Branford - In a first for Long Island Sound, 120 pounds of kelp farmed in waters near the Thimble Islands has made its way to the plates and soupbowls of New York City restaurants.

"We're the only one in the country selling a fresh kelp product," said Bren Smith, owner of the Thimble Island Oyster Co., which grew the long, wide kelp ribbons on a 20-acre plot where he also raises oysters, mussels and clams. "It has a short shelf life, but because I'm close to New York City, I can sell it directly there."

Margaret Van Patten, communications director of Connecticut Sea Grant, said the sale is significant because it marks the first time seaweed farmed in the Sound has been sold as a food product.

Sea Grant, based at the University of Connecticut's Avery Point campus in Groton, worked with Smith, as did Charles Yarish, a UConn professor of ecology and evolutionary biology who has been involved in seaweed research for decades. Before the sale took place about three weeks ago, Smith had to obtain permits from the state Department of Public Health and the state Department of Consumer Protection. The kelp was also subjected to product safety tests, which required the purchase of new equipment that was funded by Sea Grant.

"Now that this has proved successful, Sea Grant is going to be looking to work with more people who want to grow this crop," Van Patten said.

David Carey, director of the Aquaculture division of the state Department of Agriculture, said the permits created for this new crop specify that it can be grown only in areas also approved for shellfish farming, so it must meet the same water quality standards.

"We're excited about this," Carey said, adding that he sees potential for former lobstermen who lost their livelihood when the lobster population declined to repurpose their boats for seaweed farming.

"Their boats would be the perfect size," he said.

To develop this market, he said, more research and investment is needed in economical ways of processing seaweed and increasing the market.

In addition to the permits and testing for the fresh product, Smith has also obtained the approvals to blanch, freeze, package and sell processed kelp. He is using facilities at the Bridgeport Regional Aquaculture Science & Technology Education Center for the processing.

Chefs in New York are using the kelp in soups, salads, butter and some Nordic cuisine dishes, he said. Some are also working to develop dishes such as kelp ice cream, cocktails and pickles. The kelp he is growing, raised from native seed stock originally from a site off Pine Island in Groton collected by Yarish, is not the type of seaweed used in sushi dishes. While the markets and uses for local kelp are still emerging, he said, it was more commonly eaten in past decades.

"We're trying to reclaim a very old tradition," he said. "It's a really good local food."

He is also selling his harvest to Yale for use as a fertilizer on its farm. Over the next few months, he plans to triple his kelp production and try to grow other types of seaweed.

Smith said he turned to seaweed farming after 80 percent of his shellfish crop was wiped out by Hurricane Irene and Superstorm Sandy. He started doing research on the Internet about other crops he could grow in his shellfish beds, and came across references to Yarish and his seaweed research.

Yarish said Smith's success "will open people's eyes" about the potential for seaweed farming in Long Island Sound. Several areas in the eastern Sound would be suitable, he added. Areas with good water quality and water depths of 20 feet to 100 feet are required. To help foster interest in others starting seaweed farms, Yarish is working with Sea Grant to develop a kelp cultivation manual.

The kelp Smith is growing, known as sugar kelp, "is the same stuff you find walking at Ocean Beach Park.

"This is local, high yield and sustainable," Yarish said.

Yarish is growing different types of seaweed at sites off Fairfield and in the East River near New York City, among others. In addition to promoting it as a highly nutritious food, Yarish said he and UConn are also partnering with a Shelton-based startup, Sea Green Organics, on an organic seaweed-based fertilizer.

j.benson@theday.com