Keep Maine Lakes
Clear and Clean

Invasive Aquatic Species Management

As of January 2019, thirty-one lakes and ponds, and fourteen stream and river segments are known to be infested with invasive aquatic plants. Variable water-milfoil is still the most widespread of the known invasive aquatic plants in Maine.  Other invasive aquatic plants present in Maine include curly-leaf pondweed, Eurasian water-milfoil, European naiad, European frogbit and hydrilla.


Invasive Aquatic Plants Known to be in Maine

Variable water-milfoil
infestation in the Songo River at Sebago Lake State Park

Eurasian water-milfoil
infestation in a Scarborough quarry pond
photo by: Don Cameron

Curly-leaf pondweed
has infested West Pond in Parsonsfield
photo by: Ann Bove

European Frogbit
Photo by: University of Florida
European naiadEuropean naiad was first found in Legion Pond in Kittery.  (In 2010 curly leaf pondweed was also found, making this Maine’s first known “double infestation.”)
infestation in Pickerel Pond in Limerick

Infested Waterbodies

Infestations Map 2013For those of us concerned about the spread of aquatic invaders in Maine, 2011 brought both good and bad news. It also brought a new system for listing infestations. Please click here for the full update.

Please click on map for larger version.



Control Methods Used in Maine

Once an infestation has been confirmed, rapid response is crucial. The prospects for effective management or even eradication, is greatly increased by swift, well-planned, and properly executed controls. There are a number of control methods being utilized on infestations in Maine, often in conjunction. Control needs may change over the course of treating an infestation, and some infestations respond more positively to some techniques or combinations of techniques.

Benthic Barriers
Hand Removal
DASH (Diver Assisted Suction Harvesting)
Chemical Control

Maine Citizens Guide to Invasive Aquatic Plant Management

MMI Guide CoverThe purpose of the Maine Citizens’ Guide to Invasive Aquatic Plant Management is to provide the information necessary to effectively manage invasive aquatic plant (IAP) populations; to prepare for such an eventuality; and to address all associated activities. Methods described in this Guide are based upon tested best management practices for controlling aquatic plants effectively and in a manner that protects wildlife and habitat.


Diving for Milfoil

Diving For MilfoilWater-quality officials in Maine are on constant watch for non-native plants, especially variable leaf milfoil. “That’s a non-native nuisance perfectly suited for life in Maine’s ponds,” said Water Quality Manager Mary Jane Dillingham of the Auburn Water District. Nothing natural in Maine can keep it in check, which means it spreads and spreads. In the Basin, divers are removing milfoil by hand — basically, weeding underwater.

Please click here for complete article & video.

Our Mission

The Mission of the Lake Stewards of Maine (LSM) is to help protect Maine lakes through widespread citizen participation in the gathering and dissemination of credible scientific information pertaining to lake health. LSM trains, certifies and provides technical support to hundreds of volunteers who monitor a wide range of indicators of water quality, assess watershed health and function, and screen lakes for invasive aquatic plants and animals. In addition to being the primary source of lake data in the State of Maine, LSM volunteers benefit their local lakes by playing key stewardship and leadership roles in their communities.


LSM is a non-profit 501(c)(3) organization committed to the collection of information pertaining to lake water quality. For 40 years, trained volunteers throughout Maine have donated their time so that we may all learn more about one of Maine’s most beautiful and important resources — our lakes.