In a fishery with a minimum size restriction, it is important to make every attempt to reduce the time that a fish is stressed in order to release it with any chance of survival. Fishing with undersized tackle is as irresponsible as hunting an elephant with a 22cal rifle. Can you kill it, certainly the answer is yes with given time. We need to ask ourselves if killing everything that bites our hooks is the intention?
Then there are numerous reason why a 50w is not sufficient for a large fish, but the other guys have already posted that.
Responsible fishing means making every attempt to harvest the largest of the intended species while having consideration for bycatch. Breaking a fish off with 300 yards of 50# dragging behind it is a death sentence for that fish.