New fishways reopen nearly 1,000 kilometres of Lapland waterways

New fishways on the Tengeliönjoki, a tributary of the Tornio River, have reopened nearly 1,000 kilometres of migration routes for fish after the river was blocked for a century, Yle reports.

The Portimokoski fishway in Ylitornio was completed last October and will be inaugurated by Sweden’s King Carl XVI Gustaf together with Finnish ministers. A lower fishway at Hietakoski was completed in 2024.

The fishways are the most significant part of a joint Finnish and Swedish restoration project covering the 40,000 square kilometre Tornio River basin. The project aims to remove more than 3,300 kilometres of human made barriers to free flowing river channels, restore smaller waterways and add spawning gravel.

More than 3,000 fish have passed through the Portimokoski fishway this summer, according to the Lapland Centre for Economic Development, Transport and the Environment. Most have been non migratory species, including roach, dace, ide and bream. Pike and perch have also been recorded.

No migratory fish, such as salmon, trout or migratory whitefish, have yet been seen on the fishway camera. Project coordinator Marko Kangas said there were no obstacles preventing them from reaching the river, as even weaker swimmers can pass through the technical section of the fishway around the Portimokoski power plant dam.

The Portimokoski fishway combines a natural gravel channel with a technical concrete section where a camera installed by the Natural Resources Institute Finland monitors and counts fish. Some fish could already spawn in the natural section, Kangas said.

Restoration workers released trout above the regulating dam during the inauguration. Salmon juveniles were placed in the natural channel to grow.

Officials caution that completing the fishways does not guarantee the return of breeding migratory fish. The species have been absent from the Tengeliönjoki for about a century, and restoring their populations could take decades.

Restoration work was suspended in August because of flooding. The interruption is expected to increase the pace of channel restoration work in the coming years unless water levels allow workers to return before winter.