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BC Conservation Data Centre: Conservation Status Report

Pekania pennanti pop. 5
Fisher - Columbian Population

 
Scientific Name: Pekania pennanti pop. 5
English Name: Fisher - Columbian Population
   
Provincial Status Summary
Status: S1S2
Date Status Assigned: May 02, 2025
Date Last Reviewed: May 02, 2025
Reasons: Fishers, Columbian population, occur over a large range in the central interior of B.C. Population numbers are low, estimated between 272-558 mature individuals. Threats are high, with trapping being the most significant, along with habitat loss and degradation from forest harvesting and wildfire. Recent trends have shown declines of >70% due to the trapping of a population already contending with loss of forest habitat; without changes to trapping regulations and forest management this population is estimated to be extirpated within a decade. There is limited protection of good or excellent habitat. This population has been extirpated from most of the Southern Interior and southern half of the Southern Interior Mountain ecoprovinces.
 
Range
Range Extent: G = 200,000-2,500,000 square km
Range Extent Estimate (km2): 219,562
Range Extent Comments: The Columbian population of fishers (Weir et al. 2024) is found through low to moderate elevations within forested habitat in the central interior of B.C. (Weir 2003, Lofroth et al. 2010). Fishers are no longer distributed within 32,505 sq. km of their former range (Weir et al. 2024), primarily in areas within the Southern Interior and southern half of the Southern Interior Mountain ecoprovinces, equating to the Thompson-Okanagan (Okanagan Shuswap, and southern portions of the Cascades and Thompson Rivers Natural Resource Districts) and the Kootenay-Boundary Natural Resource Districts (J. Burgar, pers. comm. 2025). Efforts to re-establish fisher populations in the East Kootenay region of the formerly occupied range (Fontana et al. 1999, Fontana and Teske 2000) were not successful (Weir et al. 2003). Fishers still occupy suitable landscapes within the Central Interior, Sub-Boreal Interior, and small portions of the Coast and Mountains and Northern Boreal Mountains ecoprovinces, equating to portions of the Skeena (north-eastern portion of the Coast Mountains, throughout the Skeena Stikine and eastern half of the Nadina Natural Resource Districts), Omineca, and Cariboo Natural Resource Regions (J. Burgar, pers. comm. 2025). The range extent is estimated at 219,562 sq. km. This calculation was based on Maxent distribution modelling (Kass et al. 2018); fisher presence data was included in the model, alongside WorldClim bioclimatic variables 1-19 and elevation at 1x1 km2 pixel resolution. Fisher distribution was modelled at the provincial scale, separated into populations using Weir et al. (2024) geographic boundaries (J. Burgar pers comm).
Area of Occupancy (km2): I = >12,500
Area of Occupancy Estimate (km2): 59,472
Area of Occupancy Comments: This population occurs within the SBPS, IDF, SBS, MS, ICH, and CWH Biogeoclimatic Ecosystem Classification (BEC) zones. The estimated area of occupancy was based on the total area of range extent predicted to have =20% probability of supporting an adult female fisher territory. The rationale for using a female only predictive model was that multiple female territories can occur within a single male territory and female territories encompass habitat suitable for dispersing juveniles. Female fisher territory predictions were modelled using an Individual Based Model for adult female fishers (Fisher Landscape Explorer (https://github.com/bcgov/FLEX) and habitat spatial layers comprising primary denning, resting, and movement habitats for the appropriate fisher habitat zone (BC Fisher Habitat Working Group NDb) as well as the amount of open area (Weir and Corbould 2010) within each territory. Area of occupancy is currently estimated at 59,472 sq. km (14,868 2x2 km grid cells).
 
Occurrences & Population
Number of Occurrences: U = Unknown
Comments: The Element Occurrence concept for mammals with large home ranges does not always best represent the rarity category as used when calculating the status rank using NatureServe methods. In the case of Fisher, population size will be factored within the rarity category, which will contribute to the overall status rank.
Number of Occurrences with Good Viability / Ecological Integrity: U = Unknown
Percent Area with Good Viability / Ecological Integrity: U = Unknown
Number of Occurrences Appropriately Protected & Managed: U = Unknown
Comments: Portions of some fisher populations may exist within protected areas however they may be limited because fishers are distributed primarily within low and moderate elevation habitats (Weir 2003, Lofroth et al. 2010). Protected areas have also been affected by mountain pine beetle infestations and wildfire. There are four approved fisher Wildlife Habitat Areas, comprising 44 sq. km, within the Omineca region.
Population Size: C = 250 - 1,000 individuals
Comments: Population size was estimated using an integrated density model fit to fisher observation data from 2018-2023. The number of mature fishers within the Columbian population was estimated at 393 individuals (272-558 95% Bayesian Credible Intervals (BCI)): 60 (42-84 95% BCI) in the Cariboo, 202 (148-270 95% BCI) in the Chilcotin, and 131 (81-204 95% BCI) in the Omineca (J. Burgar, pers. comm. 2025). The integrated density model jointly analyzed fine-scale density information acquired from spatial capture-recapture studies with coarse-scale occupancy estimates to estimate population density. The analysis used two data structures: one for spatial capture recapture analysis, where individuals were identified during hair-snag surveys through DNA analysis; and another for occupancy analysis, utilizing camera trap surveys to create detection- non detection matrices (Chandler and Clark 2014; Sun et al. 2019; Jiménez et al. 2022). The integrated and hierarchical model allowed for modelling uncertainty at different levels as it combined a population dynamics model with an observation model to estimate density, probability of detection, and territory size. Canopy cover was included as a covariate to control for habitat; canopy cover was estimated using a derived Landsat-LiDAR product that provided the percentage of first returns above 2 metres at a 1x1 km pixel resolution (Matasci et al. 2018).

Ongoing fisher genetic surveys and mesocarnivore camera trap surveys in each of the regions may refine these estimates, and provide crucial trend information, in future (J. Burgar, pers. comm. 2025).
 
Threats (to population, occurrences, or area affected)
Degree of Threat: AB = Very high - high
Comments: A threats calculator was completed by a group of experts in 2024, resulting in a threat impact score of Very High ? High. Primary threats are trapping, forest harvesting, and wildfire. Despite a closed trapping season for fishers since 2021, current regulations allow for incidental trapping of fishers in traps certified for other species. Incidental fur-harvest is driving mortality higher than reproductive output can replace individuals. Habitat change from forest harvesting and wildfire is reducing the supply of habitat that can support viable populations. Forest harvesting, including salvage logging post wildfire and mountain pine beetle outbreaks, continues to be a pervasive threat; nearly one-quarter of fisher habitat within the Columbian range was logged or burned between 2017 and 2023 (R. Weir, pers. comm. 2025).

Secondary threats are loss or degradation of habitat due to livestock farming and ranching, transportation, and mining (J. Burgar, pers. comm. 2025).
 
Trend (in population, range, area occupied, and/or condition of occurrences)
Short-Term Trend: AC = Decline of >70%
Comments: 84% reduction over 3 generations (10 years) based on an estimated starting population of 571 (Fogarty et al. 2022) and averaging the decline predicted by two fur-harvest scenarios (J. Burgar, pers. comm. 2025). The different trapping scenarios, as described in Fogarty et al. (2022), consider an open trapping season with fishers harvested in all trap types (predicted 92% decline) and with a closed fisher trapping season but incidental trapping occurring in all traps other than 120-class traps (predicted 75% decline).
Long-Term Trend: AC = Decline of >70%
Comments: The range in decline is estimated between 84% and 92% but due to the uncertainty around the population size 100 years ago, the long-term trend is considered >70%. Declines include historic extirpation from most of the Shuswap, Okanagan, Columbia and Kootenay regions and continued loss of forested habitat within the current area of occurrence (J. Burgar, pers. comm. 2025)
 
Other Factors
Intrinsic Vulnerability: AB=Highly to moderately vulnerable.
Comments: Factors that contribute to the intrinsic vulnerability include low reproductive output and low survival rates (Lofroth et al. 2022). The survival rate for all Columbian fishers (adults and sub-adults) was estimated at 0.74 (0.60 ? 0.88 95% CI). The net reproductive rate of Columbian fishers was estimated at 0.92 kits per reproductive season: 1.70 ± 0.69 kits per litter and a denning rate of 0.54 ± 0.41 litters per reproductive seasons monitored. Reproductive rates for Columbian fishers were much lower (<70%) than in the Boreal population.
Environmental Specificity: B=Narrow. Specialist or community with key requirements common.
Comments: Fishers use specific habitat features primarily found in late-successional forests (Lofroth et al. 2010, Raley et al. 2012). This requirement is most specific for natal and maternal dens, where atypically large black cottonwood, trembling aspen, Douglas-fir or lodgepole pine trees are used by the females (Davis 2009, Weir and Harestad 2003, Weir and Corbould 2008). Attributes for resting locations are also tied to features of older successional stages (Aubry et al 2013, Raley et al. 2012).
Other Rank Considerations:
 
Information Gaps
Research Needs: Outputs from the Fisher Landscape Explorer tool need to be verified with detection data (e.g., camera trap surveys, genetic surveys) and then be used to delineate priority conservation areas for fishers and assist in prioritization of habitat protection and restoration. Improvements in understanding linkages between habitat condition and demographic parameters (survival and reproduction) are key to developing effective conservation and management approaches and should extend beyond the current research in the Interior Douglas-Fir BEC zone. Fisher exclusion devices have been distributed widely in the Central Interior, however use of these devices to limit bycatch of fishers is currently not required and further trials and refinement of fisher exclusion devices for trapping may be of interest. Evaluation of interim management measures to bridge habitat loss (i.e., fisher den boxes and inoculation/mechanical treatment of trees) has occurred within fisher range. Low use rates of fisher den boxes and the slow rate of inoculation/mechanical treatment are problematic features of these interim measures, and re-evaluation of these methods as well as other options should occur in 2025-2028. Genome sequencing of fishers should occur to better understand the causes of the separation between the Boreal and Columbian populations.
Inventory Needs: Inventory work (i.e., genetic surveys and camera trap surveys) is necessary in each of the three conservation regions (Cariboo, Chilcotin, and Omineca) as there is minimal genetic mixing between these regions (Weir et al. 2024). A spatially balanced sampling design, stratified by wildfire and forest harvesting has been developed to create a three-year survey plan that will estimate fisher density and population trends while also evaluating the influence of forest harvesting practices and wildfire severity on fisher populations. The first year of surveys was completed in 2025 (J. Burgar, pers. comm.). This and other inventory work will provide much needed validation of the Fisher Landscape Explorer tool, especially where predicted outputs are being incorporated into Forest Landscape Plans.
 
Stewardship
Protection:
Management:
Fishers require appropriate habitat management at landscape and stand scales. Voluntary guidance is currently available for stand level management but requires consistent application to be effective (BC Fisher Habitat Web Module 2020). Landscape management requires the use of data-driven landscape models (i.e., Fisher Landscape Explorer tool) to identify high priority conservation areas for extant fisher habitat and to prioritize areas of high fisher habitat capability for protection and restoration. Both stand and landscape level guidance should be incorporated into Forest Landscape Plans, where overlapping fisher range.
 
Version
Author: Burgar, J. (2025); Lofroth, E. (2020)
Date: April 14, 2025
 
References
Aubry, K.B., C.M. Raley, S.W. Buskirk, et al. 2013. Meta-analyses of habitat selection by fishers at resting sites in the Pacific coastal region. J. Wildl. Manag. 77(5):965?974.
BC Fisher Habitat Working Group. British Columbia Fisher Habitat and Forestry Web Module. NDa. Available: http://www.bcfisherhabitat.ca (accessed 31 January 2020).
BC Fisher Habitat Working Group. Habitat Tools. NDb. Available: https://www.bcfisherhabitat.ca/habitat-tools/
Chandler, R. B. and J.D. Clark. 2014. Spatially explicit integrated population models. Methods in Ecology and Evolution, 5(12), 1351?1360
Davis, L.R. 2009. Denning ecology and habitat use by fisher (Martes pennanti) in pine dominated ecosystems of the Chilcotin Plateau. M.Sc. Thesis, Simon Fraser Univ., Burnaby, BC.
Eng, M., A. Fall, J. Hughes, et al. 2005. Provincial level projection of the current Mountain Pine Beetle outbreak: An overview of the model and results of Year 2 of the project. Natural Resources Canada. Mountain Pine Beetle Initiative Working Paper.
Fontana, A.J., and I.E. Teske. 2000. East Kootenay Fisher Reintroduction Program. P. 693 in L.M. Darling, ed. 2000. Proc. Conf. on the Biology and Manage. Species and Habitats at Risk, Kamloops, B.C., 15-19 Feb., 1999. Vol. 2; B.C. Minist. Environ., Lands and Parks, Victoria, BC, and Univ. College of the Cariboo, Kamloops, BC. 520pp.
Fontana, A.J., I.E. Teske, and K. Pritchard. 1999. East Kootenay fisher reintroduction program final report 1996-1999. Minist. of Environ., Lands, and Parks, Cranbrook, BC. Canada.
Jiménez, J., Díaz-Ruiz, F., Monterroso, P., Tobajas, J., & Ferreras, P. 2022. Occupancy data improves parameter precision in spatial capture?recapture models. Ecology and Evolution, 12, e9250.
Kass, J. M., Vilela, B., Aiello-Lammens, M. E., Muscarella, R., Merow, C., & Anderson, R. P. (2018). Wallace: A flexible platform for reproducible modeling of species niches and distributions built for community expansion. Methods in Ecology and Evolution, 9(4), 1151?1156.
Lofroth, E. 2004. Fisher (Martes pennanti) British Columbia Population Science Assessment Review. Minist. of Water, Land and Air Protection, Victoria, B.C. 21 pp.
Lofroth. E.C., C.R. Raley, J.M. Higley, et al. 2010. Conservation of fishers (Martes pennanti) in south-central British Columbia, western Washington, western Oregon, and California - Volume I: Conservation Assessment. USDI Bureau of Land Management, Denver, Colorado, USA.
Matasci, G., Hermosilla, T., Wulder, M. A., White, J. C., Coops, N. C., Hobart, G. W., Bolton, D. K., Tompalski, P., & Bater, C. W. 2018. Three decades of forest structural dynamics over Canada?s forested ecosystems using Landsat time-series and lidar plots. Remote Sensing of Environment, 216, 697?714.
Raley, C.M., E.C. Lofroth, R.L. Truex, et al. 2012. Habitat ecology of fishers in western North America: a new synthesis. Pages 231 - 254 in K.B. Aubry, W.J. Zielinski, M.G. Raphael, et al., eds. Biology and conservation of martens, sables, and fishers: a new synthesis. Comstock Publishing Associates, Cornell University Press, Ithaca, NY, USA.
Sun, C. C., Royle, J. A., & Fuller, A. K. (2019). Incorporating citizen science data in spatially explicit integrated population models. Ecology, 100(12), e02777.
Weir, R.D, Rankin, A.M., Robinson, L., Pilgrim, K.L, Schwartz, M.K, and Lucid, M.K. 2024. Genetic structuring of fishers in British Columbia,Canada: implications for population conservation and management. Journal of Mammalogy. 105 (3) 465:480.
Weir, R.D. 2003. Status of the Fisher in British Columbia. B.C. Minist. Water, Land and Air Prot., Biodiversity Branch, and B.C. Minist. Sustainable Resour. Manage., Conservation Data Centre Victoria, BC. Wildl. Bull. B-105. 47pp.
Weir, R.D., and A.S. Harestad. 2003. Scale-dependent habitat selectivity by fishers in south-central British Columbia. J. Wildl. Manag. 67:73-82.
Weir, R.D., and F.B. Corbould. 2006. Densities of fishers in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia. Northwest Naturalist 87: 118-127.
Weir, R.D., and F.B. Corbould. 2008. Ecology of Fishers in the Sub-boreal Forests of North-central British Columbia: Final Report. Peace/Williston Fish and Wildlife Compensation Program Report No. 315. 178 pp plus appendices.
Weir, R.D., and F.B. Corbould. 2010. Factors affecting landscape occupancy by fishers in north-central British Columbia. J. Wildl. Manag. 74:405-410.
Weir, R.D., I.T. Adams, and A.J. Fontana. 2003. East Kootenay fisher assessment. Unpub. rep. prepared for Minist. of Water, Land and Air Protection. BC. 31pp.
 

Please visit the website Conservation Status Ranks for information on how the CDC determines conservation status ranks. For global conservation status reports and ranks, please visit the NatureServe website http://www.natureserve.org/.

Suggested Citation:

B.C. Conservation Data Centre. 2025. Conservation Status Report: Pekania pennanti pop. 5. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Dec 5, 2025).