Lots of good info here on FRIM and as others have stated the past research / studies on C&R mortality have varied greatly! I recall a study done up at Langara 20+yrs ago with guides/net pens showed something like a 2-4% mortality, whereas others claim it's over 50% as has been mentioned earlier in this thread. It's a complex issue to study but with the technology available today I think with UBC study and others are going to give a much more accurate picture of the impacts of C&R fishing on the survival of salmon.
One other interesting factor just to complicate these studies is the issue of cumulative effects. ie. what else could be impacting the fishes survival rate? Warming waters? Poor nutrition? Disease / pathgens? Many other factors to consider and this is all being considered by those doing the work right now.
Looking forward to SFI's best handling practices when it comes out. The one thing I can say is that all us rec fishers need to understand we don't have all the answers. What was considered best practices a while back might not be so today. We need to let the research speak for itself and adapt as new research comes in. None of us want to kill salmon we don't intend to keep but I can safely say that I, and most I fish with, have not always handled fish / caught fish / released fish / etc if the best interest of the fish. One quick example is that I had always been taught that reviving a big salmon boatside after a good fight is the best way to ensure it's survival.... Well, according to the survival stats from this UBC study to date this is not the case. Best to not handle the fish at all... even if you were handling it in the water to revive it. Anyways, i'm sure there will be lots of good results to come and I hope everyone who fishes reads them and acts accordingly as this whole FRIM issue is one that many groups are using to try to further shut down rec fishing on the coast.