Water Hyacinth and Water Lettuce Monitoring Day

Scott Caven, our Aquatic Invasive Species Coordinator, explains how to distinguish between the highly-invasive Eurasian watermilfoil and the seven watermilfoils that are native to Wisconsin.

In October 2015, water hyacinth and water lettuce – two of the most problematic aquatic invasive species (AIS) in the world – were discovered in Lake Onalaska (Pool 7 of the Mississippi River) near Brice Prairie, Wisconsin. Concerned citizens and natural resources professionals sprung to action. Representatives from the U.S. Fish and Wildlife Service, Wisconsin Department of Natural Resources, River Alliance of Wisconsin, Lake Onalaska Protection and Rehabilitation District and Brice Prairie Conservation Association, among others, teamed up to monitor and remove water hyacinth and water lettuce from Lake Onalaska. Tens of thousands of plants were removed from Lake Onalaska from October 2015 to December 2015. While all signs suggested that water hyacinth and water lettuce had been successfully eradicated, follow-up monitoring (and control efforts, if needed) were scheduled for 2016.

On June 11, 2016, River Alliance hosted the Water Hyacinth and Water Lettuce Monitoring Day on Lake Onalaska with a few goals in mind: to engage citizen scientists in AIS monitoring, to ensure water hyacinth and water lettuce were not growing in Lake Onalaska and to learn about and enhance Lake Onalaska, all while having some fun! Volunteers from the U.S. Fish and Wildlife Service, University of Wisconsin-La Crosse, River Alliance of Wisconsin, Lake Onalaska Protection and Rehabilitation District and Brice Prairie Conservation Association gathered at the Fred Funk boat landing in Brice Prairie, eager to do their part to stop aquatic hitchhikers. Before hitting the water, the group reviewed key identification characteristics for water hyacinth, water lettuce and other AIS. After launching their kayaks and canoes, it didn’t take long for the group to test out their “refreshed” AIS identification skills.

“There’s Eurasian watermilfoil! It has more than 10 pairs of leaflets!” exclaimed one participant. “This aquatic plant looks like a lasagna noodle with serrated edges. It’s gotta be curly-leaf pondweed!” proudly stated another. And they were right! During the four-hour paddle, the group properly identified Eurasian watermilfoil, curly-leaf pondweed, faucet snails, purple loosestrife and yellow iris – all of which were previously documented in Lake Onalaska. But it didn’t stop there. To this hearty group of river rats, monitoring and mapping AIS wasn’t enough; they wanted to take control, literally. So, all of the yellow iris (classified as a “restricted” invasive species under NR40, Wisconsin’s Invasive Species Rule) found during the paddle was removed, bagged up and tossed in the trash.

A dedicated volunteer removes yellow iris (Iris pseudacorus) from Lake Onalaska’s shoreline. Yellow iris is classified as “restricted” under NR40, Wisconsin’s Invasive Species Rule, meaning it is illegal to transport, transfer or introduce but possession is allowed.

Fortunately, neither water hyacinth nor water lettuce was discovered during the paddle. But just to be on the safe side, River Alliance staff and partners will continue monitoring Lake Onalaska this summer and fall to ensure that neither species shows up again. For now, it sure looks like last fall’s eradication efforts were successful, thanks in large part to dedicated citizen scientists like those that joined us for Saturday’s paddle.

River Alliance reminds you to do your part to ensure you are part of the solution, not the problem! Before launching and leaving, Wisconsin law requires you to:

• INSPECT boats, trailers, and equipment.
• REMOVE all attached aquatic plants and animals.
• DRAIN all water from boats, vehicles, and equipment.
• NEVER MOVE plants or live fish away from a waterbody.
• NEVER RELEASE plants or animals into public waters.