This porcupinefish looked like it had been in the wars somewhat. It doesn't show up well in the photo but the white patches were in fact a deep, deep cut in a crescent shape and a series of lesser cuts above the eye. Looked at from a better angle they basically form a fresh semicircular scar about 8 inches across. It doesn't take a genius to guess shark in this situation and that may well be what caused it. Of course porcupines have a defense mechanism so he may well have escaped having been bit.