For sure, Blue Marlin can be enormous and best left for fishing boats. I have seen huge Blue Marlin (not good for food) WASTED, thrown in the trash so "sport" fisherman can get their picture taken and bask in triumph at the dock. It's really such an unethical waste. White Marlin, on the other hand, are much smaller and very good eating. They are also often within a few miles of shore and can be caught by fast trolling. They usually are in the 50# range. The sword is certainly a danger. I'd suggest getting a tailrope on any larger fish, leaving it 1/2 suspended, dragging backward until you're sure they're dead. You would not want a billfish (or shark) alive and thrashing in a sailboat cockpit!
Alberg 35: With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship.