0-370 m) in elevation [10]. In the southern Sierra Nevada, fishers have been reported as high as 8,000 feet (2,438 m) [26]. In 75-year-old, even-age hardwood, mixed, and coniferous forests of White Mountain National Forest and surrounding areas of New Hampshire, use of varying elevations differed significantly (P<0.01) from expected. Based on availability fishers were expected to occur on sites from 1,100 to 2,000 feet (329-607 m) in elevation 264.7 times, and were expected on sites above 2,000 feet (≥608 m) 197.3 times. However, they preferred the low sites, occurring 363 and 99 times on low and high sites, respectively [66]. West of the Cascade Range crest in Washington, 87% of sighting and trapping records from 1894 to 1991 were from <3,300 feet (1,000 m), and none were from elevations >5,900 feet (1,800 m). However, east of the crest 70% of records were from sites >3,300 feet (1,000 m) and 18% were from sites 5,900 to 7,200 feet (1,800-2,200 m) in elevation. [13].

Fishers are likely affected by snow characteristics such as depth and consistency. Ninety-nine percent of the area in California where fishers were detected but American martens (Martes americana) were not was in the <5-inch (<13 cm) average snowfall zone; 1% was in the 5- to 9-inch (13-23 cm) average snowfall zone; and none was in the >9-inch (>23 cm) average snowfall zone [71]. In the low boreal region of southeastern Manitoba, significantly (P<0.005) fewer fisher tracks were observed during midwinter, when deep, soft snow conditions prevailed. Method of travel was also affected by snow conditions, with fishers walking in midwinter instead of bounding or galloping, and traveling on snowshoe hare (Lepus americanus) and their own trails more than they did during the thin snow cover of early winter and the crust conditions of late winter [102]. In addition, the stronger selection for low elevations west of the Cascade crest compared to the east (see previous paragraph) could have been due to the rain shadow, resulting in less snow on the east side compared to similar elevations on the west side [13]. However, in predominantly grand fir and subalpine fir cover types of north-central Idaho, fishers did not appear influenced by snow characteristics. Use of various elevations did not change over the seasons, and fishers preferred young forests in winter: a rather open habitat with large amounts of deciduous shrubs [65]. In addition, in an area of northwestern Connecticut with maximum snow depths less than 10 inches (<25 cm), there was no evidence that snow affected the fisher's habitat preferences [68].

Home range/density: Fisher home range size and density exhibit substantial variation, although male home ranges are larger than those of females. Small average female home range sizes (1,300 acres (527.5 ha), n=8) occurred in the southern Sierra Nevada [138]. Home ranges in the hardwoods and mixed-woods of southern Quebec were also comparatively small, with female (n=7) home ranges averaging 5.4 km² and male (n=3) home ranges averaging 9.2 km². Based on these estimates fishers occurred at a density of 2.7 fishers/10 km², while estimates from tracking and radio-collaring resulted in density estimates of 3.0 fishers/10 km² [53]. In conifer and mixed forests of south-central Maine, the median home range was 12.2 km² for females (n=5) and 25.5 km² for males (n=6). Density estimates in this area were 1 fisher/2.8-10.5 km² in the summer and 1 fisher/8.3-20.0 km² in winter [11]. Male home ranges in 2 California study areas, one predominantly comprised of Douglas-fir, white fir, Oregon white oak, and tanoak stands and the other primarily Sierran mixed conifer, ponderosa pine, red fir, and montane hardwoods habitats, were significantly (P<0.0001) larger (9,700 acres (3,934.5 ha), n=6) than female home ranges (2,400 acres (980.5 ha), n=15) [138]. In conifer forests of Idaho, fishers had very large home ranges. Average "year-long" estimates of home range size were 40.8 km² and 82.6 km² for females and males, respectively [65]. Powell and Zielinski [97] provide a thorough review of home ranges throughout the fisher's distribution, including notes on the methods used for calculation.

Landscape/scale effects: Fishers require large, well-connected habitat patches. In addition to their large home ranges, fishers can apparently be excluded from nearby habitat by relatively small expanses, possibly as short as 6 to 12 miles (10-20 km), of unsuitable environment [12,16]. In Douglas-fir forests of northwestern California, fishers were sensitive to habitat fragmentation. Fishers were detected in 70% of stands where <10% of the perimeter was clearcut edge and in less than 20% of stands where >75% of the stand's perimeter was clearcut edge. Fisher detections decreased markedly in stands <250 acres (100 ha) in area [106]. In mixed-wood forest of central Alberta, fishers used continuous (> 2 km²) forest blocks significantly (P<0.01) more than expected based on availability, and the woodlots (independent forested blocks ≤2 km²) used were significantly (P<0.01) larger (x=0.4 km²) than random woodlots (x=0.18 km²) [17].

Although edges between fisher habitats and open areas are apparently avoided [106], edges between various types of fisher habitat are often used. In 75-year-old, even-aged hardwood, mixed, and coniferous forests of the White Mountain National Forest, fishers occurred within 98 feet (30 m) of an edge (change in species composition, height or density class) significantly (P<0.01) more often than expected (observed=60, expected=42.5) in winter. The trend was the same in summer (observed=130, expected=114.6), but was not significant (P≥0.05) [66]. In a study in Douglas-fir, lodgepole pine, and hybrid white spruce forests of south-central British Columbia, Weir and Harestad [128] concluded that the fine-grained nature of the early and later seral stages provided sustainable fisher habitat. Likewise, fisher habitat use in central Maine suggested that areas with high interspersion of many forest types provided optimal habitat [10]. In addition, a review states that diverse forest communities would better conserve mustelids than a homogenous mature forest due to the variability of mustelid responses to conditions such as snow accumulations, microclimate conditions, prey availability, and predator densities [100].

Fishers select habitat on several scales. In predominantly upland hardwood habitat of upper peninsular Michigan, fishers used mixed pine (P. banksiana, P. resinosa, and P. strobus) habitat in accordance with availability at a fine scale (the area around fisher tracks), but used it more than expected based on its availability at a coarser scale (the general study area). Fishers selected (P<0.001) dense, lowland forests as rest sites at both these scales [95]. In forests dominated by Douglas-fir, lodgepole pine, and hybrid white spruce in south-central British Columbia, fishers displayed selectivity at the stand, patch, and element (resting, maternal den, and natal den habitat) scales [129]. In Douglas-fir forests of northwestern California, fishers were sensitive to fragmentation at the plot, stand, and 2,500-acre (1,000-ha) block scales [106].

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This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):

More info for the term: cover

SRM (RANGELAND) COVER TYPES [111]:

203 Riparian woodland

216 Montane meadows

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This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

More info for the term: cover

SAF COVER TYPES [46]:

1 Jack pine

5 Balsam fir

12 Black spruce

13 Black spruce-tamarack

15 Red pine

16 Aspen

18 Paper birch

20 White pine-northern red oak-red maple

21 Eastern white pine

22 White pine-hemlock

23 Eastern hemlock

24 Hemlock-yellow birch

25 Sugar maple-beech-yellow birch

26 Sugar maple-basswood

27 Sugar maple

28 Black cherry-maple

30 Red spruce-yellow birch

31 Red spruce-sugar maple-beech

32 Red spruce

33 Red spruce-balsam fir

34 Red spruce-Fraser fir

35 Paper birch-red spruce-balsam fir

37 Northern white-cedar

38 Tamarack

39 Black ash-American elm-red maple

45 Pitch pine

52 White oak-black oak-northern red oak

53 White oak

55 Northern red oak

57 Yellow-poplar

58 Yellow-poplar-eastern hemlock

59 Yellow-poplar-white oak-northern red oak

60 Beech-sugar maple

61 River birch-sycamore

62 Silver maple-American elm

97 Atlantic white-cedar

107 White spruce

108 Red maple

201 White spruce

202 White spruce-paper birch

203 Balsam poplar

204 Black spruce

205 Mountain hemlock

206 Engelmann spruce-subalpine fir

207 Red fir

208 Whitebark pine

210 Interior Douglas-fir

211 White fir

212 Western larch

213 Grand fir

215 Western white pine

217 Aspen

218 Lodgepole pine

219 Limber pine

221 Red alder

222 Black cottonwood-willow

223 Sitka spruce

224 Western hemlock

225 Western hemlock-Sitka spruce

226 Coastal true fir-hemlock

227 Western redcedar-western hemlock

228 Western redcedar

229 Pacific Douglas-fir

230 Douglas-fir-western hemlock

231 Port-Orford-cedar

232 Redwood

233 Oregon white oak

234 Douglas-fir-tanoak-Pacific madrone

237 Interior ponderosa pine

243 Sierra Nevada mixed conifer

244 Pacific ponderosa pine-Douglas-fir

245 Pacific ponderosa pine

246 California black oak

247 Jeffrey pine

248 Knobcone pine

249 Canyon live oak

250 Blue oak-foothills pine

251 White spruce-aspen

252 Paper birch

253 Black spruce-white spruce

254 Black spruce-paper birch

255 California coast live oak

256 California mixed subalpine

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This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the terms: bog, shrub

KUCHLER [72] PLANT ASSOCIATIONS:

K001 Spruce-cedar-hemlock forest

K002 Cedar-hemlock-Douglas-fir forest

K003 Silver fir-Douglas-fir forest

K004 Fir-hemlock forest

K005 Mixed conifer forest

K006 Redwood forest

K007 Red fir forest

K008 Lodgepole pine-subalpine forest

K010 Ponderosa shrub forest

K011 Western ponderosa forest

K012 Douglas-fir forest

K013 Cedar-hemlock-pine forest

K014 Grand fir-Douglas-fir forest

K015 Western spruce-fir forest

K025 Alder-ash forest

K026 Oregon oakwoods

K029 California mixed evergreen forest

K030 California oakwoods

K093 Great Lakes spruce-fir forest

K094 Conifer bog

K095 Great Lakes pine forest

K096 Northeastern spruce-fir forest

K099 Maple-basswood forest

K102 Beech-maple forest

K103 Mixed mesophytic forest

K106 Northern hardwoods

K107 Northern hardwoods-fir forest

K108 Northern hardwoods-spruce forest

K109 Transition between K104 and K106

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

ECOSYSTEMS [54]:

FRES10 White-red-jack pine

FRES11 Spruce-fir

FRES15 Oak-hickory

FRES18 Maple-beech-birch

FRES19 Aspen-birch

FRES20 Douglas-fir

FRES21 Ponderosa pine

FRES22 Western white pine

FRES23 Fir-spruce

FRES24 Hemlock-Sitka spruce

FRES25 Larch

FRES26 Lodgepole pine

FRES27 Redwood

FRES28 Western hardwoods

FRES44 Alpine

See Preferred Habitat.

Habitat and Ecology

Systems

• Terrestrial

Fishers prefer coniferous forests, but they are also found in mixed and deciduous forests. They prefer habitats with high canopy closure. They also prefer habitats with many hollow trees for dens. Trees typically found in fisher habitats include spruce, fir, white cedar and some hardwoods. Also, as would be expected, their habitat preference reflects that of their favored prey species.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: taiga ; forest ; mountains

Habitat Type: Terrestrial

Comments: Fishers inhabit upland and lowland forests, including coniferous, mixed, and deciduous forests. They occur primarily in dense coniferous or mixed forests, including early successional forest with dense overhead cover (Thomas et al. 1993). Fishers commonly use hardwood stands in summer but prefer coniferous or mixed forests in winter. They generally avoid areas with little forest cover or significant human disturbance and conversely prefer large areas of contiguous interior forest (see USFWS 2004). Powell (1993) concluded that forest type is probably not as important to fishers as the vegetative and structural aspects that lead to abundant prey populations and reduced fisher vulnerability to predation, and that they may select forests that have low and closed canopies. Several studies have shown that fishers are associated with riparian areas (see USFWS 2004), which are in some cases protected from logging and generally more productive, thus having the dense canopy closure, large trees and general structural complexity associated with fisher habitat (Dark 1997). Riparian areas may be important to fishers because they provide important rest site elements, such as broken tops, snags, and coarse woody debris (Seglund 1995).

Fishers are regarded as habitat specialists in the western United States (Buskirk and Powell 1994), occurring only at mid- to lower elevation in mature conifer and mixed conifer/hardwood forests characterized by dense canopies and abundant large trees, snags, and logs (Powell and Zielinski 1994). In contrast, fishers in the northeastern United States and the Great Lakes region inhabit areas with a large component of deciduous hardwood forest containing American beech (Fagus grandifolia), sugar maple (Acer saccharum), and other broadleaf species (Powell and Zielinski 1994). The majority of conifer forest habitat in Canada is characterized as boreal forest, which is different from the relatively dryer environmental conditions associated with Washington, Oregon, and California. In the Rocky Mountains of north-central Idaho, certain all-conifer habitat types, which include grand fir and Engelmann spruce appear to be important to, and preferentially selected by fishers (Jones 1991).

Fishers are adapted for climbing but are primarily terrestrial. When inactive, they occupy a den in a tree hollow, under a log, or in the ground or a rocky crevice, or they rest in branches of conifer (warmer months). In Connecticut, Kilpatrick and Rego (1994) found that tree with a dbh of 32 cm or more may provide cavities for rest sites in hardwood-dominated forests.

Young are born in a den in a tree hollow (usually), or under a log or in a rocky crevice. Large snags (greater than 50 cm dbh) are important as maternal den sites (Thomas et al. 1993). Of 19 tree dens documented by Truex et al. (1998) across three study areas in California, the average diameter was 115 cm for conifers and 63 cm for hardwoods. Of 16 maternal and natal dens located on managed timberlands in northwestern California, nine were in cavities in hardwoods and seven were in conifer snags: diameters of den trees ranged from 62.5 cm to 295 cm (Simpson Resource Company 2003). See USFWS (2004) for further details on dens used by fishers in California and British Columbia.

West Coast Distinct Population Segment:

The key aspects of fisher habitat are best expressed in forest stands with late-successional characteristics. Fishers use habitat with high canopy closure, large trees and snags, large woody debris, large hardwoods, multiple canopy layers, and avoidance of areas lacking overhead canopy cover (see references in USFWS 2004). Fishers also occupy and reproduce in some managed forest landscapes and forest stands not classified as late-successional that provide some of the habitat elements important to fisher, such as relatively large trees, high canopy closure, large legacy trees, and large woody debris, in second-growth forest stands (Klug 1997, Simpson Resource Company 2003). However, intensive management for fiber production on industrial timberlands does not typically provide for retention of these elements. It is unlikely that early and mid-successional forests, especially those that have resulted from timber harvest, will provide the same prey resources, rest sites and den sites as more mature forests (see USFWS 2004). Late-successional coniferous or mixed forests provide the most suitable fisher habitat because they provide abundant potential den sites and preferred prey species (Allen 1987). Forest structure of good quality fisher habitat should provide high diversity of dense prey populations, high vulnerability of prey to fishers, and natal and maternal dens and resting sites (Powell and Zielinski 1994). Younger forests in which complex forest structural components such as large logs, snags, and tree cavities are maintained in significant numbers, and which provide a diverse prey base, may be suitable for fisher (Lewis and Stinson 1998). [from USFWS (2004), which see for further details on habitat in California]

See also Zielinski et al. (2004) for information on habitat characteristics in California.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

See Zielinski et al. (2004) for information on home range characteristics in California.

Fishers are predators, and most of their prey are plant-eating mammalia. Fishers eat muridae, erithizon dorsatum, sciuridae, lepus americanus, aves, and soricidae, and sometimes, other carnivora. They may also feed on fruits and berries, such as beechnuts and apples.

They have also been seen to eat odocoileus virginianus, though they are most likely scavenging a deer carcass.

Fishers and martes americana are the only medium-sized predators agile in trees that also have the ability to stretch themselves to look for prey in holes in the ground, hollow trees and other small areas. Fishers are hunt alone, and look for prey that is their own size or smaller, although they are capable of taking on prey larger than themselves.

Animal Foods: birds; mammals

Plant Foods: fruit

Fishers are predators, and most of their prey are herbivores. Fishers eat mice, porcupines, squirrels, snowshoe hares, birds, and shrews, and sometimes, other carnivores. They may also feed on fruits and berries, such as beechnuts and apples.

They have also been seen to eat white-tailed deer, though they are most likely scavenging a deer carcass.

Fishers and American martens are the only medium-sized predators agile in trees that also possess the ability to elongate themselves to seek prey in holes in the ground, hollow trees and other small areas. Fishers are solitary hunters, and seek prey that is their own size or smaller, although they are capable of taking on prey larger than themselves.

Animal Foods: birds; mammals

Plant Foods: fruit

Primary Diet: carnivore (Eats terrestrial vertebrates)

Comments: Diet consists primarily of mammals (small rodents, shrews, squirrels, hares, muskrat, beaver, porcupine, raccoon, deer carrion); also birds, other small animals, carrion, and fruit.

Fishers are important predators in their ecosystems. They are often in competition for food with canidae, lynx rufus, lynx canadensis, canis latrans, gulo gulo, martes americana and mustela. Fishers rarely get diseases.

Young fishers fall prey to accipitridae, vulpes vulpes, lynx canadensis and lynx rufus. Adult fishers are generally safe from predation.

Known Predators:

• accipitridae
• vulpes vulpes
• lynx canadensis
• lynx rufus
• hawks (Accipitridae)
• red foxes (Vulpes_vulpes)
• lynx (Lynx_canadensis)
• bobcats (Lynx_rufus)

There are few documented cases of predation on fishers. However, in predominantly coniferous forest of northwestern Montana, reintroduced fishers were likely killed by mountain lions (Puma concolor, 3), coyotes (Canis latrans, 3), a wolverine (Gulo gulo, 1), a Canada lynx (Lynx canadensis, 1), and an eagle (probably Aquila chrysaetos, 1) [108]. In south-central Maine, coyotes were probably responsible for 1 fisher death out of 50 that were recorded [70]. In northwestern California, carnivores killed 4 fishers, and a juvenile was killed by another fisher [30]. No signs of predation of fishers were detected in Maine [40] or the upper peninsula of Michigan [22].

Fishers are important predators in their ecosystems. They are often in competition for food with foxes, bobcats, lynx, coyotes, wolverines, American martens and weasels. Fishers have a low incidence of diseases.

Young fishers fall prey to hawks, red foxes, lynx and bobcats. Adult fishers are generally safe from predation.

Known Predators:

• hawks
• red foxes
• lynx
• bobcats
• hawks (Accipitridae)
• red foxes (Vulpes vulpes)
• lynx (Lynx canadensis)
• bobcats (Lynx rufus)

Martes pennanti preys on:
Arborimus longicaudus

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: In the absence of good occurrence specifications and adequate population data, an estimate of the number of occurrences is not possible. But surely there are hundreds of fairly distinct populations.

10,000 to >1,000,000 individuals

Comments: Total population size is unknown but probably is at least in the low hundreds of thousands; for example, the harvest in North America during the 1983-1984 trapping season was about 20,000 (Novak et al. 1987), and the average in the 1960s and 1970s was about 13,000 (Strickland et al. 1982).

More info for the terms: altricial, avoidance, litter, polygamous, presence

Reviews state that the fisher breeding cycle begins with mating starting in March. For females this is a few days after giving birth, since fishers exhibit delayed implantation lasting about 10 months. Active pregnancy typically begins in February and lasts until March or early April, when fishers give birth to an average of 2 to 3 kits [84,94,97]. Captive females trapped in Maine had an average initial litter size of 2.7 kits, with litters ranging from 1 to 4 kits [83]. Several years of observations showed the average litter size of 12 females in coastal Maine varied from 2.0 to 2.2 kits. Females gave birth from 3 March to 1 April [87]. In north-central Massachusetts and southwestern New Hampshire, the birth of 20 litters occurred from 4 March to 24 March with the median on 17 March [99]. According to reviews, males are reproductive beginning in early March [84,97]. During this time they often leave their home ranges in search of mates [11,16,17]. Fishers are likely polygamous [40].

Females den with their altricial kits for several weeks [40]. In Maine the denning period ranged from 8 to 12 weeks, with an average of 71 days, and ended as late as 1 June. Individual dens were used for 2 to 12 weeks, with a median of 22 days [9,87]. In north-central Massachusetts and southwestern New Hampshire, maternal dens were used until 3 June [99]. Kits in south-central Maine stayed with their mothers until they were about 150 days old, with males exhibiting more variation than females. Kits occurred within their mothers' home range from August to January. During this period mothers and young showed no attraction to or avoidance of each other. Two female kits dispersed in January [12,87]. Field and genetic evidence from an untrapped population in Oregon suggests males disperse further from their natal home range than females [16]. For information on development of young fishers, see these sources: [52,94]. According to reviews, males apparently can breed after a year, but the extent to which this actually occurs is unknown. Females also reach sexual maturation at a year. Due to delayed implantation they do not give birth to their first litter until they are 2 years old [40,84,97]. A review states that fishers can live to about 10 years [97]. Average annual survival rates over a 6-year period in a trapped fisher population in coastal Maine were 0.74 for adult females and 0.33 for juveniles [87]. In the upper peninsula of Michigan, the survival rate of fishers from June to December was 0.889, with 95% confidence intervals ranging from 0.500 to 0.985 [22].

Fisher denning rates are often lower than pregnancy rates. Reviews note cases of pregnancy rates ≥95% [9,24,97]. However, denning rates are typically much lower. For instance, in south-central Maine denning rates varied from 0% to 100% (n=12 females) over several years. The average annual recruitment was 0.7 to 1.3 kits/female. This recruitment rate and the estimated survivorship suggested the population was declining [9,87]. Factors influencing reproductive success of female fishers are addressed by McMahon and deCalesta [83].

Fishers exhibit sexual dimorphism, with females much smaller than males. Average female weight (4.3-4.9 lbs (1.97- 2.24 kg)) was substantially less than average male weight (7.9-9.5 lbs (3.6-4.3 kg)) in New Hampshire [66], northwest Connecticut [68], Vermont [124], and the southern Sierra Nevada of California [26]. The ratio of average male mass to average female mass for fishers collected throughout British Columbia was 1.64:1.00 [130].

Although fishers have large home ranges and are capable of moving long distances, in at least some instances their dispersal ability may be rather poor. In Douglas-fir (Pseudotsuga menziesii), lodgepole pine (Pinus contorta), and hybrid white spruce (Picea engelmannii × P. glauca)- dominated forests of south-central British Columbia, translocated fishers moved extensively before establishing their home ranges. The average area traversed was 442.5 km² for females and 1,438.0 km² for males. The majority of fishers traveled more than 100 km before establishing a home range [128]. In Oregon, dispersal distances greater than 31 miles (50 km) were observed. However, lack of gene flow to a population approximately 31 miles away suggests there is no dispersal between the populations [16]. In mixed second-growth coniferous and deciduous forest of south-central Maine, the greatest natal dispersal distance observed was 14 miles (23 km) [12]. There are several possible reasons for the variability in fisher dispersal distances, such as the presence of recently vacated territories nearby [12] and the degree of habitat connectivity (see Landscape/scale effects).

For detailed information on fisher reproductive behavior such as territoriality, parental care, and denning see these sources: [40,87,94,97]. For information on periods of activity and regular movements of fisher, see: [9,40,66,94].

Solitary except during the breeding season.

Home range has been estimated at 10-800 sq km by snow tracking, 7-78 sq km by telemetry using minimum convex polygon model; generally the ranges of adults of the same sex do not overlap. In Maine, home ranges of females were stable between seasons and years, but males moved extensively in late winter and early spring and their ranges shifted between years. In New Hampshire, mean annual home range was about 15-25 sq km, with daily movements usually were 1.5-3.0 km. In southern Quebec, mean home range size was 5.4 sq km for females and 9.2 sq km for males (Garant and Crete 1997). Has been recorded moving 90 km in 3 days (see Nowak 1991).

Population density in favorable habitat has been estimated at up to about 1 per 3-11 sq km in summer, 1 per 8-20 sq km in winter (Arthur et al. 1989). In southern Quebec, density was estimated at about 3 individuals per 10 sq km; the high density was atrributed to the absence of trapping (Garant and Crete 1997).

Fishers have good senses of smell, hearing and sight. They communicate with each other by scent marking.

Communication Channels: chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Fishers have good senses of smell, hearing and sight. They communicate with each other by scent marking.

Communication Channels: chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

Comments: Active both day/night. Mainly nocturnal/crepuscular in summer and diurnal in winter. In south-central Maine, most activity occurred shortly before sunrise and after sunset; activity was reduced in winter (Arthur and Krohn 1991); females caring for weaned offspring showed increased diurnal activity (Paragi et al., 1994, Can. Field-Nat. 108:52-57.

Fishers can live up to ten years in the wild.

Range lifespan
Status: wild: 10 (high) years.

Fishers can live up to ten years in the wild.

Range lifespan
Status: wild: 10 (high) years.

Maximum longevity: 14.3 years (captivity) Observations: Depending on how long the implantation takes to occur, the total gestation time can vary from 270 to 370 days. In the wild, fishers may live up to 10 years (Bernhard Grzimek 1990). One specimen lived 14.3 years in captivity (Richard Weigl 2005).

No information is available on the mating system of these mammals.

The breeding season is late winter and early spring, from March to May. After fertilization, the embryos stop developing for 10 to 11 months, and start developing again late in the winter following mating. Overall, pregnancy lasts almost a full year, 11 to 12 months. The average number of young in a litter is 3, ranging from 1 to 6. Shortly after giving birth, females mate again. Healthy females first breed at age 1, produce their first litter at age 2, and probably breed every year after that. So females essentially spend almost all of their adult life either pregnant or nursing young. Males breed for the first time when they are two years old.

Breeding interval: Fishers breed once per year.

Breeding season: Fishers breed in the late winter to early spring, from March to May. Breeding times vary with location.

Range number of offspring: 1 to 6.

Average number of offspring: 3.

Range gestation period: 11 to 12 months.

Range weaning age: 8 to 16 weeks.

Range time to independence: 5 (low) months.

Average age at sexual or reproductive maturity (female): 1 years.

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous ; delayed implantation ; embryonic diapause ; post-partum estrous

Average birth mass: 35 g.

Average number of offspring: 2.5.

Average age at sexual or reproductive maturity (male)
Sex: male: 365 days.

Average age at sexual or reproductive maturity (female)
Sex: female: 365 days.

Young fishers are born blind and nearly naked. Each weighs about 40 grams at birth. The eyes open after about 53 days. Young begin to be weaned at 8 to 10 weeks, but may nurse occasionally for up to 4 months after birth. By the time they are four months old, the young are able to hunt for themselves, and they leave their mother at least one month later. Most dens in which young fishers are raised are high up in hollow trees, and females may choose to move their young up to several times if the litter is at all disturbed. Male fishers do not help raise their young.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)

Little is known about mating in fishers. Copulation may last up to seven hours.

The breeding season is late winter and early spring, from March to May. After fertilization, the embryos sit in suspended development for 10 to 11 months, and resume developing late in the winter following mating. Overall, gestation lasts almost a full year, 11 to 12 months. The average number of young in a litter is 3, ranging from 1 to 6. Shortly after giving birth, females experience a postpartum estrus and mate again. Healthy females first breed at age 1, produce their first litter at age 2, and probably breed every year after that. So females essentially spend almost all of their adult life in a state of pregnancy or lactation. Males breed for the first time when they are two years old. Females reach adult weights at 5.5 months, whereas males reach adult weights after 1 year old.

Breeding interval: Fishers breed once per year.

Breeding season: Fishers breed in the late winter to early spring, from March to May. Breeding times vary with location.

Range number of offspring: 1 to 6.

Average number of offspring: 3.

Range gestation period: 11 to 12 months.

Range weaning age: 8 to 16 weeks.

Range time to independence: 5 (low) months.

Average age at sexual or reproductive maturity (female): 1 years.

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous ; delayed implantation ; embryonic diapause ; post-partum estrous

Average birth mass: 35 g.

Average number of offspring: 2.5.

Average age at sexual or reproductive maturity (male)
Sex: male: 365 days.

Average age at sexual or reproductive maturity (female)
Sex: female: 365 days.

Young fishers are born blind and nearly naked. Each weighs about 40 grams at birth. The eyes open after about 53 days. Young begin to be weaned at 8 to 10 weeks, but may nurse occasionally for up to 4 months after birth. By the time they are four months old, the young are able to hunt for themselves, and they disperse at least one month later. Most dens in which young fishers are raised are high up in hollow trees, and females may choose to move their young up to several times if the litter is disturbed. Male fishers do not help raise their young.

Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)

Reportedly breeds late February-April or March-May, peak in March (late March-April in Manitoba); females mate probably within days of giving birth. Gestation lasts l year, including an 11-month period before implantation. Litter averages about 3 throughout the range. Births occur primarily from March to mid-April (sometimes in February or May in some areas). Young are mobile by 8 weeks, weaned in 2.5-4 months; separation from the mother occurs in the fifth month, in late summer or early fall. In Maine, young are weaned from mid-May to early June, independent probably in late August or early September (Arthur and Krohn 1991). Sexually mature in 1-2 years; not all adult females breed in a given year. Apparently promiscuous breeding. Very few males live more than 4 years, and less than 10% of females live more than 4 years.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 17 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 16
Specimens with Barcodes: 22
Species With Barcodes: 1

Logging of forests greatly affects fishers and fisher populations by destroying their preferred habitat--continuous or nearly continuous coniferous forests.

Zoos have had a hard time breeding fishers in captivity, but there has been some success. Because there are many thriving and healthy fisher populations, there has been little desire to develop fisher breeding programs in captivity.

In some areas of North America, such as Michigan, Ontario, New York, and some areas of New England, fisher populations seem to have rebounded in recent years.

Fisher populations in the southern Sierra Nevada have been said to need protection under the Endangered Species Act.

IUCN Red List of Threatened Species: least concern

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Candidate [122]

Year Assessed

Assessor/s

Reviewer/s

Justification

History

• 1996
  Lower Risk/least concern

Logging of forests greatly impacts fishers and fisher populations by destroying their preferred habitat--continuous or nearly continuous coniferous forests.

Zoos have had a hard time breeding fishers in captivity, but there has been some success. Because there are numerous thriving and healthy fisher populations, there has been little pressure or initiative to develop fisher breeding or maintaining programs in captivity.

In some areas of North America, such as Michigan, Ontario, New York, and some areas of New England, fisher populations seem to have rebounded in recent years.

Fisher populations in the southern Sierra Nevada have been proposed as candidates for protection under the Endangered Species Act.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: Large range in northern North America; extirpation from southern portion of range, due mainly to habitat loss, has been counteracted by recent natural and human-aided range expansions in the eastern U.S.; adequate population data are unavailable for much of the range, but the species currently is regarded as secure. See also information on the West Coast Distinct Population Segment.

Intrinsic Vulnerability: Highly vulnerable

Comments: Low fecundity retards the recovery of populations from declines, further increasing their vulnerability (USFWS 2004).

Population

Population Trend

Global Short Term Trend: Unknown

Degree of Threat: Medium

Comments: The fisher's range was reduced dramatically in the 1800s and early 1900s through overtrapping, predator and pest control, and alterations of forested habitats by logging, fire, and farming (Douglas and Strickland 1987, Powell 1993, Powell and Zielinski 1994, Lewis and Stinson 1998). Since the 1950s, fishers have recovered in some of the central and eastern portions of their historic range in the United States as a result of trapping closures, changes in forested habitats (e.g., forest regrowth in abandoned farmland), and reintroductions (Brander and Books 1973, Powell and Zielinski 1994). However, fishers are still absent from their former range southeast of the Great Lakes (Gibilisco 1994). [from USFWS 2004]

The extent of past timber harvest is one of the primary causes of fisher decline across the United States (Powell 1993), and it may be one of the main reasons fishers have not recovered in Washington, Oregon, and portions of California as compared to the northeastern United States (Aubry and Houston 1992, Powell and Zielinski 1994, Lewis and Stinson 1998, Truex et al. 1998). Timber harvest can fragment fisher habitat, reduce it in size, or change the forest structure to be unsuitable for fishers. Habitat loss and fragmentation appear to be significant threats to the fisher. Forested habitat in the Pacific coast region decreased by about 8.5 million ac (34,400 sq km) between 1953 and 1997 (Smith et al. 2001). Forest cover in the Pacific coast is projected to continue to decrease through 2050, with timberland area projected to be about 6 percent smaller in 2050 than in 1997 (Alig et al. 2003). Thus fisher habitat is projected to decline in Washington, Oregon, and California in the foreseeable future. [from USFWS 2004, which see for further details]

Although exact numbers are unknown, trapping caused a severe decline in fisher populations. Aubry and Lewis (2003) state that overtrapping appears to have been the primary initial cause of fisher population losses in southwestern Oregon. The high value of the skins, the ease of trapping fishers (Powell 1993), year-round accessibility in the low to mid-elevation coniferous forests, and the lack of trapping regulations resulted in heavy trapping pressure on fishers in the late 1800s and early 1900s (Aubry and Lewis 2003). [from USFWS 2004]

See also threats information for the West Coast Distinct Population Segment.

Major Threats

Conservation Actions

Management Requirements: In the Pacific Northwest, habitat conservation measures proposed/implemented for the spotted owl and marbled murrelet, and for riparian zones, generally are sufficient to prevent the extirpation of this species, but ongoing management reassessment, monitoring, and adaptive management are important (U.S. Forest Service et al. 1993; see also Thomas et al. 1993).

Because fisher populations are extremely low in northern Oregon and Washington, U.S. Forest Service et al. (1993) recommended that kill trapping of American martens should be prohibited within the overlapping ranges of marten, fisher, and spotted owl until the rate of accidental take of fishers is determined to be insignificant.

Fishers from several source populations were released in Oregon in 1961 and from 1977 to 1981; successful reintroductions (beginning in the early 1960s) have occurred in Montana and Idaho (USFWS 2004).

There are currently efforts underway to implement a conservation strategy to reintroduce the fisher into its former range along the Pacific Coast. Additional populations of fishers will reduce the probability that a stochastic event would result in extirpation of the species. Genetic data indicate that British Columbia would be the most appropriate source population for future translocations that may be necessary to recover populations in Washington and portions of Oregon and California (Drew et al. 2003).

As of 2004, the Pacific Region (Region 5) of the U.S. Forest Service was due to complete a conservation assessment for the fisher in the Sierra Nevada Mountains. This effort is part of the Sierra Nevada Framework planning document and is a collaborative effort including scientists from the State and Federal agencies. The assessment may be used to develop a conservation strategy for the Sierra Nevada fisher populations in California. The timber industry and their representatives, including Sierra Pacific Industries, Simpson Timber Company and the California Forestry Association have indicated willingness to develop a conservation strategy to, if appropriate, conduct a reintroduction and/or relocation strategy in California. Their participation could include funding, staffing, and assistance with analysis and planning. [from USFWS 2004]
The State of Washington has completed a reintroduction feasibility study and has identified several sites in the Washington Cascades and the Olympic Peninsula where sufficient potential habitat exists to support a fisher population. Reintroduction efforts and evaluation by the State are ongoing and would potentially compliment efforts to establish additional populations throughout the range of the fisher (USFWS 2004).

USFWS will evaluate a completed conservation strategy in accordance with their Policy on Evaluating Conservation Efforts (68 FR 15100, March 28 2003) to determine whether it sufficiently removes threats to the fisher so that it no longer meets the definition of threatened under the Act (USFWS 2004).

See Berg (1982) for information on fisher reintroduction.

Global Protection: Few to several (1-12) occurrences appropriately protected and managed

Comments: At least several populatons are protected in national parks.

Needs: Protect large tracts of habitat in areas well distributed throughout the range. Prevent excessive harvest.

In recent years fisher populations in some areas, particularly southern Ontario and New York, have been recovering. In these areas they may be becoming used to humans and venturing into suburban areas. There have been many reports of fisher attacks on domestic animals and even children. It is important to recognize that fishers are simply trying to find food and protect themselves. It is important to not allow them access to garbage, pet foods, pets, and domestic fowl. When startled, fishers may react aggressively to what they see as a threat. Diseased animals may react unpredictably.

Negative Impacts: injures humans (bites or stings)

Fishers are trapped and killed for their pelts. Trapping, in the past, had a large effect on fisher populations, but the problem is not as severe now. Fishers hunt erethizon dorsatum, and can effectively control porcupine populations (porcupines are known to damage timber crops by eating the bark and killing trees).

Positive Impacts: body parts are source of valuable material

In recent years fisher populations in some areas, particularly southern Ontario and New York, have been recovering. In these areas they may be becoming habituated to human presence and venturing into suburban areas. There have been numerous reports of fisher attacks on domestic animals and even children. It is important to recognize that fishers are simply trying to find food and protect themselves. It is important to restrict access to garbage, pet foods, pets, and domestic fowl. When startled, fishers may react aggressively to the perceived threat. Diseased individuals may react unpredictably.

Negative Impacts: injures humans (bites or stings)

Fishers are trapped and killed for their pelts. Trapping, in the past, had a significant effect on fisher populations, but the problem is not as severe now. Fishers hunt porcupines, and can effectively control porcupine populations (porcupines are known to damage timber crops by debarking and killing trees).

Positive Impacts: body parts are source of valuable material

Comments: Total harvest in Canada and the U.S. was about 20,200 in the early 1980s; pelts sold for an average of about $50. The highest quality pelts sold for $450 in Ontario in 1986. See Strickland et al. 1982 and Nowak 1991 for further (though somewhat dated) information on harvest and fur prices.