I gaff all striper I'm planning to keep, but not in the body - in the bottom lip. The main reason I don't gaff in the body is because I don't like getting the boat bloody b/c that means using the washdown more and when its cold I do NOT like using the washdown!
I do gaff a realeased fish. *For those I grab them by the lower lip and gill plate, remove the hook and send them on their way.
My wife caught this 30lber (her first) 2 winters ago on our anniversary trip at Oregon Inlet NC: