When you fish barbed, double 2/0 hook bait setups in saltwater, you're going to kill more salmon (especially coho) than you would using single, barbless hooks in freshwater. It's not just about the hooks and barbs (although those are certainly factors); salmon drop scales like crazy when netted and boated in saltwater, so they survive a lot of releases poorly. That's the reason for the "keep them in the water for release" rule. Once they're in freshwater and their scales have hardened, salmon become much harder to kill with reasonable handling. I see a lot of poor handling, and that's a concern, but I do think C&R could be an effective tool for maximizing freshwater opportunity.
In the saltwater, I think bonking the first two salmon you catch would probably be the best conservation/season extension strategy, but that requires leaving good fishing on the rare occasions when you find it, and who the heck wants to do that?
To
@Salmo_g 's point, classification as "food fish" has a lot to do with why C&R salmon fisheries aren't common round here. The commercial stakeholders (tribal and non) are strictly fishing for food, and they tend to oppose management that extends sport seasons at the expense of the market. Indeed, even a lot of the sporties out there during salmon season are trying to fill the freezer, so that makes about 2.5 out of 3 stakeholder groups that prefer to manage salmon for maximum harvest versus length and variety of opportunities.
Personally, I'm all for using C&R as a tool for maximizing freshwater salmon opportunity. I only harvest a handful of salmon in an exceptional year; I prefer catching them to eating them, if only slightly.
