Salmonbelly, I too am concerned about the number of fish being hurt by C&R out in the salt. Here's a couple of things that I personally do that you might consider... these are just things to think about... to each his/her own...
First off, I don't use double-hook setups in release fisheries. IMHO, single Siwash hooks do less damage than double-hook setups. I'm not claiming single Siwashe setups hook as many fish as double hook setups, but single Siwashes definitely make it MUCH easier to shake / release unclipped or unwanted fish.
For the same reason, I don't use bait. I still catch plenty of fish, but I probably don't kill as many, because they aren't hooked as deeply... and, since most bait hookups involve two hooks, they also aren't hooked in the side or top of the head as well as the mouth.
When playing a fish, I keep my boat in gear, and keep the fish coming to the boat... a wise man (Larry Williamson) once told me - if you lead them, they will come (unless we're talking 25lb+ fish). As soon as you let them turn their head, they will start to shake their head, roll around, get tangled in everything they can... and end up damaging themselves in the process. I keep my boat in gear, keep the fish moving, don't let people pause while they're reeling, and the fish come right to the side of the boat, where I can check for the fin and release them quickly if neccessary.
I use a catch-and-release net. It's got a soft, fine mesh, similar to the catch-and-release trout nets, but the mesh size is a bit bigger, and the net is normal salmon net sized, with a 36" deep bag. When I do net a fish, I see little to no scale loss in the net... I mean NONE... like I don't even have to rinse the net out in the water... it's amazing. Because of the small mesh, these nets are a little different when you dip them in the water... they have a LOT more drag... but once you get used to it, they work great.
I often times will not release any fish that are legal to keep... this may sound stupid, and some people may look at me wierd at the cleaning table with a couple of 3lb hatchery fish as part of our catch, but in the end, I'm killing less fish, and it's my choice. I could release fish all day and cull for the biggest fish, but how many fish am I going to hurt / kill in the process? It all depends on the day, and who I have fishing with me.
And this last one may sound like a plug, but it's really not meant to be. I use Salmon Scenters all the time. I think they work great on targeting hatchery fish, and I believe I catch more fish because I use them... and we all know how important "fishing with confidence" is. I've been keeping track the past four weekends while fishing Sekiu, writing down every fish we catch... and over four weekends, I've had a 47% clipped rate on fish to my boat, with a 67% clipped rate this past Saturday. I'm not sure what other people are averaging, or if they're writing down every fish, but I've heard 10%-20%.
-N.