New study shows stable fisher population in the Southern Sierra Nevada

January 28, 2013

After experiencing years of population decline on the West Coast, a recent study examining fisher populations found that—at least in the southern Sierra Nevada—the animal's numbers appear to be stable.

Scientists from the U.S. Forest Service's Pacific Southwest Research Station (PSW) and the Pacific Southwest Region collaborated to monitor the distribution of fishers across a 7,606-square-mile area in the southern . They used baited track-plate stations—an enclosure where the fisher leaves a sooted track print as it walks through—at 223 locations across three national forests. Over an eight-year period, from 2002-2009, they found that the fisher population in the southern Sierra Nevada neither increased nor decreased.

The findings are relatively good news for the cat-sized relative of the weasel family. The forest-dwelling fisher (Martes pennanti) once lived throughout most of the mountains in northern California and the Sierra Nevada, and in the , Cascades and Coast ranges. But many populations were eliminated or declined due to commercial trapping and clear-cut timber harvesting. Fishers have been reintroduced at a few locations in the western U.S., but only two —both centered in California—remain. The small population of fishers in the southern Sierra has been estimated, by other methods, to be approximately 250 individuals.

"This study is encouraging in that it demonstrates that we can monitor a fisher population over a large area, with simple methods," said Bill Zielinski, a PSW research ecologist who coordinated the analysis of the research data. "It is also encouraging that we did not discover a decreasing trend in the population, but eight years is a relatively short period."

Zielinski noted that given the short time period of this study, the effects of Forest Service management actions to protect fishers and their habitat cannot yet be fully assessed. Further study, over a longer time period is necessary to fully understand the efficacy of these conservation measures. Other factors unrelated to habitat, including road kill and the illegal use of rodenticides which poison the , must also be considered when evaluating the population.

"We hope that we can continue to monitor the fisher, so that we can witness an increase in the population as public and private groups collaborate to institute measures to protect them from various threats," he said.

Explore further: Scientists map out potential for restoring California fisher populations

More information: Results of the study appear in the online version of the Journal of Fish and Wildlife Management and can be viewed at: treesearch.fs.fed.us/pubs/42545

Related Stories

Wildlife researchers want your old socks

December 20, 2011

(PhysOrg.com) -- A University of California wildlife research team working in the Sierra Nevada is asking the public to donate clean, gently used socks for research on a rare weasel called the Pacific fisher.

Poisons on public lands put wildlife at risk (w/ Video)

July 13, 2012

Rat poison used on illegal marijuana farms may be sickening and killing the fisher, a rare forest carnivore that makes its home in some of the most remote areas of California, according to a team of researchers led by University ...

Fisher decline documented in California

July 5, 2011

The Hoopa Valley Tribe, in cooperation with the Wildlife Conservation Society and the University of Massachusetts, reported a 73-percent decline in the density of fishers—a house-cat sized member of the weasel family ...

Recommended for you

Energy-saving LEDs boost light pollution worldwide

November 22, 2017

They were supposed to bring about an energy revolution—but the popularity of LED lights is driving an increase in light pollution worldwide, with dire consequences for human and animal health, researchers said Wednesday.

Re-cloning of first cloned dog deemed successful thus far

November 22, 2017

(Phys.org)—A team of researchers with Seoul National University, Michigan State University and the University of Illinois at Urbana-Champaign has re-cloned the first dog to be cloned. In their paper published in the journal ...

Testing the advantage of being left-handed in sports

November 22, 2017

(Phys.org)—Sports scientist Florian Loffing with the Institute of Sport Science, University of Oldenburg in Germany has conducted a study regarding the possibility of left-handed athletes having an advantage over their ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.