BILLINGS — Montana Fish, Wildlife and Parks plans to remove invasive brook trout from three mountain lakes and a stream in the Beartooth Mountains north of Cooke City on Aug. 4. The project, in its second year, is intended to enhance the viability of Yellowstone cutthroat trout that live in a fourth lake in the region.
Goose Lake, about seven miles north of Cooke City in the Custer National Forest, harbors a self-sustaining population of native Yellowstone cutthroat trout that apparently never has been crossed with non-native fish. Because of the robust population and relatively easy access, Goose Lake has become a source of cutthroat trout eggs for the FWP hatchery at Big Timber. Fish from that hatchery are used to stock and restore cutthroats in lakes throughout the Beartooth Mountains and other regions.
Goose Lake drains into Goose Creek, which eventually flows into the Stillwater River. A chain of three interconnected lakes – Mutt Lake, Jeff Lake and Huckleberry Lake – are on a small tributary stream that drains into Goose Creek below Goose Lake. The three lakes are overpopulated with non-native brook trout, which are small because of crowding.
FWP’s Regional Fisheries Manager Jim Darling of Billings, said he is concerned that the brook trout could swim from Goose Creek and the other lakes and colonize Goose Lake, squeezing out the population of native pure-strain cutthroats. In 2007 FWP treated Mutt, Jeff and Huckleberry lakes and Goose Creek with rotenone, a chemical that kills only animals that breathe with gills. Such ecosystems generally require two treatments, at least a year apart, to fully purge fish, Darling said.
After all of the brook trout are removed, FWP will stock the three lakes with Yellowstone cutthroat trout. A waterfall near the mouth of Goose Creek will block non-native Stillwater River fish from repopulating upper Goose Creek and the lakes.
Rotenone has no effect on plants, land animals or amphibians that breathe air. It is toxic only to those that breathe with gills. It is not absorbed into groundwater. Biologists believe that the rotenone will break down to non-toxic levels well before it reaches the Stillwater River four miles downstream. However, plans call for an emergency detoxification station on the Stillwater River. Workers there would add drinking-water treatment crystals to the river in the unlikely situation that rotenone worked its way into the stream.
FWP plans to transport workers, chemicals and equipment to the area with a helicopter and ATVs using designated Forest Service routes.
An environmental assessment of the entire two-year project, and finding of no significant impacts, was completed in 2007.
-FWP-
FACT SHEET
· Rotenone is derived from the root of the derris plant, which is native to Central and South America. Derris root is used by natives of that area to incapacitate fish for consumption.
· Though rotenone has no effect on mammals, notice of the treatment will be posted in the area for a month in accordance with U.S. Food and Drug Administration guidelines.
· Goose Lake covers 102 acres and has a depth of 130 feet. Its GPS coordinates are 45.11656 –109.91377.
· Huckleberry Lake covers 15.3 acres with a maximum depth of 49 feet. Its GPS coordinates are 45.08739 -109.93464.
· Jeff Lake is 1.3 acres and four feet deep. Its GPS coordinates are 45.09167 –109.93656.
· Mutt Lake is 1.5 acres and 3.5 feet deep. Its GPS coordinates are 45.09925 –109.93886.
· Of the 86 species of fish in Montana’s waters, 56 are native, meaning that they were in the state when Lewis and Clark arrived. Brook trout, brown trout and rainbow trout are not native.
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