Starry Stonewort Infestations Have Spread Across Minnesota

The invasive algae has reached 40 water bodies, prompting increased state funding for management efforts.

Updated on Sept. 21, 2026 in Botany

Isometric editorial illustration of star-shaped aquatic algae and a weighted hose, representing invasive species spread in freshwater ecosystems. — Invasive starry stonewort has spread to 40 Minnesota lakes, leading the state to increase annual grant funding for species management to $1.4 million. AI Illustration. Upload story photo >

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Starry stonewort, an aquatic invasive algae, has now spread to 40 Minnesota water bodies. The state has responded to the growing threat by increasing annual grant funding for invasive species management to $1.4 million.

Why it matters

Managing this invasive species is challenging because it regenerates from bulbils left in lake sediment and lacks a vascular system. Researchers are currently investigating the long-term impact of the algae on water quality, fish populations, and native vegetation.

The Minnesota Department of Natural Resources issued 32 permits for starry stonewort management last year, accounting for 7 percent of the 482 total invasive species permits. Lake Koronis spends approximately $170,000 annually on containment.

The players

Minnesota Department of Natural Resources

This state agency manages natural resources, oversees invasive species permits, and coordinates the distribution of management grants.

The details

Contractors currently use copper-based algaecide applied via weighted hoses or perform suction harvesting to remove the algae from lake bottoms. These mechanical and chemical methods offer only a temporary reduction of the infestation rather than permanent eradication.

2015: First Minnesota starry stonewort infestation was confirmed.
2017: Starry stonewort was discovered on Grand Lake.
Last year: The DNR issued 482 total invasive species permits.
Last week: A new infestation was confirmed at Six Mile Lake.
Current year: State grant funding for management increased to $1.4 million.

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The Big Picture

The Starry Trek volunteer monitoring program follows a pattern established by citizen-science initiatives, having discovered one in four of the state's new starry stonewort infestations. This discovery rate highlights how local observation shifts the trajectory of invasive species tracking in Minnesota.

Residents and lake users should be aware that intensive chemical and mechanical management is only a temporary fix for local infestations. Because the algae spreads via bulbils, recreational water users are encouraged to follow state cleaning protocols to prevent further transmission between lakes.

The takeaway

Ongoing state funding underscores the persistent challenge of managing invasive algae that currently lacks a permanent removal solution. Local communities are essential to early detection efforts that help manage the spread of the species.