Vermont ANR confirms presence of new aquatic invasive species

October 16, 2008 WATERBURY – Aquatic biologists at the Agency of Natural Resources have confirmed the arrival a new invasive plant in Vermont, variable-leaved watermilfoil, in Halls Lake in Newbury. This is the first confirmation of a new invasive aquatic plant in Vermont since European frogbit was found in Lake Champlain in the early 1990s. The variable-leaved watermilfoil identification was confirmed by genetic analysis conducted by Dr. Ryan Thum of Grand Valley State University in Michigan.

Vegetatively, variable-leaved looks almost identical to a rare watermilfoil in Vermont. In this case, genetic identification was important as all the plants in the lake had no reproductive parts to confirm identification without this analysis. Variable-leaved is a popular aquarium trade species and is a potential vector for invasive aquatic plant spread. The agency, in cooperation with the Agency of Agriculture, Foods and Markets, inspects Vermont aquarium retailers annually. Just recently, officials found two retailers in southern Vermont selling variable-leaved watermilfoil.

Staff at the Department of Environmental Conservation’s Water Quality Division have deployed rapid-response initiatives this week to remove the nuisance plant from the lake, which appears to be limited to a small two-acre cove at the southern end.

“We may have a rare opportunity to prevent further spread of this plant in Halls Lake and to other waters in Vermont,” said Ann Bove, an aquatic biologist at the agency. “A continued response is critical to success.”

Variable-leaved watermilfoil (Myriophyllum heterophyllum) is not native to Vermont and can be difficult to control once established. It is aggressive and grows rapidly, is easily spread by plant pieces and can displace beneficial native aquatic plants, said Bove. Like Eurasian watermilfoil, already present in Vermont, variable-leaved watermilfoil can also make swimming, boating and other recreational uses difficult. New Hampshire, Maine, Massachusetts and New York have been plagued by this species for a number of years.

Early detection is vital to protecting Vermont’s waterbodies from harmful invasive plants and animals. The agency’s Vermont Invasive Patrollers (VIPs) program monitors local waterbodies for new introductions of invasive species while also learning about native aquatic plants and animals and their habitats. For more information on becoming a VIP, visit http://www.anr.state.vt.us/dec/waterq/lakes/htm/ans/lp_VIP.htm.