Back then, a salmon was a salmon was a salmon. Hatchery fish were "no problem", they were the same as wild fish.

Chum nd pink are really cheap to raise as they need very little food for a huge amount stocked. Cost/benefit is through the roof. They don't need year-around water, and a bunch of other advantages. But, harvesting down to the hatcheries' egg needs starves the local streams of nutrients.