I take out every one that I catch, and throw them up on the bank. Over the course of a given year, I might remove 40 or so.
As far as how old these fish are, i really don't know. I'm guessing 4-5 years old.
Excerpt from Robert Crais' "The Monkey's Raincoat:" "She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."