Marine specialists try to restore N.C.’s oysters

Marine specialists try to restore N.C.’s oysters

CorrespondentJune 10, 2012 

What clears up coastal waterways, gives protection to young fish and helps keep shorelines from eroding?

And on top of that, is delicious to eat?

It’s the lowly oyster – Crassostrea virginica – individually and in conjunction with its peers in an oyster reef.

The efficient little eco-worker gulps in sediment-laden water in Carolinas sounds and tidal creeks at the rate of some 30 gallons a day. It keeps the algae and other plankton as nourishment, wraps the indigestible bits of sand and organic particles into a tight ball, and when its two halves snap open and close, they spit out not only the ball but a jet of clear water.

Clear water is not only healthy to fish and a delight to water sports enthusiasts, it gives Mother Nature a chance to go to work on harmful organisms brought in by runoff.

“Sunlight can get all the way through it. Sunlight does a wonderful job of killing bacteria,” says Troy Alphin, co-director with Dr. Martin Posey of the Benthic Ecology Lab at UNC Wilmington’s Center for Marine Science.

Oyster reefs also break up the waves that lash shores of sounds and creeks during storms, hold back eroding shorelines and give shelter to a variety of young marine creatures.

A century of decline

Yet, because of a variety of factors, oysters harvested in North Carolina – variously called Eastern oysters, Virginia oysters and Atlantic oysters – have been in steep decline the past century.

Their delicious taste works against them, says Alphin. Overfishing, plus destruction of coastal habitat, disease and water pollution have shrunk the harvest to an estimated 1 to 5 percent of what it was 100 years ago.

“Most of the time, when you’re eating oysters in North Carolina, you’re eating Gulf Coast oysters,” says mariculture specialist Marc Turano of the coastal research program N.C. Sea Grant.

Bringing back the N.C. oyster, long a priority of the state’s Division of Marine Fisheries, has become a cause for environmental groups, too. They, along with DMF, build reefs of used shells, which are baby oysters’ favorite material to attach to.

Experiments by volunteers and researchers at the Center for Marine Science undergird restoration efforts and aid a budding oyster aquaculture.

DMF builds between 25 and 40 reefs a year and is seeing some success with them, says DMF biologist supervisor Clay Caroon. Harvest statistics have inched upward the last several years, to nearly 200,000 bushels in 2010.

Aquaculture accounts for an estimated 10 percent of that, but North Carolina’s industry is woefully behind neighbor Virginia’s. The N.C. crop in 2011 was valued at $266,055; Virginia’s, $7 million.

Where the wild things are

One way to successfully choose a spot for either an oyster reef or farm is to find out where conditions are such that young oysters, called spat, hang out. Spat have passed beyond the larval stage when they’re tossed around willy-nilly by the tides and have developed a “foot” that seeks a surface to settle on.

In a joint N.C. Sea Grant-UNCW marine center project, some 50 volunteers – calling themselves “The Spat-tered” – sink ceramic-tile “spat racks” in various tidal creeks and sounds.

Attracted by the tiles’ rough, shell-like surface, the spat latch on with a self-manufactured superglue. Volunteers record the salinity and temperature of the surrounding water twice weekly, then, every six weeks, they pull up the devices to scrape off and count the spat, making their observations public at

The environmentally-oriented N.C. Coastal Federation builds reefs using research from both DMF and the spat racks to determine “where, when (to build), and how tall it is and how big it is,” says Ted Wilgis, coastal education coordinator for the Southeast office.

Additional helpful information is due to come this summer as the marine center releases a GIS map of the N.C. coast. It has overlays showing a wealth of pertinent data, from water quality to location of areas closed to shellfishing.

Growers have traditionally been “mom and pop” operators who like to pick up a few oysters from their leases after a day spent at their main trade, fishing.

‘Intensive’ cultivation

In the last few years, however, a half dozen have sprung up to practice what Turano classifies as “intensive” cultivation.

From hatcheries, they buy juvenile oysters by the hundreds, then place them in cages to grow to legal harvest size, 3-inches-long.

Jay Styron, UNCW director of marine operations and president of the N.C. Shellfish Growers Association, started growing high-dollar, cage-raised oysters on Cedar Island in Carteret County five years ago. He sells 20,000 to 30,000 per season to the oysters-on-the-half-shell market, as far inland as Chapel Hill. He charges $35 to $40 per 100-oyster box and says the market is so good that “The ones I have now are already sold.”

Styron has high hopes for UNCW’s year-old Shellfish Research Hatchery, which he says “is going to make a better N.C. oyster.”

The grant-funded enterprise is crossbreeding stock from the biggest, healthiest oysters that director Ami Wilbur can find. At 6- to 10-inches across, “some …are the biggest oysters I’ve ever seen in my life,” she says.

The first generation to be crossbred and put in floating cages to grow in the nearby Inland Waterway is doing well, Wilbur says. Some will be 3-inches long by August, when they’re 20 months old, outpacing the two to three years that a wild oyster usually takes to grow that size. So far, she doesn’t know why.

The selective breeding – the same kind used to produce superior corn and hogs – may find what differentiates oysters grown in different spots along the coast. And it may find some oysters that grow better in the wild than farmed, and vice versa, she says.

The more knowledge the better, if the native oyster is to make a comeback its advocates say.

It was here when early European settlers arrived, and they marveled at its abundance.

Nobody expects that scenario again, but grower Styron doesn’t see why the state can’t at least approach the kind of thriving industry that Virginia enjoys.

“You know we’ve got just as good water quality,” he says, “and enough water to grow oysters in.”

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