We've known for years that domesticated hatchery fish aren't much good in the wild. But newer, better hatcheries that spawn wild fish are said to be...well...newer and better.
A new study says that even one or two generations in a hatchery reduces the fitness of steelhead (salmon cousin). This study supports recent decisions that hatchery fish should not be counted in considering whether salmon or trout require protection as threatened or endangered species.
We've made a gross error in the northwest, in relying on hatcheries to compensate for habitat destruction. We were warned, but the attraction was too great. We bought the promise that we could have overdeveloped rivers and salmon too. It didn't work, and there were voices raised at the time that said it wouldn't work. I hope we learn our lesson someday.