12 Aquatic Invaders

As awareness of this threat to Maine waters has emerged across the state, Mainers have taken swift and decisive action. In 2000, the State of Maine passed legislation that outlaws the sale, propagation, or introduction to Maine waters, of eleven invasive aquatic plants. Currently, six of these “outlawed” plants are known to be established in Maine waters: variable leaf water-milfoil (and a hybrid form of this plant), Eurasian water-milfoil, curly-leaf pondweed, European naiad, European frogbit and hydrilla. In 2001 further legislation was enacted, instituting additional regulations, programs and planning requirements. In addition to establishing a dedicated funding mechanism to support statewide efforts to address the threat of invasive aquatic species, the new law established an Interagency Task Force on Invasive Aquatic Plants and Nuisance Species. The Task Force, comprised of state agency personnel and private citizens representing diverse stakeholder interests, quickly got to work on Maine’s Action Plan for Managing Invasive Aquatic Species, a federally approved plan that provides guidance for statewide action in Maine. One of the primary goals laid out in the plan was the development of a practical and effective statewide early detection system.

There are 11 plants currently listed as imminent threats to Maine waters by regulatory agencies:

• European Frogbit
• Water Chestnut
• Yellow Floating Heart
• Eurasian Water Milfoil
• Variable Water Milfoil
• Parrot Feather
• Fanwort
• Hydrilla
• Brazilian Elodea
• European Naiad
• Curly-Leaved Pondweed

In addition, inflated bladderwort (Utricularia inflata) was been discovered in Lake Arrowhead (MIDAS 9715) in the autumn of 2021. Its inclusion is being reviewed by the Maine legislature.

Documented Infestations in Maine Waterbodies are listed on the  Maine DEP website and an interactive map is available.