Invasive mussels found on two boats

Just two days after the region’s third check station for boats opened in Pablo, state wildlife officials on Friday found a pair of boats containing an invasive species of mussels headed north along U.S. 93.

Montana Fish, Wildlife and Parks conservation specialist John Wachsmuth said Tuesday the mussels were dead by the time they arrived, and Arizona wildlife officials, who had decontaminated the boats after they left Lake Havasu, had alerted the state about the incoming boats.

Still, Erik Hanson, an invasive species consultant for the Flathead Basin Commission, said it underscores the importance of the regional check stations as part of a coordinated effort to keep invasive mussel species from becoming established in the Flathead Lake drainage.

“The Columbia River watershed is the last watershed in the U.S. that doesn’t have zebra and quagga mussels,” Hanson said.

He hardly discerns between zebra and quagga mussels — both of which can rapidly reproduce and cover lake beds, disrupt the ecosystems and clog irrigation pipes and dam intakes.

“Potentially, there could be a huge impact to the economy from loss of recreational opportunities,” he added. “They’re permanent. Once they get into the water body, there’s nothing we can do.”

Friday’s find was a relatively rare one: John Wachsmuth, a fish conservation specialist for the state, said that out of 37,000 inspections last year, only about five vessels had detectable contamination.

Both boat owners on Friday told officials they planned to wait the recommended 30 days before launching, and Arizona officials had likely killed the still-attached mussels during their initial decontamination before the boats left the state.

That process involves power-washing the vessel with water in excess of 140 degrees, focusing on the nooks and crannies where mussels like to attach, such as seams and joints on the bottom of the boat.

“It’s very difficult to inspect these boats to make sure they’re clean,” Hanson said, standing next to one of the fouled vessels, a pontoon boat, outside the Fish, Wildlife and Parks office in Kalispell. “It can take a half an hour to inspect a boat like this.”

But that doesn’t always guarantee a clean bill of health, and Hanson said there have been “numerous instances” of mussels turning up on already-decontaminated boats throughout the West.

Further complicating those efforts are indications that boat owners are increasingly transporting their vessels in advance of the Memorial Day weekend, according to recent studies.

The commission responded to that trend by opening the stations early this year, and interstate cooperation among wildlife agencies also has increased the probability of detecting fouled boats.

Based on when and where the boats were last launched, and how long they spent in the water, inspectors are able to focus their finite resources on the highest-risk watercraft entering the region.

Caryn Miske, the Flathead Basin Commission’s executive director, said Tuesday the check stations cost the commission about $30,000 to $35,000 for the three months of early operation. In May, Fish, Wildlife and Parks takes over management of the stations, which stay open through September.

Most of the money that supports the early-season inspections comes from grants and private donations, and Hanson noted that the commission is always looking for donors.

Check stations in Browning and at Clearwater Junction began operating March 2, but the Pablo station didn’t open until March 30 after funding from BNSF and the Flathead National Forest filled the gap.