Even though it’s winter, it doesn’t mean anglers should relax their practices against spreading invasive species that might lurk below, Wisconsin officials advise.

Invasive species are non-native plants, animals and diseases that cause ecological, environmental or economic harm, the Wisconsin Department of Natural Resources and UW-Extension warned in a news release. Aquatic invasive species can crowd out native plants and animals and threaten the quality of boating and fishing.

“Curly-leaf pondweed and Eurasian watermilfoil are aquatic invasive species that remain hardy under the ice in the winter, giving them an advantage over our native aquatic plants,” according to the Wisconsin DNR. “The plant-like algae starry stonewort dies back for winter, but its tiny, star-shaped bulbils can be present on plants yanked up through the ice or in the mud that can come up if the bottom is disturbed by augers.

Disease and the larvae of invasive snails and mussels can also be present in the water and mud in winter.”

Because of the possible spread of diseases like Viral Hemorrhagic Septicemia that can threaten fish populations, buying minnows from a licensed Wisconsin bait dealer is important, the news release recommends. Up to 2 gallons of water may be kept for minnows, provided they will be used on the same waterbody or if no lake or river water from the fishing site(s) has been added. Dead bait must be preserved in ways that do not require freezing or refrigeration. To learn more, go to the DNR’s webpage on bait preservation at https://dnr.wisconsin.gov/topic/Fishing/vhs/vhs_preservation.html. Find more rules regarding bait in the state’s current fishing regulations, https://widnr.widen.net/s/fwdfffxqzv/fishingregselectronic2324.

A few minutes of preventative action can help preserve and protect waterways for future generations, the DNR stresses. Before stepping onto the ice or into a stream this winter, anglers should —

≤ Inspect fishing equipment for attached aquatic plants, animals or mud;

≤ Remove all attached plants or animals;

≤ Drain all water from buckets, containers and gear;

≤ Never move live fish away from a water body (fish out of water = dead);

≤ Dispose of unwanted bait in the trash.

In addition, the DNR encourages anglers to leave fishing gear where it can freeze for eight hours or more, as this will kill most species. Other methods to kill aquatic invasive species hiding in fishing gear are to steam clean the gear or to soak it in either 140-degree water or a solution of 2.5 tablespoons of bleach per gallon for 10 minutes.

To learn more about invasive species and their effects on Wisconsin’s waters and economy, go to the DNR’s invasive species webpage at https://dnr.wisconsin.gov/topic/Invasives.