Ossipee — August 16, 2011 — Green and slimy, exotic milfoil species are on the march through many of New Hampshire’s lakes. Efforts to battle the invasive plant were discussed recently at a forum called the State of Ossipee Lake. Andrea Lamoreaux, of New Hampshire Lakes Association, said invasive aquatic plants are the top threat to the state’s 900 lakes and ponds. Milfoil, can tun a nice swimming hole into a thick underwater jungle. The plant can reach heights of 15 feet. Boaters inadvertently spread exotic plants from lake to lake when plant fragments get caught on propellers and other equipment and then fall off in another water body.

Selectman Morton Leavitt, of Ossipee, was “shocked” by an infestation he saw on Ossipee Lake before the lake was treated. He said the selectmen and other stakeholders need to do a better job explaining why taking care of Ossipee Lake is so important. A large part of the town’s revenue comes from having the lake, he said.

“The plant is hideous,” said Leavitt. “It’s almost scary. It reminds me of something out of the past that we shouldn’t have to put up with.”

Water body related activities, such as boating and fishing, bring the state $1.8 billion in annual revenue and support 14,000 jobs. A decrease in perceived water quality could result in in $51 million in lost sales and $18 million in lost income, said Lamoreaux. Lamoreaux had a map showing the potential impact of water-quality degradation by region. If water quality declined in the Lakes Region, which includes Ossipee, then $25 million in sales would be lost, $8.8 million of income would be lost, and 396 jobs would be eliminated. In the White Mountain region, which includes Conway, $11.8 million in sales would be lost, $4.2 million worth of income would be lost, and 189 jobs would disappear.

“This shows you the magnitude of what we would lose if we don’t start taking care of our lakes and ponds,” said Lamoreaux.

In New Hampshire there are 91 exotic plant infestations on 78 water bodies. In other words, some lakes have more than one infestation, said Lamoreaux.

The New Hampshire Lakes Association implemented the Lake Host program where volunteers and paid employees inspect boats and trailers for exotic plant fragments. Since 2002, there have been 361,938 inspections and 1,081 saves.

“A save is when a piece of exotic aquatic plant is taken off a boat or trailer,” said Lamoreaux.

The Local Battle
The battle against milfoil on Ossipee Lake was described in detail by Jim McElroy who is a member of Freedom’s Conservation Commission’s Aquatic Invasive Species Committee. He said the towns of Ossipee and Effingham are also involved in the fight. Between 2002 and 2011, the three towns spent a total of $188,550 on milfoil control. A chart McElroy displayed shows the Lake Host program was funded in Ossipee in 2009 and 2011. Of the three towns, Effingham had the least amount of milfoil infestations. In 2010, Effingham spent $1,350 to have three small milfoil patches removed.

In Freedom, the first infestation was found in 1992 and the first herbicide treatment was dispensed 10 years later on a five acre patch. Divers have hand-pulled milfoil since 2004. In 2008, Freedom began using suction harvesting, which involves an underwater vacuum cleaner that’s attached to a boat. Divers feed the milfoil into the vacuum rather than having to return to the surface to dispose of the plants they pull. Despite the upgrade, the plant continued to spread. By 2009, 22 out of 83 acres on lower and middle Danforth Ponds were infested.

Freedom used the herbicide 2,4-D for the first time in June of last year. The treatment had “favorable results” at first but the plant started growing again at the end of the season. Last June, there was a second round of 2,4-D treatment in several areas which included a patch in upper Danforth and Ossipee Lake Marina. The Danforth ponds are looking better than they have in years. However, there has been some regrowth in the Danforth ponds around docks. There has also been regrowth at the marina.

Another small patch was discovered off of Marjory Point Cove, which divers were sent to eliminate , said McElroy.

“If we can get it when it’s small and before it spreads significantly, that’s the best chance we have,” said McElroy.

Since 2002, the town of Freedom has spent $131,600 on milfoil control. The funding comes from the state, the town, and private donations. Since 2004, the town of Ossipee has spent $55,600 on milfoil control. Last June, town of Ossipee used the herbicide 2,4-D. Twelve acres on Phillips Brook and Causeway Cove were treated. A new milfoil patch was discovered in Sunset Cove by Joe Catoggio, who McElroy described as an “alert resident.” Divers will remove that patch. A fisherman reported another infestation in Ossipee but that one has yet to be confirmed. There was regrowth in Pickerel Cove. There’s a growth in Portsmouth Cove that’s 8 feet tall from the bottom.

The keys to preventing more infestation include increasing public awareness and additional boat inspections, said McElroy. There’s also need to train more volunteers to go out on the lakes to look for milfoil.

“You can’t find the stuff if you’re not looking for it,” said McElroy.

Future Treatments
The New Hampshire Department of Environmental Services has a list of recommendations for 2012. That includes fall or spring herbicide treatments for 20 acres in areas like Portsmouth Cove and Phillips Brook. DES also suggests a fall or spring herbicide treatment on 15 acres in Danforth ponds. After 2012, milfoil fighters may be able to use less herbicides. At that point, divers would become the main method of control.
McElroy doesn’t foresee any more 2,4-D treatments happening this fall in any of the three towns.

More funding will be needed because the state doesn’t have the money to cover all the areas that are impacted by milfoil, said McElroy.

Some in the audience suggested that “day tripping” boaters ought to share more of the cost of milfoil containment because they are more likely to spread milfoil than lakeside residents who don’t move their boats. McElroy said that idea has been suggested before but would be hard to implement because the state government is trying to encourage people to visit New Hampshire.