Starry stonewort (Nitellopsis obtusa), an invasive macroalgae native to Europe and Asia, poses a significant threat to Minnesota’s lakes. Since its discovery in 2015, starry stonewort has spread to 30 lakes. It is the deepest-growing, control resistant aquatic invasive species in the state. It has the potential to reduce native plant biodiversity, disrupting fish spawning, and invade wild rice beds.
Starry stonewort thrives in waters up to 25 feet deep, often appearing around high-traffic boating areas. Its dense mats can entangle props and disrupt recreational activities 
As a macroalgae, starry stonewort is resistant to traditional control methods and can be costly to manage—up to $170,000 annually for just one lake. 
In North America, only male starry stonewort has been found, meaning it spreads solely through transport of small plant fragments and star-shaped bulbils. This highlights the urgent need for stringent measures to prevent their movement and control its spread effectively.
Effective management of starry stonewort relies on prevention through containment, vigilant monitoring, and rapid response. By focusing on these best practices, we can minimize the spread ensuring timely action and effective control measures.
The Stop Starry Program addresses this issue by equipping citizens and counties with the tools and resources necessary to combat the spread of this invasive species, ensuring the preservation of Minnesota’s lake ecosystems.
90% of boaters know the risks and steps to CLEAN, DRAIN, and DRY,
…but most don’t fully comply due to a lack of equipment
24/7 Free-to-Use CD3 Cleaning Systems
CD3 stations provide around-the-clock access for boaters, ensuring continuous AIS prevention efforts. Their solar-powered operation allows them to function effectively even at remote access site Research shows that vacuum tools and high-pressure air hoses in CD3 systems are among the most effective methods for removing all types of AIS, including microphytes, plants, and algae
Find a CD3 Near You
Interested in learning how to secure a CD3 watercraft cleaning station for your local area?
Reach out to us with your lake information and access sites (you can use LakeFinder)
Jeff Forester>jeff@mnlakesandrivers.org
Sami Selter>sami@mnlakesandrivers.org
Civic Partnerships Are Key to Prevention
MLR works with lake associations, county officials, and government agencies through a discussion-based civic organizing process to address Starry Stonewort. We seek effective solutions and prevention strategies by engaging with affected communities. If you’re a concerned citizen or lake association member, contact our Director at jeff@mnlakesandrivers.org to volunteer and learn how you can help stop Starry Stonewort.
Resources:
Download and Share the Stop Starry Factsheet!
Examples of New Infestation Rapid Response Plans (NIRRPS)
AIS Explorer Tool
Check your lake’s starry stonewort risk
Watch:
Read:
- Natural Resource Research Institute tests techniques to clean boat interiors to stop spread of invasives
- Evaluating boat cleaning station efficacy on the removal of residual water from recreational boats
- A within-lake occupancy model for starry stonewort, Nitellopsis obtusa, to support early detection and monitoring
- Modeling the risk of aquatic species invasion spread through boater movements and river connections
- Construction and Integration of Aquatic Invasive Species (AIS) Prevention Areas at Recreational Boating Facilities – States Organization for Boating Access
Funding for the Stop Starry Program comes from the Legislative-Citizen Commission on Minnesota Resources through allocations from the Environmental and Natural Resource Trust Fund.
