Once trapped to extirpation in Pennsylvania, the furbearer is making a comeback
January 10, 2010 3:00 PM
Once trapped out in Pennsylvania, the fisher was reintroduced in 1994 following stocking programs in West Virginia and New York.
By Deborah Weisberg
Trappers may enjoy a short but sweet open season on fishers next year for the first time in more than a century.
Although logging and over-harvest wiped the fisher from commonwealth forests in the late 1800s, reintroduction efforts by agencies and groups from Pennsylvania, West Virginia and southern New York in recent decades have worked so well, the Pennsylvania Game Commission believes the weasel with the luxurious pelt can tolerate limited harvest here.
The agency's board is expected to give preliminary approval to a brief season in certain parts of the state at its quarterly meeting in Harrisburg Jan. 24-26. Pending public comment, final approval could be given in April.
"We introduced 190 fishers from 1994 to 1996 for the purpose of eventually establishing a harvest season and we're seeing a lot more now," said Game Commission wildlife biologist Tom Hardisky. "Fishers are abundant enough that if people want to take a limited number, the population can withstand it and still do well."
Although native to Pennsylvania, fishers disappeared along with 90 percent of the commonwealth's forests by 1900 after excessive logging destroyed their habitat. Unregulated market hunting dealt the final blow.
"A lot of forest predators were practically wiped out, including bobcats and foxes, and squirrel populations were greatly diminished," said Hardisky, who noted forest regeneration is the single most important factor in the resurgence of those species. "In the past couple of decades, our oaks have reached a point where they're producing a lot of acorns, which makes rodent populations explode. Squirrels, moles, shrews and mice are the fishers' bread and butter."
Hunter sightings, road kills and incidental releases by trappers indicate fisher numbers are growing. Jeff Larkin, an Indiana University of Pennsylvania wildlife biologist who has conducted fisher surveys, said the total number of fishers that have resulted from the Pennsylvania reintroduction program is "the $65 million question."
"We know many of these animals are from West Virginia, which began its own reintroduction effort in 1969, and genetic evidence suggests some fishers may also have come in from New York, which reintroduced in the Catskills a year later."
Hair samples taken from fishers in State Game Land 26 near Blue Knob State Forest indicate those animals originated in West Virginia, and they comprise one of the densest populations in Pennsylvania. Larkin and his students counted 58 fishers in a 200-square kilometer area during a 1 1/2-year survey.
"Thirty is the average density for an area that size," Larkin said. "To find 58 indicates some of the highest densities in the species' entire range."
As promising as their numbers appear to be, fishers are slow to reproduce, which is why Pennsylvania's trapping season will be limited, at least to start. Females don't reach sexual maturity until age 3. They nest in the hollows of trees and give birth to three or four cubs in March or April. Although they become pregnant again immediately, their eggs don't develop until the following February, a condition called "delayed implantation."
"It's nature's way of ensuring that only females healthy enough to survive winter will give birth, and at a time when there's plenty of young-of-year prey for them to feed their cubs," Larkin said. "This also gives cubs the summer and fall to get big and strong enough for winter."
The Pennsylvania Trappers Association supports conservative regulations, said its president Brian Mohn.
"It's because they're so slow to reproduce that we don't want to see overharvest," he said. "But we're also seeing more numbers as incidental catches in our traps, and our guys have been asking for a while now, 'When can we keep them?' "
Classified a mustelid, the fisher is cousin to mink, wolverine, pine marten, badger and skunk. Trappers prize them for their pelts, Mohn said, although they now fetch as little as $20 each on the commercial market.
"Their fur is unbelievably beautiful, especially the females', which is very thick and soft," he said. "Through the years only the richest people had fisher coats, so fishers have prestige. As trappers, we like the opportunity to get the game we've always heard about."
Because fishers travel alone, trapping them presents a challenge, Mohn said. "You may get a shot at one animal a season, so you've got to do your homework. You have to look at topographical maps and scout them and figure out their path, whether its mountain ridges or riparian strips."
"All mustelids run mountain and stream bank circuits, so patterning is critical," agreed Hardisky, who also traps. "It might be a week or more before they come through an area again, but they seem to run a predictable path."
With females averaging 8 pounds and males twice that size, Mohn suggests using a fox-set to trap fishers, with 1 1/2 to 1 3/4-inch foot restraints and a lure scented with beaver or skunk.
Fishers are mostly nocturnal and omnivorous, although they prefer meat and will even scavenge on dead animals.
"They have good claws and a great set of teeth," Hardinsky said. "They're voracious predators and killers, like all weasels."
"When they're moving, they're always on the hunt, looking like crazy and working off all their senses -- scent, sight and hearing," Larkin said. "Their sense of smell is especially keen."
Fishers often climb trees for both prey and cover. "They're good climbers, and will use an abandoned squirrel nest to rest in during the day, or they'll sometimes kill the nestlings and then use the nest for a day rest," he said. "They're opportunists."