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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

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August 2002

Hazardous hitchhikers

Battling aquatic invasive species.

Natasha Kassulke


Exotic – also known as invasive – species are hampering boating, swimming and other water recreation in Wisconsin waterways.

Some exotics also reduce diversity or native species abundance and disrupt ecological stability of aquatic and land ecosystems. Eurasian water milfoil, for example, can clog boating lanes, reduce fish populations and crowd out native plants.

Add to that the serious economic toll on commercial and aquatic resources.

Our best line of defense is early detection and quick response, explains Ron Martin who coordinates aquatic exotics issues for the Wisconsin DNR.

People spread invasive species through ship ballast water, recreational boating (on trailers and boats or in live wells and bait buckets), sport fish stocking and accidental releases associated with industries.

Aquatic invasive offenders in Wisconsin include zebra mussel, Eurasian water milfoil, purple loosestrife, sea lamprey, ruffe, round goby, rusty crayfish, white perch, flowering rush, curly-leaf pondweed, spiny water flea, common carp, rainbow smelt, fishhook water flea and alewife.

In response to the invasive species onslaught, Wisconsin Gov. Scott McCallum formed a Governor's Task Force on Invasive Species in May 2001 and the DNR formed a team to inventory invasive species that are, or have the potential, to become harmful in Wisconsin.

More recently, McCallum allocated $300,000 in fiscal years 2002 and 2003 to combat aquatic invasives. As of the start of the 2002 fishing season, it also is illegal to launch a boat in navigable waters if it has aquatic plants attached, or if a law enforcement officer has reason to believe that a zebra mussel may be attached.

Fines for violating these laws are $50 first offense and $100 second offense. The intent is to inform boaters of the regulations and instruct them on how to clean their equipment properly, not to issue tickets, Martin says.

Last spring, the DNR also launched efforts to inspect boats at landings and to educate boaters so that they don't unwittingly transport invasive species on their boat, boat trailer, or in live wells, bilge water or transom wells.

The DNR further spreads the word about invasives with species watch identification cards, brochures, displays at state parks, sport shows and lake conventions, and signs at boat landings. Recent public service announcements have targeted eastern Wisconsin from Racine to Green Bay, Madison and upstate areas.

Some signs at boat landings look much like traffic signs. The red "stop" sign may be posted at any water and reminds boaters to remove aquatic plants and other potential exotic species from their boat and trailer. The yellow "caution" sign is posted at infested waters. The green "help" sign contains general information on preventing the spread of aquatic exotics.

As a boater, you can take these steps every time you remove your boat from the water, regardless of whether you know the lake is infested or not:

  • Drain water from live wells, bilges and other containers before leaving the launch area.
  • Remove plant parts and animals from your boat, trailer and accessory equipment. Dispose of removed materials in the garbage either at the launch area (if cans are available) or at home.
  • Do not release live bait or aquarium pets into any waters.
  • Wash your boat and trailer thoroughly with tap water when you get home. Flush water through your motor's cooling system, live wells and other areas that hold water, or dry your boat and equipment for five days in a sunny location before transferring it to a new water body.

If you find something that looks suspicious and might be an exotic, keep a specimen and take it to your local DNR office for verification. Visit Aquatic Invasive Species or call (608) 266-9270.

"Clean boats mean clean waters" is the cornerstone of the DNR's program to prevent aquatic exotics from spreading.

Natasha Kassulke is Associate Editor of Wisconsin Natural Resources magazine.