Twan Leenders, Chautauqua Watershed Conservancy director of conservation, lifts up a pile of the invasive algae starry stonewort near Prendergast Point last week. CWC Seasonal Aquatic Invasive Species Coordinator Sandra Emke is pictured in back. Photo by Jay Young

Emerging invasive species continue to be a main target of alliance member-led programs on the lake, particularly now during the summer growing season.

For several problem species that have not yet become established at large scales, proactive management of smaller areas is often the best way to control populations at lower cost before these plants and algae spread. These types of species are often referred to as being lower down on the ‘invasion curve’, where targeted management actions are usually more cost-effective and can help prevent widespread growth.

Water chestnut continues to be managed by hand removal in the Chadakoin outlet, where it has been found growing in clusters over the past several years. The Chautauqua Watershed Conservancy’s volunteer kayak paddles covered much of the outlet during the first two events of the year. CWC Director of Conservation Twan Leenders reported that around 250 plants were removed from the upper section of the outlet during an event led out of Celoron last month. Encouragingly, no plants were spotted during the first paddle of the year out of McCrea Point. CWC’s next volunteer event is scheduled for today, July 22, at the Mayville boat launch, and a full list of events can be found at chautauquawatershed.org/ais. Hand pulling water chestnut annually appears to be keeping these populations in check, at relatively low cost. The project team continues to catalogue where and when this species is being detected and removed, and tracking populations over time using GPS. Elsewhere in the lake, where other invasive species are being addressed, other techniques are needed besides hand-pulling via kayak. Different species and locations call for different tactics.

Starry stonewort in particular is a species that presents removal challenges, with few clear-cut best practices available. In 2023 alliance members led by the CWC coordinated a pilot program to remove this invasive algae using mechanical methods, including Chautauqua Lake Association skimmers and Town of Chautauqua Mobitracs. Last year’s test appeared to show promise in removing large amounts of stonewort from Ashville Bay. Evaluation of the results of that work is ongoing and will continue throughout this year’s growing season.

In addition to that pilot test, the towns of North Harmony and Chautauqua are both working to implement state invasive species grants to do diver-assisted suction harvesting (DASH) of the algae. State funding for these projects is provided from the Environmental Protection Fund administered by the Department of Environmental Conservation. This work is expected to begin at Ashville Bay and Prendergast Point later this year, and will involve manual removal of the algae via suction hoses, which greatly reduces the chances of spread and comes with relatively few environmental concerns. Both towns have contracted with Integrated Lakes Management, the firm that has successfully used this technique on Keuka Lake. Last week CWC led a volunteer kayak paddle at Prendergast Point to assess conditions, confirming that starry stonewort growth was well underway.

Chemical management options for stonewort are also being assessed by the Chautauqua Lake Partnership at other locations of the lake. CLP indicated that pilot tests are being planned at three areas of the lower south basin, where multiple products will be tested based on DEC permits. More information about the chemical management program can be found at chqlake.org. Using a comprehensive approach to address this species, testing techniques including Mobitrac removal, DASH, and chemical treatment is intended to give Chautauqua Lake a better starry stonewort management blueprint moving forward.

Brittle naiad is also a priority on the lake’s list of emerging invasive species. In 2023 stands of it were located in the lower south basin and the beginning of the lake outlet. It continues to be tracked by lakewide plant surveys done by SUNY Oneonta and North Carolina State University, both of which reported increased populations in 2023. While species-specific management plans are underway for water chestnut and starry stonewort, brittle naiad is in need of more attention.

Addressing invasive species involves not only detection and management, but also prevention. Chautauqua Lake Association watercraft stewards are stationed at public launches throughout the summer, and work with boaters to ‘clean, drain, and dry’ to help prevent spread. More information on that program can be found at chautauqualakeassociation.org/watercraft-steward/. Invasive species are also tracked year-round on the iMapInvasives Network at imapinvasives.org so that the public can make reports and see where these plants, animals, and algae are being detected.

As with so many lake and watershed issues the public plays a key role in invasive species management. They have the ability to prevent their spread, report their detection, and remove them when they are found. There remain problem species like hydrilla that have not made their way to Chautauqua Lake yet, but pose potential threats to the system. The good news is that we have many groups and programs working to address these concerns with management plans that can be adapted to new challenges.