Fish ladders and spillway weirs are fish killers that impose a decimation on the salmon population at each elevation change. Dams destroy the estuary and natural wetland environments that salmon need to reproduce. Dams reduce water flow and silt over gravel beds. Dam impoundments cause stream and river temperatures to rise, suffocating fish. Dam removal is not just obstacle removal, it is habitat restoration and rehabilitation.

I feel like that's just a block of true-ish text but doesn't address the actual comment.

Nothing you said talked about salmon spillway weirs.

This isn’t exactly true. Fish ladders and weirs shouldn’t be grouped together like this. Many hatcheries have a weir salmon cannot cross and a ladder as the alternative path the fish take by feeling the flow of water across the ladder and going upstream. The ladders lead to hatcheries where the fish reproduce. And new tiny fish are efficiently raised in protected tanks and later released to go back downstream. In other words, the weir and ladder are a combination to make the hatchery work, and not substitutes for each other. Also ladders can work very well. There are many badly designed ones but the good ones basically let every fish move upstream.

Much of what you said is an exaggeration, for where a habitat disappears with a dam, different habitats appear.

But regardless, the point is that salmon were still breeding there. The "return" is an unwarranted claim, for they never stopped coming and spawning.

Not dams impose climate change that destroys all things.

Yeah the dams also tend to regulate flows in the river system which doesn't allow natural cycles of peaks and valleys to help regulate parasites.