LIVE FISHING BAIT INVADES AND DISRUPTS OUR LAKES AND FORESTS

ALIEN EARTHWORMS!! ATTACK OF THE RUSTY CRAYFISH!! These may sound like silly horror movie titles, but they actually reflect one of the shocking realities of live fishing bait. These species (and others), once released into Wisconsin's waters, can disrupt whole ecosystems.

Many people don’t realize that in the northern, glaciated regions of North America, the common earthworms we know and love are really exotic European invaders brought here by humans. Once exotic earthworms establish large populations, the forest floor is replaced with a dense layer of black soil—the kind you might want in your garden—but the change is hard on native forest plant communities. The changes these worms make can be dramatic, leading to declines in soil invertebrates, changing populations of small forest mammals and amphibians, and even facilitating establishment of invasive plant species.

Rusty crayfish are native to streams in the Ohio River Basin states of Ohio, Kentucky, Illinois, Indiana, and Tennessee. They were likely introduced to Wisconsin waters primarily by anglers who used them as live bait. They are still sold as bait and by biological supply companies. It is illegal to possess both live crayfish and angling equipment simultaneously on any inland Wisconsin water (except the Mississippi River). It is also illegal to release crayfish into a water of the state without a permit, and a fishing license is required to harvest crayfish. Rusty crayfish eat small fish, insects, and fish eggs. They also voraciously consume aquatic vegetation like little underwater lawn mowers, damaging habitat that is important for fish spawning, cover, and food. They are aggressive and displace native crayfish. Rusty crayfish are prolific; females lay from 80-575 eggs!

The good news is that anglers and recreational boaters can easily halt further introductions of these and other invasive species without compromising their fishing opportunities. This can be done by simply dumping unused live bait in the trash (not in the water or on land!). And to ensure that no invasive species are transported from lake to lake, make sure to: 1) Inspect and remove plants, animals, and mud from your boat and equipment; 2) Drain all water from your boat's live wells, bilge, motor, etc.; and 3) Wash your boat and equipment with high-pressure or hot water, especially if moored for more than a day, or dry your boat and equipment thoroughly for at least 5 days.

Compiled by Amy Staffen, WI Council on Invasive Species.
April 2005