Aquatic Invasive Species In Hot Water

There are 25 established invasive species, such as quagga and zebra mussels, in Lake Michigan. Photo by Katie Sikora.

Boats pulled out of Lake Michigan can be treated to an extra rinse this season – a steady stream of hot water from a watercraft decontamination unit parked near the boat launch at Sawyer Park in Sturgeon Bay.

That rinse isn’t just for cleaning off gunk and weeds. The water is heated to kill any aquatic invasive species that might have hitched a ride on the boat and be headed for another lake.

“The goal is to offer [the service] to boaters at no charge so they can have their boat cleaned and be able to go to another internal lake without worrying about transporting any invasive species,” said Greg Stacey, deputy conservation warden for the Department of Natural Resources (DNR).

The water is heated by a generator to a temperature between 140 and 150 degrees, just enough to kill any invasive species or larvae without using any chemicals.

Hot water decontamination is a trusted method of preventing invasive species spread. Decontamination units are used often in western states like Utah, and they’re effective.

“Nothing’s 100 percent, but you’re really close using a decontamination unit,” said Tim Campbell, aquatic invasive species outreach specialist for the University of Wisconsin Sea Grant. “You can be pretty sure after using one of those that you can launch anywhere else in the state and be sure you’re not spreading invasive species.”

Lake Michigan is crawling – or swimming – with invasive species like zebra mussels, quagga mussels, spiny water fleas and more. There are 25 established invasive species that are found in the lake according to DNR warden Mike Neal, and they could easily spread to pristine inland lakes.

“The only way they move is by watercraft or equipment that is used on a watercraft,” Stacey said. “We’re trying to get people to understand how critical it is.”

Female zebra mussels, a prolific invasive, can each have up to a million eggs each year according to the DNR website. Their larvae are too miniscule to see and can live for two weeks in the water.

David Farrow (right) and Mike Montenero operate the hot water decontamination unit at Sawyer Park, helping stop the spread of invasive species while spreading awareness. Photo by Carol Thompson.

“The quagga and zebra mussels in Lake Michigan are just horrendous,” Stacey said.

So if a boater doesn’t drain the boat’s bilge water before moving to an inland lake, he or she could infest another lake with mussels.

The Sawyer Park decontamination unit is manned by two DNR aquatic invasive species decontamination specialists who spray down boats and talk to boaters about preventing invasive species from spreading.

“When you’re decontaminating it’s important to get every part that the water has touched,” said David Farrow, one of the specialists.

The decontamination machine has attachments that can reach under the boat and trailer, in the live well and bilge area, on the hull and in the motor. It takes 10 seconds of exposure to kill any invasive species, and the total process usually takes 15 minutes.

“We’ve got to make sure that we get every nook and cranny,” said Mike Montenero, another specialist working the decontamination unit.

Farrow and Montenero have found that most boaters are aware of invasive species, and most of them take some precautions not to spread them. The boats that really need to be treated with the decontamination unit are those that are going from Lake Michigan to an inland lake, and only about half of those decide to stick around for the spray.

Still, the presence of the machine is helpful in spreading the word.

“Just seeing us out here gets us on people’s radar,” Montenero said.

Getting on boaters’ radars is a good thing, considering it’s illegal to move invasive species in Wisconsin, even by accident. Boaters that don’t remove weeds and aquatic animals attached to their boats and trailers, or don’t drain the water from their boats and equipment, before leaving the boat launch could be fined between $200 and $389.50.

The DNR doesn’t even have to catch boaters to give that fine. Fines could be written as a traffic citation.

The decontamination unit was moved from Peninsula State Park to Sawyer Park in early August and will remain at Sawyer Park through the rest of the boating season into September.

Bob Bordeau, Sturgeon Bay public works superintendent, said the city may consider purchasing its own permanent decontamination unit if this one works well.

“We have so much boat traffic going through Sawyer,” Bordeau said. “We all need to be stewards of the water and doing what we can to make sure it stays clean.”