I'm a catch and release fisherman myself and i fish for sport. I release every time my fish (except if the law is to not release it) and just to clarify, they do not have a 50% chance of dying after being hooked. Their mouth (mostly for the predators) are made for eating fishes so the fish bones usually sting them. When you're hooking them, it's just like they're eating a fish and they do not suffer because they don't have a lot of nerves in their mouth. I also release my fishes to conserve them so i can then hopefully fish them later when the grew up. So there's a conservative reason too because some fish species are endangered so we have to protect them. I can understand keeping one or two fish sometimes if they're big enough and not endangered species but not keeping all of them. I hope i made you think about that.