By Ben Neary
NMWF Conservation Director
Otters were extirpated from New Mexico about 100 years ago, likely incidental victims of heavy trapping for beavers. But thanks to the New Mexico Department of Game and Fish’s ongoing reintroduction program, otters are now back in the state with their numbers growing and their range expanding.
James Stuart, nongame mammal specialist with the NMDGF, will discuss the game department’s successful otter restoration program on Nov. 13. He’s the featured speaker for the New Mexico Wildlife Federation’s “Wildlife Wednesday” event in November.
New Mexico released 33 river otters into the Rio Pueblo de Taos, on Taos Pueblo land, between 2008 and 2010, Stuart said. The department released nine more this spring to improve the original population’s genetic diversity.
The game department released the initial 33 otters in batches, with all of them coming from Washington State. The nine most recent otters were from Louisiana. The department is considering releasing more from Louisiana next year, if they’re available.
A professor and students from the University of Kentucky conducted a study in 2019 that sampled otter scat at locations along the Rio Grande and its tributaries. That study estimated that the otter population had increased to between 83 to 100 animals, but also found low genetic diversity in the population.
Other states in the West that have been working to restore their otter populations also have brought in otters from various locations to ensure a healthy genetic mix, Stuart said. While many states have relied on otters from Alaska and Washington, he said Colorado brought some in from as far away as Newfoundland.
“We really don’t know how much differentiation there is across the continent,” Stuart said of the otter genetics. “A lot of states have used Louisiana exclusively as a source. Like in Arizona, their otters on the Rio Verde are all from Louisiana, and they’ve persisted for 40 years now.”
Large male otters can weigh close to 20 pounds while others are smaller. With webbed feet and powerful tails, they’re expert swimmers and live mainly on fish and crayfish.
Bobcats and mountain lions will prey on otters if they catch them in the open, Stuart said. “When they’re in the river, there’s probably not much that can take them,” he said.
The history of the presence of otters in New Mexico is murky. Stuart said there isn’t much information indicating that the state ever had very many of them. The last otter detected in the state before the current reintroduction effort was one that was trapped on the Gila River in the 1950s, he said.
Biologist Vernon Bailey, working for the U.S. Department of Agriculture, published “Mammals of New Mexico” in 1931 as a biological survey of the state.
“All he had at that time was a handful of observation reports from New Mexico, from the Canadian, the Rio Grande and the Gila,” Stuart said of Baily’s findings. “But no specimens at that time. It was even like at that time, 100 years ago, we had already pretty much lost the species from the state. Or it was very close to being completely extirpated.”
Although there’s no direct evidence of it, Stuart said he suspects that the extensive beaver trapping that was conducted in New Mexico in the late 19th century and the early 20th century essentially took out the state’s otter population.
Otters and beavers favor the same areas, and otters will often take advantage of the ponds created by beaver dams and even sometimes take over beaver dens and lodges, Stuart said.
“They actually kind of key in on that same habitat,” Stuart said. “So it’s not surprising if you’re in an area where there’s beavers, and you’re trapping for those, if there’s an otter present, you’re probably going to take one of those as well.
Since their initial release in the Rio Pueblo, Stuart said otters have spread out in the Upper Rio Grande drainage.
“We have reports now from basically all the way to the top of the Red River,” Stuart said. “They’ve been detected up near Taos Ski Valley, and the Rio Hondo up there isn’t much of a river. It’s a small stream, it’s not a river.”
It’s difficult to determine whether otters are staying in such small streams, or merely passing through, Stuart said. He said they frequently turn up at the overflow pond at the Red River Hatchery to feed on trout there.
New Mexico’s otter restoration effort dates back to the 1980s, Stuart said. He said many states began restoration efforts during that period with the intention of eventually opening trapping seasons for them.
Missouri and Kentucky have restored their otter populations and now have trapping seasons, Stuart said. He said otters remain protected in New Mexico.
Restoration efforts in New Mexico were complicated by concern that a subspecies called the Southwestern River Otter might still have been present in the state, Stuart said. He said game managers didn’t want to introduce otters from elsewhere and dilute the native population if it still existed.
The New Mexico State Game Commission required game department biologists to prepare a study addressing the feasibility of restoring otters. The commission approved it in 2006.
“We looked at the San Juan and the Canadian and the Rio Grande, just in terms of perennial water and food base, just kind of rose to the top as the best place to do it,” Stuart said.
The game department asks the public to report otters whenever they see one, Stuart said. In addition to sightings on the Rio Grande and its tributaries, he said they get sightings on the San Juan River and have had some from the upper Canadian River system, in the Eagle Nest Lake area.
“We did actually confirm one of them. Somebody got one on their Ring camera up there in Eagle Nest, it was running through their yard,” Stuart said.
Stuart’s talk will start at 5:30 p.m., Nov. 13, at Marble Brewery’s Northeast Heights Taproom, at 9904 Montgomery Blvd., NE, Albuquerque.