An invasive horde of parasitic critters is taking over Lake Champlain. The sea lamprey, originally from the Atlantic Ocean, has seeped its way into the freshwater regions of the Northeast.

Nearly one hundred years ago, the sea lamprey traveled up the Hudson River, through the Erie Canal, and into the Great Lakes. They've since migrated to Lake Champlain, via the Hudson.

Sea lamprey are parasitic non-indigenous Agnathans that attack many native fish like lake trout, walleye, northern pike and lake sturgeon. Lamprey will use their leech-like mouths to fasten onto fishes—ripping into their bodies, sucking their blood, and ultimately killing off many native aquatic species.

As a result, lake trout and landlocked salmon are taking a hit in population reduction. And the sport fishing of lake trout has dwindled as well.

Dave Richard of Richard's Bait and Tackle in Plattsburgh, New York, agrees. He says the lamprey are ruining Lake Champlain's sport fishing. "The fish were nice [in size and appearance] to start with. But then the lamprey started knocking off the big fish," he laments.

Help On The Way

Members of the New York State Department of Environmental Conservation and the US Fish and Wildlife Service are looking to rehabilitate the local fish populations.

These groups have reinstated their lampricide treatment project. The lampricide-3-trifluoromethyl-4-nitrophenol-or TFM has been applied to area waterways, including the Salmon River, the Ausable River, Putnam Creek, and Lewis Creek.

In 1990, an eight-year experimental lamprey treatment program was initiated in Lake Champlain. The project was suspended in Vermont due to insufficient funds, but it has been continual on the New York side.

Photo Courtesy of M. Malchoff, Lake Champlain Sea Grant

How bout one of these on your leg?

Not So Fast

According to a lawsuit filed by the Vermont Public Interest Group, The National Audubon Society, and Sylvia Knight, a Charlotte, Vermont independent environmental researcher and advocate, some of the stream sections that were treated with TFM contain a number of rare species sensitive to the chemical: seven of eight endangered mussel species, and the mudpuppy, a large aquatic salamander that is of special concern in Vermont.

While lampricides have been used since the 1950s in the Great Lakes, there is not any conclusive evidence of long-term effects on non-target species, according to Craig Martin, Deputy Project Leader of the US Fish and Wildlife Services in the Lake Champlain offices.

Martin acknowledges they [USFWS] do not know every detailed effect of different species in Lake Champlain, but he says they have inferred, based on long-term monitoring, that they have seen little to no effect on mussel populations.

The long term monitoring includes an environmental impact statement Martin submitted in August 2001. The four hundred plus page statement was enough for the courts to allow resumption of the lampricide treatment program.

Since lampreys hinder the growth rate by killing so many native fish, they have had a devastating effect on the local fisheries. The sea lamprey has severely depleted the lake trout populations in Ontario, Huron, Erie, and Michigan lakes.

Sea For Yourself

The application of TFM is a labor-intensive project. First off, the people have to monitor the water flow and pH levels to determine what type of TFM concentration to apply. Mark Malchoff, a member of the Lake Champlain Sea Grant Extension Project, says the lampricide is a pretty good pesticide in terms of its non-target effects. He says it doesn't kill many other organisms.

The pesticide operates on a continuous twelve-hour cycle in an effort to kill the immature sea lamprey larvae. The chemical dissipates after two to six days, rendering the water unusable for drinking, cooking, and other general purposes.

"As long as both sides of the lake [New York and Vermont] continue with their lamprey control, we will begin to see a rise in the bigger lake trout," Richard declares. "But it's going to take a few more years."

According to a press release from the Vermont Agency of Natural Resources, "most other aquatic organisms are unharmed by the dosage levels of TFM that are lethal to larval lamprey."

Knight disagrees. She says the USFWS has known, since 1994, that TFM is contaminated with several dioxin type compounds.

"Dioxins can be very toxic to humans and other life at lower concentrations. Nobody has done a full assessment of what these contaminates are, or what their effects are on the environment. No one has assessed how much of this TFM is going into the lake from one treatment or from the whole project," Knight says.

Martin explains the dioxin that was found is a tri-substituted dioxin. "This is not a highly toxic form," he says. "When there are endangered species in the waters, we treat the water at what is called a 'no-observable effect concentration.' " Martin explains that where there are threatened species they are essentially not affected by the concentration.

While the concentrations are low, Knight believes they can have a damaging effect on aquatic species, even at low concentrations. There are other persistent contaminants in TFM besides the dioxins. "None of this has been assessed for human health or ecological health," Knight attests.

A handful of other environmental groups, such as the Poultney River Group, agree with Knight's position.

According to members of the Vermont Department of Health, the loading of these contaminants into the lake and their impact on human health has to be assessed before another treatment is done.
"This is something that needs to get into the public awareness," Knight affirms.

Light In The Murky Lake

In the thick of this contamination controversy, an ultimatum emerges between the environmentalists and conservationists. Malchoff and Ellen Marsden of the School of Natural Resources at the University of Vermont, are currently using an experimental lamprey-monitoring program which seeks to satisfy both party's concerns.

To help track down where the higher populations of these lamprey are, Malchoff and team have implemented a tagging project. They insert a thin coded wire into the lamprey and release them back in the lake.

They have already tagged over 2,600 lampreys this past year. They have since been released into four streams around Lake Champlain. Malchoff and Marsden, are looking to local anglers for help in returning the tagged specimens.

While the catch may be unsightly, rigged with leech-like animals around the fish, the return of the lamprey is a necessity in learning more about these parasites.

In effect, this project will diminish the overuse of lampricide in Lake Champlain because the groups will know what sections of the lake need extra attention.

"The anglers are being very helpful. One way or another, we have about six-hundred returned lampreys," Marsden attests. "It's a very hit or miss thing; some anglers will bring in a couple hundred while others will bring in just one."

This demonstrates that no one really knows where the higher concentrations of lampreys are.

So far, there have only been about a half dozen tagged lamprey returned. Marsden says the reason why these numbers are so small is because there are still so many lamprey all over Lake Champlain. "Even though we tagged 2,600 of them, it's a drop in the bucket as to how many lamprey there really are," she points out.

As incentive to keep anglers interested in the program, the team is offering cash prizes to anglers with the most returned lamprey, lamprey caught from the farthest distance, and through a random drawing.

The lamprey control issue is an ongoing effort. More treatments will be done in the coming fall.

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