Some boats coming into Montana from Lake Powell will be locked to their trailers for a mandatory quarantine period of up to 30 days in response to the threat of invasive mussels.
All boats coming into Montana are already required to be inspected for invasive species like zebra and quagga mussels, which have caused millions of dollars of damage to hydropower dams, irrigation systems and personal property in infested waters in other states.
But some boats have compartments that can’t be seen, like ballast bags often used for wakeboarding.
Ballast bags also don’t drain all the way, and the fear is that residual water could carry live juvenile or even adult zebra and quagga mussels into other lakes and cause new infestations there.
Lake Powell’s low water level this year has exposed more mussels than normal, including live adults that are free-floating in the water and can be scooped up into boats.
"It's definitely raising alarm bells around the state of Utah," says Nathan Owens, Utah’s aquatic invasive species coordinator.
"We've already had close to 80 or 85 boats show up coming from Lake Powell that arrive at another Utah reservoir with mussels on them, primarily in this sea strainer that filters out some of the larger particles going through these internal systems."
Owens says one boat still had mussels in its motor even after two decontaminations and quarantine periods.
He says all boats coming off Lake Powell are inspected before they can go home, but a single ramp could see 300 to 400 boats on a given Sunday. Despite the high volume, no new lakes have been infested this year.
"There is hope," Owens says. "We are still staying on top of this, but it's going to take a collective effort that's probably going to expand out of Utah at this point."
In response, Montana Fish, Wildlife and Parks now requires any boat with a ballast tank that has visited Lake Powell in the past month to have its ballast systems flushed and then be locked to its trailer. Boats will be released after a period of seven to thirty days.
Tom Woolf is Montana’s aquatic invasive species bureau chief.
"This is just an extra wait time that we're adding to these boats to ensure that those mussels are dead," he says.
Woolf says FWP expects about 30 to 40 boaters will be impacted by Montana’s new dry time policy.
Montana has inspected 50,000 boats this season and found 12 carrying invasive mussels into the state. The state ramped up its inspection and monitoring program after mussels were detected in Tiber and Canyon Ferry Reservoirs in 2016. There haven’t been any juvenile or adult detections since.
Learn more about Montana's underwater invaders, with SubSurface, a podcast from Montana Public Radio.