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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

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June 2001

Managing aquatic exotics

Working across the state on many fronts to tackle some tough invaders.

Natasha Kassulke

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It has all the makings of a dramatic Saturday morning cartoon.

A superweed has invaded Wisconsin.

It is capable of stopping a speeding boat and has a chokehold on Wisconsin lakes.

It is colonizing new sites and clinging to bait buckets, motor props and trailers. As it gets chopped up into pieces, each fragment grows anew, clogging up fish habitat and crowding out native plants.

Enough is enough.

After decades of this abuse, the Wisconsin Department of Natural Resources and its partners agree that it is time for action and have stepped up the fight on this submersed and spaghetti-like invader known as Eurasian water milfoil.

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In fact, DNR staff and their partners are working across the state on many fronts to try to control a variety of nuisance aquatic exotic species.

While the Wisconsin Department of Natural Resources does not have a specific hit squad to wack invasive species, the agency is working to strengthen its efforts to research, monitor and control exotics in Wisconsin's waterways.

But the agency also is realistic that fighting exotics and managing their spread can be overwhelming – over 160 species of fish, plants, animals, invertebrates, algae and pathogens have been introduced to the Great Lakes system since the early 1800s.

"We have a lot of shoreline in Wisconsin and not a lot of staff to work on the exotics issue," notes Chuck Ledin, DNR Great Lakes and Watershed Planning section chief. "We've been trying to target the spread of exotics on a small scale and marshal our forces, but we need a core of people dedicated to this issue."

That's why the agency works with many partners on curbing the spread of exotics. Partners include such groups as the University of Wisconsin and University of Minnesota Sea Grant institutes, University of Wisconsin-Extension, the U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, the Minnesota and Michigan departments of Natural Resources, and other research institutions. Together, these organizations monitor the presence of exotic aquatic plants and animals through underwater diving, aerial photography and reports of "alien" sightings from concerned citizens. Public reporting of new exotic species occurrences is critical.

Eurasian water milfoil covers this diver's head. © Robert Queen.
Eurasian water milfoil covers this diver's head. © Robert Queen.

In its attack against Eurasian water milfoil, researchers from the Department of Natural Resources along with local lake organizations and the University of Wisconsin-Stevens Point are finding that the pest may have met its match in a native beetle, the milfoil weevil. While no funding source currently exists to systematically stock lakes with beetles, lake organizations can organize and finance their own control efforts with the Department of Natural Resources providing some technical advice.

Bill Swenson, a biology professor in Superior and a fisheries specialist for the University of Wisconsin-Extension, has educated people about the threats of exotic species on aquatic ecosystems in the state for 20 years. He says Wisconsin needs the kind of comprehensive public education program that Minnesota has.

"We have a neighboring state as an example of what a state can do when they have the resources they need to tackle the issue," he suggests.

Wisconsin is in the midst of developing a comprehensive state management plan to deal with exotics. The plan would meet the goals of the National Invasive Species Act of 1996, and provide the framework to address the problems caused by aquatic exotic species.

DNR Water Division Administrator Susan Sylvester says controlling aquatic exotics is one of her top priorities.

"I'm excited that Governor McCallum included $300,000 (annual appropriation) in his budget as a first step to implement this program," Sylvester says. "We will keep moving toward improving our control of these exotic organisms.

The scope of activities outlined in the plan are broad and aimed at preventing new introductions, controlling the spread of exotic populations and to reducing exotics while safeguarding public health and the environment.

"We are trying to find a balance between control and prevention, but if we're going to be effective we have to act now before these species become a problem," Ledin says. "Once an exotic is established it is nearly impossible to eradicate."

Finally, the Department of Natural Resources has developed a draft policy to react when unintended exotics are discovered. It will provide a blueprint for all state agencies that collectively work together to control an invasive exotic species.

"We need a state policy that makes it illegal to import exotics, raises public awareness by listing 'bad' exotics and forms a statewide management plan to control particularly bad species," Ledin suggests. "Laws prohibiting in-state transport also are critical."

State Representative Dan Vrakas (R-Hartland) agrees that exotic species is becoming a hot issue statewide.

He became interested in the issue about two years ago when his constituents in Waukesha County, became concerned about zebra mussel invasions. Vrakas has a biology degree from UW-Stevens Point and is on the Assembly's environmental committee. He says he is familiar with the threat exotics such as zebra mussels can have on the environment.

Two years ago, he and Lieutenant Governor Margaret Farrow called for a summit on exotic species in the state. The group has met several times, formed a task force on exotics and secured $50,000 in the previous state budget for education on exotic species. The Department of Natural Resources uses that money to fund educational materials and post signs at boat landings.

"I'm encouraged an additional that $300,000 was set aside in the Governor's budget each year of this biennium for invasive species to more aggressively measure, control and possibly eradicate some aquatic invasive species," Vrakas notes. "We need to develop a plan in Wisconsin and work with the Department of Natural Resources and other state agencies so that we can qualify for some federal funding as well."

"The threat is real, and our efforts to combat these invasive species must be quick, focused, and effective," Vrakas says.

Farrow and Vrakas supported additional funding to educate the public about exotics.

"Zebra mussels are what called my attention to the issue," Farrow recalls. She had left a line in the water off her pier on Lake Michigan during a 10-day trip and when she returned she found that a large collection of zebra mussels had formed on the line.

"I paid attention to that," Farrow notes.

She then did research on the species and found that it is a native of the Caspian Sea and while it can help increase water clarity by eating plankton, zebra mussels have such a voracious appetite that they reduce the amount of food available to fish species. Zebra mussels also taint and contaminate potable water supplies and encrust boat hulls.

"There are even layers of zebra mussel shells in the sand of beaches on Elkhart Lake. They can cut feet and kids have to wear shoes to get to the water," Farrow notes.

Farrow, a former teacher, stresses that education is our best tool to stop the spread of exotics.

She believes the DNR's job should be to work statewide to make educational materials on exotics available to the public, as well as tailor educational materials to species of concern in each region. But she also believes there should be local effort to educate boaters and other water uses about what they can do to help control the spread.

Among her suggestions is that lake-area taverns and restaurants offer car wash coupons to boaters so that they can more efficiently clean their boats and trailers of zebra mussels and aquatic exotic plants. She also says the sanitary districts and lake associations can play an educational role.

Farrow calls Charlie Shong, superintendent of the Lake Pewaukee Sanitary District, a hero for his efforts to educate children about exotic species and discuss how these species will impact the next generation.

"Hopefully, the educational efforts we're making now will have a long lasting effect on our water quality and the aquatic community and aquatic community," Farrow notes.

Farrow agrees that coupling a state management plan and exotics policy with additional funding and education is the best strategy we have to reduce the risk of new introductions of invasive aquatic species while minimizing biological and economic consequences to natural ecosystems.

"We can't always stop exotics from getting into our waters," Farrow notes. "But we have to try to stem their growth. We need to be vigilant in how we take care of our boats and our waterfront property. We need to look at the toll that exotics can take on our waters and we have to try to manage them."

Natasha Kassulke is Associate Editor of Wisconsin Natural Resources magazine.