Cascades Fisher Reintroduction Project 2020 Progress Report

Cascades Fisher Reintroduction Project 2020 Progress Report

Conservation Northwest / Dec 22, 2020 / Fishers, National Forests, Restoring Wildlife

Since winter 2015, we have released 170 fishers in Washington’s Cascades. Our project partners plan to continue aerial telemetry flights through the summer of 2021, with supplemental ground-based telemetry and wildlife monitoring to obtain location data and determine the survival status of released fishers in the North Cascades.

Cascades Fisher Reintroduction Project: Progress report for April 2019 to June 2020 prepared by the Washington Department of Fish and Wildlife, National Park Service, Conservation Northwest and The Calgary Zoo.

December 2020 – View online report (PDF)
Prepared by Jeffrey C. Lewis, Jason I. Ransom, Tara Chestnut, David O. Werntz, Sandie Black, Jose Luis Postigo, and Axel Moehrenschlager



Aerial and ground telemetry locations (n=261; 167 female [white diamonds], 94 male [orange circles]) obtained from December 2018 to June 2020 for 89 fishers released in the northern portion of the Cascade Fisher Recovery Area in Washington (see Table 4). Blue stars indicate the locations of release sites. Additional confirmed non-telemetry detections (n=33) are depicted as black squares. Click to enlarge.
Fishers (Pekania pennanti) were extirpated from Washington due to over-trapping, habitat loss, and predator eradication programs. A mid-sized member of the weasel family, fishers occurred in the coniferous forests of Washington until the early and mid-1900s. We established a partnership between federal, state, and non-profit organizations with the goal of restoring fishers to their former range in Washington. This partnership reintroduced 90 fishers from British Columbia to Olympic National Park from 2008 to 2010.

We are now in the fifth year of a reintroduction project to restore fishers to Mount Rainier National Park (MORA), Gifford Pinchot National Forest (GPNF) and the larger South Cascade Ecosystem, and in the second year of reintroducing them to North Cascades National Park Service Complex (NOCA), Mount Baker-Snoqualmie National Forest (MBSNF), and the larger North Cascades Ecosystem.

To date, we have released 81 fishers (69 fishers (38 F, 31 M) from British Columbia, Canada, and 12 fishers (7 F, 5 M) from Alberta, Canada) into MORA and GPNF in the South Cascades Ecosystem. We have collected 1,016 locations of these fishers using radio-telemetry, and this phase of monitoring is complete. The majority of fisher locations occurred within the boundaries of the recovery area.

Annual survival of reintroduced fishers has remained above 50% each year and across both sexes, and thus remains within the parameters for likely population establishment. We confirmed reproduction of fishers in the South Cascades in 2017, when female F023 was photographed with one kit at her den tree, and again in 2018, when female F082 was photographed with one kit at her den tree.

We have now also translocated 89 fishers (48 F, 41 M) from Alberta into the North Cascades Ecosystem, including NOCA and MBSNF. We have collected 261 locations of these fishers using radio-telemetry, and 2020 will be the first denning season when reproduction is expected. Data are still insufficient for calculating annual survival, but 24 mortalities have been detected and several have been attributed to predation. In addition to monitoring movements, survival, and reproduction in the North Cascades, we also report on the progress of several research studies aimed at better understanding reintroduction success and improving animal welfare throughout the process.

View the full report as a PDF or on the National Park Service website

Locations of male (orange circles) and female (white diamonds) fishers from Cohort 1 (those released fall/winter of 2015/2016; all at one release site, the Cispus Learning Center; left graphic) and from Cohort 2 (released at two release sites, fall/winter of 2016/2017; right graphic). The two blue stars indicate the Mount Rainier National Park – Longmire (northern star) and Cispus Learning Center (southern star) release sites. Click to enlarge.

Project status and plans for 2020/21

Since winter 2015/2016, we have released 170 fishers in the Washington Cascades Fisher Recovery Area, and have exceeded our goal of releasing at least 160 founders. We have completed radio telemetry monitoring of fishers released in the southern portion of the recovery area and are now in year two of three for radio telemetry monitoring in the northern portion of the recovery area.

To reach our target goals, we plan to continue aerial telemetry flights through the summer of 2021, with supplemental ground-based telemetry, to obtain location data and determine the survival status of released fishers in the north. During the spring of 2020 and 2021, our flights will focus on obtaining locations for females in an effort to document denning and reproductive success. As in previous years, if reproduction occurs, our goal is to document kit(s) from at least one den site. We will continue to collect data points in an effort to estimate minimum home ranges for all released fishers.

Female fisher F082 was photographed ascending her den tree with a mountain beaver (Aplodontia rufa) in her mouth on 16 June 2018 (left), was detected with a kit on 4 July 2018 (center), and about to ascend a den tree at a second location on 11 September 2018 (right).

Our field efforts will also include recovering any additional mortalities that occur. Additionally, we will continue outreach and education to local communities to facilitate an understanding of project goals and outcomes and as a means to protect fishers that interact or come into close contact with humans (e.g., as non-target captures by trappers in the region, visiting residences, seen near roads)

We will also begin analysis of the complete capture, handling, stress, and behavior data from the associated fisher studies (as described below), as well as continue our support of two current graduate student research projects that are focused on fisher prey and competition in the northern portion of the Cascades Recovery Area.

Fishers being released in the North Cascades on October 24, 2019. Photo: David Moskowitz