Predator "preservationists" pounce on Fisher population trends

Does anyone remember those Magic Eye puzzles from when you were a kid? When I was but a wee lad, my friends would order the Magic Eye picture books through our school’s Scholastic program and take turns announcing what they saw in each puzzle (I was a typical 90’s kid). I recall one puzzle supposedly depicted a tugboat. I never saw it, but my friends were convinced. I tried really really hard, but I just didn’t get it. I brought that picture home and obsessed over it for an entire weekend, staring intently as I peered close and slowly drew the blurry image away from my face over and over again. Finally, three days later I convinced myself there was a tugboat in the picture; complete with a smoke stack and a little captain at the helm. It wasn’t until days later that a friend told me I had the picture with a race car in it instead.

It just goes to show - if you stare at something really hard, you’ll start to see what you’re looking for - even if it isn’t really there.

The Fisher ( Pekania pennanti )

The Fisher (Pekania pennanti)

Speaking of obsession, there’s been quite a bit of criticism over NH Fish and Game’s trapper-furnished CPUE data trends. CPUE stands for Capture Per Unit Effort. Its a measurement to monitor population trends for wildlife taken during regulated seasons. Its applied most commonly to lobster and commercial fishing records, but New Hampshire has actually been utilizing the matrix for keeping tabs on the state’s furbearing mammals. The records which make up these yearly data reports are mandatorily turned in by licensed trappers each year. Every furbearing species in New Hampshire has a yearly CPUE tally. In fact, New Hampshire is one of the only states in the region to make CPUE data reporting mandatory for trappers, going back decades.

This year critics of regulated hunting & trapping activities in New Hampshire have asserted that predatory furbearers, such as fox, fisher, and mink, are on a downward spiral towards “certain extinction”; based solely on the numerical decline in these CPUE reports.

Back in the spring of 2018, we reported on the contentious tug-o-war over fox hunting seasons; with critics citing a decline in the CPUE trends as reason enough to abolish management of the species. It was also suggested that fisher populations were “declining” and hunting/trapping of this species should be halted as well. In the end, the NH Fish & Game Department opted to leave the fox seasons alone until more scientific data could be gathered into these perceived “declines”. The fisher season on the other hand, was further restricted with a conservative 2 animal bag limit statewide during the 31 day trapping season.

Apparently, some people refused to accept the new restrictions; publicly demanding a full close to the 2018 fisher season before it even started. It was also suggested (by the same people) that the state’s hunters and trappers are in some kind of cabal with the NH Fish and Game Department - mischievously twirling our mustaches whilst scheming on how to “get one over” on the non-hunting public. (We meet for tea every Tuesday, in case you were wondering.)

Not All Fisher Who Wander Are Lost

The Fisher (Pekania pennanti), sometimes referred to in New England dialect as the “fisher cat” is a small to medium-sized carnivorous mammal native to North America. It is a member of the mustelid family, which includes martens, weasels, mink, and wolverines to name a few. Their range covers boreal forests in Canada to the northern United States. Through reintroduction efforts, the fisher even thrives in the unlikely urban areas of states like New York, Massachusetts and Connecticut. They are trapped during regulated seasons, primarily for their pelts, or in some cases due to nuisance situations with livestock or pets.

With a varied diet, fisher will feast on small rodents, carrion, berries and acorn mast. As skilled hunters, they are built for running down squirrels in tree canopies, as well as stalking turkeys, nesting bird species and even the occasional suburban cat or two. Its important to note that even though fisher have been known to take house pets (I’ve read reports of the animal pulling small cats and dogs through window screens here in southern NH), they often get blamed for more missing pets than they actually take. Hawks, owls, coyotes, fox, and bobcats are all equally skilled and capable of running down “Fluffy” the tea-cup poodle or “Jinx” the cat.

(Photo | USFWS)

Any skilled trapper will tell you the fisher is known for its short attention span and rather large home range. Fisher are fairly easy to trap - if they’re around. During the 31 day season here in New Hampshire, it may take the full month just to have a fisher pass the area you’ve placed your traps. Add the fact that written landowner permission is required to place those traps, it doesn’t take a state biologist to determine that the odds are stacked in the fisher’s favor - as they should be. Understand, it takes skill, an eye for terrain, and frankly a big heaping stroke of luck to “bag” a fisher in the woods of New Hampshire.

In other words, you have to be dedicated and committed for the full 31 days of the season. You have to be in the right location to connect. And you need to have something that interests a fisher in a forest full of alternate food sources. One could place a trap in the middle of the forest for a full 31 days. If theres’s no fisher passing by in that 31 day span, or if the conditions aren’t right, you won’t catch them. It doesn’t mean there’s “no fisher” anywhere else.

Checking The Trends

Obviously, the suggestion that fisher are declining is concerning. To assert that trappers are to blame (as some people have with this subject) is even more concerning. Needless to say, it gets my attention.

So, I studied the CPUE data going as far back as the 1970’s. Sure enough, there is a noticeable decline through the late 1990s and early 2000s. I should note that the decline in fisher during this time ironically correlates with other conducive events, including an increase in bobcat presence in NH (a direct fisher competitor), and continued forested habitat loss. New Hampshire has become quite the “quaint little nesting spot” in recent decades, and all that prime wildlife real-estate has been mowed down for housing development and human expansion. For the voracious predator the fisher is, its really a big ol’ softy when it comes to environmental change.

Back to those CPUE numbers. I found it pretty astonishing that despite the assertions from trapping critics that fisher population numbers were declining, the last decade of data actually doesn’t show much change over year to year trends (see Table 1). On the contrary, it’s been relatively flat. Fisher numbers haven’t really moved that much lately, and actually increased last year. Apparently, NHFG biologists came to the same conclusion this past week in a radio interview on NH’s 107.7 The Pulse, with host Peter St James.

(Table 1) With data furnished from NH Fish and Game, the CPUE totals for furbearing species are laid out from seasons 2005 to 2017. Note the steady continuance of the fisher’s year to year CPUE.

Wildlife Division Chief, Mark Ellingwood, and Furbearer Project Leader, Patrick Tate joined St. James to discuss the accusations that the fisher population is in decline, and the Department (as well as licensed trappers) are “complicit” in said decline.

“In the past ten years, I’d say its arguable as to whether that decline is continuing or at the very least its slowed, or stabilized.” said Ellingwood, who also pointed out that the criticism comes in the midst of the NHFG Department’s newly conservative reduction in fisher take from a 5 to a 2 animal yearly bag limit.

“With the support of both the (NH Fish & Game) Commission and the trappers, we’ve made 4 adjustments to bag limits in response.”

“The Department, I think, has done due diligence.” “Within the last 10 years, we’ve gone from 15, to 10, to 5, and most recently 2 in the bag (limit).”

“I think we’re on the right track and I hope the public realizes that.” stated Ellingwood.

To add to the many questions behind a potential fisher decline, state wildlife managers have recently detected a strain of Canine Distemper Virus (CDV) amongst local populations of furbearers; most notably fisher and fox.

Licensed trappers in New Hampshire have recently been called upon to turn in carcasses of legally trapped furbearers, including fisher and fox, for a myriad of scientific studies - including multiple CDV testing programs.

“We’ve recently detected distemper in fisher, and that is very uncommon.” Ellingwood said during the interview. “So working with support of the New Hampshire Trappers Association, the Department has recently reached out to NH’s diagnostic lab at UNH… and we are beginning a pilot effort to try to get a better handle on the prevalence of distemper in our furbearer populations.”

I played with some of the CPUE data myself and discovered, based on 2017 numbers, approximately 14% of the overall fisher population is finding their way to areas with set traps. On the scale of everything that a wild animal is faced with on the landscape, pressure from human trappers is minimal to say the least. Distemper, predatory competition, and loss of habitat are all potentially playing a part; and it may very well be trappers who assist with finding a real cause.

interpretation is Subjective

Its important to note that when New Hampshire was faced with a controversial proposal to re-open bobcat hunting and trapping seasons, I stated on this very website that I feared other meso predators would feel the effects of an expanding, and unregulated bobcat population - namely fisher. More importantly, the science and biological data figures behind supporting a bobcat season were not “good enough” for trapping critics at the time. Suddenly, three years later, the very same science and concepts seem to now point to a need to close future management on other predators? The same folks chanting a need to “listen to the state’s biologists” one day, are now chanting that state professionals are in “cahoots” with the hunting community today. The double standard is real, folks.

A fisher captured on a hunter’s trail camera in New Hampshire (photo | Rob Richardson Jr)

Even more intriguing, some citizens question whether there really is a decline at all. In the days leading up to the writing of this column I was bombarded on social media with countless trail camera pictures from local hunters; all showing fisher recently roaming the woods of the Granite State.

Are we finding our way out of a cyclical “boom and bust” fisher trend? CPUE is great for checking trends, but it doesn’t give you the root cause of a perceived decline. Biologists have stated fisher appear to be adapting (and thriving) in more urban areas; have these creatures abandoned the dense hemlock groves where trappers roam for the dumpsters and back decks of suburban sprawl?

Regardless of what side of the debate you sit on its important to recognize who’s lifting a finger to address a perceived decline, and a potential remedy. Lest we forget that the same data used by trapping critics to assert that fisher populations are “trending down”, were furnished directly by the very trappers those critics now want to shut out of the equation. I don’t claim to be a genius, but if I’m suffering from the flu, I’m not about to chop my leg off in hopes of feeling better.