Jeff Lewis, who was holding an antenna high above his head, walked through the Cascade Mountains, southeast of Seattle, in search of an antenna. As he navigated fallen fir logs and dripping ferns, he heard it: a faint “beep” from a radio transmitter implanted in an animal code-named F023.
F023 is a fisherman (Pekania pennanti), an elusive member of the weasel family that Lewis fondly describes as a “tree wolverine.” Resembling a cross between a cat and an otter, these sleek carnivores hunt in forests in Canada and parts of the northern United States. But fur trapping and habitat loss had wiped out Washington’s population by the mid-1900s.
Lewis, who was monitoring F023, kept tabs on her radio signals from a plane about two to three times per month. He also tracked the signals of dozens other recently released fisherman. Come spring, he noticed that F023’s behavior was different from the others.
Her locations had been clustered close together for a few weeks, a sign that she might be “busy with babies,” says Lewis, a conservation biologist with the Washington Department of Fish and Wildlife. He and his colleagues ventured into woods to confirm that she had actually given birth. It would have been the first documented wild-born fisherman in the Cascades for at least half a hundred years, if it was true.
As the faint beeps grew louder, the biologists found a clump of fur snagged on a branch, scratch marks in the bark and — the best clue of all — fisher scat. The team installed motion-detecting cameras in the trees. The team finally found the right photo after looking through hundreds of images about squirrels and deer. It was a grainy shot of F023 carrying her kit from her high-up den in a tall hemlock tree. The scientists were delighted.
“We’re all a bunch of little kids when it comes to getting photos like that,” Lewis says.
Chasing babies
This significant birth took place during the second phase in a 14 year fisher reintroduction project. The project moved its focus east from Seattle after 90 fishers had been released in Olympic National Park between 2008 and 2010. From 2015 to 2020, it relocated 81 fishers to the South Cascades, home to Mount Rainier National Park, and then 89 fishers to the North Cascades, from 2018 to 2020. They were imported from British Columbia and Alberta. The final batch of fishers was released by researchers at the end of last year.
A project’s success is measured by the number of baby animals. As part of Washington’s Fisher Recovery Plan, biologists set out to document newborn kits as an indicator of how fishers were faring in the three relocation regions.
Before F023’s kit was caught on camera in May 2017, biologists had already confirmed births by seven relocated females on the Olympic Peninsula, where the whole project began. Two of the seven females had four kits, “the largest litter size ever documented on the West Coast,” says Patti Happe, wildlife branch chief at Olympic National Park. The majority of females have between one and three kits.
Lewis is frequently asked why he would spend so much effort to restore a critter that many people have never heard about. His answer? A wide range of carnivores makes ecosystems more resilient.
Happe admits to another motive: “They’re freaking adorable — that’s partly why we’re saving them.”
The missing piece
Contrary to their name, fishers don’t hunt fish, though they’ll happily munch on a dead one if it’s handy. They are mostly small mammals but will also eat reptiles or amphibians as well as fruit, insects, fruit, and even carrion. A male can grow to 6 kilos and is approximately the same length as a female. Fun fact: Females raise their young high above the forest floor, in hollowed-out spaces made by tree trunks. Fish can face-first descend tree trunks by turning 180 degrees their hind feet. They are extremely sharp with partially retractable claws and have razor-sharp teeth. And they’re incredibly agile, leaping up to two meters between branches and traveling as much as 30 kilometers in a day.
Fishers’ stubby legs and unique climbing skills make them a threat to tree-climbing porcupines. It isn’t pretty: A fisher will force the quill-covered animal down a tree and attack its face until it dies from blood loss or shock. The fisher then skins the prickly prey and eats most of the bones and quills.
However, these predators were not able to take on humans. Trappers started targeting fishers to get their fur in the 1800s. The glossy brown-gold pelts, which were soft and luxurious, sold for up to $345 per piece in the 1920s. Fishers were driven out of Washington by this demand. This led to fishers fleeing from Washington as well as from over a dozen other northern states. The Great Lakes region and New England were ravaged by porcupines after fisherman populations dropped. The porcupines ate up the seedlings of trees, causing havoc in forests.
Private timber companies joined forces with state agencies in an effort to reduce the number of porcupine population. These efforts and stricter trapping regulations have resulted in fishers being back abundant in Michigan and Wisconsin as well as New York and Massachusetts.
Like most West coast states, Washington’s fisherman numbers were still low. Since the beginning of the 21st Century, no fisherman had been seen in Washington for more than three decades.
Private timber companies in Washington, like in New England and the Midwest, supported the return of fishers. Although porcupines are uncommon in Washington, mountain beavers — a large, primitive rodent endemic to the Pacific Northwest — fill a similar role in Washington’s evergreen forests: They eat tree seedlings. They are also eaten by fishers.
The state devised a plan to import the animals from Canada in 2006. “It was a big opportunity to restore a species,” Lewis says. “We can fix this.”
A new home
Like the other Canadian fishers moved to Washington, F023’s relocation story began when she walked into a box trap in British Columbia, lured by a tasty morsel of meat. The bait had been set by local trappers hired by Conservation Northwest, a nonprofit that is one of the recovery project’s three main partners, along with Washington Fish and Wildlife and the National Park Service. After her health was checked and she received antiparasitics and vaccines to make her comfortable in her new environment, F023 was transported across the border with a radio transmitter that had been surgically implanted.
Members of the fisher recovery group met her and released her south of Mount Rainier National Park. The forest’s towering Douglas fir, western red cedar and western hemlock trees were full of cubby holes and cavities to hide in, and the undergrowth held plenty of small mammals to eat. At the release, upward of 150 people gathered around F023’s box, part of the team’s effort to engage the public in championing fisher recovery. Everyone cheered when a child opened the doors and the furry male bolted into the snowy woods.
Each fisherman was monitored for two years by the team to determine if each project met the following key benchmarks: at least 50% of fishers survived their first year; at least half established a home range close to the release site; and at least one confirmed kit being born to a female.
“We met those marks,” says Dave Werntz, science and conservation director at Conservation Northwest.
One bypass that was built over and under the roughly 25-kilometer stretch Interstate 90 east to Seattle may have assisted in this effort. One of these structures is the largest wildlife bridge in North America, an overpass “paved” with forest. A remote camera captured a picture of what appears to be a fisherman moving through one the underpasses in 2020.
“Male fishers go on these huge walkabouts to find females,” Werntz says. While biologists assumed fishers would cross the freeway to search for mates, having photographic proof “is pretty wonderful,” he says.
Happe and others hope that they will one day see wildlife crossing Interstate 5. She states that the major obstacle to the Olympic or Cascade populations is the freeway which runs north-south along the coast. “We’re all working on wildlife travel corridors and connectivity in hopes the two populations hook up.”
Learning curve
Radio tracking shows that the majority of the 90 initial fishers who moved to the Olympic Peninsula were settled into their new homes. The location was released in the following year. The average survival rate for fisherman was 73 percentThey are, however, dependent on the year and the season in which they were released as well as the sex of the fishermen.
Males did better than females. Seventy four percent of recorded deaths occurred in females. There were 24 carcasses that were recovered. Cause of death could be determined14 of the victims were killed in predator attacks, seven were struck with vehicles, two drowned, one died in leg-hold traps. Lewis, Happe and their colleagues reported this in the April 20,22. Journal of Wildlife Management.
The animals struggled to find mates after the first fishers who moved to the Olympic Peninsula had been released at different locations. The result was that only a handful of parents were able to produce the next generation.
Six years after the relocation, the researchers were concerned by the genetic diversity of Olympic Peninsula fisherman. Happe and co-workers set up 788 remote camera and hair-snare station: triangular cubbies with chicken legs at one end, and wire brushes protruding on the other to grab fur strands. Analyzing the fur’s DNA Inbreeding raises red flagsHappe, Lewis and others agree.
“Models showed we were going to lose up to 50 percent of genetic diversity, and the population would wink out in something like 100 years,” Happe says. The team added 20 fishers to the Olympic Peninsula’s gene pool in 2021. These animals are from Alberta while the original population came from British Columbia.
Based on lessons learned from the Olympic Peninsula, the team adapts as the Cascades reintroduction effort moves into the Cascades. To increase the chances of fishers finding each others more quickly, the animals were released at less sites that were closer together. The animals were also released before January to allow females time to establish a home before the spring mating or birthing season.
Locating their food
More unanticipated discoveries were made as the experiment continued. The southern Cascades was home to the Fishermen You were more likely to survive for the first year.According to the June final project report, which was released in June, this is a higher percentage (76%) than those who were relocated north from I-90 (40%) Remote-camera data suggest that’s because there are less prey and slightly more predators in the North Cascades, says Tanner Humphries, community wildlife monitoring program lead for Conservation Northwest.
Happe notes that both in the Cascades, and on the Olympic Peninsula, fishers are using different habitats than biologists expected. The mammals — once assumed to be old-growth specialists — are using a mosaic of young and old forests. Fisherman require large, mature trees with plenty of cavities to denning and rest. However, prey may be easier in younger forests where trees have been cut or thinned.
Live traps from the South Cascades back this theory. Fishers’ preferred prey — snowshoe hares and mountain beavers — were most abundant in young regenerating forests. In older forests, traps Primarily, mice, voles, chipmunks were detectedMitchell Parsons (a Utah State University wildlife biologist in Logan) reported the findings in 2020 with Lewis, Werntz and other fishers. Forest Ecology and Management.
Future is coming back to life
After F023’s baby was caught on camera five years ago, the mother’s tracking chip degraded as designed — the hardware lasts less than two years. Washington has seen many fisher kit births since then.
These furry carnivores are actually one of North America’s most successful translocated mammals. Lewis says that 41 translocations across the continent have resulted in fisher population growth. They now cover 68 percent of the historical range they occupied in 2000, compared to 43 percent in mid-2000s.
The relocation phase has concluded with the delivery of last batch of fishers to Washington in 2021. Lewis, Happe and their partners plan to continue monitoring how these sleek tree-climbing carnivores are faring — and how the ecosystem is responding. Fishers, for instance, are very much in demand. Mountain beavers are seedling-eating mountain beavers.According to Happe, Lewis, and other researchers, this is according to 2021 research Northwestern Naturalist.
Animals worldwide face many challenges due to climate change, ecosystem degradation and species loss. Lewis states that Washington’s fisherman are once more thriving, which is a sign of hope.
“It’s a hard time, it’s a hard world, and this feels like something we’re doing right,” he says. “Instead of losing something, we’re getting it back.”
