Maine, New Hampshire Officials Confirm European Naiad Infestation in Salmon Falls River

October 6, 2015

Contact: David Madore, Communications Director, david.madore@maine.gov or (207) 287-5842

(AUGUSTA) — Biologists from the Maine Department of Environmental Protection (DEP), together with their New Hampshire counterparts, have confirmed a late September discovery of the invasive species European naiad (scientific name: Najas minor) in a 1040-acre impoundment within Salmon Falls River, a border water body with shorelines in Lebanon and Acton, Maine and Milton, New Hampshire. The impoundment includes Northeast, Milton and Town House Ponds.

Able to overtake native lake habitats by shading and outcompeting ecologically valuable aquatic plants, European naiad grows from an annual seed into 7-foot long plants. A productive, one-acre infestation can generate tens of millions of seeds per season. Dense infestations can alter water chemistry and oxygen levels.

“We’re finding well-established populations in Northeast Pond and in the narrow thoroughfare leading to Milton Pond with the thickest growth in northern portions of Northeast Pond,” says biologist John McPhedran of the Maine DEP. “It is our immediate objective to monitor the extent of this infestation throughout the entire impoundment so that we can consider response options with New Hampshire for 2016.”

The infestation was first documented in early September by an area volunteer citizen scientist. Subsequent monitoring has been provided by trained volunteers coordinated by the York County Soil and Water Conservation District, the local interstate Three Ponds Protective Association, New Hampshire Department of Environmental Services (NH DES) and Maine DEP.

European naiad has been confirmed in one small Maine Pond in Kittery and in a handful of New Hampshire water bodies this growing season.

The invasive plant had been documented previously in two New Hampshire water bodies, but populations declined on their own without management, according to Amy Smagula of the New Hampshire DES. “European naiad has not been a common problem species in this area, though with several new infestations documented in New Hampshire in 2015, that may be about to change. It warrants further investigation.”

Maine DEP and NH DES have distributed invasive species warning signs to be posted at boat ramps urging boaters to inspect for and remove plant debris before and after accessing the impoundment. Also notified were boat ramp and other land owners, fishing tournament organizers, and fisheries and warden services from both states.

Maine has been fortunate in recent years to remove water bodies from the statewide list of infestations. To date, of Maine’s 5,700 named water bodies, only 46 are now documented as infested.