SOUTH KINGSTOWN — In seven years, Perry Raso has grown his business sevenfold.

Matunuck Oyster Farm started as a 1.3-acre aquaculture operation, grew to 3.8 acres and then to 7 acres last year. It is in wading-depth water off the southern shore of Potter Pond, a salt pond connected to Point Judith Pond.

Raso, who earned a master’s degree in animal and veterinary science at the University of Rhode Island last year, grows oysters, littlenecks, steamer clams and bay scallops.

During his first year of farming oysters, Raso had none to sell. Getting a harvest of oysters after buying “seed” stock takes at least two years — sometimes longer.

But last year he sold 400,000 oysters, his largest annual harvest. He also sold 50,000 littlenecks. “They’re more difficult to grow, and they are worth less on the market,” he said.

Aquaculture is a seven-day-a-week job, he said. During the winter, two employees work in the water with him. They maintain the shellfish beds and harvest daily — sorting, scrubbing and shipping shellfish to wholesale distributors and restaurants around the country.

Chef Todd Lesakowski, of the Coast Guard House restaurant in Narragansett, described Matunuck Oysters in Providence Monthly Magazine as “incredibly clean tasting, very briny, with a surprisingly sweet finish.” Several restaurants throughout the state sell Raso’s oysters, and they are also available at Whole Foods and at the Hope Artiste Village farmers market on Main Street in Pawtucket every Saturday morning, even during the winter.

Rhode Island has 27 aquaculturists, Raso said, adding that a small group of them in South Country work cooperatively to ship shellfish and are planning to form a more structured co-op soon.

Wholesalers handle about 85 percent of the growers’ harvest.

Besides growing shellfish for sale, Raso conducts group farm tours and educational field trips year-round.

Visitors are given chest waders so they can immerse themselves in the experience.

“With our tours,” he said, “we hope to encourage our visitors to take an active interest in supporting local aquaculturists and farmers….

“The farm’s educational component is to help people make better decisions about aquaculture,” he said. “Maybe they’ve only heard negative things.

“The wild-salmon industry has done a great job of making aquaculture a bad word. I’ve see the results directly at farmers markets. A lot of people will come up and say, ‘I don’t want anything farm-raised.’ A farm-raised oyster does plenty of good for the environment, providing a filter and habitat value. It’s important from an industry perspective, to get that word out.”

Raso buys his seed — more than a million one-millimeter baby oysters — and grows them in tubes until each is about 20 millimeters long. Then they are transferred to plastic-mesh bags made in Spain. The bags are arranged in rows, as potatoes would be on a terrestrial farm.

“There are other similarities to traditional agriculture,” he said. “You buy the seed, you plant the seed, you thin the stock. Then, like a livestock farmer, you take out the market-size animals.

“On a traditional farm, you have silos where you keep your feed. On our farm, the silos are where we keep juvenile oysters. Weather has a big impact on the crop and how it grows — sun and temperature come into play…. We’re at the mercy of mother nature,” Raso said.

A narrow barrier beach separates Potter Pond from Block Island Sound. If the ocean were to breach the beach during a hurricane, it could devastate Raso’s farm, he said. Ice on the pond can lift gear off the bottom and damage it.

“Starfish and crabs can do a number on your crop,” he added.

Diseases also affect shellfish. Raso and other aquaculturists in the state are working with researchers at the University of Rhode Island to identify and breed disease-resistant stock.

Raso generally leaves the farm on Saturdays so he can get to the farmers markets. Like many of the other growers there, he said he’s selling more than what he grows. He said he’s there to educate customers about the value of local foods and farmers.

“Knowledge of renewable resources, he explained, “can lend to an invaluable contribution to many aspects of society, both social and economic.”

To contact Raso about group farm tours, e-mail: perry@rhodyoysters.com

tmeade@projo.com