By Associated Press • 

Invasive fish in Oregon lake sparks new eradication effort

 

MEDFORD — Oregon fish managers are going all-out to eliminate tui chub in Diamond Lake after a single fish of the species was found there.

The unwanted tui chub was discovered in October, nine years after the state's $5.6 million effort to eradicate the invasive species, reported The Mail Tribune.

“I'm hoping it was the only tui chub, but I'm operating on the assumption that it wasn't,” said Oregon Department of Fish and Wildlife's Greg Huchko. He's the Umpqua District fish biologist heading the department's effort. “I'm hoping, in a year or two, this becomes a non-issue.”

ODFW plans to stock as many as 25,000 fish-eating tiger trout in the lake this spring. That will be followed by workers searching for the unwanted species literally day and night during the summer.

Tui chub took over Diamond Lake after someone used the species as live trout bate in 1954 and in the early 1990s.

After they were discovered in the lake in 1991, their population hit 30 million before agency biologists had a fully-funded plan in place. It soared to 90 million by 2006.

By overrunning the lake, the tui chub altered its ecosystem dramatically. That allowed a massive toxic blue-green algae bloom to spread through the water.

Eventually, a state, federal and private partnership studied and funded the use of rotenone to kill everything in the lake in 2006. They restarted from scratch in 2007.

“The playing field's a little different now because we were able to catch it early,” said Huchko. “This isn't ideal, but we want to be as proactive as we can.”

The fish found in October was 4 years old, too young to have survived the kill-off. Biologists don't know where it came from.

Biologists have tried to eliminate the chub using several different fish-eating fish. Huchko said they're now focusing on the tiger trout, a sterile brown trout and brook trout hybrid.

“We've tried a lot of different options in the past and never really had great success with the rainbow varieties we've tried,” he said. “I'm just hopeful this time that we can keep things at bay for a while.”

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Information from: Mail Tribune, http://www.mailtribune.com/

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