Mapping of the River Kallojoki salmon distribution : Spawning target setting

Abstract

The River Näätämöjoki is a significant Atlantic salmon river located in Northern Finland and Norway and runs to Barents Sea via Neidenfjorden. The river sustains important salmon fisheries both at sea and at the river itself. Recently, salmon spawning targets for different parts of the Näätämöjoki were set to enable population specific and target-based management. Spawning targets were set to the known salmon distribution areas of the Näätämöjoki system, but at that time knowledge of salmon distribution from the tributary river Kallojoki (Gállotjohka) was missing. Salmon distribution of the River Kallojoki was mapped by electrofishing in August 2024. These data together with knowledge from local fishers, habitat information based on field observations and aerial photos were then used to set the spawning target for the Kallojoki salmon. The electrofishing survey conducted in 2024 proved that considerable salmon juvenile production still occurs in Kallojoki and in its tributary Vuosttamušjohka despite the decreased discharge caused by the water direction to the Gandvik power plant. Salmon juveniles were caught from all the electrofishing sites (n=19) except the site, which was located above a c. 4 m high waterfall in the Kallojoki main stem. The spawning target of the Kallojoki system was estimated to be rather small, c. 324 000 eggs (180 kg of females). This is partly caused by the fact that part of the Kallojoki production area has been lost due to the lowered discharge. Secondly, very limited spawning habitats and nursery areas for 0+ salmon juveniles are available in the system. The overall Näätämöjoki spawning target defined in 2022 increased slightly (5814 kg vs. 5634 kg of female salmon) after including the Kallojoki system. The inclusion of the Kallojoki system did not affect the overall spawning target share between Finland and Norway.