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Starry Stonewart, an invasive species, has been spotted in Conesus Lake

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

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 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; fragments can then readily reproduce into new plants. Starry Stonewort can grow tall and form dense mats that make fishing, boating and lake recreation nearly impossible. Dense growth may displace native plants and fish habitat. Starry Stonewort is common throughout the Great Lakes basin and is the focus of the Starry Stonewort Collaborative managed by David Carr of the Finger Lakes Institute/FL-PRISM.

The Conesus Lake Watershed Council, the Conesus Lake Association, Finger Lakes Institute/FL-PRISM and their partners have initiated 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 very fortunate to have early detection of Starry Stonewort in our Lake; the first specimen was collected by one of our Watercraft Stewards during a rake toss at the Conesus Lake State Boat Launch. 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.”