Rivers on the New York side of Lake Champlain will be treated with chemical pesticides this fall in an effort to control parasitic sea lamprey.
Lamprey larvae live in river systems for four years before swimming to the open lake, where they attach themselves to fish, often wounding or killing them.
Bradley Young, with the U.S. Fish and Wildlife Service, said the river stage of their life cycle provides an opportunity to target them.
“It's kind of a nice focused location for us to be able to control them,” Young said. “Once they're in the lake, they're out of our reach as far as being able to do anything about control.”
Twelve sites in New York tributaries will be treated in September and October; eight are in river systems, and four are in deltas. Officials will impose water-use advisories to minimize human exposure to the two separate pesticides that will be applied.
The Vermont Department of Health recommends that treated lake and river water not be used for drinking, swimming, fishing, irrigation or for livestock watering while the advisories are in effect.
Young said the long-term program has resulted in healthy populations of landlocked salmon and lake trout.
“And we're seeing some really good things happening with the age and size structure of both lake trout and Atlantic salmon ... My favorite line is, an angler told me: 'These are the good old days,'" Young said. "That things are finally starting to improve, and people are catching more fish than ever, bigger fish than ever."
Biologists also credit the lamprey program for helping the population of endangered lake sturgeon, an ancient fish that was almost wiped out in Lake Champlain.
“So we’ve got a population of lake sturgeon that have been on the edge of recovery for quite a while. And as soon as we started to get sea lamprey under better control, we then saw a resurgence in lake sturgeon as well,” Young said.
The lamprey control program will start up again this fall with its focus on the New York tributaries to Lake Champlain. Next year, the program will focus on streams at the southern end of Lake Champlain.