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A representative specimen of Nitellopsis obtusa. Photo credit: Paul Skawinski

Nitellopsis obtusa (common name: Starry Stonewort), a highly invasive aquatic plant, has recently been confirmed in two locations of Conesus Lake. This is a plant-like macro-algae characterized by its ability to dominate a waterbody and aggressively form thick beds.  Once established these beds displace native vegetation and alter the local ecosystem. They can also significantly impact fishing, boating and other water recreation.

The Finger Lakes region has confirmed Starry Stonewort populations in several other lakes including Owasco, Cayuga, Keuka and Canandaigua.

Starry Stonewort from Yates County, NY. Photo credit: David Carr

This is the first ever confirmation of Starry Stonewort in Conesus Lake, and given the comprehensive monitoring employed on the lake, these are likely very recent infestations.  According to Eric Randall, an active member of the Conesus Lake Association, “Our best chance of getting ahead of this nuisance is to have as many people aware of its presence and willing to contact someone of their find.”

IMapInvasives (NY Department of Environmental Conservation; NY Natural Heritage program) data showing Nitellopsis obtusa infestations across the Finger Lakes region of NY.

Native to Europe and Asia, Starry Stonewort can be found invading freshwater lakes, ponds, rivers, and canals. It has a long, stocky, stem like structure with whorls of 5-7 branchlets. As this is a macro-algae it has no roots like a vascular plant, but rather clear rhizoids (resembling fishing line) that anchor it to the sediment.  Along the rhizoids are tiny star shaped bulbils (reproductive structures) from which Starry Stonewort’s name is derived. Like some other aquatic invasive plants, Starry Stonewort is easily fragmented which can then readily reproduce into new plants. Starry Stonewort is common throughout the Great Lakes basin and is the focus of the the Starry Stonewort Collaborative managed by David Carr of the the Finger Lakes Institute/FL-PRISM.

A sample of predominately Starry Stonewort from Yates County, NY. Photo credit: David Carr

The Conesus Lake Watershed Council, the Conesus Lake Association and their partners are executing the Conesus Lake Watershed Council’s Invasive Species Prevention and Response Plan for control, outreach, and coordination of this newly discovered infestation in Conesus Lake. Mary Underhill, Conesus Lake Watershed Manager said, “We are fortunate to have early detection of Starry Stonewort in our Lake. With early detection and working with our partners on rapid assessment and response actions, we will have the greatest likelihood of eradicating this prolific invasive.”

Remember to DOCUMENT any suspicious invasive by taking multiple pictures and marking the area with GPS points. REPORT your finding to FLPRISM@gmail.com or in iMapInvasives. STOP THE SPREAD by knowing what to look for. Check out the fingerlakesinvasives.org website or http://nyis.info for more information on this organism or other invasives.

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