I like the In-Fisherman approach published many years ago. In effect it proposed a C&R limit that assumed a certain number would die "even under the best conditions." It realistically asks, "How many fish do you want to kill or risk killing?" For example, assuming an 80% survival rate, your C&R limit is 10 to avoid killing more than two. A lot of guys are bothered by the math or do not believe any of the fish they release will die. So it is a hard sell. The last time I tried, I was accused of being an ignorant butcher who did not know how to remove a hook.

My pet theory on C&R adds a genetic component. If there is an aggressive gene or genetic makeup in fish, we probably catch the more aggressive fish. If these are killed, the remaining gene pool becomes less aggressive. In effect the fish become harder to catch. The coin has another side. There may be a shy or cautious gene. In that case if we take out the normal fish, we are left with a very skitish population again hard to catch.