Invasive aquatic plants, such as Eurasian milfoil, can spread quickly in lakes, displacing native plant and fish populations, as well as human swimmers, anglers and boaters. According to the Maine Department of Environmental Protection, most Maine lakes are currently unaffected by invasive plant species, but once established, invasive plants can be very difficult, and expensive, to eradicate.

DEP and the Department of Inland Fisheries and Wildlife spend more than $1 million annually fighting invasive aquatic plants in the 46 Maine water bodies currently affected.

Unwary humans are the primary carriers of exotic invasive plants to lakes and ponds. Plants attached to boats, trailers or float plane pontoons can readily establish in shallow water. The best way to stop invasive plants from getting a foothold in Maine lakes is by preventing their entry into Maine waters.

To this end, the West Harbor Pond Watershed Association is hosting a Free Boat Inspection Workshop from 11 a.m. to noon, Saturday, June 23 at Boothbay Harbor Public Works parking lot on Middle Road.  Rob Stenger, Stewardship Educator of Damariscotta Lake Watershed Association, will lead the workshop. 

Leslie Volpe and Elin Haugen of the West Harbor Pond Association hope the workshop will be attended by West Harbor Pond and Knickerbocker Lake cottage owners, as well as boat owners. “We have a lot of people who rent out and a lot of those renters bring small boats with them, said Haugen.

Knickerbocker Lake has a public boat launch off Barter’s Island road and although there is no public launch at West Harbor Pond, many shoreside residents allow people to launch from their property. Each waterbody is also home to a resident float plane. 

Haugen said that many boaters and planes that visit other lakes may unwittingly return with hitchhiking plant pieces. This concern is not limited to “boats from away” or those that recreate in distant waters. The invasive plant Hydrilla was discovered in Damariscotta Lake in 2009. Since its discovery, DEP and volunteers have used chemical and mechanical methods to eradicate the plant from the waterbody. “There are people who fish in West Harbor and Knickerbocker, who also fish in Darmariscotta lake,” Haugin said.

In 2008, Haugen began annual surveys of submerged aquatic plants around West Harbor Pond, looking particularly for invasive species. Haugen has not, as yet, found Eurasian water milfoil or other serious invasives in West Harbor Pond. However, last year, she did identify another native milfoil that she had never seen before in the pond. Haugen said she does not expect it to spread widely because lake bottom and shoreline oak stands do not favor its spread. Haugen will continue her West Harbor Pond surveys this year and hopes to survey Knickerbocker Lake as well.

A simple inspection of the underside of trailer, boats and float plane pontoons could help ensure that undesirable plants don’t find their way into local waterbodies, said Volpe and Haugen.“When any of Maine’s lakes are endangered by aquatic invasive species, we are all endangered,” said Volpe. 

For directions or more information on the boat inspection workshop or local watershed programs contact the West Harbor Pond Watershed Association, email thewhpwa@gmail.com or call 207-380-5722.