If a fishway would be constructuted, it would probably increase the amount of tourists in the area. The Mustionjoki River used to be a famous place for fishing. Nowadays there are not many good rivers for fishing in Finland, especially in southern Finland. For example, many peole are travelling from Helsinki to Tenojoki River to fish.
If a fishway is constructed next to a hydroelectric power plant, the amount of produced hydroelectric power will be reduced because a part of the running water is led to the fishways. Therefore constructing a fishway may not be financially reasonable for the owner of hydroelectric plants. Also the construction of fishways is relatively expensive. However, if the hydroelectric power plant in Åminnefors and in Billnäs would have fishways, the migrating fishes could rise all the way up to the hydroelectric plant of Peltokoski. From Åminnefors to Peltokoski there would be many possible reproduction places for the migrating fishes. On the grounds of financial and ecological reasons it was reasonable to plan fishways to Åminnefors and Billnäs because that would make the reproduction of the migrating fishes possible in the river. To ensure the possibilities for reproduction for different species, some hectares of the possible breeding ground should be restored (Suomen ympäristökeskus 2010, p.88)