POST FALLS - The discovery of two mussel-infested boats en route to North Idaho on Thursday, including one destined for Lake Coeur d'Alene, underscores the seriousness of the threat to area lakes and tourism, government officials said.

In an email to local officials on Monday, Amy Ferriter of the Idaho State Department of Agriculture, the agency in charge of inspection stations aimed at keeping out invasive species, said the state dealt with one boat from Lake Mead in Nevada and another from the Great Lakes at the station on westbound Interstate 90 near Wallace.

"This absolutely points out the threat is real and everyone needs to pay attention or it will be too late," said Post Falls Mayor Clay Larkin, who has coordinated with the state on the stations.

"This is only May, and I would predict we will hear of more infestations in this area than we have before."

The boat from Lake Mead will be decontaminated today at a boat shop in Post Falls. The other is being held by Washington as it's destined for Gig Harbor, Wash.

Mussels range in size from microscopic to the size of a fingernail, depending on the life stage. They are prolific breeders and attach themselves to hard and soft surfaces, fouling freshwater ecosystems and clogging intake pipes drawing water from infested water bodies. They cause significant maintenance challenges for raw-water systems, costing millions of dollars a year to treat.

Although populations have been widespread in the Great Lakes for about two decades, the mussels were found for the first time west of the Continental Divide in the past three years, specifically in parts of Nevada, California, Arizona, Colorado and Utah.

Ferriter said she was advised by the Nevada Department of Wildlife about the boat pulled from Lake Mead and headed for Lake Coeur d'Alene. She contacted the commercial hauler, who cooperated by having the boat inspected near Wallace.

While an ISDA staffer was waiting for the boat to arrive, a 30-foot sailboat from the Great Lakes with mussels near the rudder pulled in.

Pamela Juker, ISDA spokeswoman, said it hasn't been determined what type of mussels were on the boats. The most common threats are zebra and quagga mussels.

Juker said seven infested boats have been intercepted statewide this year, including three at the Wallace station, two at the Juniper station and one each at the Hollister Port of Entry and Bruneau.

However, she said it's too early to say how bad of a problem it will be this year.

The station near Wallace is one of five in North Idaho this year. Others include Highway 53 at the Idaho/Washington line, eastbound I-90 at Huetter, Oldtown and Samuels. The stations will be open through Sept. 9.

All boaters must stop at the stations when open.

For information about the inspection program, contact Matt Voile at (208) 332-8667 or Matt.voile@agri.idaho.gov.