Free: Contests & Raffles.
It depends on the method of fishing. Methods that dont endanger the fish other than the fight makes releasing them easy. Bait is a no go as it increases the odds of more harm to the fish.
I think any fish species that is threatened or endangered should just be left alone and not played with by the C&R generation. Never could understand why anyone would want to spend the time and money to stress a fish out, kiss it on the lips and send it on it's way.