Somewhere on this BB this came up. The salmon reared in South America commercially and other many had there origins from PMW hatcheries. Their size has increased due to the fact they do not have marine fisheries and are evolving back toward themselves. The egg sales I did were all Coho and went to Chile if I recall correctly. I think the Cowlitz sold surplus Chinook eggs but it has been a bit back. Long and short of it feed being down reduces a fish for his time but feed back the size is back. The gene pool removal by marine troll and sport for the 5 & 6 yr old fish has downsized our Chinook but they will also recover over MANY generations with no harvest.

You see there is a answer but lord your not going to like the price. Catch here is they cannot be wiped out to recover and spawning success will be greatly reduced by the smaller adult size extending the time line. In other words we manage Chinook about as ass backwards as a humans can do ( and we do some really stupid things ) and we do it with great fanfare each year. We have met the enemy and it is us.