Knee deep in a box culvert, Anton Kaska slowly pulls apart the matted structure of sticks and mud holding back the pond.

As the culvert’s trickle grows into a rush, the sheath of ice across the water cracks like gunshots and the new current stirs up the smell of rotting leaves. It took a single beaver only a day to build up the dam Kaska just broke down. He estimates it held back more than 1,000 gallons of water that residents of this subdivision, and the town that hired him, will be happy to see flow down the culvert and not across their road.

But Kaska knows many people won’t be happy with what he does next: set a foothold trap that will snap shut on the resident beaver and drag it underwater for him to collect later.

During prior jobs, he’s had a gun pulled on him and the lug nuts loosened on his truck.

“The beaver that lives over here is a resource. It belongs to the lady over there and the guy up there,” Kaska says, gesturing to two nearby houses. “It belongs to all of us. It’s our responsibility to use it wisely.”

But the value of that resource has become increasingly complicated in recent years as economic, environmental and social factors have diminished trapping to a hobbyist’s retreat.

In 2013, a top-quality beaver pelt could fetch $170 at auction, according to North American Fur Auctions. This year, trappers would be lucky to get $38 for it, and an average eastern beaver pelt may sell for less than $13.

Russia and China prop up the world’s fur markets, but the demand in North America and Europe has shrunk amid an intense anti-fur campaign waged by animal rights activists who reject arguments that trapping helps manage wildlife populations and see it as abject cruelty.

Lawmakers in California, one of the nation’s fashion capitals, have proposed a statewide ban on fur sales. And in New Hampshire, several bills have already been proposed for the new legislative session that would limit certain kinds of trapping and hunting.

“They’re not managing species for the betterment of the wildlife. They’re out doing it for themselves, because it’s a tradition,” said Kristina Snyder, a vociferous opponent of trapping from Chester. “They go against nature. They’ll use nature as a defense for what they do, but they go against nature because they’re taking out many of the animals that would regulate this.”

Trapping’s efficacy as a wildlife management tool and the morality of the practice will continue to be fiercely debated. What’s certain is that trapping is on the decline in New Hampshire.

Trappers caught 6,635 fur-bearing mammals — including fox, mink, fisher, otters, raccoons, beavers, and coyotes — during the 2009-10 season. By the 2015-16 season, the haul had shrunk to 5,431, according to data from the Department of Fish and Game.

And last season saw a dramatic 45 percent drop to just 2,956 animals.

New England built by trappers

Trapping was once a foundation of the New England economy. It led to some of the first trade agreements between native tribes and colonists and fueled new world conflicts between European powers.

“From Canada and New England within these six years hath come neare 20,000 Bever skins,” Capt. John Smith wrote in 1622, according to “The Northwest Fur Trade,” by Wayne Edson Stevens.

More than 100 years later, it seemed the trade still hadn’t reached its zenith.

“The fur trade, already very valuable, will naturally extend itself to the greatest degree it is capable of, after a few years peace with the Indians, whose necessities will drive them to you for supplies which they can obtain of no others, were they so inclined, and can pay for only by furs and peltry,” future New Hampshire Gov. John Wentworth wrote in a 1765 dispatch to the British government.

That history remains a source of pride for modern-day trappers, even though few of them can still make a living from the trade.

“I like carrying on the tradition. I think it’s an important part of Americana,” said Kaska, who was born in the San Francisco Bay Area in a family that neither hunted nor trapped. “America was built on the back of trappers and I like to keep the tradition going.”

Kaska’s 13-year-old son now has a trapping license. He accompanies his father on many of his jobs and sews his own beaver-pelt hats with deer sinew.

Growing bans and restrictions

Decades ago, Massachusetts banned many types of steel jaw and body-gripping traps, and other states have followed.

Efforts to restrict trapping have moved slower in Northern New England, but each year sees more pressure from groups like the Humane Society and NH Citizens Against Recreational Trapping.

Trappers argue that their work serves a communal purpose. They’re often the first ones to notice signs of disease in furbearers and their catches provide the data Fish and Game uses to estimate animal populations.

And as humans increasingly encroach on habitat and kill predators, including by trapping, the practice serves as a check on prey species that would otherwise grow out of control until they starved, trappers say.

“Trapping is a mechanism to remove surplus animals off the landscape,” said Pat Tate, a wildlife biologist who leads the furbearer project for the Department of Fish and Game.

But with trappers setting fewer traps, and catching fewer animals, as they have in recent years, their role is reduced.

“The effects of trapping on wildlife populations depends on season lengths and number of individuals, meaning humans, participating,” he said. “With very few individuals targeting wildlife species, the effect of the management is small.”

Tate believes trappers have a role to play in monitoring New Hampshire’s wildlife, but Fish and Game and the Legislature are increasingly under pressure to put more limits on the practice.

Snyder said she and other activists understand that trapping may be the only option for some nuisance animals, like beavers that threaten property, but they would like to see recreational trapping eliminated.

“Trapping is kind of declining, which is a good thing and I think people should understand that that’s the direction society is going,” Snyder said.