Burbot — an aggressive, eel-like fish that eat young trout — have been illegally stocked in a reservoir in southwest Wyoming, and officials say they now pose a threat to some of the state's premier trout water in the upper Green River (search).

Craig Amadio (search), fisheries biologist for the Green River Region of the Wyoming Game and Fish Department, said the department found some young burbot, also called ling, in nets it set in Fontenelle Reservoir (search) in late October. He said that while burbot (search) have been found below the reservoir in the past, the dam has kept them from spreading upstream until now.

"Somebody has obviously put burbot upstream of Fontenelle Dam," Amadio said. "It's a pretty selfish action for somebody to take. They wanted fishing for burbot closer to home."

He said this is just the latest instance of illegal "bucket biologists" taking it on themselves to plant exotic fish species in waters around the state. Although the biological effects of such illegal stocking can take decades to manifest themselves fully, they can be devastating.

"It should really enrage most of the anglers in the state when they read something like this," Amadio said. "Really the people who are paying the price for this are the anglers. Whoever did this is destroying angling opportunities for the public."

Burbot are native to the Wind River/Big Horn river drainages and coexist with trout there, Amadio said. However, Amadio said rivers that hold native burbot populations also hold small "forage fish" that burbot eat.

Lacking such forage fish in the Green River system, Amadio predicted that burbot will feast on young trout. Burbot commonly grow larger than 10 pounds, and he said a predator fish of that size eats a lot of smaller fish.

"They will be able to coexist," Amadio said of trout and burbot populations on the Green River. "But I really do believe that the numbers of trout we have, the trout abundance, is going to decline pretty drastically because of the ling population.

"I don't look for that to occur in the next five years. But looking 20 or 30 years down the road, I think that the numbers of trout we have per mile is going to decline with the existence of an aggressive predator," Amadio said.

Robert "Chico" Pistono (search), executive director of Trout Unlimited in Wyoming, agreed that whoever stocked the burbot in Fontenelle Reservoir is profoundly selfish.

"It's one of the top fisheries, that Green River," Pistono said. "All the way from the Green River lakes on down to the Flaming Gorge."

Pistono, of Cheyenne, served more than 35 years with the Wyoming Game and Fish Department and retired as the department's assistant chief of fisheries. He said there's nothing the state can do at this point other than watch.

"I know they found them, and I know they can be a problem," Pistono said. "Whether it develops into a major problem or not, we'll have to just wait and see."