We were tuna fishing about a mile off shore and we were catching 30lb tuna on live sardines, using 35lb fluorocarbon leader and 40lb line. Suddenly, I had a big hit, and the fish went deep. "Victor! I have a big fish on!", I yelled. Victor yelled back, "BIG TUNA!" A few minutes later the fish began to come up to the surface! "Victor! I think it is a marlin!" "Nooooo, BIG TUNA!", Victor yelled back as he was baiting another rod. And then, that bad boy showed himself. We could see him about 50 yards out, in clear water, all lit up and iridescent. He was a big fish, that was for sure. Suddenly it was Victor who yelled out, this time in his Mexican accent with, "SH_T! BIG MARLIN!" Now, this was the only time that I have ever heard Victor use profanity. But, it was justified because that marlin was in the 500lb class! I fought him for about 90 minutes, very careful not to put too much stress on the light line. But, I don't think he ever even realized that he was hooked. He just moved around the boat at will, then headed deep. Finally, I started to put some pressure on him, in an effort to turn him and bring him up. And "boing" the line broke at the hook. The biggest blue marlin that I have caught was about 250lbs. This one would have doubled my personal best!