From the jazz bars of New Orleans to restaurants and kitchens across the country, oysters are the essential food of coastal culture in the USA. People there devour 2.5 billion oysters every year. Whether grilled, fried, or slurped raw on the half-shell, it all adds up to a lot of oyster shells - a resource taken from the sea and rarely returned.

Now those shells are being recycled to help rebuild oyster reefs and restore coastal wetlands. In little more than a year, a programme operated by the Coalition to Restore Coastal Louisiana (CRCL), a non-profit organisation, and funded by Shell has collected just over a thousand tonnes of shells from restaurants to place along the shoreline. That’s enough to fill more than 88 dump trucks and makes the programme the largest of its kind in the USA.

This winter, volunteers will stuff the sun-bleached shells into mesh bags and deposit them along the coast.

Louisiana is home to 40% of the country’s wetlands and oysters are important natural engineers of this environment. “The baby oysters like to cling to other oyster shells,” explains Nick Collins, a fourth-generation oyster farmer who tends the family reefs alongside his father and brothers. “They clump together into reefs.”

Oyster reefs trap sediment. This helps create shallow marshes and estuaries—the nurseries for one of North America’s largest commercial fisheries and refuge for more than 5 million migratory birds. The wetlands also help shield homes, businesses and ports on Louisiana’s storm-lashed coast.

But the Louisiana wetlands are vanishing. Every year, an area larger than the city of Athens, Greece is lost to erosion caused by hurricanes and other natural events as well as activities such as the construction of dams and levees along the Mississippi River.

As the coastal landscape has changed, oyster harvests have declined. Nick remembers when the family’s two boats came home full every day. Now they are lucky to harvest a few bags.

Oyster farmers and government agencies are trying to rebuild the depleted reefs with concrete, but the oysters prefer natural shells. However, most oyster shells are thrown away after the oysters are eaten, meaning the reefs are not replenished. 

Oyster lovers in New Orleans are happy to help restore the deficit of shells to the reefs. In the CRCL programme, the Phoenix Recycling company collects empty shells from 12 restaurants. The shells then dry for several months at a site managed by the Louisiana Department of Wildlife and Fisheries before they are placed along the coast. 

"It may seem like a drop in the bucket, but every little bit helps," says Nick’s father, Wilbert Collins.

Oyster facts

  • As oysters filter algae through their gills, they also remove nitrogen from sewage, as well as fertilisers and other pollutants that wash from the land.*
  • A single oyster can clean up to 190 litres of water every day – more than the amount of water used by a 10-minute shower.*

* Source: The Nature Conservancy

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