I use to keep up on this salmon recovery tech, but lately I have found it kind of discouraging to see the phd. scientists can't agree on some seemingly basic issues. It's getting hard to sort out the politics from the science. It seems the NMFS biologists have studies showing offspring from hatchery fish spawning in the wild have very low adult returns. They are concerned that any inter-breeding with wild fish will weaken the genepool with unknown and likely negetive effects. Here is a link to a long technical read if anyone is interested.
http://www.nwcouncil.org/library/isab/isab2001-3.htm