So the smolt migrate into the mainstem Wilson, then turn down river, where they encounter rip rapping, dikes and stabilized stream banks, the riparian zone from Mills Bridge to the mouth is nonexistent, now the smolt enter the estuary where there is zero cover, avian predators are now feasting on the smolt because all the structure has been removed from the bay.
I think the problem is most folks don't really know anything about what habitat salmonics need to thrive, and your a classic example.
You make your living from the resource, yet you don't even know the basic habitat requirements for a healthy stock.