The salmonid enhancement program, which has been around for 40 years, has spent a significant amount of time looking at that question, namely, when is enhancement good and when is it not good?
It has created guidelines to ensure that any enhancement activity falls within the acceptable practices, so that you can produce more fish, but you're not endangering the genetic diversity or impacting the stocks of concern.
It is a really important question to ask. The salmonid enhancement program has done a lot of work on it. There is still more work we can do to improve it.