The fishkill is a tragedy, a lot of things are going haywire in the timing of things lately.
The life cycle of wild Pacific salmon means they inevitably die after travelling up winding creeks and streams.
I think the author needs to do a little more research. It isn't inevitable. Steelhead salmon are "wild pacific salmon" that come inland, spawn, and then return to the ocean.
Most Pacific salmon die shortly after spawning, with the exception of steelhead.
I have caught steelhead fresh inland from the ocean that still have lampreys attached.