“The invaders are knocking at our door. We don’t have any time. Once they are here, there is no going back.”

-- Tim Mihuc, lake researcher, State University of New York at Plattsburgh

BRIDPORT — Laurel Casey never expected summers at her lakeside cottage to include regular contact with slime.

Most days, she paddles a child’s rubber raft along the shore, hauls in long, algae-coated strands of Eurasian watermilfoil and burns them on her rocky beach.

“I’ve declared war on the weeds,” Casey said. “They are disgusting.”

Her 84-year-old mother, Pauline, enjoys swimming; it is her only exercise, Casey said. Only daily weeding keeps the near-shore water usable.

“I call it ‘Lake Shame-plain,’” said Casey, a performance artist and entertainer not given to understatement. “You can’t boat, you can’t swim. You pull up the weeds and there are zebra mussels climbing up the stem. Things have gotten to the point of absurdity.”

Along the southern shores of Lake Champlain, boaters, swimmers and cottage owners echo Casey’s complaint — it’s harder and harder to use the lake they love. It’s here, where the lake narrows like a river, that foreign plants and animals often appear first, disrupting life in the water.

Vermont and New York have spent millions of dollars to study the invaders, reduce infestations of water chestnuts and protect sewer and water pipes from zebra mussels. The invaders alter the lake’s web of life, reduce lakefront property values and rob lakeshore owners like Casey of their pleasure in clean, clear water.

Milfoil from Europe has turned many bays into watery hayfields. Asian water chestnut paves other inlets, choking out native plants. Sharp-edged zebra mussels from Russia’s Caspian Sea encrust the lake bottom and steal food from young native fish.

Species spread quickly once they arrive. Most invaders are impossible to eradicate once they are established.

Zebra mussels and milfoil have become nuisances all the way to the Canadian border. Non-native white perch are competing with native yellow perch in Missisquoi Bay. Alewives, natives of the Atlantic Coast, arrived recently in the northern lake, raising fears they will push out native smelt.

Worse might be yet to come.

Hydrilla has reached smaller New England lakes. The feathery Asian plant grows more than an inch a day and can choke a bay or small lake in a single year. Southern states already spend millions every year fighting the weed.

A fish called the round goby, another escapee from the Caspian Sea, has spread through the Great Lakes where it devours the eggs and young of bass, walleye and perch. Anglers out after walleye sometimes report catching only goby.

Dave Tilton, U.S. Fish and Wildlife Service project leader for Lake Champlain, worries about a fish called the northern snakehead, the nightmarish Asian import that can survive out of water for three days.

Lake Champlain has escaped these invasions, but biologists warn it might be only a matter of time.

The Great Lakes are just 130 miles away, connected to Champlain by canals and rivers. Careless humans also help foreign species travel from one lake to another, in bait buckets or bilge water.

Lake Champlain has shown itself resilient, fisheries biologists say. The invaders have yet to damage native fish stocks. No one knows how badly the new arrivals might disrupt the lake’s ecosystem in the long run.

“Invasive species cause dramatic changes, slowly. I think they are in the process of that transformation in the lake,” Tilton said. “Nobody knows what the lake is going to look like in 15 or 20 years.”

State fisheries biologist Bernie Pientka said it is not any single exotic species he fears, but the accumulation of invaders competing with native species and each other.

“I’m not sure we’ll ever be able to point back at what was the straw that broke the camel’s back. It will be a combination of many things,” he said of his fears for the future.

“The invaders are knocking at our door,” says lake researcher Tim Mihuc of the State University of New York at Plattsburgh. “We don’t have any time. Once they are here, there is no going back.”

Global trade brings invaders to our shores

Who is to blame when exotic species hitch a ride to a new world and then from lake to lake?

Modern life, the experts say.

“It’s global commerce. We just move around a lot more easily than in the past,” said Mike Winslow, the staff scientist at the Lake Champlain Committee.

Many of the invaders arrived by design, imported because they were pretty or interesting or a source of food. Water chestnuts escaped from a researcher’s pond at Harvard in the 19th century. Northern snakehead has been sold, alive, in ethnic markets.

Others arrive by accident or carelessness. The zebra mussel and round goby traveled in the ballast water of international freighters and found a new home when the freighters docked in the Great Lakes.

Successful foreign species put rabbits to shame in their ability to multiply and spread.

Zebra mussels made it to Lake Champlain in 1993, less than five years after they debarked near Detroit. A year or two later, human swimmers and waders around the lake began showing off sliced toes and heels from stepping on the razor-sharp mussel shells.

“Once the vast majority of species are here, there is virtually no chance of controlling them,” said Mihuc, director of SUNY-Plattsburgh’s Lake Champlain Research Center.

It has cost at least $1.7 million since 1993 to keep water systems, sewer pipes and marinas clear of zebra mussels. Vermont and New York spend $480,000 a year yanking water chestnut plants from the South Lake — nearly $7 million in the past 25 years.

In all, Vermont spends $2 million a year in federal, state and local money coping with invasive species. (That does not include the more than $15 million spent since 1990 on controlling sea lamprey in Lake Champlain. The lamprey is a native species, but its numbers have risen to nuisance levels. The eel-like fish weakens lake trout and salmon by sucking their blood.)

Two retirees fight odds with homemade machine

Thad Bronson, 74, and Charles Barry, 70, spend their summers trying to salvage usable waterfront from Ferrisburgh to Benson by mowing down milfoil.

They pilot a homemade scow of 3/4 inch plywood, built by another retiree, 78-year-old surgeon Frank Russell. A volunteer protection group, the Lake Champlain Restoration Association, sponsors the vessel’s work.

One late July day, Bronson and Barry headed out to help several cottage owners who had paid $97.50 apiece to have the milfoil removed from their lakefront. The feathery plant grows in dense beds with strands that can reach up through 25 feet of water.

The scow putt-putted out of Lapham Bay in Bridport pushing a raft-like barge — another homemade item — on which the men pile the milfoil.

They anchored the barge 50 yards from shore, where an A-frame cottage perched on a bluff. Barry lowered the scow’s cutter, a kind of rack with a wire cable stretched across the bottom. Bronson revved the engine.

He cruised back and forth, back and forth across the water, exactly like a man mowing his front yard. Underwater, the cable cut the milfoil about 6 feet below the surface.

Weeds caught on the rack like green spaghetti.

“Think we’ve got a load,” Bronson called to Barry. Barry turned on the motorized winch to raise the rack. On it sagged a dripping, 500-pound mass of green weeds, algae and water.

“Rrrrrrrrrrip.” A tearing sound cut across the engine’s mutter. The weeds were too heavy. The winch platform and milfoil-laden rack tilted dangerously over the back of the boat, wrenching free the nails and bolts that held them to the transom. The whole apparatus seemed headed for the bottom of Lake Champlain. Fortunately, one edge caught on the nearby barge.

The two men contemplated the wreckage in silence.

“We’ll have it fixed today,” Bronson said.

“Never give up,” Barry said.
Humans fight back but usually lose the battle?

Bronson and Barry repaired the scow and soon were back at their harvesting. The state has pledged to replace their homemade vessel next year with $293,000 worth of mechanical harvesting equipment.

But mowing does no more than give lake users a respite. The milfoil will grow back in a month or less.

Laurel Casey knows: “I had them harvest one year, but the weeds were back in two weeks.”

Most of the time, “managing” or “controlling” invasive species simply means preventing them from spreading to still other lakes.

Only in the case of water chestnut, an annual plant, can humans claim some success. Since 1998, Nature Conservancy volunteers have hand-pulled 233 tons of water chestnut. Government contractors have used mechanical harvesters. The work stopped the weeds’ northward march and pushed them back south.

In smaller lakes, control can take dramatic form: killing all the fish in a lake to destroy the alewives, or draining all the water to control milfoil. None of these measures is feasible in a lake of Champlain’s size.

“What you can do is drastic, and limited,” says Ellen Marsden, a University of Vermont biologist and lake researcher. “You are playing God, and that is really, really tough to do.”

State bans invaders, but they continue to arrive

Slamming shut the door to Lake Champlain can be just as difficult — or impossible.

Vermont depends on regulation and education, imperfect tools, to keep out new exotic species.

“Unfortunately, it’s not 100 percent foolproof,” state fisheries biologist Shawn Good said. “There’s always somebody who breaks the rules, wittingly or unwittingly.”

A strand of milfoil wrapped around a boat propeller in one lake can spread if the boat is transported to an uninfested lake. It’s thought the alewife was deliberately (and illegally) introduced into Vermont’s Lake St. Catherine by an angler hoping to provide food for the lake’s bass.

It’s not clear how alewives reached Lake Champlain, but they now threaten to replace smelt as the bottom-of-the-food-chain fish on which the health of game species like trout and landlocked salmon depend.

That would be very bad news for the sport fishery, Good said, since alewife populations crash unpredictably, leaving starving game fish behind them.

Vermont has made it illegal to introduce live fish into a Vermont water body, or to transport invasives like milfoil and zebra mussels, or even to possess hydrilla and seven other invasive plants that haven’t reached the state. The Fish and Wildlife Department is working on a similar blacklist of fish and shellfish that might be brought to Vermont as bait or for aquariums.

Game wardens began inspecting boats at fishing access ramps two years ago, looking for hitchhiking plants and animals.

The wardens began with boater education and formal warnings. They have issued only one $199 ticket, according to Robert Rooks, head of law enforcement at the Fish and Wildlife Department. A crackdown is coming, he said.

Some states do more. Maine has closed its borders to the importation of any live baitfish.

Bait dealers import bait by the tractor-trailer load, Good said. If that bait is wild-caught, the load could accidentally include exotic invaders.

Good said no decision has been made about whether to ban live bait imports. Vermont law requires the benefits of such a ban to be weighed against the financial impact it would have on bait dealers, he said.

Meanwhile, on shore, Vermonters continue to fight the exotic species that upset humans.

Laurel Casey will continue her personal milfoil patrol. She is bitter about changes in the lake she loved as a teenager. She worries about her financial future, too.

“This is all I have,” she said her of lakefront cottage and a small annex. “I’m an entertainer, so I’m broke. I thought I could rent this little bungalow — but who’s going to rent this place with all the weeds in the water?”

Contact Candace Page at 660-1865 or e-mail cpage@bfp.burlingtonfreepress.com