Louisiana collected 200 tons of discarded oyster shells from 19 restaurants and built a 400-foot reef; it now shields Pointe-au-Chien tribal land from erosion

Louisiana's coastline is vanishing fast. The US Geological Survey found that since 1932, the state has already lost almost 2,000 square miles of its territory, an area nearly the size of Delaware. For the Pointe-au-Chien tribe, who have been farming, fishing and living along the coast for generations, it is not just a mere statistic. Their land is disappearing into the water around them. So they decided to take action in a very unusual way: using the leftover oyster shells from restaurant kitchens.

A reef created from restaurant leftovers

The Coalition to Restore Coastal Louisiana collected approximately 200 tons of used oyster shells from 19 restaurants across South Louisiana. Instead of going into a landfill, those shells were cleaned, cured and laid down along the shoreline to create a 400-foot reef. The project cost $45,000 and was funded by a Regional Coastal Resilience Grant from NOAA’s Office for Coastal Management and through a partnership with the Gulf of Mexico Alliance. NOAA's coastal management office also completed the environmental assessment before construction.

Community members and volunteers did much of the physical work themselves, hauling and placing shells to form a barrier that was not there just a few years ago. Now the reef lies between the open water and land that has supported Pointe-au-Chien families for generations, including sacred tribal mounds that date back to about 900 BCE. In more recent generations, this coastal area has sustained livestock, family fishing operations, and gardens that included fruit trees and other crops. This way of life depends on soil that is dry and firm enough for building and farming. Instead, water levels are increasing and causing flooding and erosion along the coastline. A reef built from recycled shells cannot reverse years of erosion, but it can slow the water enough to help protect the remaining land and the people on it.

How a pile of shells can hold back the sea

A reef made of recycled shells may sound fragile, but it works with nature, not against it. Oyster larvae swim around in the water and attach to hard surfaces like shells, and over time they build new oyster colonies right on top of the reef. As the colony thickens, the whole thing gets taller and rougher, helping to absorb wave energy before it even hits the shore. This is not a local idea. A peer-reviewed study published in the journal PeerJ by researcher Megan La Peyre and colleagues examined specifically restored oyster reefs along the Louisiana coast and found that reefs placed in the right locations may significantly decrease shoreline exposure and support long-term erosion control. Coastal scientists increasingly see living reefs like this one as a lower-cost alternative to concrete seawalls.

There’s a bonus too. Oysters are natural water purifiers. NOAA's Office of Response and Restoration notes that a single adult oyster can filter as much as 50 gallons of water a day. The Pointe-au-Chien reef is growing and attracting more oysters, which may help clean the surrounding water and support local fish populations.

Why does the coastline keep shrinking?

The USGS report cited earlier found that, at recent slower rates, coastal Louisiana has been losing a football field of wetlands every 100 minutes. Several factors explain this. There is natural subsidence, where the land is gradually sinking, and there is also the aspect of rising sea levels. Hurricanes strip away the marshlands within a few hours. Human activity has also contributed to the problem. For decades, levees and canals have been constructed through the wetlands, altering the processes of sediment transport, thus compromising the strength of the soil that binds everything together. The oil spill disaster of 2010, called Deepwater Horizon, further contributed to the deterioration of the soil composition. For a community like Pointe-au-Chien, sitting low along a bayou with no high ground to retreat to, these pressures add up to a real threat to homes, culture and livelihoods built over generations.

A model for other communities

This reef is not an isolated project. It is part of a larger $892,700 Regional Coastal Resilience Grant, awarded in 2019. It is part of the Gulf of Mexico Alliance, which aims to address resilience gaps at Pointe-au-Chien and nine other vulnerable coastal communities. This approach is quite straightforward. Rather than transporting the shell waste from restaurants to a landfill, simply return the shell to the waters where it will develop into a living, self-healing barrier. It will take more than one 400-foot reef to solve Louisiana's land loss problem. But for Pointe-au-Chien, it buys time, protects sacred ground, and shows that sometimes the best defense against a rising sea is something as simple as the shell left on your dinner plate.