Inside the Local War on Zebra Mussels

With boating season ramping up, Minnesota’s Department of Natural Resources (DNR) is cracking down on aquatic hitchhikers.

were discovered last year in Lake Minnetonka, the state’s 19th inland lake with a confirmed presence.

In an effort to raise public awareness and slow the spread of zebra mussels and other invasive species, state inspectors took their fight to the front lines Tuesday for the season’s first round of boat inspections and chats with the public.

“State law requires boaters to remove visible aquatic plants and zebra mussels from their boats and trailers prior to leaving public waters  in the state of Minnesota,” conservation officer Adam Block said today as he stood at the public access to Gray's Bay on Lake Minnetonka. “It also requires boaters to remove water from the boat, live wells and bilges.”

Boats leaving a lake with confirmed invasive species, such as Lake Minnetonka, must also drain water from bait buckets. Fines for boaters found to have spread zebra mussels or other invasive species can be as high as $250.

Zebra mussels overtake native shellfish, clog intakes of lakeshore property owners, facilitate algae growth, harm fish and can even cut fishing lines. The extent of Lake Minnetonka's zebra mussel presence is still being determined. Zebra mussels were first discovered in Minnesota in 1989, in Duluth Harbor. The Mississippi River soon followed.

“Barges covered in zebra mussels coming from Lake Michigan were coming up the Mississippi to St. Paul, so we found it that way,” Luke Skinner, a DNR invasive species supervisor, said.

The DNR will hire 110 boat inspectors this year—20 more than 2010—in its effort to tamp down the spread of invasive species. Half of all inspector time this summer will be spent on the shores of lakes with zebra mussels.

“Our concern is that we’re finding (zebra mussels) in big, heavily used lakes like Minnetonka, Mille Lacs and Gull,” said. “These are high use lakes, and the risk of spreading from these lakes is very high.”

Skinner added that Lake Minnetonka was one of two new lakes found last year to contain zebra mussels. Four others were discovered in 2009.

As he prepared to launch his boat Tuesday morning, Minnetonka resident Phil Priest said he was surprised to learn last year that zebra mussels had been found in Lake Minnetonka, a favorite early season destination of his. Priest said he has been following the path of invasive species ever since they were discovered in the Mississippi and St. Croix rivers and that doing his part to prevent spreading was a regular part of his boating routine.

“I’m always pretty sure that I’m not carrying debris on the boat or trailer,” he said. “I was born and raised on Pike Lake near Duluth, and I was shocked to find out they got it last year. It’s important.”

Zebra mussels are just one of the invasive species being tracked by the DNR. Eurasian Milfoil, a non-native nuisance plant that was first discovered in Lake Minnetonka back in 1987, has at present spread to nearly 250 lakes in Minnesota.

“That sounds like a lot, but we’ve really been able to keep it to a minimum,” Skinner said. “It’s only been about 10 new lakes a year.”

State conservation leaders are also concerned about a plant called Hydrilla, a milfoil type plant currently being found in Indiana. The fish disease viral hemorrhagic septicemia, which essentially causes fish to bleed to death, is also being tracked closely as more and more cases are being confirmed around the Great Lakes.

“The big one though is Asian carp,” Skinner said. “They are moving up the Mississippi, and they are moving on their own, so we’re looking for ways to slow their spread within the system.”

From the DNR:

• When swimming or wading, wear protective footwear to protect your feet from being cut by razor-sharp zebra mussel shells.
• Drain all water from your boat after each use to protect the cooling system of your boat.
• When you take your boat out of Lake Minnetonka, thoroughly clean your boat and trailer. Scrape off any encrusted mussels and spray your boat and trailer with high pressure and hot water.
• Before launching in another lake let it dry for at least five days. This will reduce the risk of spreading zebra mussels and other invasive Species.
• Livewells and portable bait containers must be drained before leaving the lake because the water could contain larvae of zebra mussels.