Trout project begins in Jewel Basin

By LAURA BEHENNA

Bigfork Eagle

This fall, Black and Blackfoot lakes in Jewel Basin will become the first of 21 mountain lakes the Montana Department of Fish, Wildlife and Parks will treat to rid them of nonnative and hybrid fish, FWP officials said April 3.

The Westslope Cutthroat Trout Restoration Project will remove invasive fish species and restore native trout in lakes in the South Fork Flathead drainage during the next 10 years.

FWP staff will use a fish toxin called rotenone to kill all the fish in the lakes before restocking them with pure westslope cutthroat trout, the officials told an audience of about 30 people at a public meeting.

“Rotenone” has a sinister ring to some people, but FWP insists it is safe for humans, mammals, birds and the environment, and has only mild effects on insects and amphibians at the low concentration - one part per million - FWP will use. It kills gill-breathing animals by destroying their ability to use oxygen.

The treated lakes should be rotenone-free and ready for restocking next spring. The four Jewel Lakes in Jewel Basin were treated with rotenone and restocked with native cutthroat in 1986, resulting in populations that are still pure, FWP fisheries manager Jim Vashro said.

Made from plants in the pea family that are native to central America, rotenone breaks down into carbon dioxide and water when exposed to light, heat and oxygen. The Environmental Protection Agency has approved rotenone for use as a fish toxin and an insecticide. It is not currently approved for organic agriculture, although it has been in the past.

Numerous lakes in the South fork were stocked with rainbow trout and Yellowstone cutthroat trout from the 1920s to the 1940s, FWP fisheries mitigation coordinator Joel Tohtz said. These nonnative trout species interbreed easily with westslope cutthroat trout, resulting in hybrids that continue to reproduce. As the hybrid populations increase, they threaten to wipe out the westslope cutthroat trout. In addition, hybrids tend to move around to other streams, unlike the pure native trout.

“This is a controversial project, as well as the right thing to do,” FWP Region One supervisor Jim Satterfield said. Anglers with whom the agency has discussed the project were “split down the middle” in their opinions of the plan to poison existing fish in order to restore genetically pure westslope cutthroat trout to the lakes, he said.

Satterfield emphasized that the agency has already made the final decision to carry out the plan after going through a long environmental review process, and that FWP was holding the public meeting to provide information and answer questions, not to accept public comment. The agency has made a special commitment to inform the public every year about the project’s status. If the effort isn’t working well after two to four years, the agency may consider ending the project.

Success would mean all fish in treated lakes would die, no other fisheries would suffer, and healthy populations of pure westslope cutthroat trout would thrive, safe from nonnative species. FWP expects success because the agency has used the same strategy with several other lakes in this region, such as the Jewel Lakes, with good results. Tom Tom Lake, farther south in the South Fork, was treated in 2000.

“I’ve been to Tom Tom Lake nine times in the past three years and the [westslope cutthroat trout there] are the same size they were before we treated” — up to 13 inches long, FWP fish biologist Mark Shnee said.

Up to 12 of the 21 lakes included in the restoration plan, including Pilgrim and Big Hawk lakes in Jewel Basin, may be treated without toxins, Tohtz said. “Swamping,” or stocking lakes heavily with westslope cutthroat trout, has shown partial success in beating back the numbers of hybrids, he said.

The South Fork of the Flathead has 10 percent of all the pure westslope cutthroat trout in Montana, he added. Historically, the species abounded all over western Montana and part of eastern Montana. Currently the South Fork is the largest of a handful of small areas where the native trout still predominates.

Successful completion of the project could play an important role in keeping the westslope cutthroat trout off the list of threatened or endangered species under the U.S. Endangered Species Act, Satterfield said. Endangered and threatened species complicate the FWP’s management burden and its ability to carry out its mission to provide both good wildlife stewardship and recreational opportunities, he said.

FWP has launched a new Web site with extensive information about the Westslope Cutthroat Trout Restoration Project. The Web address is fwp.mt.gov/r1/wctproject/default.html.

For more information contact FWP at 752-5501 or e-mail wctproject@mt.gov.