And coho. You harvest the fastest growing fish all the time and you end up with smaller fish.

The Chinook were big and old because that is what worked best in the environment they lived in. Big fish can spawn in big water. What are creating is piscivorous Chums. The evolutionary hope for Chinook will be streams with enough flow to accept a 10-15 pound spawner in September but still have small enough gravel so they can dig in it.