Many aquatic plants exist within Chautauqua Lake. Its nutrient-rich sediments provide a fertile growing bed for vegetation. Some of the lake’s plants are native to our area and provide critical ecological and environmental benefits, while those that are invasive (introduced from distant locales) can negatively impact the ecological function, recreational use, and economic value of the lake. To help combat these invasives and other nuisance plants in Chautauqua Lake, the AIS Early Detection Network was created, which consists of Chautauqua Watershed Conservancy staff, volunteers, and program partners.

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For the past several years, Chautauqua Watershed Conservancy, with funding assistance from the Chautauqua Lake & Watershed Management Alliance, has held a series of public programs focused on these invasive plants. Through targeted education and outreach efforts, we trained volunteers in the identification of invasive species through online and in-person training sessions. We then took to the water in various locations around the lake to re-survey areas where invasives have been previously reported and also survey new sites for them as well. When any were found, they were reported through the online reporting portal iMapInvasives (www.imapinvasives.org), and the offending plants were carefully removed.

 

In 2023, we unfortunately noticed a significant increase in growth of the macro-algae Starry Stonewort in the two known areas where it had already reached nuisance levels, and we also detected it in a few new locations in the lake. Similarly, another invasive, Brittle Naiad, seemed to have recently greatly increased in density in a few localities in and near the outlet. The good news, though, is that we were once again able to manually remove all the Water Chestnut that has been growing in the outlet for several years now, and we seem to have that species under control so far!

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We also took the lead on an experimental pilot removal effort in Ashville Bay using Mobitracs and skimmers to remove volumes of Starry Stonewort from the lake. This effort was supported by the NYSDEC and carried out in collaboration with our partners the Chautauqua Lake Association, the Chautauqua Lake & Watershed Management Alliance, and the Towns of North Harmony and Chautauqua. This new method of harvesting Starry Stonewort has never been attempted previously, and we are still carefully monitoring its effectiveness over the longer term. However, our initial assessment of this collaborative effort was very positive.​​

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In 2025, CWC conducted 13 on-water surveys across 10 sites, which confirmed the extent of two historic starry stonewort sites, led to the discovery of brittle naiad at two new locations, and identified the current extent of water chestnut in the Lake’s outlet. During a public paddle on the Chadakoin River, 400 water chestnut plants were removed, helping move us toward the possibility of full eradication of water chestnut in the outlet. In addition, a number of potential hotspot sites were monitored to ensure no new threats were developing. 

 

One of the year’s biggest challenges was managing starry stonewort, a fast spreading macroalgae that forms dense mats  and reproduces through small white bulbils (star-shaped  reproductive structures) hidden in lake sediment. It spreads rapidly through fragmentation, often caused by boats and other watercraft passing through infested areas.

 

CWC staff and volunteers also identified an extensive patch of starry stonewort in the Elmhurst area. Floating fragments had been found there in the past, but this was the first time that patches of starry stonewort were observed growing there. CWC was able to obtain a permit from the NYS Department of Conservation to deploy a Diver Assisted Suction Harvesting (DASH) team to address the new infestation. Also this summer, CWC, NYSDEC, the Chautauqua Lake & Watershed Management Alliance, the Chautauqua Lake Association, and the Towns of North Harmony and Chautauqua collaborated on a large-scale starry stonewort removal effort in Ashville Bay and Prendergast Bay using a combination of Mobitrac harvesting and DASH. A heavy emphasis was also placed on clearing navigation channels, both to maintain safe boating and to reduce fragmentation.

 

These efforts marked the most comprehensive starry stonewort management project attempted on Chautauqua  Lake to date, and the combination of using Mobitracs along with DASH is unprecedented. The method allowed for precision removal of starry stonewort with minimal negative impact on native submerged aquatic vegetation.

 

While removal is an important step, we recognize that more needs to be done to keep the macroalgae from  returning. As a result, CWC launched a pilot revegetation project this year to restore native plants to areas cleared of starry stonewort. Nearly 2,000 eelgrass plants were installed using biodegradable burlap bags and bare-root methods. Eelgrass is a hardy native species with strong roots that stabilize sediments, provide fish habitat, and make it harder for starry stonewort to return.

  

Aquatic invasives act as a potential threat to Chautauqua Lake’s ecology, recreation, and economy. However, thanks to the combined efforts of CWC, its partner organizations, and dedicated volunteers, our AIS Program is continuing to make real progress toward a healthier, more resilient Chautauqua Lake.

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For more info on these and other aquatic invasive species in Western New York, visit the Western New York Partnership for Regional Invasive Species Management at www.wnyprism.org.