The problem is see, with pinnipeds, is that they are taking many of the fish early in the growth cycle. Others in the food chain, including humans, are generally taking fish later on. With hatcheries pushing out huge numbers of smolts as mitigation in a shorter time period and with obstacles like the hood canal bridge, these predators can basically wipe out a large percentage and knock the entire food chain out of whack. The number of fish returning would probably be low enough that the runs would fall and the predator population would collapse, but the hatcheries then pump up production and produce enough to continue the cycle. It eventually will collapse, but the process is going to take a much longer time that it has in the past. And, for it too happen, the returning runs will have to be so correct that a natural correction may not be possible.

Like it or not, humans are part of the ecosystem and have altered it in many ways. Altering it in one area and not in another can have serious implications.