Hundreds of salmon fry die in Langinkoski, Kotka due to hydropower flow reduction

Hundreds of salmon fry have reportedly died in the historic landscapes of Langinkoski, Kotka, along the Kymijoki River. The fish became trapped in the river’s side channels, ponds, or on dry land after the Koivukoski hydropower plant reduced water flow to 20 cubic meters per second at the beginning of September.

“This year, the water was very high in the spring and early summer. The salmon fry spread widely below Koivukoski, reaching far into the side channels and away from the current shoreline,” said Matti Vaittinen, a water management official from the Southeastern Finland ELY Center. The sudden drop in river flow left the fish unable to adapt quickly enough, leading to their entrapment.

According to Vaittinen, a slower reduction in water flow would have prevented such substantial fish mortality. Local residents have previously reported salmon deaths due to changes in water flow at Langinkoski, but the current incident is notably severe.

Kolsin Voima, the company operating the hydropower plant, has acknowledged that it has acted according to current licensing conditions. However, the fish deaths are attributed to management practices. “It is evident that something must be done. The current practices cause significant harm,” Vaittinen emphasized.

Kolsin Voima has begun its own investigations into the incidents. “We have been trying to manage water flow as permitted. We are checking the fluctuations,” CEO Kimmo Lehtonen stated.

Efforts to mitigate the negative impacts of hydropower regulation are now underway in a newly initiated project involving several environmental organizations and universities. If another solution is not found, there may be a move to amend the licensing conditions for water management.

Vaittinen highlighted the importance of preserving the salmon population, noting that these fry, born in the wild, are particularly valuable. The loss of these fish represents a significant setback for both fisheries and species conservation efforts.