A huge 454-pound blue shark was caught during the tenth annual Oak Bluffs Monster Shark Tournament held over the weekend. The shark could be the largest blue ever caught, a world record.

The shark was caught by Pete Bergin of Shrewsbury in his boat Quality Time. Mr. Bergin's boat was one of 65 participating in the Boston Big Game Fishing Club's annual event. Competing boats filled the Oak Bluffs waterfront for most of the weekend. On Friday and Saturday a large number of fish were caught, and even more were released.

Greg Skomal, an expert on sharks, said he expects the tournament's largest shark, measuring 11 feet, three inches, to break a record set in 1976, when a 437-pound blue shark was caught off the Australia coast.

Mr. Skomal said it took more than six hours for the captain of the boat to bring in the fish. Mr. Skomal, a fisheries biologist with the state Division of Marine Fisheries, is one of the top authorities on sharks.

Blue sharks are a common fish in the oceans of the world. Mr. Skomal said the big one was caught at least 20 miles south of the Vineyard using the popular technique of chumming the waters with pieces of fish.The blue shark is a perfect recreational fish. It is fairly common in the open ocean, inedible and awfully angry when caught. "They feed primarily on squid and small fish, bluefish if they can catch them. They have been known to feed on the bottom on skates," Mr. Skomal said.

This is not a scavenger hunter. This is a fish with enormous sharp teeth that likes its meal fresh and alive. "They grow rapidly," he said. Mr. Skomal estimated this shark is probably 16 years old, as old as they get. While there are many species of shark that fisheries scientists and managers are concerned about, Mr. Skomal said, the blue shark appears to be in healthy numbers. No one eats it. So, the blue shark is the mainstay for shark tournaments in Massachusetts and off Montauk. "This is the bread and butter of the recreational shark fishery and fun to catch," Mr. Skomal explained.

While these sharks appear south of Vineyard waters in the summer, in the winter they migrate south and east. "By the end of October they move south," he said.

Blustery weather on Saturday cut into the success of the tournaments. There were only five boats that went out.

Mr. Skomal said for all the fishing on Friday and Saturday, there were 22 sharks brought to the dock and weighed in. Emphasis in the tournament is put on "catch and release" fishing. The fishermen are limited to a 300-pound minimum size and that means a lot of fish were released. The mako shark minimum size in the tournament was 200 pounds. Mr. Skomal said that 740 sharks were released. "They were mostly blue sharks. Four makos were brought to the dock and all of them were undersized."

Mr. Skomal said the water temperature was a key factor in the tournament and probably accounts for the large number of blue sharks caught.

Rene Ben David, the Oak Bluffs marina manager, said: "Last year we had thresher sharks caught in the tournament. I think the water temperature was too cold for thresher." He said the water tempeature offshore was around 64 degrees. "Normally it is 68 or 69 degrees."

The tournament ended with an awards ceremony Saturday night at Lola's Restaurant at Harthaven. Plaques were handed out. Even though Mr. Bergin caught the biggest shark, he did not win the tournament. Winners accumulate points by catching more than one shark. Mr. Bergin only caught one fish and so he fell into second place.

First place went to Reel Good, captained by Tom Good, from Fiddler's Cove. He caught a 356 and a 305-pound blue shark. Third place went to Indian Princess, captained by Bob Sylvester from Maine. He caught a 407-pound blue shark.

"Now we must get ready for the next fishing tournament," said Mr. Ben David. In August there will be another deep sea tournament, the Shark's Landing Shootout. It takes place from August 15 to 17. The fishermen will compete for the largest mako shark and the different varieties of tuna. There is a purse of $12,000. First prize in the contest is $6,000.

Mr. Ben David said they've already set the dates for next year's 11th annual shark tournament, from July 24 to 27.