Fish poisoned in creek to help trout project

PROVO (AP) — State and federal agencies are taking a number of steps to create better habitat for declining populations of Bonneville cutthroat trout in an effort to keep the fish off the federal endangered species list.

On Wednesday, employees of the Utah Division of Wildlife Resources dripped seven gallons of poison — rotenone— into headwaters of Diamond Fork Creek and three tributaries, said the agency's Don Wiley.

It was the second such poisoning this summer. This time, no dead fish surfaced, which indicates the poisoning a month ago was successful, Wiley said.

By killing all the existing fish in the 21-mile stretch of the Diamond Fork, fish managers hope to establish hospitable habitat — free of predatory and competitive fish — for 10,000 3-inch to 4-inch Bonnevilles, which will be released into the stream next month.

The state is trying to replenish the Bonneville population to keep it from being listed for federal protection, which would mean restrictions on land use and fishing in areas traditionally populated by the trout, Wiley said.

The U.S. Forest Service built a fish wall of boulders above the Three Forks confluence, creating a 4-foot waterfall that brown trout and other non-native species of fish will not be able to breach, Wiley said.

Aggressive brown trout, which were introduced to Utah about the time the transcontinental railroad was completed, are the primary reason for the plummeting numbers of Bonneville trout.

During Wednesday's poisoning, fish from hatcheries were submerged in the creek in cages at several points, both below and above the fish dam, to indicate whether the treatment was working, Wiley said. A second chemical was added to the stream below the dam to neutralize the poison before it could reach the Three Forks confluence. The fish in cages above the dam died, proving the poisoning was working, while fish below the dam did not, showing the neutralizing agent worked.

No other brown trout fisheries outside the Diamond Fork headwaters were affected by the poisoning, Wiley said.