I cut their throat immediately and bleed them (over the side of the boat on a tail rope), put them on ice, skin them and they taste great. I remember in 1970’s when akingfish were used as cat food and never available in fish shops as no one would eat them -different story now.
my wife crumbs them in Panko bread crumbs and lightly fry’s them for 2-3mins. They are good eating, mind you, I don’t like break and really only like Kingfish, blackfish, Dolphin fish, flathead and Mulloway. Catch plenty of other species, but give them away.