Minnesota volunteers uncover four new starry stonewort infestations in 2025

Volunteers in Minnesota have discovered new infestations of starry stonewort, an invasive algae that disrupts lake ecosystems. The findings came during the annual Starry Trek event, where trained participants surveyed waterways across the state.

The invasive species can crowd out native plants and alter habitats for fish and wildlife. Early detection remains key to managing its spread, with local groups and state agencies working together on the effort. In August 2025, Starry Trek volunteers identified starry stonewort in four previously unaffected lakes. The new detections included Garfield Lake in Hubbard County, Gull Lake and Three Island Lake in Beltrami County, and Two Rivers Lake in Stearns County. These discoveries mark the first confirmed cases in those waterbodies.

The event, coordinated by Megan Weber and staff from the Minnesota Aquatic Invasive Species Research Center, relies on trained volunteers to monitor high-risk areas. Jane Bartelme, president of the Grand Lake Area Association, has taken part in Starry Trek for four years, helping survey local lakes. Her involvement reflects broader community efforts to track and report invasive species before they spread.

Early action has already proven effective in some locations. In Stearns County, prompt detection allowed managers to contain starry stonewort in Grand Lake and Carnelian Lake. Training sessions, like those led by resource conservationist Mike Hirst at Zippel Bay State Park, ensure volunteers can recognise and report the algae correctly. A public map now displays participant activity and findings from past surveys, offering a clear picture of monitoring efforts statewide.

While no new infestations were officially recorded between 2017 and 2024, the Minnesota DNR had confirmed 14 affected lakes by 2023. These included Big Marine Lake in Washington County, first detected in 2015, and Tetonka Lake in Le Sueur County, identified in 2022. The DNR continues to lead long-term monitoring, supported by programmes like Aquatic Invasive Species Detectors, which educate boaters and lake users on prevention methods.

For those seeking more details, the AIS Detectors YouTube channel provides resources on identifying and reporting starry stonewort. The algae's dense mats can choke out native vegetation, reducing biodiversity and altering water quality over time. The 2025 Starry Trek results highlight the ongoing threat of starry stonewort in Minnesota's lakes. With four new detections, managers and volunteers will now focus on containment and further surveys.

Statewide collaboration between agencies, researchers, and local groups remains critical. Their combined efforts aim to limit the algae's impact on freshwater ecosystems and protect native species.