As the Martha’s Vineyard Bass and Bluefish Derby rounds into the final week, those anglers on the grand leader board are preparing for a little white knuckle fishing as their competitors, more than 3,000 of them, try to knock them off the top spot.

One person who can feel fairly secure is Ray Cabot.

Mr. Cabot’s bonito, weighed in this past Sunday evening, was the talk of the weigh station at 11.75 pounds, the second largest bonito to hit the scale in the history of the tournament. The derby record for bonito is 12.44 pounds, caught by Gary Look in 1994.

Ed Jerome, the longtime derby president who died unexpectedly last month, was fond of saying it only takes one fish to win the top prize. Mr. Cabot, an executive at a private prep school in New Jersey, may well prove him correct. He got in exactly one day of fishing after driving up to the Island to visit his parents Dan and Nancy Cabot, who live in West Tisbury.

“This is the first and only fish I’ve weighed in, in the derby,” Mr. Cabot said Tuesday. “I’ve fished the derby a couple of times as a kid, but living in New Jersey and working in the school business, it’s hard for me to sneak away in the fall. I made the effort to drive up this year, and if I’m only going to weigh in one fish, that’s a pretty good one.”

Mr. Cabot said he was fishing with his brothers and his nephews aboard a boat Sunday. They had a rotation set up. Both of his brothers had already caught a bluefish, when it was his turn on the rod.

“The rod went over and the fish went on a pretty good run when we first hooked up,” Mr. Cabot said. “Everyone in the boat assumed it was going to be another bluefish. When we actually got it close to the boat and looked down in the water, and saw first of all that it was a bonito, and second of all how big it was, I think there was both instant panic and instant exhilaration.”

He landed the fish safely, and immediately started dreaming big.

“When that fish came over the rail and was down in the boat we all kind of looked at one another and at least in the back of my mind, thought that might be a fish big enough to win the derby.”

It was quite an event for the Cabot family. There was a predictable reaction when Mr. Cabot came to derby headquarters in Edgartown to weigh the fish.

“It’s the closest I’ll ever get to feeling like a rock star,” he said. “Put it on the scale and the numbers kept going up. The crowd kind of gasped and it stopped at 11.75 pounds. It was a big moment.”

The derby runs until 10 p.m., Saturday, Oct. 13. The following day an awards ceremony is scheduled at Farm Neck, which is open to the public. One of the grand leaders in the shore category will win a Cape Codder fishing boat, and one of the grand leaders in the boat categories will win a Subaru Forrester from Clay Suburu.