Exotic species are spreading in Wisconsin's lakes at a rapid pace.  Eurasian water milfoil, purple loosestrife and zebra mussels are particularly problematic. The primary way they spread is by hitching a ride on boats and boat trailers or in live wells or bait buckets from infested waters. Since May 2002, it has been illegal to launch a boat or boat trailer in Wisconsin’s navigable waters with an aquatic plant or a zebra mussel attached.

To help educate boaters about the new law and the need for it, the Department of Natural Resources will have boat inspectors at launches on popular Wisconsin lakes throughout the summer. These inspectors will talk to boaters about invasive aquatic species, hand out information and offer to show boat owners where aquatic plants or zebra mussels may be attached. They’ll also encourage boat owners who are leaving for the day to empty any water from their live wells, bait buckets, motor or bilge to get rid of any zebra mussel larvae and other exotics that may be in the water.

Zebra mussels form dense clusters that attach to hard surfaces, and can decimate native mussel populations, decrease the oxygen that fish and other aquatic species need, and worsen smelly, unsightly algal blooms. In addition, the zebra mussels can clog boat engines and intake pipes for utilities, and their sharp shells can wash up on shore and make walking on the beach hazardous. Eurasian water milfoil, which forms dense mats at the water’s surface that can hamper boating, fishing and swimming, can also crowd out native aquatic plants that provide important habitat for fish and other aquatic life. The invader first entered Wisconsin in the 1960s; it spreads to new water bodies from cuttings attached to boats and trailers.

Boaters and anglers can take a number of steps to prevent spreading zebra mussels and other aquatic invasive species to new waters:

Before leaving a boat launch:

Inspect your boat, trailer, and boating equipment and remove any visible plants and animals.

Drain water from the motor, live well, bilge, and transom wells while on shore and before leaving any water body.

Dump unused bait on shore. Never release live bait into a water body, or release aquatic animals from one water body into another.

Spray your boat and boating equipment with high-pressure water or leave it in the sun to dry for 5 days.

For more information on Wisconsin's invasive species, visit the DNR’s web site