From The Denver Post (Bruce Finley):
Colorado Parks and Wildlife biologists say that, after completing the reintroduction of about 120 young male and female otters 25 years ago, otters are multiplying with a statewide population now numbering in the hundreds.
The recovery here, mirrored in other states that reintroduced otters decades ago, stands out in the struggle for wildlife survival because biologists consider otters a “sentinel species” that is highly sensitive to pollution. It shows how a relatively modest state effort to keep an imperiled species off the federal endangered species list — the U.S. ecological equivalent of an emergency room — can lead to a comeback.
State-run reintroduction “has made a significant contribution to the conservation of river otters throughout the state of Colorado,” U.S. Fish and Wildlife Service biologist Leslie Ellwood said. “We’re now seeing river otters in streams and lakes where they had not been seen for the past 100 years.”
Although Colorado officials could not produce current population survey data or a peer-reviewed study, and while otters still are classified as “threatened” in the state, CPW tables indicate otters exist in 38 of 64 counties.
This means habitat suitable to otters in Colorado is relatively healthy, said Reid DeWalt, assistant director of wildlife and natural resources for the state. “CPW is vested in the long-term sustainability and balance of wildlife for future generations.”
Otters eat practically any animal that moves in riparian corridors: fish, frogs, snakes, turtles, crayfish, birds, salamanders. They grow to be 3- to 4-feet long, with males weighing about 25 pounds and females about 18 pounds. When predators such as coyotes lurk, otters have the ability to chase them away. And they energetically chase one another, sliding crazily along muddy banks — activities biologists describe as pure play for fun.
The prospect of a widening recovery has emerged as a success at a time when conservationists warn that scores of other plant and animal species are vanishing…
Starting in 1976, Colorado wildlife crews reintroduced river otters at five sites: Denver Water’s Cheesman Reservoir, Rocky Mountain National Park, and the Gunnison, Piedra and Dolores rivers. Similar efforts were happening elsewhere in the United States. The International Union for the Conservation of Nature estimates that more than 4,000 otters were reintroduced across 21 states.
Colorado kept up the reintroductions until 1991.
In 2003, members of the Colorado Wildlife Commission decided to down-list the status of the river otter to “threatened” from “endangered.” It’s still illegal to hunt them.
Colorado wildlife officials contend that the reintroduced otters are thriving with established populations around the Western Slope in waterways, including the Colorado, Green, Yampa, Dolores, Gunnison and San Miguel rivers, as well as tributaries in each basin.
Yet state monitoring is limited. CPW relies on Colorado residents to serve as eyes and ears — filling out and submitting forms giving details when they spot otters. Mink, beavers and muskrats share the same habitat as otters and, sometimes when seen swimming, are confused with otters.
U.S. Fish and Wildlife Service officials, charged with enforcing the federal Endangered Species Act, welcome state efforts to head off crises, said Marjorie Nelson, the USFWS regional chief of ecological services.