Congratulations to the crew of the Whoo Dat with a 712 lb Blue Marlin !
As for the 13 hr fight; fish are like people, some in better shape than others. 13 hrs s very possible, but the fish was probably dead and they may have had to plane it up from deep water a few feet at a time. If this was the case, they are damn lucky to have landed it and not broken the line or straightened a hook.
I know these guys and they play by the rules and have always been honorable fishermen--- hats off to yah guys! Nice fish.