Wawasee Spink

how to prevent its spread StarryStonewort:

by Carolina Kegan, Lilly Center for Lakes & Streams photos provided by Starry Stonewort Collaborative

It’s finally time to take your boat out of storage! As we prep to put boats in the water, let’s also prep to prevent spreading starry stonewort, which tends to lurk beneath, and attach itself, to boats.

Here’s what you need to know about that pesky invasive species, starry stonewort, and how to diminish its spread this summer. (If you would like to learn more about the invasive species’ presence in our county, visit lakes.grace.edu/original-research.) Starry stonewort was accidentally introduced to the United States in the 1970s when fragments of the plant were transferred from a ship into water channels that led into the great lakes. It is a non-native aquatic plant, coming from between the west coast of Europe and Japan.

This invasive species was first discovered in Indiana lakes in 2008. In Kosciusko County, the first lake found with starry stonewort was Lake Wawasee. Since, it has had an impressive growth rate, which has negatively impacted aquatic ecosystems.

Starry stonewort grows in mats across the surface of the lake, impeding the flow of water—but it does not stop there. Dense mats can form beneath the surface, overtaking other native aquatic vegetation and clogging the aquatic ecosystem. This can harm fish, accumulate phytotoxins and lead to excess nutrients, all of which are detrimental to the health of the lake.

Much like pollen sticking to bees and transferring from flower to flower, starry stonewort attaches fragments of itself to fur, feathers, fishing gear, boats, and virtually anything else to transfer from lake to lake. To impede the spread of starry stonewort, be sure to thoroughly clean everything that has been in the lakes after its use, especially anything that frequently contacts the lake water, such as the hull of your boat, recreation equipment, and fishing gear.

To identify starry stonewort, look for its characteristic starshaped bulbils. It is a softer plant and has a light green color. It can be mistaken for Chara, a similar aquatic plant species. Chara has rougher stems and round bulbils rather than star-shaped ones.

If you encounter starry stonewort, do not try to get rid of it yourself, as this can accidentally cause it to spread. Instead, call the experts. We recommend speaking with your lake association or calling Aquatic Weed Control and Aquatic Control; they can help you diminish the spread.

The Lilly Center for Lakes & Streams at Grace College conducts research, provides resources, engages and educates residents, and collaborates with local organizations to make the lakes and streams of Kosciusko County clean, healthy, safe, and beautiful. To date, the Lilly Center has conducted scientific research on over 30 streams and 40 lakes. The Lilly Center is driven to create a legacy of stewardship by equipping community members, visitors, and future generations to understand and enjoy the county’s natural beauty. For more information, visit lakes.grace.edu.