Editor's note: Below the story is a Maine DEP map that details the European naiad infestation in Milton Three Ponds.
LEBANON - The Lebanon Conservation Commission will host an informational session on Nov. 19 on the European naiad recently discovered in Northeast Pond.
Laurie Callahan of the York County Invasive Aquatic Species Project and Melissa Brandt of York County Soil and Water will be there to answer questions about what the arrival of this invasive plant means for Lebanon and Milton, and how ordinary citizens can help prevent invasive aquatic species.
A lead biologist in the effort to thwart the invasive plant recently discovered to be prolific in Milton Three Ponds told The Lebanon Voice last month that its existence could threaten the lake's established plant and fish populations.
"From what I've seen it's very dense," John McPhedran of the Maine Department of Environmental Services said on Wednesday. "I can't say exactly how bad it is, but any invasive plant could alter the food availability for fisheries."
McPhedran said the area most severely affected by the European naiad thus far is the Lebanon side of Northeast Pond just east of where the Salmon Falls River flows into it.
He said Northeast Pond has shallow areas far from shore that could easily hold the plants, which can grow to around seven feet.
European naiad was first discovered in Milton Three Ponds by an invasive plant spotter volunteer while snorkeling in Northeast Pond.
While snorkeling was used exclusively to assess the weeds infiltration in Northeast Pond, Town House Pond and Milton Pond were inspected by both boats and snorkelers.
Milton Pond and Town House Pond showed no European naiad presence, however, the channel or "River" from Northeast to Milton pond did, McPhedran said.
European naiad can overtake native lake habitats by shading and outcompeting ecologically valuable aquatic plants. A productive, one-acre infestation can generate tens of millions of seeds per season. Dense infestations can alter water chemistry and oxygen levels in the water which can impact other plants and fish.
Milton Three Ponds is currently home to varied fish stocks, including black crappie, rainbow trout, brown trout, chain pickerel, horn pout, white perch and smallmouth and largemouth bass.
European naiad has also been confirmed in a Kittery pond 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 who is the lead biologist from the Granite State.
"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," McPhedran said.
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 Milton Three Ponds. Also notified were boat ramp and other land owners, fishing tournament organizers, and fisheries and warden services from both states.
McPhedran said a more thorough assessment of how prolific the plant's presence is in Milton Three Ponds is warranted.
He said with winter fast approaching any eradication efforts will wait until spring, but added the best time to fight an invasive plant like European naiad is in the early stages.
European naiad is an annual plant, which produces seeds on plant leaves that can easily be broken into fragments and carried to a new area.
"Even a paddle going through it could break off a fragment," McPhedran said.
Norman Turgeon, a board member of the Three Ponds Protective Association, a Three Ponds watchdog group, said he's not surprised that an invasive weed is threatening the body of water, but said of all the perceived threats he'd been aware of, European naiad was not one of them.
"This one was off our radar," he said.
Turgeon, a former association president, said they were waiting to hear more back from the two states' biologists, but stood ready to do whatever it takes to protect a vital resource for both Lebanon and Milton.
"We hope to be able to manage it and get rid of it," said Turgeon, whose group has had a weed monitoring program for the last 10 years during which time, "we never found a dirty boat."
He said his group would be doing a lot of monitoring, making presentation to town officials in both New Hampshire and Maine and scouting for funding sources to help in whatever effort that ensues.
Both McPhedran and Turgeon agreed careful boat inspections will be key.
For more info on TPPA go to http://threeponds.org.
Next week's meeting at Lebanon's Martha Sawyer Community Library begins at 6:30 p.m.
Please contact Ruth Gutman at (207) 370-4191 for more information, or firstname.lastname@example.org