ALBUQUERQUE, N.M. — It was nearly 60 years ago on the Gila River. That’s the last time anyone had documented a river otter in New Mexico. A government trapper found the dead animal in a beaver trap he had set.
Now, the chance of otters making any kind of a comeback in the upper reaches of the Gila is being put on hold indefinitely by New Mexico wildlife officials, a move that is frustrating conservationists and others who see the sleek mammals as the best hope for preserving endangered fish in the troubled river.
Stretching from the mountains of southern New Mexico into southeastern Arizona, the Gila is an example of what has happened to rivers throughout the West. From choking drought conditions and habitat changes to an influx of exotic species, a number of factors have helped push populations of native fish to dangerously low levels.
It’s those endangered fish that the New Mexico Game and Fish Department says it’s worried about. The department contends Arizona wildlife officials and the U.S. Fish and Wildlife Service have expressed similar concerns.
Playful and highly social, otters love to eat fish.
Supporters of the reintroduction program argue the otters’ first choice will be invasive crayfish and larger, slower nonnative fish like bass and carp.
“We’re aware of the arguments — and I agree with a lot of the arguments — that having a species that preys on fish might actually be beneficial to some extent because of the large number of nonnative fish in the Gila,” said Jim Stuart, a biologist with the department’s Conservation Services Division. “But you can’t tell an otter what to eat, and we do have some populations of listed fish down there that are in pretty bad shape right now. They’re right on the edge.”
The decision to pull the plug on otter reintroduction was spelled out in a three-paragraph letter sent recently by Stuart to members of the New Mexico River Otter Working Group.
Supporters of the program balked at the state’s reasoning, pointing to Utah, Colorado, Arizona and other states that have had success in reintroducing otters, even in rivers that are home to endangered species.
Utah’s otter reintroduction program got under way in 1989, when officials released the first of 67 otters along the Green River. Since then, the Utah Division of Wildlife Resources has also reintroduced otters to the Provo River, a blue-ribbon trout fishery, and the Escalante River in Southern Utah.
Justin Dolling, game mammals coordinator for the DWR, said that while they will eat trout, otters prefer crayfish and are more likely to target slower-moving fish like sculpin, whitefish, carp and suckers.
Future reintroductions could happen on Top of Utah waterways, as the division’s otter management plan calls for reintroduction throughout the otter’s historic range, which includes the Bear, Logan, Ogden and Weber river drainages.
In New Mexico, more than 30 otters were released into the upper reaches of the Rio Grande between 2008 and 2010 and that population seems to be holding its own. Releases on the Gila were initially planned for 2010 but the program stalled despite a biological opinion on the potential impacts and an intensive monitoring plan.
Donna Stevens of the Upper Gila Watershed Alliance said otter reintroduction is “the only inexpensive and practical way” to save the Gila’s native fish.
Work to return the otters to New Mexico rivers has been about a decade in the making. The animals were once plentiful in the upper and middle Rio Grande, the Gila, Mora, San Juan and Canadian river systems.
Decades of trapping and habitat loss are believed to be factors that led to their disappearance.
More than 20 states have successfully reintroduced river otters, which biologists say play an important role in keeping semi-aquatic ecosystems healthy and diverse.