Dam removal begins to restore trout migration routes in Joutsa

The dam at Tammen Mylly has not been operational for over a century, located on the Seinäkoski stream in Leivonmäki, Joutsa. The mill itself has long since been removed, and the dam has deteriorated significantly. It has become a barrier to the migratory routes of brown trout, preventing them from reaching their spawning grounds from Rutalahti to Rutajärvi.

The Rutalahden fishing association has applied for a permit to dismantle the dam, and work began this week. The removal is a collaborative effort between the North Päijänne fishery area and the Central Finland Fisheries Centre, with plans to convert the streambed to its natural state. This restoration will create new spawning opportunities for the endangered lake trout population in Päijänne.

Joonas Pysäys, a fisheries biologist leading the restoration project, noted that the renovated stream will align with the landscape of the nearby Leivonmäki National Park. The estimated cost of the restoration is between €90,000 and €100,000.

Efforts to restore rivers in Central Finland have been ongoing for years, yielding positive results, according to Timo Meronen, director of the Central Finland Fisheries Centre. Successful initiatives have included the Vesangan route and the Joutsan Myllykoski area, where restored rivers have proven beneficial for trout offspring.

However, reviving a trout-less spawning river is a lengthy process that requires patience. Newly hatched trout spend 2-3 years in river waters and an additional 2-3 years in Päijänne before returning to spawning grounds, typically 5-6 years post-stocking. Factors such as climate change pose uncertainties in the restocking efforts, and there is still much work to be done to restore other river systems in the region.