Picture it: summer along the north shore. Bright blue skies, warm sun, and you at your favorite fishing hole or boat launch. 

If you're an angler or boater, you know the drill to prevent the spread of aquatic invasive species: when you leave a spot, you clean your equipment, drain or dump any water, properly dispose of bait, and let your items dry before hopping onto the next lake. 

But what about in the winter? The ice is frozen over, and most things below the surface of concern surely can't survive our harsh winters, right?

Boreal Community Media spoke with Amanda Weberg, Aquatic Invasive Species Supervisor at the Cook County Soil and Water Conservation District about invasive species and winter. 

Aquatic Invasive Species in Winter

"Yes, AIS spread is always possible regardless of water and air temperatures", Weberg said.

The two invasive species that are present in Cook County are rusty crayfish and spiny water fleas. 

According to Weberg, when the water temperature hits 50 degrees or lower, both the rusty crayfish and spiny water flea go dormant. 

"However, they have adapted well to survive long, cold winters", Weberg added.

"Spiny water fleas lay resting eggs on the lake bottom in the fall that will hatch when the water temperature reaches above 60 degrees.

Rusty crayfish hunker underneath substrate and eat detritus in the winter. They start to move around with 50-degree water temperatures."

Dumping bait

It's not just fishing or boating equipment that anglers need to be mindful of to prevent the spread of aquatic invasive species. 

According to Weberg, dumping bait into lakes can introduce a number of diseases to local ecosystems. 

"I’d like to add the importance of not dumping bait into the lake. Live bait fish (especially fathead minnows and shiners) are typically not native to our lakes, and are the main vector to spreading viral, bacterial, and parasitic diseases to fish populations which can cause mortality events," she said.

To help prevent the spread of diseases from live bait, it is advised to throw it away or bring tap water with you so you can change out the bait water, just like you would do in other parts of the year. In Minnesota, it is illegal to transport lake or river water with you. 

Weberg acknowledges that taking these extra steps may seem like a hassle, but "they will become common practice with time. Similar to wearing a seat belt or brushing your teeth."

To learn more about aquatic invasive species in Minnesota, visit the Department of Natural Resources site here. 

If you'd like to get involved with the efforts to prevent the spread of aquatic invasive species, Weberg adds: "summer will be here eventually and the AIS team will hire watercraft inspectors for the season. Please reach out if interested in joining the crew!"