I thought I posted here yesterday but it looks as if that one got lost in space. That was way early in the discussion and I see that what I said has been covered now at great length. I'm pretty sure you'll agree with me that whether or not a fish is bleeding at the time of release there is another very important factor when considering post catch mortality. To encapsulate the thought I'll simply say this, use a heavy enough leader so that fish can be brought to net - hand - shore, whatever quickly. I have been practicing what I preach for many years, from the lower 48 to here. I've seen people fishing for huge steelhead with a 4 pound leader and nymphing trout in swift waters with 6 & 7 X tippets. I have reached the point where I feel that If I need to go to some extreme in light leaders or fly sizes just to catch a fish, then that fish was not meant to be caught and released.
Some may scoff at what I put forth but I can assure you that once you get past the 'I have to catch that fish no matter what' point, you may see the sense in what I suggest. While it is true that some fish may shy away from an 8 pound strand of fluorocarbon, when you do hook up you just reel the fish in. Of course the hook may pull out if you rush too much but what you don't worry over is the leader breaking because it's a 3 pound test or less, with a 5 pound fish attached. Some fish that are hooked badly will need to be killed or if released they may die due to the injury or an infection due to same. What I don't struggle with is the thought that I am somehow torturing the fish because of some long protracted 'fight' that we were raised to believe is the coolest part of catching fish. To me the cool part is catching them and being able to do so with very little in the way of theatrics.