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Variable milfoil, and its more aggressive relative, Eurasian milfoil, can choke ponds and lakes, making them virtually unusable for swimming, boating and other recreation. Keeping milfoil at bay can cost millions of dollars.

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Asian long-horned beetles have infested a 65-square-mile area near Worcester, Mass., and Maine officials fear tourists could inadvertently bring them here. The imports can devastate hardwood forests.

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Diver Ryan Daniels holds the end of the hose that he uses to suction milfoil plants from the bottom of Mumford Cove, on the west side of Little Sebago Lake.

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Each summer, the Little Sebago Lake Association hires workers to pull milfoil. Crew leader Steve Johnson, left, and Hans Nielsen show weeds ripped up in Mumford Cove.

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Northern pike were discovered in Sebago Lake in 2003, and several have been caught since. Biologists fear that the huge fish, which can run 50 inches long or more, pose a threat to Sebago’s landlocked salmon.

 

 

Moe MacDougall is spending his summer on the front lines of a biological war.

MacDougall, who just graduated from Lake Region High School in Naples, is a courtesy boat inspector at a busy Bridgton launch. His mission, for $9 an hour, is to keep foreign invaders such as milfoil from getting into Long Lake by clinging to a propeller or boat trailer.

Should a fragment of the weed get by MacDougall and the other inspectors, one of Maine's premier recreational lakes could join a growing list of infestation sites.

Vacationers aren't the only visitors heading to Maine's lakes and forests this time of year. Summer also is high-alert season for invasive species such as variable milfoil, rock snot and Asian long-horned beetles.

MacDougall is part of an army of scientists, summer workers and volunteers trying to protect the state from non-native plants and critters, which could arrive by clinging to a fly fisherman's boot or hiding in a bundle of campfire wood on its way up the Maine Turnpike.

Those that get through and adapt to their new homes may have no natural predators and quickly eat up or outcompete native species. Some fill lakes with tangles of dense weeds. Others kill fish, trees or crops.

"Invasive species have been called the environmental threat of the 21st century," said Paul Gregory, an environmental specialist with the Maine Department of Environmental Protection.

While not a singular global issue such as climate change, the growing list of invasives includes threats to native wildlife, public health, water quality, recreational uses, property values and industries such as tourism and agriculture.

The risk is increasing as people and goods have become more mobile. "There are more opportunities for these opportunistic species," Gregory said.

At the same time, however, Mainers and others are becoming more vigilant and more careful, he said. "We have a better-armed and better-informed defense."

At least five state agencies are now engaged in the fight against invasives here.

Maine's forest biologists, for example, are warning campers against transporting their own firewood because it could harbor a tree-killing Asian long-horned beetle. Fish and wildlife experts are trying to contain northern pike and other foreign fish, and marine biologists are tracking the northward progress of the Asian shore crab. Some state officials are asking fly fishermen to wash their boots so they don't introduce a fast-spreading form of algae known as "rock snot."

OVER $1 MILLION TO CONTROL MILFOIL

The battle against milfoil is likely Maine's most costly.

Variable milfoil and its more aggressive cousin, Eurasian milfoil, can clog lakes with dense, thick weeds and make them essentially unusable for boating, fishing and swimming. Infestations are virtually impossible to eliminate, but they can be managed by aggressive – and expensive – removal programs.

More than $1 million is spent statewide each year on control efforts such as boat-launch inspectors and removal operations at about 30 infested lakes. The state contributes about $600,000 from boating fees, but more money is raised by nonprofit groups and lake associations.

The Lakes Environmental Association in Bridgton, for example, has spent about $200,000 over several years slowing the spread of milfoil in the Songo River and Sebago Lake in Naples.

The group also trains a network of more than 400 boat inspectors who serve either as volunteers or paid workers like MacDougall.

MacDougall tries to inspect each boat and trailer as it arrives and leaves the launch. But, with 6,000 lakes and ponds in Maine, he and other inspectors see educating the boat owners as the best defense.

"That's our goal this summer," he said. "I guide them through an inspection. Most of the people are willing."

Another group, the Maine Volunteer Lake Monitoring...