Invasive Aquatic Plants

 Variable leaf milfoil  ( Image taken from Maine Volunteer Lake Monitoring Program)

Variable leaf milfoil

(Image taken from Maine Volunteer Lake Monitoring Program)


Variable Milfoil is an aggressive invasive aquatic plant.  It was found in 2014 at the boat launch in Annabessacook lake.  We must take action against variable milfoil because it spreads quickly and forms thick mats.  It is also more difficult to get rid of once it becomes established.  It has no natural enemies or controls to keep it in check, so our actions are the only ones that can stop it.




 Eurasian Water-milfoil  ( Image taken from

Eurasian Water-milfoil

(Image taken from


Eurasian Water-milfoil is another aggressive invasive aquatic plant, that has recently been found in the norther end of Cobbossee Lake.  Due to its aggressive nature it is imperative that this outbreak be taken care of immediatley.  Much like variable leaf milfoil, once established eurasian water-milfoil is incredibly difficult to eradicate.


Additional Facts:

  • Grows in shallow areas up to 15' in depth.
  • Reduces property values and recreational opportunities.
  • Can impact businesses that rely on a clean, healthy lake.

For more information about variable milfoil and how to handle and identify it click here.


For more infromation about eurasian water-milfoil and how to handle and identify it click here.

European frog-bit is an aggressive invasive aquatic plant, that has recently been found on the north end of Cobbossee Lake. European frog-bit is a free floating plant that has heart shaped leaves. During the summer months it will produce a white flower that has three petals and a yellow center. 

  • European frog-bit forms mats as it grows, blocking out the sun light for native plants.
  • Once the frog-bit dies, the decomposition of it depletes  the water of oxygen that native fish require.


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Cobbossee/annabessacook Milfoil Project  (C.A.M.P.)

A three year campaign to:

REMOVE invasive variable milfoil

SURVEY vulnerable areas of both lakes

EDUCATE the public about the threat of invasive aquatic species

Work will take an estimated $250,000 during the 2018-2020 project period.


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Prevention- Courtesy Boat Inspectors

Trained boat inspectors staff 10 public boat launches in the watershed, covering 8 lakes on weekends and holidays from Memorial Day Weekend to Labor Day.  During inspection, CBI's share information with boaters on the importance of preventing the spread of invasive plants. 

For more information about our CBI program click here.

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Early Detection- Plant Survey

Trained surveyors search shallow water areas for signs of invasive plants.  GPS points are used to create electronic maps depicting location, area covered and density of native and/or invasive aquatic plants.

For more information about Plant Survey click here.

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Removal- Plant Control

Our goal is to reduce existing communities of invasive aquatic plants.

Hand Pulling - Individuals must be trained to in how to  properly remove invasive plants to avoid further spreading of the plant.

Milfoil Mats  (Benthic Barriers) -  These barriers are placed on top of invasive aquatic plants, providing both a physical and photo (or light) barrier, causing plants to die off and allow natives to re-establish.

Diver Assisted Suction Harvester  (DASH) - Diver pulls invasive plants out off the bottom and sends them up to the surface using a vacuum hose to collect on deck.  Harvested plants are incinerated. 

For more about the Friends of the Cobbossee Watershed DASH Team click here.