All good points. I am never sure how these studies are constructed when we are given a synopsis of their findings.

Catch and release is far from perfect but catch and kill is 100% mortality. I think how a fish is caught and released is very important. How about barbed versus barbless hooks. I have fished the Montana waters with guides who all use barbed hooks. Sometimes they play hell with getting the hook out and I wonder if the fish ever makes it. I have also seen little effort expended to revive the fish, just get the hook out and dump it back in. Likewise, catching and playing a fish either just for the fun of it or by using tackle that is too light has got to wear the fish out -- only to be followed by unhooking and releasing the fish (either from a net or by releasing without taking it out of the water) without any revival time. What about keeping the fish too long while taking a picture?

How about our ocean waters for Salmon? They often have a size limit and you sure don't know what size you have on until after you have landed the fish -- especially if it is close. Those fish probably get dumped back into the water with little chance of survival. Perhaps having to take the first fish you catch is the way to go, regardless of size (but then you have the upgrading problem).

Interesting topic.