LIMA - Foreign fish are showing up in Upper Red Rock River, where they shouldn't be, a state fisheries biologist says.
Crews gathering eggs from grayling last week found several rainbow trout that appear to be hatchery fish, suggesting they were dumped into the river by "bucket" biologists, said Dick Oswald.
The rainbows had heavily worn fins. Six were found in less than a half mile of river.
"That's a classic give-away of a hatchery fish," said Oswald. "It was clear that someone had been playing bucket biologist again. In doing so, they're playing Russian roulette with our fishery."
Oswald also said biologists detected bacterial kidney disease for the first time in samples taken from the Red Rock River grayling.
The disease can be found in hatcheries, he said.
Illegal fish plants have occurred in the Centennial Valley before.
In 1986, illegal plants of rainbow trout and Utah chubs were discovered in Elk Lake. Another illegal plant was found after that, said Oswald.
"We don't know who did this," he said. "But if anyone has a lead, they can call a warden of TIPMONT. I'd be very happy to catch the person doing this."
Oswald said the state learned its lesson in the early 1970s that wild and hatchery fish don't mix.
Disease, genetic contamination and competition for a limited food source are problems created by illegal plants, he said.
"The dangers are inherent and they far exceed the short-term benefits," he said.