• One of the newer invasive species challenging Chautauqua Lake is the macroalgae starry stonewort.

• This invasive has been detected in the lake in small amounts since 2009, but large fields of dense growth were identified during targeted surveys in two areas in 2022. Given the scale of the growth, and the algae’s negative environmental impacts, local stakeholders are prioritizing monitoring and management of starry stonewort areas.

• Several different tools and techniques are available for starry stonewort management. Stakeholders performing work on Chautauqua Lake are continuing to pursue a combined approach that utilizes the management tool/tools best suited for conditions at particular work sites.

• Alliance Members working to combat starry stonewort on Chautauqua Lake include the Towns of Chautauqua, North Harmony, Ellicott, and Ellery; Chautauqua County, Chautauqua Watershed Conservancy, Chautauqua Lake Association, and Chautauqua Lake Partnership.

What Is the Problem?

• Like other invasive species, starry stonewort adapts well to new environments and has traits that allow it to out-compete native species. Major issues include:
  1. Easy spread via fragmentation.
  2. A growing season that peaks late in the summer, causing dense mats of algae that often impair recreation and crowd out native plants and fish.
  3. Formation of a reproductive bulbil bank in the lake bottom, which gives starry stonewort a strong foothold in areas of new growth and makes eradication difficult. 
  4. Potential spread to other waterbodies if small fragments are transported on boats or trailers. Each branchlet of the algae is an individual cell that can regrow itself.

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Management Timeline

• Because of these unique traits, management of starry stonewort is a difficult task. Stakeholders have utilized several different removal methods since active management began in 2022
  • 2022: Chautauqua Watershed Conservancy detects large-scale growth at Ashville Bay and Prendergast Point. Small scale manual removal pilot test at Ashville Bay site.
  • 2023: Pilot test of mechanical removal by Mobitrac amphibious barges and support vessels at Ashville Bay.
  • 2024: Chautauqua Lake Partnership begins developing an algaecide pilot project and secures DEC permits (treatments did not occur in 2024). State grants secured for management via diver assisted suction harvesting (DASH) at Ashville Bay and Prendergast Point.
  • 2025: Begin DASH in combination with mechanical bulk removal at Ashville Bay and Prendergast Point sites. DASH also performed at new site detected near Townline Road in Ellery/Ellicott.
  • 2026: Planning and coordination underway. Multiple management actions are expected contingent on DEC permitting and growth conditions.
• Ongoing monitoring and mapping of starry stonewort is vital to effective management, and is led by CWC Director of Conservation Dr. Twan Leenders, and North Carolina State University under the direction of Dr. Rob Richardson.

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New York State DASH Grants for Chautauqua and North Harmony

• Planning management also takes into account nearby wetlands and wetland check zones. In discussions with state officials, the local team determined that the use of diver-assisted suction harvesting (DASH) would likely be a good fit at Ashville Bay and Prendergast Point. This technique is very targeted, and is well-suited to the permitting requirements when working near wetlands. 
• In late 2023, Alliance staff worked with the Town of North Harmony and Town of Chautauqua to submit state grant applications seeking funding for DASH management of the algae. These are the Chautauqua Lake Ashville Bay Starry Stonewort Control Project and the Chautauqua Lake Prendergast Point Starry Stonewort Control Project.
• Grants of $100,00 each were awarded to the Towns in early 2024, as part of the NYSDEC Invasive Species Grant Program, with state funding from the Environmental Protection Fund as administered by NYSDEC: https://www.governor.ny.gov/news/governor-hochul-announces-nearly-3-million-grant-awards-support-invasive-species-prevention
• These grants total $125,000 each thanks to $50,000 in matching funds provided by the Alliance Lake Maintenance Operations and Capital Fund.
• DASH commenced for the first time on Chautauqua Lake in July of 2025 by Integrated Lakes Management at both Prendergast Point and Ashville Bay.

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Combining Approaches

• Due to the amount of biomass present at both Prendergast Point and Ashville Bay, the project team determined that a combined approach of DASH and mechanical removal would be the most effective strategy available.
• Working with staff from DEC, permits were secured during the 2025 season to perform mechanical removal of starry stonewort using Town of Chautauqua Mobitracs and Chautauqua Lake Association equipment. This combined approach allows larger equipment to address bulk removal of starry stonewort monocultures while DASH can be deployed in more targeted areas.
• In addition to the two primary work sites, CWC staff also identified a new starry stonewort growth area located near Elmhurst in the South Basin of the Lake. Leenders worked quickly to secure a DEC permit, and ILM crews performed DASH removal at this new work site in 2025. This additional effort was funded by the Town of Chautauqua using a grant from the Chautauqua County’s 2% Occupancy Tax Program.
• In addition to mechanical removal and DASH, chemical management options are still being considered. The Chautauqua Lake Partnership is continuing to evaluate the possibility using chemical treatment to address starry stonewort.
• Evaluation of prior work, and future planning for starry stonewort management on the lake is also informed by input from the Alliance’s lake management consultant, GEI.
• Annual plant surveys conducted by North Carolina State University and SUNY Oneonta have played key roles in monitoring this invasive species. Containment of spread has been aided by watercraft stewards stationed at public launches thanks to staff from CLA and WNYPRISM.

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