Sea Lamprey, Wikimedia Commons

Invasive sea lamprey latch onto a native lake trout.

Four Vermont rivers leading to Lake Champlain will be treated for invasive sea lamprey in the coming weeks, according to the U.S. Fish and Wildlife Service.

Starting in late September, the Winooski, Missisquoi, LaPlatte and Lamoille rivers will each be treated with so-called “lampricides” – chemicals used to target lampreys’ larvae.

Since their suspected introduction to Lake Champlain in the 1800s, parasitic sea lamprey have “severely” affected native fish populations and have been connected to declining populations of walleye and state-endangered Lake Sturgeon within Lake Champlain.

Sometimes known as “vampire fish,” sea lamprey can be identified from their eel-like body and sucker-like mouth used to latch onto fish.

The U.S. Fish and Wildlife Service has declared control of Lake Champlain’s sea lamprey population “essential for restoring the health of Lake Champlain’s fisheries.”

According to the U.S. Fish and Wildlife Service, efforts to control lamprey populations within the Lake Champlain Basin have led to a fewer number of fish being found in Lake Champlain with lamprey wounds, but “lamprey-wounding” remains above federal targets within the watershed.

Officials are expected to begin applying lampricides to the Lake Champlain watershed starting next Sunday with the Winooski River, according to a notice from the U.S. Fish and Wildlife Service.

Lampricide applications are scheduled for Missisquoi Bay and the Missisquoi River on Oct. 6 and on stretches of the Lamoille River and its Lake Champlain outlet on Oct. 20.

While TFM, a chemical commonly used for controlling sea lamprey, has been shown to be nontoxic for humans and other animals at the concentrations used for lamprey control, Vermont’s health department recommends against drawing water from rivers and lakes where TFM is being applied.

During applications, the state will have an advisory in place against drawing water for consumption and irrigation or against fishing and other forms of recreation on affected waterways, according to a U.S. Fish and Wildlife Department notice.

Advisories will be lifted once lampricide concentrations fall below the state’s thresholds for water-use advisories, and, according to the U.S. Fish and Wildlife Service, municipal water supplies will not be affected by lampricide use.

Advisories typically last between one and four days, according to officials.

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