Aquatic invasive Species

Aquatic invasive species (AIS) are nonnative animals and plants that do not naturally occur in our waters and may cause ecological or economic harm. See images below of some AIS that have been found in Minnesota.

You can help prevent the introduction and spread of AIS by following both the required and recommended actions listed on page 16 before moving your boat, bait or other equipment from one waterbody to another.

Report new infestations: If you suspect a new infestation of an AIS, note the exact location, take a photo or keep the specimen, and call 888-MINNDNR

Invasive carp captures must be immediately reported to the DNR, call 651-587-2781 or email [email protected]. Please take a photo, keep carcass cool but do not freeze, and make arrange ments with the DNR to transport the carp to the nearest area fisheries office. You may keep invasive carp for personal use with a special permit, which is available on the DNR website at mndnr.gov/invasive-carp.

Red swamp crayfish

2 to 5" long. Raised bright red spots on claws.

Spiny waterflea

Long tail, white with black spots, looks like gelatinous globs on fishing line, small (up to 3⁄8").

Eurasian watermilfoil

12 to 21 leaflet pairs per leaf.

Faucet snail

Up to ½" long, light brown to black, 4-5 whorls.

New Zealand mudsnail

Up to 1⁄5" long, light to dark brown, cone-shaped shell, 5-6 whorls.

Round goby

Single scallop-shaped pelvic fin, fish is usually 3-6" long.

Starry stonewort

Grass-like algae with a small, star-shaped structure called a “bulbil” less than ¼-inch in diameter.

Zebra and quagga mussel

The only freshwater mollusks that attach to objects with byssal threads (up to 1½"); larvae float in water and are too small to see.

Bighead and silver carp

Eye located at lower part of head below the mouth; Silver can jump more than 10 feet high.

Ruffe

Spots between rays of dorsal fin, no gap between fins.

Required Actions—It’s the Law!

Most anglers and boaters follow Minnesota’s Clean, Drain, Dispose laws to help prevent the spread of aquatic invasive species:

Clean all visible aquatic plants, zebra mussels and other prohibited invasive species from watercraft, trailers and other water-related equipment before leaving any water access or shoreland.

• It is illegal to transport prohibited invasive species—including zebra mussels—whether dead or alive.
• You can find a complete list of prohibited invasive species by visiting dnr.state.mn.us/invasives/laws.html#prohibited

Drain water-related equipment (boat, ballast tanks, portable bait container, motor) and drain bilge, livewell and baitwell by removing drain plugs before leaving any water access or shoreland property.

• Keep drain plugs out and water-draining devices open while transporting watercraft.

Dispose of unwanted bait, including minnows, leeches and worms, in the trash.

• It is illegal to release bait into a waterbody or release aquatic animals from one waterbody to another.
• It is illegal to release worms in the state; worms are not native to Minnesota.
• If you want to keep your live bait, on shore before leaving, you must always drain all water from your bait container and refill it with bottled or dechlorinated tap water.

Recommended Actions—Protect Your Waters

To further decontaminate your watercraft and equipment, it’s important to spray, rinse or dry everything before going to another waterbody, especially if your boat has been in the water or moored for more than 24 hours—or if you have recently been in zebra mussel or spiny waterflea infested waters. Do1 or more of the following:

• Dry for at least 5 days.
• Spray with high-pressure water.
• Rinse with very hot water. To reduce the risk of spreading zebra mussels, use water that is 120 °F at the point of contact and spray each area for at least 2 minutes, or use 140 °F water for at least 10 seconds on each area.

Lakes and Rivers Listed as “Infested”

What do I need to do when I visit a lake or river on the infested waters list?

You should follow the same aquatic invasive species regulations: Clean, Drain, Dispose— every time you visit any lake or river, infested or not.

• If you are harvesting bait, commercial fishing, or diverting or taking water, you need to follow special regulations in infested waters.

How do I know which waters are listed as infested?

• For the most complete and current infested waters list, visit mndnr.gov/AIS or request a copy from [email protected] or call 651-259-5100.
• You can use LakeFinder to find out if a particular lake is listed as infested: mndnr.gov/lakefind.
• Infested waters are posted with orange Invasive Species Alert signs at the public access.

Watercraft Inspections

The Minnesota DNR has had a watercraft inspection program since 1992 to help prevent the spread of AIS. With the help of our partners, today nearly1,000 authorized watercraft inspectors are working at lakes and rivers across Minnesota. The information below will help you prepare for a watercraft inspection. In 2021, 95 percent of boaters surveyed by inspectors arrived while following Minnesota’s Clean, Drain, Dispose laws.

What should I expect from an inspection?

Inspectors are trained to:

• Introduce themselves as a watercraft inspector.
• Provide tips on how to inspect your own equipment.
• Physically inspect your boat, trailer and any other water-related equipment— meaning they may touch your boat or trailer to feel for tiny attached zebra mussels or other invasive species.
• Physically inspect compartments that may hold water, such as live wells or bilge areas.
• Deny launch if: 1) the inspector finds invasive species or any plants attached, and until the invasive species or plants are removed; or 2) you refuse an inspection.
  • Although inspectors have the authority to deny launch, they will work with you to try to bring your watercraft into compliance.
  • Inspectors will not deny launch based solely on where, or when, you last used your watercraft.
• Ask questions to help improve the DNR’s inspection program. You are not required to answer these questions.

How should I prepare for an inspection?

When entering an access:

• Always follow all state laws regarding AIS and arrive in compliance with Clean, Drain and Dispose laws.
• Open the lids of closed compartments that could hold water, like live wells, so the inspector can see they are drained. Your drain plugs should all be open while you transport your boat.
• Remember to install the drain plug after the inspection and before launching.

When exiting an access:

• Remove any plants, mud, and invasive animals.
• Pull all drain plugs.
• Open water-holding compartments to allow inspection.

What about on-site watercraft decontamination?

An inspector may require your watercraft to be decontaminated prior to launching or before leaving an access, if a unit is on-site. Most decontaminations can be done quickly. Trained inspectors use hot water to target areas to kill AIS. An inspector may also use high-pressure water. The DNR performs watercraft decontaminations free of charge.

How do I find a decontamination station?

The DNR posts decontamination unit locations online at mndnr.gov/decon.

At these sites, inspectors will perform a courtesy inspection and determine if any decontamination is required.

Tell us how we’re doing at: [email protected]