Source: Lake Geneva Regional News

DNR puts alien invaders in hot water

by Chris Schultz

June 14, 2012

DELAVAN — John Kaiser, a state deputy water guard, fired up the boat decontamination unit and then directed a high pressure stream of hot water at the hull of Don Roszak’s 17-˝-foot fishing boat.

Roszak of Chicago and his brother, John Roszak of Gurnee, Ill., spent Friday morning angling on Delavan Lake.

Ready to go home in the late morning, the brothers decided to let the state Department of Natural Resources decontaminate their boat before they left the Delavan Lake boat launch in the town of Delavan.

“We thought, let’s give it a shot,” John Roszak said, while Kaiser changed attachments on the hose, and continued his decontamination process.

John said he and his brother often fish in southeastern Wisconsin’s lakes, and they’re very conscious of the problems caused by invasive species migrating from lake to lake.

When the 10-to-15 minute wash down was completed, the Roszaks’ boat got a clean bill of health from the DNR.

And it was free.

“It’s a good deal,” Don said before they drove off. “Let’s keep the stuff clean out here.”

The DNR brought its new boat decontamination unit to Delavan Friday as part of its effort to educate boaters and anglers about invasive species, and the need to clean boats to make sure that the invaders don’t get a free ride from lake to lake.

The DNR Southeast Region’s education efforts are focused in Walworth, Racine and Waukesha counties, according to DNR information. Conservation wardens and deputy water guards are distributing educational material about aquatic invasive species and how to stop their spread.

The teams will visit area bait dealers, sports retailers and dive shops, as well as at boat landings, a press release said. Many invasive species, like the zebra mussel and the lake weeds Eurasian milfoil and curly-leaf pondweed were imported from Europe and Asia.

One of their main weapons is near invisibility.

For example, the larval stage of the zebra mussel, called a veliger, is so small it is invisible to the naked eye. The curly-leaf reproduces from a small burr called a turion, which can be easily overlooked. And even the smallest cutting from a Eurasian milfoil can produce a full-grown plant.

The hot water treatment makes sure these tiny hitchhikers don’t survive the ride, Mickelberg said.

Kaiser said the decontamination unit has a diesel-fired water heater, a 225-gallon tank (good for about three boats) and the pressure unit is powered by a gasoline engine. Using a variety of hoses and hose heads for various parts of the boat, the unit can decontaminate most fishing boats in 10 to 15 minutes.

High pressure is used on the hull. A moderate pressure clears the outboard and prop. Low pressure is used to decontaminate the live well and interior of the boat.

It isn’t the pressure that kills. Kaiser said studies show that water heated to 140 degrees Fahrenheit will kill most invasive species.

The unit sprays only tap water, Kaiser said. No chemicals are used.

He said the unit, mounted on a trailer that can be towed by a pickup truck, costs between $12,000 and $13,000. On Friday, the DNR took its unit to locations in Waukesha and Racine counties, as well.

The DNR has one. But not everyone can afford that.

Fortunately, there are less expensive ways to decontaminate a boat. First, boaters and anglers must remove all loose lake weed from their boats’ hulls and engines before they leave the boat launch area. The easiest method is to let the boat dry out over five days before launching it again. Or, put a couple tablespoons of bleach in a couple gallons of water and use a household sprayer to spread the bleach water over the boat inside and outside, Mickelberg said.

Finally, for those who catch and keep, the DNR requires that the boat’s live well be drained. Once the water is drained, the fish in the live well are considered dead, said Mickelberg. Killing the fish reduces chances that viral hemorrhagic septicemia will be transported from lake to lake, Mickelberg said. There are no signs that the disease, also called VHS, affects humans, but it is deadly for nearly 50 species of fish, including species found in local lakes.

The DNR doesn’t want live fish transported from lake to lake privately, Mickelberg said.

Audrey Greene said Delavan Lake has zebra mussels, Eurasian milfoil and curly-leaf pondweed.

Greene, Walworth County lake specialist and aquatic invasive species coordinator, said invasive species are nothing new, and anglers and boaters aren’t the main culprits by a long shot.

Curly-leaf pondweed, native to Europe, Asia, Africa, and Australia, was accidentally introduced to United States waters in the mid-1880s by hobbyists who used it as an aquarium plant.

It only took a few aquarium cleanings for curly-leaf to establish itself in American lakes.

Curly-leaf forms under the ice in winter, making it one of the first nuisance aquatic plants to emerge in the spring. In mid-summer, when most aquatic plants are growing, curly-leaf die off. The decaying plants contribute to algal blooms and create stinking messes on beaches.

Greene said Delavan Lake had a recent close call with a new invasive called yellow floating heart, which was used for years as a water garden plant until it was banned in 2009. She said a colony of yellow floating heart was found in a pond near Delavan Lake.

“We talk to homeowners and gardening clubs about invasive species,” Greene said. “It’s not just boaters.”