I return about 95% of what I catch and only the keep a few fish a year for tea. The rest go back to swim (and fight) another day. It is the way we are all going now, conservation is becoming a major part of most of our angling trips, which can only be a good thing.
I was brought up on freshwater fishing so for me it has always been a catch and release policy as there a chance that you could catch that fish again when it had grown bigger. To me there is no better sight than a fish swimming away safe and sound.