Warren Doty stood atop a small blue cooler, beckoning the crowd at the West Tisbury Farmers’ Market over to the side of the Grange Hall last Saturday like a ringmaster at the circus. As the crowd grew larger, people peered over each other’s shoulders, curious as to what the secret ingredient would be. Home Port chef Johnny Graham stood on Mr. Doty’s left, and Sidecar chef Kyle Garell on his right. The two were about to cook head-to-head in the first challenge of its kind on the Vineyard: a seafood throwdown.

Could it be halibut? Sole? Scallops? Mr. Doty, president of the Dukes County, Martha’s Vineyard Fishermen’s Association, hopped off the cooler, opened the lid and presented to the crowd the local fish the chefs would be cooking with: fluke, caught that morning by Greg Mayhew.

The chefs were given $50 to buy produce from the farmers’ market, 15 minutes to shop, and a little over an hour to cook. After preparing two dishes for the judges, a pan-seared fluke paired with a Peruvian potato pancake and a separate filet with a pineapple-wasabi salsa, Mr. Graham won this round of the Vineyard version of Iron Chef. Mr. Graham scored a total of 92 points from the judges; Mr. Garell earned 89.

“It’s fun to get out of the kitchen and great to walk around the market,” Mr. Graham said. “I couldn’t fit it all in one dish so I decided to do two. There’s so much great produce out there.”

Johnny Graham and Karen Ambrose of Home Port. — Mark Alan Lovewell

The throwdown was sponsored by the Northwest Atlantic Marine Alliance, which has sponsored events like this up and down the East Coast. “There’s a lot of good conversation going on, people are asking questions,” alliance director Niaz Dory said. “We want people to shift their consciousness of the market through activities like these.” The alliance is involved with communities like the Vineyard to promote eating local fish and supporting local fisheries by educating people about seasonality of fish through activities like the throwdown.

“This is exactly the conversation we wanted to start,” Ms. Dory said.

The chefs maneuvered through the crowded farmers’ market, dodging strollers, darting back and forth between stalls, careful not to run into a fellow customer. They were respectful and didn’t cut the lines at Mermaid Farm, Stannard Farms, 7a Farm, Morning Glory Farm and Bob Daniel’s stall. They bought eggs, corn, potatoes, tomatoes and the like; Mr. Graham even bought fresh lobster and cooked it in a broth with a whole fish.

Warren Doty and Greg Mayhew reveal secret ingredient. — Mark Alan Lovewell

Chefs were judged on taste, creativity, presentation and use of the entire fish. After returning from what seemed to be a market jog, the chefs enlisted their sous-chefs to start filleting the whole fish, chop vegetables furiously, and begin to heat up their pans. The alliance provided two tents that held a portable grill, a three burner-oven top, and water coolers for the chefs to rinse out their cooking utensils. The rest was up to the chefs.

Market shoppers drifted in and out of the area to watch the chefs get into their rhythm; the chefs stayed cool under pressure until the last few minutes of the competition. “What were your three ingredients you brought from your kitchen?” asked one observer, referencing one of the allowances to the competition. “Milk, butter and flour,” Mr. Garell said. “Pineapple, wasabi and balsamic vinegar,” replied Mr. Graham.

While the two chefs cooked, Mr. Doty spoke to people about the properties of fluke and other local fish. Between presenting a whole fish to onlookers, he promoted the fishermen’s association’s new wild-caught logo, promoting fish such as fluke over farm-raised fish. “We didn’t want to disrupt the market but we wanted to encourage the idea that seafood and the farmers’ market go together,” Mr. Doty said. “We might even expand seafood at the market in future years.”

“He’s a tornado, you don’t know what’s going on,” one of Mr. Graham’s fans said from the crowd of onlookers. “Kyle lucked out because fluke is one of his favorites,” Sidecar Café owner Scott Mullin said. “We’re psyched to be here.” Waitresses from the restaurant had gathered around Mr. Garell to cheer him on as he made melt-in-the-mouth corn chowder alongside his fluke fillets.

“It’s really fun,” Mr. Garell said, adding to a broth he had on the stovetop. “I kept my head down the whole time and didn’t even notice the crowd. I feel good about my food.”

“We want people to know that locally caught is the best way to go,” said Chilmark selectman and commercial fisherman Jonathan Mayhew. “It’s Saturday; we can’t fish [commercially] on Friday and Saturday for fluke, that’s why we’re here and not working,” he said.

“We’re trying to emphasize local fish as a good thing to eat rather than it traveling long distances to your plate,” his brother Greg Mayhew said. “It’s a great fish for people to get. Much like a farmers’ market, you’re helping local fishermen, you’re getting fresh fish and it tastes good.”

Fishermen’s association’s new logo promotes local catch. — Mark Alan Lovewell

With four minutes left on the clock, Mr. Graham had already begun to plate his dishes; in the last minute, Mr. Garell presented his filet of fluke beautifully on square plate. The crowd cheered on the chefs in the final seconds and Mr. Doty sounded the horn.

“Very good,” one observer said after making his way to Mr. Garell’s station. The crowd remained civil, waiting in line to taste the chef’s creations. “It’s just fine,” said another. “It’s fluke and potatoes. You can’t go wrong.”