Or SG in most cases the habitat is what it is and natural production is the optimum level for the watershed. It is limited by habitat only if the starting point is in the past pre settlers and development. As people are not going any place and human impacts at best will remain the same, then the starting point needs to be where the habitat became what it is. Habitat can only be the limiting factor if the number of fish spawning are at the optimum natural level and survival is low. Then you can say habitat or that your allowing more fish to spawn then the stream can support so harvest can be increased as less spawning will still produce the same amount of adults. Sound familiar?

Simple fact except for the OP streams, which time will slowly help, in WA the habitat limits only the natural production if your base is in the past before human impacts. Those impacts are not going away, will only continue to increase, and the goals for natural production and harvest or associated impacts will require the reduction of harvest ( over harvest ) until the proper balance in TODAYS watersheds ( not past what ever many thousands it used to support ) is achieved.

It is the penalty that fish pay for sharing the planet with humans, like it or not. Frankly I don't like it but I am not going to save the world and I doubt anyone else on this BB will either.