Hydrilla, the most aggressive invasive aquatic plant in North America, was spotted by a Jefferson resident in a small cove on the lake's west shore.

State biologists say an infestation of a highly-aggressive invasive aquatic plant has been confirmed in Damariscotta Lake, near the town of Jefferson.  The infestation of hydrilla, a plant that can grow and spread rapidly, was spotted Monday by a Jefferson resident, and state biologists confirmed the finding yesterday, according to Maine's Department of Environmental Protection.

DEP spokesman Paul Gregory says Paul Butterfield, a volunteer with the Damariscotta Lake Watershed Association, noticed what looked like hydrilla in a small cove on the lake's west shore.  Gregory says Butterfield noticed the plant because he had taken a workshop on invasive plants last spring.

Hydrilla is the most aggressive invasive aquatic plant in North America, Gregory says.  The plant can grow an inch a day, and with no natural predators, it quickly overtakes lake habitats, choking off valuable native plants.  Small fragments of the plant can root and start new infestations.  Dense infestations can alter water chemistry and oxygen levels, officials say.

Efforts are already underway to contain and eradicate the infestation.  Gregory says DEP biologists will screen off the cove's mouth today to prevent fragments of the plant from migrating into greater Damariscotta Lake.  In addition, Damariscotta Lake Watershed Association volunteers will begin monitoring the lake. 

Gregory says 31 of Maine's 5,700 ponds and lakes are infested with invasive aquatic plants, but hydrilla has been found in only one other location, Pickerel Pond in Limerick.