Nov. 17, 2008
Ladders Boost Fish Recovery in Idaho’s Big Lost River
Idaho Water Project clears habitat hurdle: Whitefish can’t jump
Idaho Falls, Idaho – A rare strain of native whitefish is poised for recovery in Idaho’s upper Big Lost River, thanks to Trout Unlimited’s Idaho Water Project. In October, TU and partners retrofitted three existing dam diversions with fish passage structures, removing barriers and reconnecting fish populations on several reaches of the Big Lost.
The fish ladders and bypass channels, at Blaine and the Swauger diversions on the Big Lost, and Antelope Creek, a tributary to the Big Lost, will reduce fragmentation of critical habitat on the Big Lost watershed – allowing native whitefish populations to move out of stream reaches that become uninhabitable and helping them to complete life-cycle migrations.
The whitefish in the Big Lost River basin are a unique form of mountain whitefish found nowhere else in the world, according to Bart Gamett, a U.S. Forest Service biologist who worked closely with TU on the project. Although mountain whitefish were once prolific in the river, by 2005 their populations in the Big Lost basin had declined to only about 2 percent of historic levels, he said.
Gamett’s research revealed a key problem: Whitefish can’t jump. That wasn’t true with cutthroat or brown trout or other sport fish he tested for leaping ability. But Big Lost River mountain whitefish, he found, couldn’t get past even small vertical drops or dam barriers.
“These diversions were significantly impairing the ability of fish to move through the Big Lost River,” Gamett said. The obstacles appeared to be a key reason for the fishery decline.
Trout Unlimited partnered with landowners, the Big Lost River Irrigation District, the Salmon-Challis National Forest, Idaho Department of Fish and Game, Natural Resources Conservation Service, and the U.S. Fish and Wildlife Service to provide fish passage at several diversion points on the river.
“This kind of cooperative work isn’t possible without the strong partnerships with both agencies and landowners,” said Kim Goodman Trotter, director of Idaho Water Project. “Projects like this go a long way in keeping healthy fish populations,” she added.
Since 2004, TU has been working with a wide range of partners to address a significant decline in populations of both native and sport fish in the Big Lost. Their three-pronged recovery plan includes researching fish populations, reconnecting flows and restoring habitat throughout the Big Lost watershed.
“Trout Unlimited has done an absolutely outstanding job implementing these important restoration projects,” said Gamett. “These projects are a great example of the tremendous good that can be accomplished when people decide to work together.”
Trout Unlimited is the nation’s oldest and largest coldwater fisheries conservation organization, with over 150,000 members from coast to coast. TU’s mission is to Protect, Reconnect, Restore and Sustain trout and salmon habitat in the United States.