Environmentalists: Lampricide doing more harm than good
Toolbox
By Tom Mitchell Staff Writer - Published: November 16, 2008
Editor's note: The online edition of this story includes a clarification of comments attributed to Anthony Bushway regarding the impact of the cessation of lampricide on fishing in Lake Champlain.
SWANTON — A program using chemicals to kill sea lamprey in Lake Champlain tributaries hasn't reduced the lampreys' wounding of trout and salmon, and appears to harm other species while falling short of the financial gains originally planned, some environmentalists assert.
"Our big concern is that they are expanding treatment (this year) to new streams," said Mike Winslow, staff scientist for the Lake Champlain Committee, a nonprofit group based in Burlington. Last year officials did a substantial treatment in the Poultney River, and have treated the Ausable River delta last year, he noted.
Another treatment in early October of the Winooski River killed 16 juvenile mudpuppies and killed or put at risk other non-target species, Winslow said.
In the face of the many lamprey that have reproduced after surviving treatments, Winslow sent a letter to the U.S. Fish and Wildlife earlier this year, asking for re-evaluation of the program.
The eel-like parasites, which grow to nearly two feet in length, attach to the sides of fish and suck out their fluids. When anglers hook a trout or salmon, they are frequently pulled from lake with the lamprey hanging off them — something anglers don't like to see.
Although the program has led to an extensive kill of the sea lamprey, federal officials agree it has fallen short as far as reducing the woundings to trout and salmon.
"It certainly hasn't reached the targets that we have proposed," said David Tilton, a Fish and Wildlife biologist.
The program has undergone a number of revisions since its inception, Tilton said. A high percentage of young lamprey living in the Poultney River were killed in a treatment of that stream last year, he said.
After Mill Brook in Port Henry, N.Y., the Winooski River was treated in October. A second Vermont treatment was slated for early November in the Mississquoi River and finally went forward Nov. 10, apparently marking the first time that two Vermont streams have been set for treatment in one year, officials said.
In addition, based on the finding of a steady increase in the number of young lamprey in the Lamoille River, treatments are now authorized in that stream, possibly in 2009.
However, Winslow said the state and federal fishery biologists' move to add new streams for treatment was not justified before the impacts of a 2007 treatment in the Poultney River had been assessed adequately over a period of at least two years.
"The (Lake Champlain Fish and Wildlife Management) cooperative has offered insufficient reason to believe that the environmental and economic benefits described for the sea lamprey program would actually be achieved by the expansion," Winslow said.
Effects of treatments out in the lake are seen over a two- to three-year period after a treatment is done, according Tom Berry, Lake Champlain program director for the Nature Conservancy.
"You are killing three years' worth of lamprey" during a treatment, Berry said. "You are seeing some effects in the first (year), some in the second and some in the third."
His sense is that the program is reducing young lamprey in streams.
"They are killing a lot of lamprey," he added commenting on what the program has accomplished. "We do not support (lamprey) treatments," Emily Boedecker, a communications representative for the Nature Conservancy, said Friday. "When a treatment is mandated by management agencies, we advocate for the lowest concentrations, to minimize the impacts to non-target species."
Levels of chemicals permitted for use last year in the Poultney River were as much as 20 percent higher than the level of one-time minimum lethal concentration that the Nature Conservancy requested in its comments on the plan last year.
"We need to move beyond the use of lampricides," Boedecker said.
Mollie Matteson of the Center for Biological Diversity, a nonprofit group with an office in Richmond, is worried that recent treatment of the Mississquoi could hurt species that live there, including the mussels.
"We are going to have impacts on species in a federal wildlife reserve," Matteson said.
Herpetologist James Andrews, who has sought legal protection for the mudpuppy, the imperiled species killed in the Winooski, also has been concerned about the treatments and potential effects on all the non-target species.
"I am always nervous when they move into an ecosystem they have not treated, saturating an entire river with pesticides. … That makes a lot of us nervous," Andrews said.
There are a wide variety of non-target species that can be hurt by pesticides, he said. "One of the groups that really gets hit is the other kind of lamprey," Andrews said. He added that the northern brook, silver and American lamprey are three native species vulnerable to the effects of the chemical.
Wounding rates stay high
Winslow and Matteson have begun strenuously objecting to the program's inability, in any significant way, to reduce fish woundings to the stocked native lake trout, Atlantic salmon or wall-eye pike.
In terms of lamprey wounding rates seen in the last few years, studies have show that the limits of wounding fell short of the goal of 15 wounds per 100 fish for Atlantic salmon. Instead, the woundings rose to 71 per 100 salmon in 2006 and stayed the same in 2007.
The number of wounds per 100 lake trout has also remained well above the target of 25 per 100 fish in 2006. In 2007, the numbers of wounds did drop to 46 per 100, but that occurred with a smaller number of trout sampled, Winslow noted.
Berry of the Nature Conservancy cited that reduction as a positive move in wounding rates, although he acknowledged that the wounding to lake trout is still well off the mark of 25 wounds per 100. The program should be working to meet its goal of bringing wounding rates to that goal, he said.
The high number of lamprey has stayed high in Lake Champlain seems to represent a predator imbalance in its ecosystem, Berry said. "It is certainly out of balance now with the ecosystem," he said.
Believing that chemical treatments of sea lamprey has been good for the survival of salmonids in the lake, members of groups like Trout Unlimited and the operators of a number of charter boats have expressed support for the program.
Not only are the stocked trout and salmon caught as trophy fish in deeper water in summer, Berry noted, but anglers also fish for them from shore when the lake gets colder in the spring and fall.
"When water temps are less than 55 (degrees) Fahrenheit, these fish can be caught in just a few feet of water," he said.
"River mouths and causeways are particularly good" for anglers wanting to reel in the salmonid cold-water fish, said Berry, who fishes for salmon in a canoe in the Winooski River or otherwise close to shore.
In summer, when the same salmon and trout species seek out the colder depths, he said, "one needs a big boat, down-rigging gear and fish finder to have much success."
Anthony Bushway, who makes his living as operator of An Bradon Charters in South Hero, said he'd seen a boom in fishing on Lake Champlain in the 1990s due to lamprey controls. Treatments were so effective, fishery officials cut back on the stocking of lake trout, Bushway said.
However after treatments stopped in the 1990's, fishermen again saw a decline in the quality of fishing, he said. Fishermen had also seen a decline in fishing before the (initial) chemical treaments started (about 20 years ago.) Bushway said he supports continued use of chemicals, while other controls are explored.
In terms of reducing sea lamprey, the program achieved a pretty good kill in a 2004 treatment of the Winooski River, according to Brian Chipman, a biologist and a supervisor for the treatment program.
But up to 175,000 young lamprey were found in the Winooski River in a survey last year and targeted in this year's October treatment, he said. The extent of the recent kill will not be determined until future testing is done in the next year or so.
Other fish that lamprey attach to include the protected lake sturgeon, channel catfish and lake whitefish, Chipman has said. State officials say they don't not know why lamprey numbers have remained high, but one theory is that as the tributaries got cleaner, the lamprey have fared better.
Contact Tom Mitchell at tom.mitchell@rutlandherald.com.
34