Communities in the Finger Lakes region have become familiar with invasive aquatic species like hydrilla, a highly invasive aquatic organism that gets a lot of attention in our region but is fortunately known to infest only a few locations. However, there is another growing aquatic threat in our region that is much more common and is already present in both Keuka Lake and the Keuka Lake Outlet: starry stonewort (Nitellopsis obtusa).

Emily Staychock, watershed/environmental educator at Cornell Cooperative Extension of Yates County says Starry stonewort is a highly invasive organism that negatively impacts aquatic ecosystems and interferes with aquatic recreation.

In Oct. 2015, CCE, working with the Keuka Lake Association, confirmed the presence of starry stonewort in the Keuka Lake Outlet from the Penn Yan village boat launch to the western edge of the marshland. In Sept. 2016, another infestation was identified at the mouth of Sugar Creek in Branchport, and by July 2017, it had spread a few hundred feet into the lake.

In response to the risk of boats spreading starry stonewort, the Keuka Watershed Improvement Cooperative (KWIC), an inter-municipal organization representing the six towns and two villages in the Keuka Lake Watershed, took action. Awarded a DEC grant to control the infestation, KWIC has contracted with CNY Aquatic Harvesting to carry out a mechanical harvest of portions of Keuka Outlet over 2 or 3 days, beginning the week of Aug. 28, to remove as much stonewort as possible.

Starry stonewort is a macroalgae, a large, multicellular algae that looks like an aquatic plant. Algae differ from plants in that they lack vascular tissue that transport nutrients and water, as well as true roots, stems, or leaves. It is native to Europe and Asia, and was first observed in the U.S. in 1978 along the St. Lawrence River; likely introduced in the ballast waters of international ships. It is currently found in Minnesota, Wisconsin, Michigan, Indiana, Pennsylvania, New York, and Vermont. In the Finger Lakes region it is also found in Oneida, Owasco, Waneta, Cayuga, and Canandaigua Lakes. It is similar in appearance to other native macroalgae species, and may remain unnoticed until its population becomes invasive. It is best identified by its star-shaped bulbils which anchor it to the bottom.

Starry Stonewort forms dense mats that cover the waterbody floor, crowding out native aquatic species and preventing fish spawning and nesting. This has a large impact on fish species such as bass, sunfish, darters and minnows. As dense infestations grow in height to reach the surface, they block sunlight and reduce the levels of oxygen required by other aquatic life.

Starry stonewort also has a negative impact on recreation. It gets tangled in motors and makes boating, fishing, and swimming difficult. Fragments that get caught on watercraft and transported to new locations can form new infestations.

While a relatively new problem for New York, several Upper Midwestern states have been attempting to manage starry stonewort infestations for over a decade. No effective way to eradicate this organism has been found. Chemical treatments kill only the top half of the organism and do not penetrate completely. Mechanical harvesting and hand-pulling, including the use of scuba divers and suction to capture pulled organisms, are effective means for limiting infestation growth, but the time involved in hand-pulling is not realistic for large infestations. Efforts to date have focused on reducing infestation size and controlling growth around boat launches to reduce the risk of boats snagging fragments and transporting the organism.

The Keuka Lake Association, Yates County Soil and Water Conservation District, and Cornell Cooperative Extension are partners providing KWIC with technical support for this project.

Now, municipalities and organizations around Keuka Lake have a plan to control the invasive. Gary Leroux of CNY Aquatic Harvesting has been contracted to harvest from the main watercourse of the Outlet used by boat traffic, not in the marshland. Leroux has previous experience harvesting starry stonewort. Once harvested, the stonewart will be offloaded and allowed to drain at the Penn Yan boat launch, and then removed by road crews from the Village of Penn Yan, Yates County, and Town of Jerusalem.

DEC Grant funding will allow KWIC contractors to harvest twice a year for three years. Because starry stonewort grows later in the season, harvesting will occur in August and again in September and October as new growth requires.

The project was granted a DEC permit required due to the protected marshland area, and reviewed the potential risk for harvested fragments to escape and float downstream. Expert consultants from the Minnesota Dept. of Natural Resources gave assurance that any escaped fragments are expected to sink rather than float, due to their weight.

Staychock says, “The Keuka Lake community is fortunate to benefit from strong partnerships between organizations and agencies that help steward the Lake. We’re also fortunate that the Keuka Lake Association’s watercraft steward program remains vigilant in inspecting watercraft to prevent the spread of aquatic invasive organisms. These partners will continue to work together to address additional starry stonewort infestations, and may seek volunteers from the community to assist in future efforts.”

For more information, contact:

• Patrick Killen, Keuka Watershed Improvement Cooperative:315-595-2287 or killentoj@gmail.com

• Emily Staychock, CCE of Yates County and the Keuka Lake Association: 315-536-5123 x4127 or ecs268@cornell.edu

• Dennis Carlson, Keuka Lake Association President: info@keukalakeassoc.org