SACRAMENTO - The U.S. Forest Service approved a plan Tuesday to restore what wildlife officials call "the rarest trout in America" to 11 miles of a Sierra Nevada creek after first removing nonnative fish from the waterway.

The plan is controversial because the planned removal this fall involves the use of a fish poison to eliminate competition from the nonnative trout. That prompted an environmental group's lawsuit that delayed the process for a year while a federal environmental impact statement was prepared.

Wildlife officials say restoring the Paiute cutthroat trout to its native habitat in the Carson-Iceberg Wilderness is worth the damage to other species, most of which they expect to repopulate the creek within a couple years.

"A lot is sometimes made of the chemical used, but this is the only place this fish exists" in its original habitat, said Carson District Ranger Gary Schiff. "Here's a chance to take a species off the (endangered species) list."

The Paiute cutthroat trout was declared endangered in 1970, but was upgraded to threatened in 1975. If all goes as planned, wildlife officials hope to eventually reopen a portion of Silver King Creek to catch-and-release fishing for the trout.

"It'd be the only place in the world you can do that," Schiff said.

The trout evolved into a separate species after it was cut off from other waterways about 5,000 years ago. It is distinguished by bright orange-red markings below the gills.

Silver King Creek flows into the Carson River south of Lake Tahoe.

The California Department of Fish and Game proposes to use what officials say is a less-damaging formulation of the fish poison Rotenone to kill nonnative trout in Silver King Creek, its tributaries and Tamarack Lake.

The chemical has been used in unsuccessful attempts to eradicate nonnative fish from the creek and from Lake Davis to the north. Officials believe this time it will work.

Because the department wants to use chemicals and machinery in a wilderness as part of the plan, the state needed federal approval.

A U.S. Fish and Wildlife Service recovery plan says the reintroduction of the trout would also help the rare mountain yellow-legged frog and Yosemite toad.

Paiute trout were transplanted about 100 years ago into four other waterways where pure populations survive: the North Fork of Cottonwood Creek and Cabin Creek in the Inyo National Forest, and Stairway Creek and Sharktooth Creek in the Sierra National Forest.

On the Net:

Read the finding of no significant impact at www.fs.fed.us/htnf