It was only a matter of time.

The long-feared, but expected, arrival of exotic freshwater mussels has been confirmed. The Utah Division of Wildlife Resources (DWR) announced late Tuesday that two DNA samples tested positive for the presence of zebra mussels at Electric Lake in Emery County.

The invaders are prolific breeders and can multiply in numbers big enough to clog pipes in dams, power plants and irrigation lines, invade nooks and crannies in boats, destroy fisheries and litter beaches with stinking shells. The potential economic impact is daunting: The U.S. Fish and Wildlife Service estimates the potential cost of mussel infestation in just the Great Lakes region from 2000 to 2010 will be $5 billion.

"Life becomes miserable for a water user with these mussels," said Larry Dalton, aquatic invasive species coordinator for the DWR. "The [Electric Lake] fishery is in jeopardy."

DWR is awaiting confirmation from other waters where initial tests indicated the presence of mussels, Dalton said.

Once mussels are found in a body of water, there is little that can be done to check their spread, Dalton said. Researchers are now studying a bacteria that can be placed in the water and interferes with the mussels' digestive system once they are consumed.

The zebra mussel, and its somewhat larger cousin the quagga mussel, attach themselves to pipes, docks, boat props and anything else in a body of water. They also filter zooplankton from lakes and reservoirs, stealing food resources for fish.

States across the nation have spent millions, if not billions of dollars, to clean pipes in dams, power plants and irrigation canals that were plugged by mussels. The mussels have also been blamed for damaging fisheries on the Great Lakes.

"It is a tough situation given the intractable nature of the mussels. Once they begin to grow they are very difficult to eradicate," said Dave Eskelsen, a spokesman for Rocky Mountain Power. "We certainly are interested in more data from the state and we will need some time to evaluate that data so we can develop a plan to respond to whatever threat there is."

Electric Lake, as its name suggests, was built as a storage reservoir in the 1970s to provide cooling water for the Huntington electric generation plant and agricultural water for the Huntington-Cleveland Irrigation Co.

State and federal wildlife officials have been working to prevent the spread of the mussels with a massive informational campaign, officers at boat ramps asking if launching boats have been in known infested waters and required decontamination.

The efforts have largely been focused on the state's biggest waters such as Lake Powell and Flaming Gorge, but was also aimed at the most popular fisheries in the state.

Already this year, DWR biologists have talked to more than 50,000 boat owners and decontaminated 800 boats on-site.