Seduto in cima alla coffa di una piccola chiatta, il capitano della barca si è schermato gli occhi dal sole di luglio e ha rivolto lo sguardo al trambusto sottostante.

Il ronzio delle attrezzature pesanti e il rumore delle conchiglie di ostrica ruppero il silenzio mattutino mentre le squadre di lavoro accumulavano migliaia di libbre di conchiglie essiccate sul ponte, creando alla fine un cumulo di 12 piedi di altezza.

Quando l'ultimo proiettile è stato posizionato sulla pila, il capitano ha manovrato la chiatta lontano da Russ Point Landing e giù per un torrente di marea vicino a Fripp Island in missione per salvare le ostriche selvatiche.

Il lavoro sponsorizzato dallo stato faceva parte di uno sforzo per proteggere le popolazioni di ostriche in pericolo restituendo conchiglie dai ristoranti, arrosti di ostriche nel cortile e altre fonti alle zone di marea. Rimettere le conchiglie nel fango ricostruisce le barriere coralline, i rifugi di cui hanno bisogno le piccole ostriche per crescere e moltiplicarsi.

Ma gli sforzi per ripristinare le barriere di ostriche in luoghi come la contea di Beaufort devono affrontare una minaccia che potrebbe colpire praticamente chiunque dipenda dalla raccolta delle ostriche selvatiche.

La Carolina del Sud e gli stati vicini hanno difficoltà a trovare le conchiglie di cui hanno bisogno da riporre nelle aree di marea per ripristinare le popolazioni di ostriche.

Un tempo considerati rifiuti marini, i gusci di ostriche sono diventati un bene prezioso, ma limitato, lungo la costa dell'Atlantico meridionale.

"Questo è sicuramente un problema nazionale multi-stato:trovare le conchiglie", ha affermato Ben Dyar, uno specialista di ostriche presso il Dipartimento delle risorse naturali della Carolina del Sud.

Senza un'adeguata fornitura di conchiglie, le popolazioni di ostriche potrebbero soffrire, riducendo il raccolto commerciale e facendo salire il prezzo dei molluschi nei ristoranti. Meno barriere di ostriche e popolazioni più basse potrebbero anche significare corsi d'acqua più inquinati perché le ostriche filtrano i contaminanti nell'acqua.

Ci sono molteplici ragioni per la carenza di proiettili, incluso il pedaggio che la raccolta eccessiva ha richiesto nel corso degli anni negli stati dell'Atlantico meridionale. Ma le persone buttano via i gusci anche dopo aver servito le ostriche nelle case di pesce o negli arrosti di ostriche della comunità. Le persone usano i gusci per pavimentare vialetti e migliorare i giardini. E stanno schiacciando conchiglie per venderle come mangime per polli o come ingredienti in prodotti cosmetici.

La carenza è così pronunciata che alcuni stati hanno speso milioni di dollari nel corso degli anni per l'acquisto di conchiglie per ripristinare e ricostruire le barriere di ostriche, a volte in competizione per le conchiglie limitate offerte dalle case di sgombero dal Texas alla Virginia.

I prezzi sono aumentati da ben meno di un dollaro per moggio due decenni fa a molte volte di più rispetto a oggi. Il costo ora va da $ 3 a $ 7 per staio, affermano alcuni proprietari di case e funzionari statali della fauna selvatica.

La Carolina del Sud, con vaste paludi e centinaia di ristoranti di pesce, spende, in media, circa $ 100.000 all'anno per l'acquisto di conchiglie da altri stati, secondo il Dipartimento delle risorse naturali della Carolina del Sud.

Nel complesso, lo stato, utilizzando una varietà di fonti di finanziamento, ha speso quasi 1 milione di dollari dal 2012 per acquisire più di 407.000 stai di gusci di ostriche, che equivalgono a circa 22 milioni di sterline, secondo il DNR.

La Carolina del Sud pagava meno di $ 3 per staio, ma il prezzo medio è balzato sopra i $ 3 negli ultimi due anni, afferma il DNR.

Mercato competitivo

Anche molti altri stati sono affamati di gusci di ostriche.

La Georgia spende circa $ 138.000 all'anno per l'acquisto di proiettili e il loro trasporto su camion nello Stato di Peach. Le conchiglie provengono spesso dalla Florida e talvolta dal Texas.

Alcune delle maggiori spese sulla costa dell'Atlantico meridionale sono intorno alla baia di Chesapeake nel Maryland e in Virginia.

La Virginia spende dai 2 ai 3 milioni di dollari all'anno per l'acquisto di gusci di ostriche da sgusciatori interni e altre fonti dello stato, hanno affermato i funzionari statali.

Il Maryland ha persino acquistato vagoni ferroviari di gusci di ostriche fossilizzate dalla Florida per aiutare con i suoi programmi di ripristino delle ostriche nella baia di Chesapeake, dove le popolazioni di ostriche sono crollate rispetto ai livelli storici.

"L'intera faccenda è pazzesca", ha detto Ted Wilgis, uno specialista della barriera corallina con la North Carolina Coastal Federation senza scopo di lucro. "È appena diventata una guerra di offerte."

Alcuni stati, inclusa la Carolina del Sud, hanno recentemente avuto più successo nell'acquisto di conchiglie rispetto alla Carolina del Nord perché lo Stato del Tar Heel ha un limite su quanto può spendere. In Georgia, i funzionari affermano che non è sempre facile trovare ostriche quando vogliono acquistarle.

"Il guscio di ostrica è diventato un bene prezioso, con una domanda che supera di gran lunga l'offerta", ha affermato Cameron Brinton, biologo marino della Georgia Coastal Resources Division.

Le ostriche, che crescono nella maggior parte delle zone costiere degli Stati Uniti, hanno un ciclo di vita che dipende dalle maree e dal successo delle ostriche larvali nel trovare superfici dure.

Le piccole ostriche, poco più che una sostanza appiccicosa indistinta dopo la deposizione delle uova, galleggiano sulla marea e si attaccano a superfici dure, che vanno dalle barriere di ostriche esistenti alle palafitte dei pontili o ai supporti dei ponti. 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. + Esplora ulteriormente

Una soluzione rapida per ripristinare le barriere di ostriche

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