March 24, 2018
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Maine lakes in danger of being overtaken by invasive plants

By Heather Steeves, BDN Staff

ROCKLAND, Maine — There are monsters lurking in some Maine lakes and attempting to take them over. Volunteers fighting on the front lines are tearing the tiny beasts off boats and hunting them down in lakes trying to prevent their spread.

The villains of this story: milfoil and four other invasive aquatic plants that have infiltrated more than 30 lakes in as many years.

“They’re hunting very carefully for something they hope to never find,” said Roberta Hill of her  army of 2,500 volunteers, which leads the mission to obliterate the spread of foreign lake weeds. Hill’s volunteers scuba dive, wade on boogie boards and canoe around lakes on the lookout for invasive aquatic plants.

Right now 33 of Maine’s 6,000 or so lakes are known to be infested. Experts say there surely are more but they have not been identified yet because the problem starts small.

A boat from an infected lake launches into a clean lake. Soon, any plant fragments stuck on the boat’s motor or between the boat and its trailer are released into the lake. Because many invasive plants reproduce by dividing into smaller fragments and then growing those fragments, it doesn’t take long for the once-clean lake to become a mess of weeds.

It might not seem like a major problem. Less than 1 percent of Maine lakes are infected.

“Every other state in the country is dealing with a higher percentage of infested lakes than Maine. We’re really lucky,” Hill said.

But like the one human left in a zombie apocalypse, Maine is in an anxious position. Everyone around is infected. In neighboring New Hampshire, more than 60 water bodies are overtaken with invasive weeds. Those boats come up to Maine carrying invasive plants and help spread them.

“An infestation is destructive economically. It will affect property values. That in turn affects the towns’ tax structure,” said Peter Lowell, the executive director of the Lakes Environmental Association. “Once you get a heavy infestation it becomes difficult or impossible to swim or fish or boat in the water.”

It’s also both expensive and time-consuming to try to eliminate the weeds from a lake — and the efforts rarely work.

Lowell’s nonprofit organization stations volunteers at boat ramps around Maine to check boats to make sure they aren’t transporting weeds.

“Having plants instead of nice, clean water is a huge environmental degradation,” he said. “The best way to prevent it is through the boat inspection process — you are cutting off the plants from coming in.”

According to the Maine Department of Environmental Protection, Lowell’s organization rounded up hundreds of rampside boat inspectors who last year inspected 73,000 boats at more than 150 boat launches. They found about 2,400 plants, and of those, about 240 were invasive.

Roy Bouchard, a DEP biologist and lake assessment supervisor, said the state spends more than $600,000 on this issue yearly.

As for the future of Maine’s lakes, Bouchard said, “We’re going to get more [invasive weeds]. Is it inevitable that this spreads to a large degree? It’s not that inevitable, but we will get a lot more.”

It’s about buying time, Bouchard said. It’s especially important that Maine prevent the infestation of its clean lakes because roughly $3.5 billion is at stake. That’s the estimated amount of money generated annually by lakes, including tourism, boat-related purchases, increased waterfront property values and more in Maine.

“People say, ‘Why don’t you give up? It will spread anyway.’ My answer is: If you give up, then you really give up control,” he said.

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