Spawning targets for Atlantic salmon in the River Näätämöjoki/Neidenelva

Abstract

Salmon populations should be managed in a population-specific and target-based manner, and therefore biological reference points and consequent management targets should be established for each salmon population. In Norway, first-generation management targets in the form of spawning targets were established in 2007. In the case of the transboundary River Näätämöjoki/Neidenelva spawning targets were then set only for the Norwegian side of the river system. In this report we present the estimated spawning targets for the whole Näätämöjoki/Neidenelva system including the Finnish side. The spawning targets are presented separately for the Näätämöjoki/Neidenelva mainstem, for tributaries Silisjoki and Harrijoki and for the whole system. Spawning target of the Norwegian side was also updated by using more accurate habitat knowledge. The total spawning target of the River Näätämöjoki/Neidenelva system was estimated at slightly over 10 000 000 salmon eggs. This converts to 5634 kg of female salmon when using fecundity of 1800 eggs/female salmon kg and 4558 kg when using the fecundity level of 2225 eggs/female salmon kg. Based on the production area size and their value to salmon production 66% of the spawning target is situated in Finland and 34% in Norway. In practise depending on the chosen fecundity level, c. 650–800 female salmon averaging a weight of 4.65 kg are annually needed on the Finnish side and c. 330–410 females on the Norwegian side of the Näätämöjoki/Neidenelva to fulfil the spawning targets. Although the spawning targets are expressed in female salmon biomass and numbers, male salmon are also needed for successful spawning and recruitment.