Chautauqua Lake and Watershed Management Alliance

Chautauqua NY

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Emerging Invasive Species

Starry Stonewort

(Nitellopsis obtusa)

  • 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 have begun prioritizing monitoring and management of starry stonewort.
  • Click buttons below to jump to individual management projects. 
Mobitrac Pilot Test
Chemical Pilot Test
Diver Assisted Suction Harvesting
  • Ashville Bay, Town of North Harmony
  • Prendergast Point, Town of Chautauqua
Pictured above are two infestations of starry stonewort which were mapped via Chautauqua Watershed Conservancy kayak surveys in 2023. The Ashville Bay field can be seen at left, while the Prendergast Point field can be seen at right. Source: CWC.

 

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. 

What Tools Do We Have?

  • Because of these unique traits, management of starry stonewort is a difficult task. Several different management tools are being considered for use on Chautauqua Lake, including new pilot programs to test effectiveness. In the fall of 2022 and 2023 local stakeholders came together to evaluate mechanical and manual removal of the algae in Ashville Bay. In 2023 this approach included the use of Town of Chautauqua Mobitracs and Chautauqua Lake Association skimmers to collect the algae as seen below. These pilot tests have been organized by Chautauqua Watershed Conservancy Director of Conservation Twan Leenders.
  • Chemical management options are also being considered, see more details below. 

Moving Forward: New York State DASH Grants for Chautauqua and North Harmony

  • Planning management in these two areas must also take into account nearby wetlands and wetland check zones. In discussions state officials, local stakeholders determined that the use of diver-assisted suction harvesting (DASH) may 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 removal is scheduled to take place beginning in the late summer of 2024.
    • This process allows divers to manually target starry stonewort and leave native species intact. It can also be used to remove the algae near the lake bottom where its bank of reproductive structures is stored.
  • Pictured above is a lakewide map of starry stonewort populations surveyed by North Carolina State University in 2023. Map Source: NC State. Modified by CLWMA.
DASH has been used to manage starry stonewort a few hours away in Keuka Lake, as seen above. Video of the DASH process begins at the 12-minute mark.

Additional Pilot Tests & Support

  • In addition to mechanical removal and DASH, chemical management is also being evaluated. The Chautauqua Lake Partnership is pursuing a potential pilot test using chemical treatment to address starry stonewort. Click here to visit the Chautauqua Lake Partnership’s website for an update on the program.
  • The figure above outlines the current state of starry stonewort management on Chautauqua Lake. 
  • 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.