As the sport-fishing boat Cookie Too backed into the slip in Oak Bluffs harbor on Saturday evening, nervous chatter rippled through the onlookers who had congregated around the dock.

The Oak Bluffs Monster Shark Tournament had come to a close and the crowd wanted to know: What large beast was hidden in the vessel's stern, and, more importantly, was it big enough to vault captain Cookie Murray and his crew into first place and win the $130,000 grand prize?

The Cookie Too, last boat of the night to weigh in, was 432 points behind the Magic Lady, and thus needed to produce a sizable shark for the victory. The crowd let out a collective gasp as a large tail was hoisted into the sky.

It was a thresher, and judging by its massive, uniquely elongated tail, it was a big one.

So big, in fact, it took an additional tournament staffer to haul the shark up onto the scale.

After calibrating its weight, Greg Skomal, the state's leading shark fisheries biologist, began reading off the numbers: 548 pounds, not only more than enough for the win, but also a new Massachusetts state record for a thresher shark.

The crowd erupted in a roar, capping an unprecedented weekend of shark fishing off Martha's Vineyard.

"It was just an incredible ending that couldn't have been better for everyone involved in this tournament," said Steve James, the weekend's organizer and president of the Boston Big Game Fishing Club. "The size of the event alone was tremendous, but with the weather and the phenomenal fishing, it was simply the most successful tournament in our 18-year history."

More than 125 boats entered the tournament, more than ever before, mixing Vineyard anglers with shark hunters from as far away as Florida.

Boats from Pocasset and Marshfield, East Greenwich and Green Harbor lined the harbor.

The cable television sports channel ESPN was also present, filming the event for a four-part series to be aired in September.

The weekend brought in sharks of all kinds, with a 400-pound porbeagle shark joining the Cookie Too's thresher as new state records. Large makos and blue sharks were also brought in. Only sharks of a certain weight qualified for a weigh-in, with a point system assigned to each species. Blue sharks over 300 pounds qualified for one point per pound; threshers over 200 pounds equaled 1.5 points per pound. Points were deducted for those that did not meet the strict size qualifications.

"Of the thousands of sharks caught this weekend, only around 50 of them were killed," said Mr. Skomal, who oversees the weigh-in and dissection of the sharks. "The rules are designed to protect the species, and it was an incredibly successful weekend in that respect."

Island charter fisherman Morgan Reitzas said this year's event was busier than previous years, citing the increased media coverage and the hefty prize as primary reasons. His boat, the 24-foot Saxxycat, brought in a 223-pound thresher, the only shark he submitted to be weighed in, but he said his crew caught more than 30 sharks over the two days.

"There was a lot more going on this year, for sure," Mr. Reitzas said. "We had a great crew and the weather was nice. We just couldn't find the big ones."

Tom Nee of the Aldenté was participating in his fifth straight year. After landing the biggest mako of the 2002 tournament, the best he could do this year was hook a 166-pound mako. "We'll get 'em next year," he said, smiling.

The boats left the harbor before dawn on Friday and Saturday, a giant convoy of vessels roaring out to sea. Some scattered to the east while many headed south to the fertile fishing grounds where the warmer Gulf Stream currents run off the continental shelf and mingle with colder waters. White hulls dotted the horizon off the Dumping Grounds, a popular fishing spot south of Noman's Land. The boats produced long fishing slicks made with codfish oil and cut bait.

"It was pretty choppy out there on Friday," said Andy van Rooyen, who was onboard the Saxxycat. "But the wind laid down a bit on Saturday and it wasn't as bad."

Tension mounted throughout the day on Saturday as the final points were tallied. At one time, just a single point separated the top two points leaders. Toward the end of the day, Magic Lady overtook Concrete Idea for first place with a big thresher and seized a formidable lead with little time remaining. Cookie Too's record-setting haul, the last fish to be weighed for the tournament, dealt a crushing blow to the crew of the Magic Lady.

"We knew we had a big fish," said Dan Tortora, one of the anglers aboard the Cookie Too. "We caught it around 1 p.m. and figured we had a 500-pounder, but you never know until you get it up on the scale. To win with a record fish is even sweeter."

Mr. Tortora became the first to win the tournament twice. He claimed first place in 1998.

Mr. Skomal praised the tournament as a vital component of shark research. Keeping track of the thousands of sharks caught during the tournament provides him and his staff with crucial data needed to track shark populations.

"The release forms tell a story of over a thousand sharks caught and released this weekend, and that helps us paint a picture of what is going on with certain species," he said. "Only 50 sharks may have been brought in, and the data acquired from them is invaluable, but the sharks that didn't come back give us just as much useful information."

Mr. Skomal noted the abundance of thresher sharks in the waters off the Vineyard this year. In past tournaments, makos have increased in numbers and been the most prominent shark at the weigh-in. This year, however, close to 30 threshers made their way to the scale. "Last year saw a spike in threshers weighed in with 16. I never thought that would be matched," he said.

Mr. Skomal also said that all parts of the sharks brought in were employed in a useful way. All of the shark meat was donated to the Long Island Council of Churches to be distributed among charities throughout the region.

ESPN plans to broadcast the event in four parts on Tuesdays from 8 to 9 p.m. beginning Sept. 28 and running through Oct. 19.