Oyster shells are not garbage. That is the message from conservation groups, which say people have been recycling shells along U.S. coastlines for generations.
Today's recycling efforts are highly organized. Nonprofits like the Coalition to Restore Coastal Louisiana (CRCL) can recycle hundreds of pounds of oyster shells every day.
"We're the only oyster shell recycling program in the state of Louisiana," said Kellyn LaCour-Conant, the Restoration Programs Director for CRCL. "We've been in operation since 2014, and since then we've recycled over 10 million pounds of shells from New Orleans restaurants."
LaCour-Conant described the Coalition's oyster shell recycling program as the largest in the U.S.
There are similar programs or nonprofits in every coastal U.S. state.
"North Carolina was one of the first to adopt," said Tom Bliss, the director of the Shellfish Research Lab at the University of Georgia. "They actually changed their state laws to require people to recycle their shells."
The recycling process is a slow one.
First, recycled shells are cured in the sun for months for sterilization purposes.
The piles can be several feet high.
"To the untrained eye it just might look like a mess," said LaCour-Conant. "When it first comes in from the restaurant, maybe it has a little butter on it, or lemon, or a little bit of oyster meat. So we put that in a pile so it can start to break down by power of the sun."
Once the curing process is finished, the shells are repurposed into man-made "reefs," where aquatic wildlife can build a habitat.
The oysters at the reefs help keep the water clean, filtering as many as 50 gallons in a day.
"I forget who coined the phrase, but oysters are called 'ecosystem engineers,'" said Bliss. "Over years, you get many oysters growing on those bars or reefs, and it creates a hard substrate, which can help reduce wave energy."
Those reefs are often referred to as living shorelines. Some can extend for more than a mile.
"It's an engineered shoreline, but it naturalizes very quickly over a few years," Bliss said. He said his team at the University of Georgia has been using oyster shells to create living shorelines for about 15 years. "If we can help make certain areas more resilient, with the ability to adjust to changes, that's really what we're hoping to do."
CRCL finished its first reef in November 2016. The half-mile-long Biloxi Marsh reef was built using almost 1.7 million pounds of recycled shell.
"Over five-plus years, we've seen shoreline erosion rates have been reduced by about 50% compared to reference sites," said LaCour-Conant. "We also see great recruitment of baby oysters season-to-season, and a lot of fishes and other interesting organisms, like barnacles."
In recent years, LaCour-Conant said, CRCL has opted to build smaller reefs in culturally significant areas.
"We have worked with local tribes to protect traditional mound sites that the communities have stewarded for many generations," LaCour-Conant said, citing CRCL's work with the Pointe-au-Chien and Atakapa-Ishak/Chawasha tribes. "These were sacred sites, they were burial sites, they were community sites, and many modern-day tribes still go to these sites to offer prayer, reflect and honor their heritage."
The work, according to LaCour-Conant, reflects CRCL's commitment to Louisiana.
"We're the canary in the coal mine for climate change and coastal land loss," LaCour-Conant said. "We actually serve a really great niche, working with communities that are on the front lines, and being able to work with them respectfully and sensitively."