To study and improve the eel’s survival rate, Holmen took part in a research project, ‘Krafttag ål’. The project was run jointly by a number of hydro power companies and the Swedish Agency for Marine and Water Management with the aim of learning more about eel behaviour so as to reduce mortality rates in eel migration past power stations.

Survey of eel behaviour

Holmen took part in a project that sought to study the factors affecting eel migration and explore technical solutions at hydro power plants to improve the eels’ passage downstream. In autumn 2016 field trials began in Motala ström where migrating eels were tracked with radio transmitters to find out how and when the eels were moving. Motala ström runs through Norrköping, where Holmen owns two power plants between the Baltic Sea and Glan lake.

90 000 adult eels have been moved past hydro power plants

The research and development projects conducted under the Krafttag ål initiative have increased our knowledge of a species that we previously knew very little about. The project produced new insights into eel migration and on how power plants can be modified to make downstream passage easier.

As part of Krafttag ål, since 2011 more than 90 000 adult eels have also been moved past hydro power plants in four important rivers, including Motala ström. This has enabled the eels to then swim on to their spawning grounds on the other side of the Atlantic. In the same period over 2.8 million elvers have been released into the wild.

Improved knowledge means effective measures

As the owner or part-owner of 21 hydro power plants, Holmen are involved in various initiatives and projects to improve biodiversity in our watercourses. One of the things we do is carry out electrofishing* around our power plants in Iggesund, Norrköping and Junsterforsen to gather information about local fish stocks.

The challenge lies in finding solutions that protect biodiversity while also meeting society’s need for sustainable energy production. More information will make it easier for us to take effective action.

* Electrofishing is a method where an electric field is created in the water which stuns the fish, enabling them to be caught. Once the fish have been counted and measured, they are released again.