Control of fish with electric barrier : Attempts to control migrating fish in Harrbäcken, Norrbotten

The purpose of this study was to investigate whether it is possible to control fish that migrate during spawning season with the help of an electric barrier. The results aim to increase knowledge about electric barriers as the method so far is scarcely used in Sweden. Examples of situations where the method could be useful are when monitoring restoration measures of wetlands and when controlling fish at hydropower plants. This study was conducted in Harrbäcken, where fish migrate during spring to spawn. The fish migrate up through Harrbäcken, partly to spawn in the stream itself and partly to spawn in Sladaviken just upstream. Attempts to control the fish with an electric barrier were carried out and data were collected via recordings from three different fish counters. The results showed that the electric barrier did not impede fish spawning migration, although this result was not entirely convincing. Furthermore, the electric barrier influenced which fish counter the fish chose. Finally, the result show that the electric barrier influenced which fish counter larger roach (Rutilus rutilus) chose. Larger roach chose to swim beside the electric barrier when it was turned on and through the electric barrier when it was turned off. Although this study contributes to an increased understanding, more studies within the subject are desirable