Just my two cents worth...I think how the fish is handled has a lot more to do with mortality than whether or not there's a barb on the hook. This summer on Anderson bar there were some guys that caught several steelhead, unceremoniously dragged them up on the rocky beach, then proceeded to KICK them back into the friggen' river. We found some of those fish floating belly up later, they all probably died. The guy said they were "only hatchery dinks", and he didn't want to keep such small ones (7-9 pounds). Granted, some fish will die no matter how well you handle them, but I found this pretty disgusting.
Greg