>>13238103i've been going to watch the salmon fight at the same spot every september for the past 8 years and it seems like about the same amount of fish in that spot every year. 8 years ago was when the dam was removed. the salmon that used to try and breed at the foot of the dam occupied the available upstream habitat as soon as it became available.
grand coulee dam on the columbia river has no fish passage, if you want more salmon to be around then making the columbia river headwaters available for breeding will do the trick, most of the salmon breeding habitat on that one massive river is off limits and that explains a lot of the world's missing salmon. they used to get fish returning all the way to missoula, but there is no home for those fish anymore.
