Preventing the Spread of Invasive Species

The most important thing you can do about aquatic invasive species is to avoid spreading them from one waterbody to another.

Because aquatic invasive species are often difficult or impossible to remove from a waterbody once they’re established, the best time to take action on invasive species is before they arrive. Even if your lake or stream already has some invasive species in it, you can protect it from additional invasive species that haven’t made it there yet, and you can avoid spreading your waterbody’s invasive species to less invaded waters.

Aquatic invasive species can “hitchhike” on our boats or gear from one waterbody to another, but cleaning your equipment can reduce this risk.

Step 1: Inspect your boat, trailer, waders, or other equipment.

Remember to check nooks and crannies, like underneath your boat trailer or inside your wading boots. Try to look from multiple angles to make sure you don’t miss anything.

Step 2: Remove all attached plants, animals, and mud.

Use a boot brush to scrub down waders, especially the underside of your boots, or use a hose to help remove muck. Make sure plants and animals are either returned to the waterbody they came from or properly disposed of well away from any other waterbodies.

Step 3: Drain all water from boats, vehicles, and equipment.

Empty live wells and transom wells, and turn kayaks and canoes upside down so they can drain.  Drain water from any other gear, like waders or duck decoys.

Step 4: Never move live plants or animals away from a waterbody.

Don’t move live fish away from a waterbody. Return plants and animals that you pick up accidentally to the waterbody that they came from.

Click here for more information about how you can follow these steps, whether you are a fisher, boater, or other water enthusiast.

Other Steps You Can Take To Prevent the Spread

Decontamination can sound scary, but it just taking steps to prevent small plants or animals from surviving on your gear. Even after we clean off what we can physically see, very small or even invisible plants or animals may remain behind. Preventing them from surviving on your gear can keep you from accidentally moving them to another waterbody.

Not every decontamination step works against every invasive species. If you’re not sure which step is best for your situation, consider taking more than one of the below steps, or contact us for advice.

Options for decontaminating your gear

  1. Soak in a dilute Formula 409 solution for five minutes. Use one part household Formula 409 to one part water. Rinse after soaking. Note: This method is recommended for waters with New Zealand mudsnails, which are resistant to many other methods.
  2. Soak in dilute bleach solution for 10 minutes. Use 2.5 tablespoons of 5.25% sodium hypochlorite household bleach per gallon of water. Rinse after soaking.
  3. Soak in a 2% Virkon solution for 20 minutes. Rinse after soaking.
  4. Steam clean.
  5. Soak in hot water (125° F) for five minutes.
  6. Dry for five days. This method does not work in very humid environments or on gear with lots of nooks and crannies that do not dry out well.
  7. Freeze for at least 24 hours.

Check out WDNR’s website for more information on decontamination, including details about how and when to use each of the above methods.

If you have added lake or river water to your live bait container, you should use that bait only on the same waterbody or discard it. Do not bring the bait to a different waterbody, as doing so could spread fish diseases, like Viral Hemorrhagic Septicemia (VHS).

When you take your boat out of the water, you may keep up to two gallons of water for your minnows, but you must drain all other water from your boat.

Click here for more information on fishing with live bait.

If you keep a water garden or pond, make sure that you are not planting or releasing invasive species. Do not purchase invasive species, and use native species instead where possible. Visit the WDNR for Wisconsin’s current list of prohibited and restricted invasive species.

Keep your water garden plants contained. Don’t plant them in a lake, stream, wetland, or stormwater pond, and dispose of any unwanted plants properly.

If you can’t care for a pet anymore, surrender it to a qualified animal rescue rather than releasing it into the wild. Releasing fish, turtles, or other animals into the wild can be harmful for both the animal and the environment. Some common pets, like goldfish and red-eared sliders, have become invasive because of people releasing them into lakes and rivers.

If you don’t know where to bring your pet, J&R Animal Rescue may be a good option. They often hold events across Wisconsin where pet owners can surrender unwanted exotic pets, no questions asked.


Learning to identify invasive species can help you understand what is going on in your local lake, river, or wetland. What invasive species are already present? Are their populations growing or shrinking over time? Has this invasive species been documented here before?

The Wisconsin AIS Early Detector Handbook from the Wisconsin Department of Natural Resources will get you started on learning how to recognize invasive species. Download the Handbook (free online), or purchase a physical copy, here.

Hands-on opportunities to learn about invasive species identification are also available as part of Snapshot Day, Citizen Lake Monitoring Network, and Project Riverine Early Detection. Learn about upcoming events in these programs here.


Every year, community members are responsible for hundreds of reports of new aquatic invasive species statewide. If you find an aquatic invasive species that is new to a waterbody, you can help by reporting it.

Once WDNR and others know about your find, they can launch a response to it. This response could include searching for the species in nearby waterbodies, educating people about how to prevent spreading it further, or, if feasible, attempting to control or eradicate it.

How to report invasive species

Step 1: Check the WDNR’s website to see if the invasive species has already been documented on the waterbody. If the species has already been reported, there is no need to report it again. If the invasive species has not been documented there before, continue to the next step.

Step 2: If possible, collect specimens. Collect several specimens in a plastic bag and freeze them. This will keep them in good condition in case they need to be examined by an expert. If you’ve found a plant, collect as many parts of the plant as possible: leaves, flowers, seeds, stems, and roots.

Step 3: Take photos. This is especially important if you cannot collect a specimen for any reason. Take several close-up, well-lit photos of the species itself. Include another object for scale and show any identifying characteristics. If possible, also take several landscape-scale photos to show the extent of the population and where it is located.

Step 4: Record other information. Write down where and when you found the invasive species. Record GPS coordinates if possible. Estimate how many individuals there are, and how much space they cover.

Step 5: Tell someone promptly. Contact your regional aquatic invasive species coordinator. Reaching out as soon as you can will allow them to respond quickly to any high-risk invasive species. Hold onto your specimens in case they are requested for identification help.


Knowing what invasive species are in your waterbody can be helpful information, whether you are managing aquatic plant growth, decontaminating your gear, or just hoping to learn more about your lake.

Visit the WDNR’s website to learn what invasive species have been found where. You can search by waterbody or by species.

We have created a StoryMap showing known aquatic invasive species populations in Dodge County. Check it out here.