MONTPELIER, Vt. — The number of landlocked salmon that swam up the Winooski River from Lake Champlain this fall was the highest since a program began in 1993 to help the fish get around a series of power dams so they could reach their spawning grounds, officials said.
The 189 landlocked salmon that reached the Winooski One hydro dam this fall represented a 44 percent increase over the 130 fish total from 2010, which was itself a record.
“This has been the best year we’ve had since the lift began operating in 1993,” said Nick Staats, a U.S. Fish and Wildlife Service biologist who monitored the salmon run.
The average size of the fish was 21 inches with the largest being 28½ inches.
Officials credit the increase to a program that controls sea lamprey in Lake Champlain by killing young lamprey in the rivers and streams where they hatch. Lamprey are external parasites that attach themselves to fish such as salmon and trout.
Landlocked Atlantic salmon are close relatives of the species that spawn in inland rivers and streams and then spend their adult lives in the Atlantic Ocean. They adapt to live their lives entirely in fresh water.
The upstream migration of salmon on the Winooski was blocked in the late 1700s when the first dam was built. It wasn’t restored until the Winooski One project began in 1993.
“This kind of increase two years in a row is a hopeful sign that the fishery is being restored,” said John Warshow, owner of Winooski One Partnership that operates the hydro-electric station on the river where it separates Burlington from Winooski.
Until several years ago the fish were captured at the Winooski dam and then carried by truck upriver where they were released above two additional power dams so they could spawn in the streams where they were released as fingerlings, about four inches long.
That practice was ended several years ago because of concerns the fish from the lake could spread a viral disease that affects fish in the Great Lakes basin, said John Hall, a spokesman for the Vermont Department of Fish and Wildlife.
Now the fish are captured at the Winooski dam, measured and released there. It’s possible they spawn in the river below the dam, although conditions are not ideal, Hall said.
Young salmon are still stocked in tributaries above the dam, and when they grow up they swim down river to the lake.
The cost of the project is shared by Winooski One and Green Mountain Power, the owner of the next two dams upstream in South Burlington and Essex Junction.
The eight-week spawning season ended Nov. 10.