Made in N.C.

Made in NC: Oyster farmers work to propel aquaculture in NC

dblustein@newsobserver.comAugust 18, 2013 

  • About the series

    North Carolina has lost hundreds of thousands of manufacturing jobs in the past two decades, but people still make a vast array of goods here. We’ll visit some of them this summer.

  • The benefits of oysters

    In addition to boosting jobs and food production, the oyster plays several very important roles in coastal waters:

    •  Water filtration: As filter feeders, oysters clean water of toxins and chemical pollution, filtering up to 60 gallons of water per day.

    •  Shoreline stabilization: Oyster reef structures stabilize shorelines, reducing erosion and providing a buffer during storms.

    •  Fish habitat: Oyster reefs and farms support a wide range of other marine organisms including shrimp, crabs and commercially important fish species such as drum and grouper.

— The bays and sounds of North Carolina once yielded hundreds of thousands of bushels of oysters a year, before pollution, overfishing , disease and other factors caused their populations to decline.

Now a small group of scientists and growers is laying the groundwork to revive the industry by cultivating oysters in cages and bags. So far, oyster aquaculture has produced modest returns in North Carolina, accounting for less than 21 percent of a $2.9 million oyster industry.

But proponents look north to Virginia to show what’s possible. There, the state has invested heavily in developing strains of oysters that do well in aquaculture, and production from oyster growers has increased by more than 35 times since 2005.

“They’re going crazy with producing oysters right now,” said Marc Turano of N.C. State University and N.C. Sea Grant, an organization that supports coastal activity.

Nearly a dozen fish and shellfish are now raised through aquaculture in North Carolina, including trout, catfish, tilapia and even sturgeon. But unlike most other species, which are raised in tanks inside buildings, oysters are cultivated in the same public waters where wild shellfish live.

That means the benefits of oyster farming go beyond the farmers, who can attain year-round, large-scale production without relying on natural stocks that continue to dwindle. The oyster also helps the environment by filtering water, stabilizing shorelines and providing habitat for other commercial fisheries.

But oyster farmers face challenges, including storm damage, disease and theft. Meager state support to develop domesticated oyster lines and the interests of coastal landowners also put pressure on the industry.

From larvae to market

Raising oysters is intensive, hands-on work. What eventually becomes a 3-inch oyster on a dinner plate starts out as a microscopic swimming larva.

Joey Daniels, who started oyster farming operations for the Wanchese Fish Company near Manteo, buys the tiny larvae for his nursery, 7 million at a time, which he puts in tanks with downward current to coax them to settle onto pieces of ground up oyster shell.

About 10 percent of the larvae will develop into oysters of about 6 millimeters in length that he puts out on his 9.5-acre farm. As they grow, Daniels, 40, often sorts them by size and redistributes them into different bags and cages that have the mesh size and space necessary for the oysters to thrive. About half of the baby oysters will grow to market size on the farm.

A more expensive but less intensive approach is to skip the nursery process and purchase baby oysters. Ranging in size from a few millimeters up to an inch long, the oysters are big enough to be put directly out on a farm. Farmers who purchase larger oysters hope reduced mortality offsets the increase in cost, said Craig Hardy, a section chief at the state Division of Marine Fisheries.

Many oyster farmers in the state use domesticated lines of oysters from Virginia to stock their farms.

Scientists at the Virginia Institute of Marine Science use selective breeding to develop oysters that grow quickly and resist disease, coveted traits for any farmer. These oysters usually have an extra set of chromosomes that renders them sterile so they grow without expending energy on reproducing.

But the selected lines of oysters from Virginia don’t always do well in North Carolina waters, said Ami Wilbur, director of the shellfish hatchery at UNC-Wilmington.

In 2011 the state-built hatchery opened to support the industry and develop its own domesticated oysters. Last year, Wilbur gave oysters to four North Carolina farmers, and next year the farmers will return the biggest and best oysters to her for selective breeding.

Salt to taste

The perfect oyster is a matter of personal preference. “Bitingly salty” or “subtly buttery” are some of the flavor adjectives, as detailed as a sommelier’s description of a vintage pinot noir.

An oyster’s flavor is shaped mainly by the salinity of its habitat, and some say by the plankton it filters from seawater.

Oysters can tolerate a wide range of salinities: They’re found from the brackish Neuse River estuary to salty inlets closer to the open ocean, such as on Daniels’ farm, near Oregon Inlet. Oysters taste like “the last thing they drink,” he said. And with salinity levels changing with the tide, a farmer has control over how the oysters taste coming out of the water.

“You can just wait and take ’em out on the right tide and you should have what you want,” Daniels said.

A process called “wet storage” even lets farmers pull oysters out of the water and store them in salted, refrigerated tanks to carefully adjust their salt profile.

Jim Swartzenberg, 72, a farmer from Jacksonville, thinks that areas such as Stump Sound with lots of algal growth make for a better tasting oyster. But taste preferences vary wildly, and some say detecting subtle differences in oyster flavor requires side-by-side sampling.

Farmers also strive to produce oysters that are popular with consumers by using techniques that create consistent shapes, deep and meaty cups, and clean shells.

Jay Styron, 46, grows his Cedar Island Selects in partially submerged bags that float at the surface attached to lines hanging between two vertical poles about 300 feet apart.

The wave action near the water’s surface causes the shells to rub together. As they bang against one another, the lips of the shells get knocked off, like the pruning of a bush, said Turano of NCSU and Sea Grant. This causes the oyster to grow deeper rather than longer.

Daniels has had success growing oysters in triple-stacked submerged cages. To encourage deep cups, he runs his oysters through a tumbler several times during their 1- to 2-year growth cycle.

“They’ve been purposely beaten up throughout their lives,” he said.

The “containerized culture” techniques these farmers use result in much higher yields than traditional “oyster gardening” methods that rely on bottom harvesting only.

Challenges remain

No matter the approach to farming, when oysters are out on the water, farmers face a variety of challenges in maintaining their crops.

“Our biggest issue is probably storms,” said Styron, of Cedar Island.

Since most of his farming gear is floating at the surface, he’ll occasionally have to tow everything into a harbor before a big storm.

Runoff from developed areas can lead to elevated levels of bacteria that can temporarily shut down an oyster farm after periods of heavy rain. The state’s Department of Shellfish Sanitation monitors water quality, testing thousands of samples each year, and closes areas with high levels of fecal coliform bacteria.

Fouling organisms such as barnacles and boring worms can reduce the marketability of oysters. Farmers can fight unwanted shell growth by intermittently drying oysters or flipping floating bags to provide more even exposure to sunlight.

Devastating diseases, such as the Dermo parasite, can wipe out entire crops.

Moving oysters forward

But there’s no reason the same sort of economic development going on in Virginia can’t happen here, said Wilbur of the UNC-Wilmington hatchery.

One hurdle to large-scale development in North Carolina is a 50-acre individual or corporation limit on areas that can be leased from the state for shellfish aquaculture, according to Hardy of the Division of Marine Fisheries.

“We have never had anybody really come in and try to do aquaculture at industrial scale,” he said.

A moratorium on shellfish leases in Core Sound east of Beaufort, pushed by some coastal landowners, has limited opportunities for fishermen in that area.

But Hardy says that there are still plenty of suitable areas for aquaculture available. He and other officials say the future of North Carolina’s oyster aquaculture industry will be shaped by the success of a small group of farmers using new techniques.

“I really hope that there can be an outgrowth of those few to demonstrate to others that this is a viable industry and that the industry can grow,” he said.

Next week: Beer

News & Observer is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere in the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

Commenting FAQs | Terms of Service