Eurasian Watermilfoil
Purple Loosestrife
Curly Leaf Pondweed
Spiny Waterflea
Rusty Crayfish
Zebra Mussels

Aquatic Invasive Species

Invasive Species Watch


Eurasian Watermilfoil

Forms dense mats that interfere with boating and swimming. Long spaghetti-like stems with delicate feather-like leaves. Leaves arranged in circles of 3-5 around stem. Similar to native Northern watermilfoil (7-10 leaflet pairs).


Purple Loosestrife

A hardy perennial which can degrade wetlands and diminish their value for wildlife habitat. Grows a 3-7’ spike with small purple flowers with smooth-edged leaves. Mature plants have a root crown that produces many stems.


Curly-Leaf Pondweed

Forms weed mats that shade out native plants. It’s wavy leaves are 1/2” wide to 2-3” long. When it dies off back around mid-sum­mer, it releases nutrients, which cause algal blooms and other problems.


Spiny Waterflea

Competes with small fish for food and fouls gear. This crus­tacean is less than 1/2”. Difficult to distinguish without magni­fication. Clumps look and feel like gelatin.


Rusty Crayfish

Grazes on and can eliminate aquatic plant beds. Adults grow up to 3-5” long. Their claws are larger and smother than other crayfish. It displaces and can hybridize with native crayfish.


Zebra Mussel

Filter feeders which take plank­ton out of the water that young fish rely on for food. They are yellow-brown striped clams with a “D” shaped shell and grow up to 2” long.



It’s The Law

It is unlawful to:

  • Transport aquatic plants, ruffe, round goby, zebra mussel, or other prohibit­ied invasive species on public roads;

  • Transport infested water (including in livewells and bait containers) Note: To keep unused bait at spiny water flea- or zebra mussel-infested waters, drain and replace with tap or spring water;

  • Launch a watercraft with aquatic plants, zebra mussels or prohibited invasive species attached; and

  • Harvest bait (minnows, frogs, crayfish or other wild animals) from infested waters. Exception: Harvest for person­al use is permitted in waters infested SOLELY with Eurasian watermilfoil. Harvested bait must ONLY be used in the water from which it is harvested. Bait may only be harvested using a cylindrical minnow trap not exceeding 16 inches in diameter and 32 inches in length.


How you can help!

Remove visible plants, animals, and mud from your boat, trailer, and other boating equip­ment before leaving the water access.

Drain water from your boat, motor, livewell, and bait containers before leaving the water access. You must remove the drain plug prior to leaving any water access in the state while transporting.

Dispose of unwanted bait in the trash. Never release live bait.

Spray, rinse, or dry boats and recreational equipment before transporting to another body of water. Spray/rinse with high pressure and/or hot tap water (above 120º F) or dry at least five days.