The Wednesday night weigh-in at headquarters for the Martha’s Vineyard Striped Bass and Bluefish Derby appeared to follow a familiar pattern. The first fish of the night was a bluefish, followed by a striped bass, then a bonito. Then came a cooler full of blues, with a striper thrown in for good measure.

But something was missing, at least until David Kadison of Vineyard Haven stepped up to the table with son Dylan. There was no mistaking the iridescent gleam of the sleek fish that weighmaster Joe El-Deiry was about to place on the scale.

“There’s one,” someone in the large crowd of onlookers said. “The elusive false albie.”

“We should give you something just for bringing one in,” weigh station administrator Amy Coffey told Mr. Kadison.

Mr. Kadison’s fish was the first of eight false albacore weighed in on Wednesday. For the first four days of the derby, only one albie had made an appearance — Philip Albertson’s 10.04 boat-caught fish, which remains at the top of the leaderboard. By contrast, 101 bluefish, 47 striped bass and 41 bonito had been weighed as of Wednesday. “Today [the false albacore] showed up, so we’re relieved and happy,” derby chairman John Custer said on Wednesday night. “By nine [this morning] we’d started hearing reports . . . I think people were starting to get nervous.” It was only day four of the derby, he said, but “people go crazy for albie,” and the speedy fish’s arrival was eagerly anticipated.

Ms. Coffey said that when the first albie reports arrived, they came from both boaters and shore fishermen.

“That means they’re not fickle,” she said. “They’re swimming the Island.”

Nick Welz of Cohasset brought in the first shore-caught albie just after Mr. Kadison weighed in. Mr. Welz’s fish weighed 8.61 pounds and currently stands alone in the division.

Eleven-year-old Katherine O’Brien of Oak Bluffs also stands alone in her division, as the only junior entrant to have landed an albie thus far.

The first week has been a particularly strong one for junior entrants. One contestant, Emma Toomey, age 9, is currently a grand leader in the shore bluefish division. Emma caught her 14.18 pound fish on Monday evening while out with brother Chase, age 6, and her parents. It was a good night of fishing for the Toomey family. Mother Polly reported that Emma landed the blue just seconds after Chase caught a 21.18 pound striper. Chase’s fish was a grand leader for about an hour on Monday before being bumped off. He is still leading the junior division, however.

Staying on the top of a division “can be literally a matter of minutes,” Mr. Custer said.” It’s an everchanging leaderboard.”

Such was the case Wednesday night when Lynne Silva’s 24.34 pound boat striper was bumped to second place a half-hour after weigh-in by Kyle Jeglinski’s 27.33 pound catch. Mr. Jeglinski is a first-time derby participant, and remains in the lead as of Thursday.

Stephen Amaral of Oak Bluffs, who is participating in his 67th derby, is the overall leader for shore-caught bass with a 27.15 pound striper. He has also caught the second largest bluefish from shore. Joseph Diodati is tops in the boat bluefish category with a 14.76 pound catch. Patrick Jenkinson’s 9.34 pound catch leads the way in the boat-caught bonito category. There have been no shore-caught bonito.

“Day one was exceptional,” Mr. Custer said. On Sunday night, he said, lines wrapped around derby headquarters for upward of 40 minutes, one of the longest lines he’s ever seen at the derby. Nearly 1,500 participants are registered so far, with two hundred more waiting to be entered in the computer.

More than 2,700 pounds of fish have been weighed in as of Thursday morning. Registration for the derby continues throughout the event. Super Saturdays begin this week, with bluefish up first as the designated fish. The angler with the heaviest bluefish caught on Saturday, Sept. 21, will win $500. The annual Kids Derby takes place this Sunday, Sept. 22, at the Oak Bluffs ferry wharf from 6 a.m. to 8 a.m. The event is free and no registration is necessary.