Remember, too, that O. mykiss is optionally anadromous. In southern California they appear to have gone decades to even centuries of drought where they were wholly resident. When wet times returned, they became anadromous again The Elwha is about a century of dams, but even then the migratory/big water fish had the lakes and some below-dam anadromy.

As Rivrguy says, the big Chinook may come back only after we quit killing them in the ocean and let them grow to older ages. It is my understanding that there are still a minuscule few of the biog old fish left. Stop killing them, let them grow up, and let them have food in the ocean.