MISSOULA (AP) — A new fish ladder intended to help native trout spawn in Rattlesnake Creek is allowing cutthroat and rare bull trout to reach the stream's upper reaches, biologists say.
It's the first time the trout are free to return to their historic spawning stream since a dam was built on the river by Montana Power Co. in 1903.
This spring, a permanent fish ladder was built at the dam, now operated by Mountain Water Co., which provides a passage around the dam for native trout.
"It works great," said Ladd Knotek, a fisheries biologist for the Montana Department of Fish, Wildlife and Parks, who helped test a temporary test ladder last spring.
He said the start of the cutthroat spawning run is showing more of the native trout are spawning in the stream.
The fish ascend a series of 11 eight-inch steps in a curving channel that was sculpted into the bank on the east side of the creek about 100 feet below the dam. Then they swim about 100 feet through an underground culvert to the reservoir above the dam. A series of grates on the surface provide a light source for the fish to follow. The total length of the ladder is 160 feet.
At the upstream end of the reservoir, the fish enter a trap, which biologists check daily.
The biologists net all the fish, placing the native fish into the stream above the dam, where they can continue their migration to the critical spawning habitat in the Rattlesnake Wilderness Area.
All nonnative fish, including rainbow and brown trout, are returned to the stream below the dam.
Knotek said the rainbows and browns can spawn in the five-mile stretch below the dam, but the native fish prefer the more specific habitat conditions that are found in the upper 15 miles above the dam.
The project was a cooperative effort of Mountain Water Co., FWP, Missoula's Westslope Chapter of Trout Unlimited, the Forest Service and the federal Bureau of Reclamation, Knotek said.
"It's so cool, I'm speechless," said Bruce Farling, executive director of Montana Trout Unlimited. "In the 10 years I've been involved with Trout Unlimited, I've worked on 100 to 200 restoration projects in the state. I can't think of one that's going to have a more significant and measurable benefit to wild fish in Montana."
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