Releasing that overly large female trout kept that egg producer in action. If he had killed it, Ida shook my head and sighed - she probably produces 1,000,000 eggs at a pop. We catch and release some when fishing. My first goal is dinner, too small and big breeder fish go back in.
I don't think laker is bad, not much diff from other trout. Once fish reach "too big" size they get fat layers between the meat and taste yucky - grouper especially.
As for tranquilizing an animal for photos... Either you want to shoot, kill, and eat it or you want a photo. You can take amazing photos without risking harm to the animal.