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Coastal Heritage – Winter 2013
 
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Lowcountry Living Shorelines: Restoring Carolina's Reefs
VOLUME 27, NUMBER 2, WINTER 2013                   PDF FILE          

Coastal Heritage is a quarterly publication of the S.C. Sea Grant Consortium—a university-based network supporting research, education, and outreach to conserve coastal resources and enhance economic opportunity for the people of South Carolina. To subscribe, email your name and address to Annette Dunmeyer.

Executive Director: M. Richard DeVoe                        past issues of Coastal Heritage
Director of Communications: Susan Ferris Hill
Editor: John H. Tibbetts
Art Director: Pam Hesse Graphic Design

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Lowcountry Oyster Shorelines Coastal Heritage cover photo

Lowcountry Living Shorelines: Restoring Carolina's Reefs
By John H. Tibbetts

It’s quiet on the Ashley River after Michael Hodges cuts the engine. The only sound is the wake lapping on shore. The city marina is across the river, but on a Monday morning under a gray-and-black sky threatening rain, this stretch of Charleston Harbor is still sleeping.

Hodges has landed the 20-foot aluminum boat on a mound of loose, dead oyster shells along the shore. He steps into the shallows, his rubber boots crunching on the bottom, and then reaches down, grabs a shell, shakes out salt water, and holds it like a cup.

“There,” he says, running his finger across dime-sized bumps on the shell’s pearly inner surface. “Those are young oysters. Attached a few weeks ago.”

An empty oyster shell looks like a humble thing, but don’t throw it away. Recycle it. A shell is the best substrate, or foundation, to attract swimming young oysters looking for permanent homes.

Hodges is the lead field biologist for several oyster-restoration efforts, including the influential South Carolina Oyster Restoration and Enhancement program (SCORE), one of the first statewide, all-volunteer efforts outside the Chesapeake Bay.

Today, though, he’s checking on other projects in Charleston Harbor, also managed by the S.C. Department of Natural Resources (SCDNR).

Oyster RestorationOne is a $1 million mitigation project funded by the Port of Charles­ton for a facility expansion; two others provide $472,500 and $121,478 for mitigations as part of court-ordered settlements to address past industrial contamination of harbor sediments; and the fourth is a $100,000 erosion-control effort supported by federal “stimulus” funds.

Since 2008, Hodges and his team have planted about 34,000 bushels of loose shell annually on 40 sites—14 acres total—for the four restoration projects. So far, measurements show that empty shell planted in 2008 is attracting oyster larvae, and reefs are growing substantially larger.

These oysters aren’t for human consumption. The harbor is polluted, and fishermen—recreational and commercial—harvest shellfish only from clean waters.

Instead, harbor oysters are being restored for their ecological services. Oyster reefs filter large volumes of water, help stabilize salt marsh fringing shorelines, and provide essential habitat for many species of finfish and invertebrates such as crab and shrimp.

Restoration scientists hope that more coastal residents and visitors will learn to see oysters in a broader way—not only as food but as keystone species in healthy estuaries and salt-marsh ecosystems.

The Eastern oyster (Crassostrea virginica) is a hardy, adaptable species. During the last ice age, the Eastern oyster grew along stretches of the North American coastline and migrated inland along with the rising sea level. After the Earth’s climate and sea level stabilized about 8,000 years ago, it colonized shorelines along thousands of miles from Canada into the Gulf of Mexico and south to Brazil.
 
Various oyster species once flourished in temperate estuaries around the world where reefs were the dominant ecological feature. Now most of those reefs are gone. Oyster populations have lost more than 90% of their historical abundance in North America, Europe, and Australia, according to a 2001 study published in Science by Jeremy Jackson, an ocean­ographer at Scripps Institute of Oceanography.

A recent report produced by The Nature Conservancy, Shellfish Reefs at Risk, estimated that globally 85% of oyster reefs have been lost since the 1880s and 1890s because of pollution, overharvesting, disease, habitat loss, and other impacts.

South Carolina’s oysters, though, are in comparatively good shape in many locations.

“When I moved to South Carolina from Virginia four years ago, I was amazed by the abundance of oysters here,” says Peter Kingsley-Smith, associate marine scientist and shellfish research section manager at the SCDNR Marine Resources Research Institute. Now, as a Sea Grant researcher, he is studying the potential for producing single, more valuable triploid oysters (having an extra set of chromosomes) with improved meat quality and superior growth.

Boze Hancock, a marine restoration scientist with The Nature Conservancy, says that South Carolina is one of the few places in the world where oysters are in reasonable abundance and in good fishing condition. The great majority of other temperate estuaries have seen their oyster resources “crushed by overfishing,” he says. “You should keep looking after your oysters in South Carolina.”

Even so, wakes from boats, ships, and jet skis are eroding South Carolina salt-marsh shorelines and damaging reefs. Runoff pollution continues to threaten oyster habitats. Dredging for navigation, moreover, removes marsh-building sediments and deepens waterway channels, increasing stream flows that cause more shoreline erosion.

South Carolina estuaries are blessed with vast numbers of oyster larvae but far too little shell and other substrate for them to settle on.

Oyster larvae attach to dock pilings, concrete, broken pottery, glass bottles, floating tree limbs—you name it. If the surface is hard and clean, larvae will settle on it. Still, a young oyster strongly prefers an oyster shell (empty or not, doesn’t matter) for its texture, firmness, and chemical cues.

South Carolina shucking houses and canneries once held gigantic mounds of empty shell to be planted along shorelines for reef substrate. But the last cannery in the state closed in 1986, and just one shucking house, the Bluffton Oyster Company, is still in operation. The company stockpiles shell on-site to replant on locally leased bottoms.

Loose shell for Charleston Harbor restoration sites is trucked in from shucking houses in the Gulf of Mexico at a cost of about $2.50 a bushel. Most of that price tag is for diesel fuel. Says Hodges, “It’s getting a little more expensive every year.” Shell, in fact, is now in short supply all around the United States.

Hodges pushes the boat off the Ashley River shoreline and steers north, passing the Battery, into the Cooper River. He rides under the Ravenel Bridge against an ebbing tide, crosses the ship channel to the Wando River, and turns into Hobcaw Creek where handsome homes and boat docks line one shore, and salt marshes, mud flats, and small reefs cover the opposite shore.

Oysters are subtidal in estuaries from Chesapeake Bay to New England, where they spend their lives under­water. In South Carolina, though, 95% of the oyster reefs by acreage are intertidal—that is, they are under water at high tide and exposed to the air at low tide.

South Carolina has nearly 5,000 acres of oyster beds growing along fringes of salt marsh bordering creeks and rivers, and along isolated mud flats, according to recent estimates from an almost decade-long survey of oyster reefs by SCDNR scientists. South Carolina once had considerable populations of subtidal oysters, most of which have been lost because of silta­tion, overharvesting, and other impacts.

In Hobcaw Creek, the sun briefly comes out, and Hodges points to a restored reef along a muddy shoreline. Young, bright-green shoots of cordgrass (Spartina alterniflora) have colonized pluff mud immediately behind the reef. That’s one of the results, he says, of the oyster’s function as a shoreline stabilizer.

When a high tide washes over a reef, some suspended sediments fall out and sink onto the muddy bottom behind it. Later, when the tide lowers, the reef blocks some of these sediments from washing back into the creek. Over time, sediments can accumulate behind the reef like a snowdrift against a wall.

As more sediments fall out, they firm up the shoreline in some cases. Finally, the fringing marsh sends out Spartina rhizomes—plant stems that spread underground—to colonize the site. The growing reef functions as a breakwater for the salt-marsh fringe, protecting it from waves, tidal currents, and boat wakes and allowing the marsh to build more habitat.

In the construction of new intertidal reefs and replenishment of existing ones, scientists depend on the oyster’s extraordinarily high fertility and its ability to colonize a variety of hard, clean surfaces.

When a South Carolina estuary turns balmy in May, a single mature female oyster will release millions of microscopic eggs, and a mature male discharges countless sperm.

oyster castlesFolklore traditions say that an oyster’s reproductive vitality is passed to the person who slurps it down—that is, it’s supposedly an aphrodisiac. Casanova claimed that he ate as many as 60 a day. “Do oysters enhance sexual prowess?” asked the British scholar Rebecca Stott in a 2004 book. “Well, if they don’t do so chemically, they certainly do so by their age-old associations with flesh, hunger, and intimacy.”

As the songwriter Cole Porter pointed out, “Even oysters in Oyster Bay do it.” The Eastern oyster does it most prolifically in the months from late spring to mid-summer, months without an “R” in their names—May through August—in salty waterways of South Carolina, but spawning can continue into November if the weather is warm.

Fertilized eggs quickly develop into swimming larvae that feed on microscopic algae in the water column. During this swimming period, which typically lasts two-to-three weeks, winds, tides, and currents carry larvae large distances into estuaries where they can colonize existing reefs or start new ones on dead shells or other substrate. Fish and other animals eat countless larvae, so even under pristine conditions only a tiny percentage of them survive.

Each larva grows a single, sturdy appendage—a foot—while building up a store of sticky, cement-like material. A larva must find a permanent place to land or it will die within a few days; its window of opportunity is short, and closes quickly.

If the larva lands on a soft, mucky bottom, it will be smothered; a paper-thin layer of sediment becomes a burial ground. If a larva lands on a hard but fouled or slimy surface, it can be washed away, failing to cement itself to the underlying substrate. The lucky larva, though, finds a just-right substrate—such as an oyster shell—and attaches using its sticky foot.

Location, location, location—it’s not just a formula for real estate. The best sites for a young oyster are found where currents and tides will bring well-oxygenated water and plentiful food; where shorelines are somewhat sheltered from destructive boat wakes, wind waves, and strong tides; where sediments won’t smother it while the young oyster is still small; and, of course, where substrate, especially oyster shell, is clean and available.

Once attached, the young oyster is called “spat” because fishermen once referred to clouds of sperm and eggs in waterways as “spitting.” A spat draws lime-like material—calcium carbonate—from surrounding waters to build two thick, sturdy shells. As the spat grows larger, it must build armor against predators such as starfish, blue crabs, sponge borers, and a few fish species with very strong jaws. 

The oyster is a filter feeder that draws in the estuary’s rich organic soup through its open shell and gills, consuming microscopic plants and animals called plankton. The oyster diverts undigested materials—called pseudo-feces—and mixes them with mucus and feces to form long strings of ­nutrient-rich goop.

Invertebrates and juvenile fish gobble up this goop, and the leftovers dribble onto bottom sediments where they are processed by bacteria and released through the water column into the atmosphere as inert nitrogen gas. In this way, the oyster helps ­remove excess nutrients from the estuary. One mature oyster can filter and help remove excess nutrients from 1.5 gallons of water in an hour.

An oyster can start reproducing as early as four-to-six months after settlement, and it can grow to a very large size and potentially live for decades.

In a mature reef, however, generations of young oysters settle on shells of older oysters, eventually blocking their access to food and oxygen. Older oysters smother or starve beneath the growing colony. Yet dead oysters are critical to a mature reef’s structure. They form the “rock” base of a reef, which is eventually covered by a ­veneer of live animals.

Shrimp, blue crabs, gobies, blennies, and other creatures look for food and shelter in the reef. Gag grouper use oyster reefs during their juvenile stage for a temporary refuge. Studies also show that various juvenile finfish populations are more abundant in waters near oyster reefs compared with waters near mud flats. And ­mature bigger fish—red drum, spotted sea trout, and sheepshead—feed in and around reefs.

In the 1990s and early 2000s, a research project with support from the S.C. Sea Grant Consortium established that lowcountry oyster reefs are crucial habitat for dozens of estuarine species.

Loren Coen, a marine scientist who was then at SCDNR and is now at Florida Atlantic University and the College of Charleston, and his team found more than 75 invertebrate species on natural and constructed oyster reefs when reefs were exposed to air at low tide and 59 finfish and invertebrate transient species using reefs when submerged. Numerous other filter-feeding bivalves, such as mussels, were also found on reefs along with oysters. In addition, the scientists compared faunas on adjacent natural reefs as well as mud bottoms and fringing salt marsh.

Oyster spat“This research project was one of the first to refocus efforts on oyster restoration for restoration’s sake in the U.S. Southeast,” says Coen. It was also the first and perhaps best monitored and sampled intertidal restoration effort, with reefs built and monitored for 10 years.
 
Ecological history

Charleston Harbor was once oyster-rich. Native Americans called it “Oyster Bay,” and the peninsula of Charleston was known as “Oyster Point.” Archeologists have found gigantic ancient mounds known as middens where Native Americans consumed huge volumes of oysters and piled up empty shells. One midden discovered in Awendaw, about 25 miles north of Charleston, is the size of three football fields.

Carolina’s oyster riches impressed 18th century naturalists and explorers. In his 1709 book, A New Voyage to Carolina, the Briton John Lawson wrote: “Oysters, great and small are found almost in every Creek and Gut of Salt-Water, and are very good and well-relish’d.” He noted that Native Americans built canoes with double hulls to guard against sharp-edged oysters. 

In the 1720s, British naturalist Mark Catesby visited the Atlantic coast from Virginia to Carolina. “At low water there appears in the Rivers and Creeks immense Beds of Oysters, covering the muddy Banks many Miles together; in some great Rivers extending thirty or forty miles from the Sea; they do not lie separate but are closely joined to one another, and appear as a solid Rock a foot and half or two Feet in Depth, with their Edges upwards.” Ship logbooks of the same era describe vast “live rock”—usually oyster reefs—in the mid-Atlantic.

Farther north, the Hudson River estuary of New York and New Jersey continued 350 square miles of oyster beds.

Reefs lined the shores and inlets of Manhattan, Brooklyn, Queens, Staten Island, and City Island. Ellis Island was called Little Oyster Island. Oyster beds stretched up the Hudson more than 35 miles as far as present-day Ossining.

The first commercial oyster fishery in North America began in the lower Hudson estuary in the early 1600s. The Dutch colonists were oyster gourmands, and in 1658 local officials outlawed destructive shellfish dredging along some stretches of the Manhattan shoreline. 

The English, who captured Manhattan in 1674, gorged on oysters too and shipped pickled ones to the West Indies.

By 1715, some reefs were overharvested, so New York officials banned oystering from May to September 1—spawning season—and prohibited slaves and servants from taking or selling them, according to historian Mark Kurlansky in his 2008 book, The Big Oyster.

The colonies of New York and New Jersey subsequently battled over access to lucrative oyster beds. A nonresident caught harvesting oysters could have his vessel and equipment confiscated. 

In the late 18th century, dredgers were destroying many New England reefs. A dredge would rip away the upper surface of a reef, capturing living oysters but also removing dead oyster materials below, shrinking the reef’s height. Dredgers “ground the reefs down strip by strip, pass after pass, until there was nothing firm left for juvenile oysters to settle on,” writes Callum Roberts in a 2007 book.

By the beginning of the 19th century, some of the natural Great Beds of New York and New Jersey were declining as growing numbers of fishermen used long, scissor-like “tongs” to harvest them. Oystermen traveled to distant bays of Long Island and New Jersey, where they would rake up immature or “seed” oysters and bring them home to sell to coastal land­owners who would “bed” them in local waters.

“Bedding” oysters was profitable as consumer demand continued to accelerate. In the 1820s, a group of Staten Island ship owners acquired oyster seed from Chesapeake Bay and bedded them. Before long, schooners would arrive each spring in New York with hundreds of thousands of bushels of seed oysters from the Chesapeake and other wild-reef regions.

In the 1840s and early 1850s, refrigerated rail cars from New York hauled huge volumes of raw, unshucked oysters first to Cleveland, then Chicago, and then St. Louis. Railroads from Baltimore carrying Chesapeake oysters soon followed. Live, unshucked oysters, if kept chilled, were sturdy travelers for a week or more, and every ambitious burg on the prairie hankered for the juicy bivalves. As a young politician and attorney, Abraham Lincoln hosted oyster parties in Springfield, Illinois, a small city on the windy western plains a thousand miles from the sea.

For decades after the Civil War, the Eastern oyster was America’s favorite protein. Saloons in Rocky Mountain mining towns served Eastern oysters for free, to be washed down with beer.

Wealthy Londoners swallowed Eatstern oysters with champagne. Celebrations—birthdays, anniversaries, job promotions—called for oysters and more oysters, many of which were harvested from Chesapeake Bay, where from 1860 to 1920 harvesters removed 75% of the oyster habitat.

By the end of the Civil War, New Yorkers had learned the art and science of farming large, succulent oysters on the harbor bottom. Some 9,000 acres of New York Harbor bottom, split up in various sized plots, were leased from the state and marked off by hemlock poles.

By the 1890s, New Yorkers, who consumed a million oysters a day, comprised the nation’s largest oyster market.

Ernest Ingersoll, a naturalist and author, described New Yorkers’ passion for oysters that were “pickled, stewed, baked, roasted, fried, and scalloped; oysters made into soups, patties, and puddings; oysters with condiments and without condiments; oysters for breakfast, dinner, supper; oysters without stint or limit, fresh as the pure air, and almost as abundant, are daily offered to the palates of the Manhattanese, and appreciated with all the gratitude which such a bounty of nature ought to inspire.”

Some Staten Island bedders became so rich that they built big wooden mansions, but when typhoid was traced to sewage-polluted harbor beds in the 1920s, the New York City Sanitation Department shut them down. New Yorkers continued to eat oysters, though not ones from once-productive harbor beds.

The lowcountry experience

South Carolina was late to America’s oyster boom. The lowcountry’s small-sized oysters grow in dense, vertical clusters. They were unappealing to consumers who were seeking large, single oysters from the Chesapeake Bay or New York.

Still, there was a strong local oyster trade. In winter, Charleston’s “mosquito fleet”—a group of local black fishermen in small boats—harvested oysters along lowcountry shorelines. Oysters were peddled on streets or sold in local eating establishments where people ate them raw on the half-shell.

Shells were crushed for use in chicken feed, lime for farms, and primitive concrete called “tabby.” Virtually every lowcountry town and many rural areas built and repaired roads with shell. In 1890, Charleston applied 36,000 bushels of shell to maintain Meeting Street.

That same year, L.P. Maggioni and Company opened the state’s first oyster cannery in Port Royal. Gullah men harvested the oysters, and Polish-American workers, recruited from the Chesapeake Bay area, labored in the steam canneries. For a time, the Maggioni Company was the largest producer in the world for “cove” oysters, as steamed oysters were called.

In 1891, the South Carolina legislature created a leasing system for oyster beds and required leaseholders to plant a certain volume of substrate—usually oyster shell—per acre during spawning season. One reason that South Carolina took this step was to prevent neighboring Georgia from gaining valuable shell.

The great majority of oysters harvested from Chesapeake Bay and the New York Harbor were distributed whole to markets around the country and abroad, especially to Britain. Of course, shells were scattered far and wide, so they weren’t available to be planted in estuaries, and overharvesting permanently damaged or destroyed many reefs.

By contrast, most of South Carolina’s commercial oysters were shucked and most often canned or eaten along the coast at oyster roasts and in restaurants, and many shells were stockpiled locally. Several lowcountry shell-crushing factories sold this material for road construction and other purposes. But leaseholders ­understood that it was in their best interest to hold shell to cultivate oyster beds. No shell planting meant eventually no new oysters.

From 1893 to 1908, the peak years of South Carolina’s oyster production, 16 canneries operated in South Carolina. Most were in Beaufort County, close to Savannah’s railroad yards. During fall and winter, men went out in flat-bottomed boats called “bateaux” or in larger sloops or engine-powered scows. They used short-handled “grabs” to harvest oysters from the creek banks and long-handled “tongs” to get them from deeper water.

Harvested oysters were hauled by sailboat to canneries, where they were steamed, shucked, and canned. In spawning season, Gullah men shoveled empty shells onto oyster grounds to attract larvae.

During the Great Depression, South Carolina’s oyster industry contracted sharply because of rising labor costs and lower consumer demand. New York’s typhoid alarms of the 1920s struck down U.S. oyster harvests. Although canneries heat-treated oysters and killed pathogens, many Americans stopped eating them.

Shortly after World War II, some South Carolina canneries reopened in Beaufort and Charleston counties. But during the 1960s and ‘70s, pollution closures, rising labor costs, and competition from cheap Asian oysters squeezed lowcountry canneries, ­according to a 2003 history by the late Victor G. Burrell, Jr., a former director of the SCDNR Marine Resources Research Institute.

In 1986, the last cannery—on Lady’s Island in Beaufort County—closed and the lowcountry oyster industry turned to supplying oyster roasts and similar events.

Also in 1986, SCDNR became responsible for managing three categories of oyster beds: public shellfish grounds harvested by recreational fishermen; state shellfish grounds used by both recreational and, today, about 500 commercial harvesters; and culture permits in areas that had once been leased.

In 2011, there were 130 culture permits containing about 2,200 acres of intertidal oysters. Permits allow holders to harvest oysters from specific areas and require them to plant reef-replenishing shells or other substrate.

SCDNR plants a total of 35,000 to 45,000 bushels of shell annually on public and state shellfish beds during spawning season and closes overharvested beds, sometimes for half of a year or more, sometimes for several years in a row.

“The fishing pressure is very high,” says Nancy Hadley, manager of SCDNR’s Shellfish Management Section. “As soon as oysters are there, they are going to be harvested. So planting shell is never completely finished. It’s a process every year to replenish the habitat, and it’s expensive.”

Canneries and shucking houses once provided shell that leaseholders could plant each spring. Shell planting was a privately funded effort, though monitored by the state.

Today, most oysters are sold live to caterers and restaurants, and SCDNR is responsible for acquiring shell and planting it on public and state shellfish grounds.

“Now that the canneries are gone, there just isn’t as much shell out there” in the estuaries, says Ben Dyar, manager of the SCDNR Oyster Recycling and Planting Program.

About 240,000 bushels of oysters a year are consumed in South Carolina, including about 120,000 shipped here from the Gulf.  The vast majority of those empty shells are thrown in the trash or used as road materials.

consuming oystersThe SCDNR’s shell-recycling program acquires about 20,000 bushels of oysters from restaurants, caterers, and dropoff sites in nine counties, less than 10% of the shell that
should be available for recycling in the state.

To make up the difference, SCDNR purchases shells from out-of-state shucking houses, purchases that are supported by recreational saltwater fishing stamps.

“Our biggest hurdle is public education and awareness,” says Dyar. “We advertise and do other activities to get our message out, but many people still don’t realize that we do recycling, or they don’t understand why we do it. But when they hear about us and learn that the shells are going right back into the water, creating new oyster beds, they are more willing to recycle and talk to their neighbors and communities about it.”

Jamie Westendorff, owner of Charleston Outdoor Catering, who sends empty shells to the SCDNR’s recycling program, says, “I have to turn down a lot of people, and I’ve made some enemies. People want to use crushed shell on their driveways because that says, you know, that you’ve arrived on the coast. Crushed shell is a hallmark of the coast. But I explain to them that they need to look out for their grandchildren. If shell isn’t put back into the water, there will be fewer oysters in the future.”
       
Volunteers planting shell
   
Bill Thielfoldt, a retired sales and marketing executive, found a new way of understanding the natural world when he volunteered for the South Carolina Oyster Restoration and Enhancement (SCORE) program managed by SCDNR.

It was in the early 2000s that scientists, government agencies, and nonprofit groups began building volunteer efforts to restore reefs in U.S. estuaries and build grassroots networks for coastal stewardship.

Established in 2000, SCORE was initially supported in part by the S.C. Sea Grant Consortium as one of the first statewide oyster-recycling programs outside of the Chesapeake Bay region.

About 17,000 SCORE volunteers have donated more than 43,000 volunteer hours to build over two acres of oyster-reef habitat at more than 50 sites along the South Carolina coastline.

Volunteers fill polypropylene mesh bags with shell and plant them fire-brigade style along shorelines to provide a clean hard substrate for oyster larvae to settle on.

Bags of oyster shell are used to elevate the substrate’s profile off intertidal muddy bottoms; loose shells are more likely to sink in the mud. SCORE volunteers also test water quality, oyster survival and growth, and other parameters near restored reefs.

Three years ago, Thielfoldt joined a SCORE restoration effort near his home on Daniel Island. “We could see the difference in a very short period of time as the Spartina grew up behind the new reef, stabilizing the shoreline. We’ve gone back every year and added shell to the original reef, and the oysters have grown up into towers. This experience has made me very interested in the environment of the coast. It’s piqued my interest in all of the things that go on in this magnificent estuary.”

Some SCORE volunteers have become ambassadors of reef restoration, distributing literature, assisting with school field trips, collaborating with restaurants and caterers to find ways to increase shell recycling, and aiding SCDNR staff with the management of recycled shell.

Fishing clubs are joining SCORE too. The Coastal Conservation  Association (CCA)–South Carolina Chapter donated a trailer for the state recycling program and two johnboats to build SCORE reefs on otherwise inaccessible shorelines such as the one at Daniel Island. Fishermen organized volunteers for the annual Boone Hall oyster roast, where they emptied shells into recycling stations and passed out information.

Most Atlantic and Gulf coast states rely heavily on oyster shell to restore and enhance reefs. Because oyster shell is increasingly scarce, many new restoration programs are constructing reefs out of various materials including fossil-mined shell, concrete, and other recyclable materials.

Many of these newer structures are constructed to rise several feet off the muddy bottom, providing vertical relief where oysters can grow into “live rock,” according to Nancy Hadley of SCDNR.

Some states like New York have very low numbers of oyster larvae in their estuaries, according to assessments by Hudson River Foundation and their collaborators. New York oyster populations, for instance, are small compared to what they once were in the 18th and 19th centuries, so researchers often set spat on shells in hatcheries and then deposit them in estuaries.

But in places like South Carolina, larvae from abundant adult populations are plentiful. Substrate is what is limiting. It’s troubling, then, that
so many empty shells in South Carolina—almost a quarter-million bushels in total annually—end up lost to landfills, road construction, and decorative uses on building facades.

More of those shells could be planted to attract oyster larvae looking for permanent homes. As Loren Coen puts it, “If we plant it, they will come.”

next story Oysters and the Public Trust Doctrine


Last updated: 4/30/2013 8:51:32 AM
Coastal Heritage – Winter 2013

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