UNM BIOLOGIST SEARCHES FOR RARE ELUSIVE SOUTHWESTERN RIVER OTTER

June 19, 2003

UNM BIOLOGIST SEARCHES FOR RARE ELUSIVE SOUTHWESTERN
RIVER OTTER

University of New Mexico Research Associate Professor Paul Polechla is in search of an animal subspecies that hasn’t been collected in New Mexico for 50 years or in the desert Southwest in nearly 30 years. But the river otter population is thought to live in every other mainland state. Still, that doesn’t deter Polechla, whose research on the elusive Southwestern river otter is featured in the June/July issue of National Wildlife Federation magazine.

“The Southwestern river otter is one of the most endangered mammals in North America,” Polechla said. “Even more so that the Mexican gray wolf. There is no captive population and no one has identified an existing population in the wild. For example, we have both wild and stocked populations of the Mexican wolf and the black-footed ferret.”

Polechla has studied the otter and its habitat from Alaska to Florida, Maine to California and Canada. He has even studied the Neotropical (or Southern otter) of Mexico. Now, one of his primary search areas for the Southwestern river otter is located along the rivers in the Gila Wilderness near Silver City, N.M., which is the area where the Southwestern species was last captured in New Mexico. Unfortunately he has yet to uncover any hard recent evidence of the elusive carnivore.

Once a thriving species across the state, the last time a Southwestern river otter was caught in New Mexico was in 1953, which a state wildlife officer caught. The stuffed specimen sits in a display case at UNM’s Museum of Southwestern Biology.

“Although I continue to receive reports of them in New Mexico, I’m searching for something that has been officially regarded as locally extinct,” Polechla said. “Yet, few thorough surveys have been done by competent observers in New Mexico and the Southwest. I started studying the otter 20 years ago in Arkansas where their populations are healthy. They are secretive and exceedingly difficult to see in nature. You have to be skilled and a very lucky biologist. Usually, all you get to see are their tracks, droppings and the signs they leave behind.

“Unaided by live traps or radiotelemetry, I’ve seen otters on 12 occasions and I have each sighting stamped in my head of who I was with, where I was and the lay of the land. The last time I saw one was on the North Payette River in Idaho last fall. I saw a mother and her two pups fishing for over an hour. It’s a great feeling when you see one. It even gives me a thrill when I see their tracks and scats.”

There are seven different North American river otter subspecies, some of which have been reintroduced into the wild in the Southwest. Polechla studied one of their populations in Southwestern Colorado last year. Otters vary in size, but generally grow to about four feet long weighing in at approximately 25 pounds. River otters spend part of their time on land and part on the river. Otters use the river to hunt and travel. Unlike land animals, otters follow drainages, which is why Polechla searches waterways for clues of otter presence.

He says that the otter’s prey, as well as the otters themselves, are dependent on good water quality and ample fish and or crayfish prey. His search areas include what he calls the “corridor of dispersal” and the otters possible route of movement, which involves several of the main waterways in New Mexico including the northern Rio Grande, San Juan River, Pecos River, Canadian River and the Gila. He has completed five major studies in New Mexico and other states and has two proposals for additional funding and research.

“Otters like adequate amounts of water,” Polechla said. “Otters are indicators of good water quality for humans. They are also a great model for the health of the aquatic environment. Everything is hooked or linked together. Our jobs as biologists is to discover the details of those links.”

Currently he is studying the diet of a presumably stocked population. So far he has found suckers, sculpin, trout, stone flies and crayfish in their scat. Polechla has performed otter research for many entities including the U.S. Forest Service, U.S. Fish and Wildlife, Defenders of Wildlife, and while he might be searching for something that has been ignored in the desert Southwest, it doesn’t dampen his enthusiasm.

Copies of the June/July issue of National Wildlife World edition magazine featuring Polechla can be ordered through Mark Wexler, editorial director, National Wildlife Federation, 11100 Wildlife Center Drive, Reston, Va. 20190-5362 or on the Internet at www.nwf.org. Interested individuals with questions, comments and or observations about otters, can contact Polechla at ppolechla@sevilleta.unm.edu.

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