Rainbows survive hook-and-release and eat king salmon eggs. King salmon hooked and released might survive but do not spawn. Kenai kings are now on average 10 pounds smaller. The hook and release of Kenai kings on spawning beds is not a sustainable fishery. While it does pander to opportunity this type of management has led to more smaller males. As far as steelhead are concerned, soon enough there will be none of these left. This has been a hook-and-release fishery for years and aside from misunderstood mortality many steelhead do not make it back to the water. In fact a common cause of death like their rainbow brothers would be flashburns from modern digital cameras. These days the demand far exceeds the supply. Hook-and-release might represent a good opportunity for man, but it is bad for fish. In a few decades we can see an unintended genetic impact on the once giant Kenai kings.
I could blather on about kill-and-release but the pressure on some stocks is too much to justify this type of management. The more you hook and release, the more do not spawn, the more die. What might be good for man (opportunity) but bad for fish and their future.