River otters are making a splash on Long Island, popping up in waterways where they had been absent for decades. A new survey looks at their rebound in the Peconic Bay watershed.
The semi-aquatic mammals are native to Long Island, but an unregulated fur trade, water pollution and habitat loss wiped them from the region in the mid-1800s. By the 1930s, New York placed a moratorium on trapping for a few years to help the population rebound. That did help kick-start recovery in more northern parts of the state.
It was only a few decades ago that environmental officials reintroduced otters to western New York, but their return to Long Island has happened naturally.
“The source population for Long Island is Connecticut, possibly Rhode Island, and Westchester. So they have to cross Long Island Sound, and that’s a challenge," said Mike Bottini with Seatuck Environmental Association. He started surveying for otters back in 2008. Early results found signs of otters all along the north shore, but mostly concentrated around Oyster Bay and Nissoquoge River.
"The million-dollar question we always get asked as wildlife biologists is 'well, how many otters are out there?'" Bottini said. "They're tough to spot, they're very nocturnal — that's why most people don't know they're out there. They also have large home-ranges...they average about 20 miles of shoreline, and that's a big area."
There are other ways to "spot" an otter. More than 100 volunteers assist with the survey efforts by looking for otter scat and the remains of their favorite foods—fish and crustaceans. They also monitor trail cameras placed in areas where otter signs had been found.
The latest survey around Peconic Bay, which separates Long Island's north and south forks, finds evidence of their presence, but it is limited in comparison to the north shore.
“There’s still a lot of good habitat in the Peconic Estuary, about 40 to 50% of really good otter habitat hasn’t been occupied yet by otters,” Bottini said.
Recent survey results also show an increase in otter-car collisions on Long Island. Fifteen have been recorded over the last 20 years, twelve of which have happened since 2018.
"Long Island has a very dense network of roads. They're not going to stay in one watershed necessarily; they might use three or four. And to get from one to the other, they might cross over roads, even at night," Bottini said.
Bottini said this indicates that work remains to clear culverts and other connecting waterways. He hopes that the more their presence is known, the more people will pay attention.
“They’re a very charismatic species. Otters are cool! People who aren't necessarily that interested in wildlife, so to speak, get excited about otters being around in the area.”
This is all part of a multi-year survey of all Long Island mammals, now in its final year.
