Assis au sommet du nid de pie d'une petite péniche, le capitaine du bateau se protégeait les yeux du soleil de juillet et tournait son regard vers l'agitation en contrebas.

Le bourdonnement de l'équipement lourd et le cliquetis des coquilles d'huîtres ont brisé le silence de la matinée alors que les équipes de travail ont empilé des milliers de livres de coquilles séchées sur le pont, créant finalement un monticule de 12 pieds de haut.

Lorsque le dernier obus a été placé sur le tas, le capitaine a manœuvré la barge pour l'éloigner de Russ Point Landing et descendre un ruisseau de marée près de Fripp Island dans le cadre d'une mission visant à sauver les huîtres sauvages.

Le travail parrainé par l'État faisait partie d'un effort visant à protéger les populations d'huîtres en péril en renvoyant les coquilles des restaurants, des rôtis d'huîtres de basse-cour et d'autres sources vers les marées. Remettre les coquilles dans la boue reconstruit les récifs, les refuges dont les bébés huîtres ont besoin pour grandir et se multiplier.

Mais les efforts pour restaurer les récifs d'huîtres dans des endroits comme le comté de Beaufort font face à une menace qui pourrait affecter pratiquement tous ceux qui dépendent de la récolte d'huîtres sauvages.

La Caroline du Sud et les États voisins ont du mal à trouver les coquilles dont ils ont besoin pour remettre dans les zones de marée pour restaurer les populations d'huîtres.

Autrefois considérées comme des déchets marins, les coquilles d'huîtres sont devenues une denrée précieuse, mais limitée, le long de la côte sud de l'Atlantique.

"Il s'agit définitivement d'un problème national impliquant plusieurs États :trouver une coquille", a déclaré Ben Dyar, spécialiste des huîtres au Département des ressources naturelles de Caroline du Sud.

Sans un approvisionnement adéquat en coquillages, les populations d'huîtres pourraient souffrir, ce qui réduirait la récolte commerciale et ferait grimper le prix des coquillages dans les restaurants. Moins de récifs d'huîtres et des populations plus faibles pourraient également signifier des voies navigables plus polluées, car les huîtres filtrent les contaminants dans l'eau.

Il y a plusieurs raisons à la pénurie de coquillages, y compris les conséquences de la surexploitation au fil des ans dans les États de l'Atlantique Sud. Mais les gens jettent également les coquilles après avoir servi des huîtres dans des maisons de fruits de mer ou dans des rôtis d'huîtres communautaires. Les gens utilisent des coquillages pour paver les allées et embellir les jardins. Et ils écrasent des coquilles pour les vendre comme aliments pour poulets ou comme ingrédients dans des produits cosmétiques.

La pénurie est si prononcée que certains États ont dépensé des millions de dollars au fil des ans pour acheter des coquillages afin de restaurer et de reconstruire des récifs d'huîtres, parfois en concurrence pour les coquillages limités offerts par les maisons d'écaillage du Texas à la Virginie.

Les prix sont passés de bien moins d'un dollar le boisseau il y a vingt ans à plusieurs fois plus qu'aujourd'hui. Le coût est maintenant de 3 $ à 7 $ le boisseau, disent certains propriétaires de maison et les responsables de la faune de l'État.

La Caroline du Sud, avec de vastes marais et des centaines de restaurants de fruits de mer, dépense en moyenne environ 100 000 $ par an pour acheter des coquillages d'autres États, selon le Département des ressources naturelles de la Caroline du Sud.

Au total, l'État, utilisant diverses sources de financement, a dépensé près d'un million de dollars depuis 2012 pour acquérir plus de 407 000 boisseaux de coquilles d'huîtres, ce qui équivaut à environ 22 millions de livres, selon le DNR.

La Caroline du Sud payait moins de 3 $ le boisseau, mais le prix moyen a bondi au-dessus de 3 $ au cours des deux dernières années, selon le DNR.

Marché concurrentiel

De nombreux autres États sont également avides de coquilles d'huîtres.

La Géorgie dépense environ 138 000 dollars par an pour acheter des coquillages et les transporter par camion dans l'État de Peach. Les coquillages viennent souvent de Floride et parfois du Texas.

Certaines des dépenses les plus importantes sur la côte sud de l'Atlantique se situent autour de la baie de Chesapeake, dans le Maryland et en Virginie.

La Virginie dépense entre 2 et 3 millions de dollars par an pour acheter des coquilles d'huîtres auprès de maisons d'écaillage de l'État et d'autres sources dans l'État, ont déclaré des responsables de l'État.

Le Maryland a même acheté des wagons de chemin de fer remplis de coquilles d'huîtres fossilisées de Floride pour l'aider dans ses programmes de restauration des huîtres dans la baie de Chesapeake, où les populations d'huîtres ont chuté par rapport à des niveaux historiques.

"Tout cela est fou", a déclaré Ted Wilgis, spécialiste des récifs ostréicoles de la North Carolina Coastal Federation à but non lucratif. "C'est devenu une surenchère."

Certains États, dont la Caroline du Sud, ont récemment mieux réussi à acheter des coquillages que la Caroline du Nord, car l'État de Tar Heel a une limite sur le montant qu'il peut dépenser. En Géorgie, les responsables disent qu'il n'est pas toujours facile de trouver des huîtres quand ils veulent les acheter.

"La coquille d'huître est devenue une denrée précieuse, la demande dépassant de loin l'offre", a déclaré Cameron Brinton, biologiste marin à la Division des ressources côtières de Géorgie.

Les huîtres, qui poussent dans la plupart des zones côtières des États-Unis, ont un cycle de vie qui dépend des marées et de la capacité des larves d'huîtres à trouver des surfaces dures.

Les bébés huîtres, un peu plus qu'une substance gluante indistincte après le frai, flottent sur la marée et collent aux surfaces dures, allant des récifs d'huîtres existants aux piliers de quai ou aux supports de pont. In South Carolina, this process occurs during the spring and summer.

Once attached, they nestle into cracks and crevices, where they form their own shells and grow up.

But the best hard surfaces for baby oysters to stick to are existing oyster reefs, experts say.

'Shells are the profit'

Jeff Milliken's family has run oyster shucking businesses for more than 60 years in the coastal crossroads of Shallotte, North Carolina, selling canned oysters to grocery stores and restaurants.

Oyster sales always kept his family business afloat, providing a decent living for the Millikens.

But for years, oyster shells left over from the shucking process were little more than waste material. Piles of oyster shells at the shucking house were virtually given away.

That began to change in the 1980s, as people increasingly sought to buy the shells, Milliken said. And that has enriched his family business.

The company sometimes sells what it calls scoops of oyster shells, the amount that can be held in the bucket of a front-end loader, for about $500. In the 1980s, the charge was closer to $50, he said.

"My dad always made the point that the oysters pay the bills and the shells are the profit," Milliken, 60, said. "The shells have become very lucrative."

The South Carolina Department of Natural Resources buys large amounts of Milliken's shells to restore oyster beds.

"South Carolina has pretty much bought all of our production for reseeding the beds in South Carolina," Milliken said. "We do sell to the public but not like we used to. A lot of it is held for the state of South Carolina."

In addition to buying shells from people like Milliken, states are trying to re-use oyster shells, rather than letting them be dumped in landfills and in the woods, or crushed and used to pave driveways.

Commercial harvesters who lease oyster grounds from state agencies for private use often must put back a substantial percentage of oyster shells after they pluck shellfish from the mud.

Some states have launched oyster shell recycling programs that encourage restaurant owners to hold the shells until state natural resources officials or environmental groups can pick them up and replant them on public oyster grounds in the wild—as the South Carolina DNR did this summer near Fripp Island in Beaufort County.

State agencies and environmental groups from Maryland to Georgia have established shell drop-off sites on the coast for people who haul whole oysters home for backyard and community oyster roasts. State officials and volunteers then pick up shells at these drop-off sites and return them to marshes and sounds.

Additionally, some states have begun to allow oyster farming that could offset losses from wild populations.

Meanwhile, in North Carolina, Virginia and Maryland, resource managers are working to establish artificial reefs to offset the shortage of oyster shells and replenish wild shellfish populations near the Outer Banks and in the Chesapeake Bay.

For those reasons, oysters aren't likely to disappear from the landscape as a result of the shell shortage, many natural resources officials say. But losing wild oyster reefs could deplete the populations, they say. Even with some success from artificial oyster reefs, returning shells to the wild is generally considered the best way to replenish and enhance natural reefs, some experts say.

Some restaurant owners say it's vital to recycle oyster shells.

"If oysters are harvested but none of the shells are recycled," Hilton Head Island restaurateur and chef Chris Carge said, "the oyster seeds are just going to drift away" and eventually, the local oyster population will dwindle significantly.

Should oyster populations drop because there aren't enough shells to restore wild populations, it could diminish local fishing economies, drive up oyster prices for restaurants, hurt water quality and affect other marine species that thrive around oyster reefs, state officials say.

In South Carolina, for instance, more than 100 species of marine animals rely on oyster reefs for survival. These mounds of shells, which are submerged below the water at high tide, provide habitat for small bait fish, which then attract larger, popular sports fish, including red drum, sea trout and flounder, according to the state Department of Natural Resources.

Commercially caught oysters generate a dock value, or wholesale value, of some $3 million annually in South Carolina, making oysters the state's fourth-largest fishery, the DNR said in a report last winter.

Without an adequate supply of shells to replenish populations, oyster harvesting seasons might need to be shortened, a change sure to upset commercial and recreational fishermen.

"At some point, it is very plausible that there would have to be other measures and other tools taken to help manage that resource, meaning closing areas down for harvest for longer periods of time," Dyar said, noting it could have a corresponding effect on oyster prices.

Maintaining healthy oyster populations also is important because they filter out pollution in water, keeping tidal creeks cleaner.

Chicken feed and makeup

Perhaps the biggest reason for the lack of shells is historic over-harvesting in some areas, as well as the decline of shucking houses in others.

The Nature Conservancy found that 85% of the world's oyster reefs have been lost since the late 1800s because of over-harvesting, pollution and other factors, according to a South Carolina Sea Grant Consortium report.

Places like South Carolina also no longer have canneries where large supplies of oyster shells could be found to return to the salt marshes for restoration. At one point the state had 16 canneries, but the last one closed in 1986, according to the state DNR.

Some years, it is harder to find shells than in other years, depending on how many oysters are harvested. Beyond that, the lack of oyster shells may result, in part, from the public's increasing appetite for buying oysters in the shell, rather than in cans, and demand by a variety of businesses.

Poultry farms, construction companies and cosmetics manufacturers are among businesses that use oyster shells in their products. The calcium in oyster shells is believed to enhance many products, prompting efforts to find shells and grind them up.

Some poultry farmers purchase chicken feed supplements made from oyster shells. When fed to chickens, crushed oyster shells are believed to make egg shells harder.

Lesa Vold, a spokeswoman for the Egg Industry Center, said egg farmers like shell-based feed, but also are using other sources of calcium in places where shells are hard to find. The center supports egg producers across the country.

Milliken said his company for years sold crushed oyster shells to farm supply stores for sale to chicken farmers.

"We crushed just a huge amount of them," he said. "It's the best calcium for chicken egg-laying there is."

One marketing study, released this summer, said the oyster shell calcium market is expected to grow by 5% by 2030, fueled by an array of industrial demands for shells. Calcium carbonate in oyster shells is highly sought after, the study said.

The study, cited on the website Researchandmarkets.com, says oyster shell powder is useful in some skin-care products.

Worldwide, some manufacturers harvest oyster shells, crush them and blend them into facial cleansing powder, soaps and shampoo, according to a June 8 story on the website Premiumbeautynews.com.

Backyard oyster roasts

Another issue has arisen that has depleted the amount of oyster shells available to replenish wild populations.

Many shells are being scattered across the countryside, rather than returned to the salty tidelands of the southern Atlantic coast, after restaurants serve them or neighbors hold backyard oyster roasts.

Oysters harvested from the black pluff mud of Charleston may wind up sold to seafood markets whose customers are from Columbia, Greenville, Florence or Rock Hill. Those shells often are discarded in landfills or other places miles away from the coast.

"Quantities spread throughout the state (make) it a lot more difficult to capture that shell and bring it back to the coast," Dyar said in a report to the DNR board earlier this year.

It's difficult to say how many oysters have been removed from bays and creeks across the southeast and hauled inland, but natural resource managers say it's a problem, despite their best efforts.

South Carolina has one of the region's most robust shell recycling programs, with 30 sites where people can drop off shells after they've eaten oysters. Most of the sites are along the coast, although the DNR has them in Columbia and Greenville, as well. Once the shells are picked up, they are kept at multiple locations for months to dry out, which kills bacteria inside the shells.

But the state only captures about 12% of the shells that are harvested annually, meaning 88% of the shells from oysters sold in South Carolina are not recycled, according to a report by the S.C Department of Natural Resources.

Jean Fruh, executive director of The Outside Foundation, said the smell of keeping the oysters for typical once-a-week pickup, the cost, and additional training scare away some restaurant owners. However, the cost, Fruh and participating restaurateurs will tell you, is nominal:about $150 a month.

She said it's worth it.

"If you don't have oysters, you don't have fish, shrimp and crab," she said, because oysters create a critical habitat for the three during their juvenile period.

About 65 South Carolina restaurants collect shells for recycling, most of them in the Charleston area. Only a handful are in the Hilton Head Island and Myrtle Beach areas, according to the DNR.

Despite the struggle, natural resource managers in multiple states say they're still trying to maintain habitat for oysters, either through the use of artificial reefs, tighter laws on shell disposal, or recycling.

Dyar, the state DNR oyster specialist, said South Carolina's recycling program offers the best hope of maintaining enough oyster shells to replant in the marshes.

"We have seen over the last several years that sources are starting to become more scarce and the shells are becoming more expensive, causing an even more critical need for us to increase shell recycling within the state," Dyar said.

Oysters needed

During the July oyster planting trip, Michael Hodges, an oyster restoration biologist with the state DNR, directed the operation in the summer heat.

Hodges and his work partner, Kevin Swain, pushed the pile of oysters onto the barge with a front end loader. After the barge hauled its cargo to the destination point, a man aboard the barge fired a water cannon at the mound of shells, scattering them into the salt marsh at high tide.

It took only 20 minutes to lay the shells in about seven feet of water along a salt marsh bank. When the tide went out, the fruits of everyone's labor were obvious—a 390-yard line of human-planted oyster shells. It is expected to take about two years for a full row of mature oysters to develop.

Over the summer, the DNR set out to plant 10,000 bushels—or 550,000 pounds—of oyster shells in Beaufort waters, another 5,000 in Georgetown and 27,000 in Charleston.

Hodges said the program works—if the state has enough shells.

Without them, "we would see a decrease in the health of the oysters but also the health of the estuary, since they're so tied to habitat, water quality and all the ecosystem services that they provide," Hodges said. + Explorer plus loin

Une solution rapide pour restaurer les récifs ostréicoles

2022 The State.

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