A change to environmental regulations in Vermont may halt plans to treat Lake Champlain for a pest that has devastated the lake’s fishery for decades, and fisheries advocates are concerned about the possible impact.
The Vermont Department of Health drastically cut the allowed level of the lampricide TFM in the state’s drinking water, to a level that lake advocates believe will not be strong enough to kill young sea lamprey. The allowable level had been 35 parts per billion, but the Department of Health earlier this month changed that threshold to 3 parts per billion.
The decision had fisheries experts in both Vermont and New York scrambling to figure out how to adjust and keep the successful lamprey treatments going. It was unclear what effect, if any, the Vermont rule change would have on New York treatments.
Vermont and New York, working through the U.S. Fish & Wildlife Service, have alternated annual treatments of lake tributaries for lampreys since 2002. No treatments were planned in New York this year, but three northern Vermont tributaries — the LaPlatte and Missisquoi rivers and Stone Bridge Brook — were scheduled to be treated later this year.
Each tributary lampreys are found to use for significant reproduction is treated every four years. Locally, the Poultney River, Putnam Creek and Mount Hope Brook have been treated in recent years.
New York’s maximum standard for TFM in water is 50 parts per billion.
James Ehlers, executive director of Lake Champlain International, a lake advocacy group, questioned the change. The LaPlatte is one of the biggest lamprey-producing waters on the lake, Ehlers said. Halting the treatments would “squander” all of the work that has been done to fight lampreys in recent years, he said.
Trout Unlimited members on the New York side expressed concern about the possible halt to lamprey treatments but were awaiting word on whether a compromise could be found, said Bill Wellman of the Lake Champlain TU chapter.
Louis Porter, the commissioner of Vermont’s Department of Fish & Wildlife, said a meeting of the Lake Champlain Fish & Wildlife Management Cooperative held Thursday did not yield any concrete plans for future treatments, but the agencies were reviewing their options.
He said the Vermont Department of Fish & Wildlife plans to work with federal and New York fisheries experts to determine if treatments can be worthwhile this year at the lower chemical limits.
“We are working to figure out whether a treatment can be done this year,” he said.
The agency also plans to study the effects of TFM.
Tributaries where there are not public water systems could be viewed differently under the rule change. Filter systems were put in place in at least one bay in Vermont to filter TFM several years ago after a treatment on the Winooski River, near where the Burlington, Vermont, water district draws water.
The U.S. Fish & Wildlife Service had no comment on the rule change as of Friday.
New York’s Department of Environmental Conservation planned to continue to work with Vermont and federal wildlife officials to figure out the best treatment plan for the lake while also addressing water quality issues, DEC spokesman David Winchell said.
“New York remains committed to an effective sea lamprey control program and the resulting enhancement to the recreational fishery and associated economic benefits derived from that healthy fishery,” Winchell said.
Lamprey latch onto fish and bore through their scales to suck their bodily fluids, severely injuring and even killing them. Trout, salmon and walleye are particularly susceptible.
Lamprey wound rates at their peak in the early 2000s, before the current treatment program began, were 93 per 100 salmon, compared to 15 per 100 salmon in 2014. Fish size has also improved dramatically.
“The program has been a tremendous success, both in terms of wound rates and size of fish,” Porter said.
Use of the chemical has been controversial among some environmentalists for years, with critics pointing to studies that show it may kill other waterborne life, such as mussels.