Southeastern Finland to remove dam blocking endangered sea trout migration

A 70-year-old hydroelectric plant in Lappeenranta, southeastern Finland, will cease operations to restore access to spawning grounds for the critically endangered sea trout, public broadcaster Yle reports.

The Joutsenkoski dam on the Urpalanjoki River—the last remaining obstacle blocking fish migration—will be partially dismantled, reopening a long-blocked route to upstream breeding areas. The move follows years of decline in sea trout populations due to dams, water pollution, and dredging along the 100-kilometre river, which flows into the Gulf of Finland near the Russian border.

The shutdown of the Joutsenkoski power plant, operational since the 1950s, marks the end of an era for its owner, Tarja Ahola, whose father founded the facility. “We’ll continue running the mill on a small scale using purchased electricity,” Ahola said, adding that she accepts the compensation offered for lost revenue. Funding for the dam’s removal and river restoration—estimated at over €200,000—comes primarily from a government programme aimed at reviving migratory fish stocks.

Work could begin later this year if permitting proceeds without delays, according to the Southeast Finland Centre for Economic Development. The project includes replacing the dam’s floodgates with a new bottom structure to stabilise water levels in the upstream Suurijärvi lake. Environmental planners note that while sea trout were once abundant in the river, human activity has nearly eradicated them from the Finnish side, though a few individuals still migrate annually from Russian waters.

Conservationists hope the restored route will improve spawning success, as upstream areas offer cooler, more suitable conditions than the warmer waters near the river’s mouth.