CELS scientists seek better understanding of growing fisher population

A fisher perches on a tree stump in a photo captured on a URI trail camera last year. (Photo courtesy of the URI Dept. of Natural Resources Science)

Scientists at the University of Rhode Island have begun a three-year effort to capture and track fishers throughout western Rhode Island to better understand their population numbers and movement as the animals expand into more developed areas of the state.

Funded by the Rhode Island Department of Environmental Management, the project aims to gather data about the secretive predators so they can be managed more effectively.

“It’s fascinating to me to see how this creature that was once known as a deep dark forest-dwelling animal is now living in people’s backyards and in urban settings,” said Laken Ganoe, a URI doctoral student who is leading the project along with Assistant Professor Brian Gerber. “It’s a unique landscape for us to study a creature that we don’t know much about in the state.”

Fishers are carnivorous mammals found throughout the forests of the northern United States and Canada. Extirpated from Rhode Island when forests were cleared for agriculture in the 1700s and 1800s, they have returned in recent decades and appear to be expanding their range in the region. They feed primarily on small mammals like chipmunks and squirrels, though in more northerly regions their preferred prey is snowshoe hares.

In Rhode Island, fishers are legally trapped for their fur by licensed trappers during a 25-day trapping season in December.

Ganoe will use trail cameras set up at 200 sites in Providence, Kent and Washington counties to document where the animals are found. She also plans to capture up to 20 fishers in each of the next three years and place tracking collars on them to monitor their movements and activity levels throughout the day.

“We hope to learn how fishers are interacting with their environment in this matrix of urban and forested landscape,” Ganoe said. “Are they spending more time out and about in urban areas at night while being more active at dusk and dawn in forested areas? Are human activities constraining their activity patterns?”

“Tracking individual fishers for the winter will get a really fine scale idea about how they cross roads, what forests they are selecting for, what areas they’re avoiding,” added Gerber. “If we do it right and we’re lucky, we’ll be able to estimate how many fishers there are in certain regions of Rhode Island. Hopefully all of this will give us guidance to foresee the future so we can change management tactics quickly as necessary.”

A native of Clarion, Pennsylvania, Ganoe earned a master’s degree at Pennsylvania State University and studied fishers in the Sierra Mountains of California before enrolling at URI. She became interested in the animals as a teen when she watched as a fisher caught a chipmunk and ran up the tree from which she was hunting and ate it right beside her…[Read more]