Oyster shells are probably more valuable than you imagine. Shells from oyster shucking houses, for example, are sold to be made into chicken feed and for use in road construction.
But there's reason to think that shells do the most good when they're put back into the water, where they help oyster reefs regenerate and grow, according to research and the long experience of oyster farmers around the country.
A Louisiana group, the Coalition to Restore Coastal Louisiana, has just initiated a project to collect oyster shells from restaurants in New Orleans—after patrons are done slurping out their delicious, prized cargo—and to put them back into the ocean.
The project is funded by a $1 million gift from the Shell Oil Company and has begun partnering with Drago's restaurant and Acme Oyster House, two New Orleans establishments. The coalition hopes to expand and work with other restaurants, said Hilary Collis, the restoration program director for the coalition.
Eventually, the group would like to set up locations where individual residents can drop off oyster shells to be returned to sea.
Oyster shells are the ideal materials for oyster larvae to attach to, Collis said. "Oysters like to grow on other oysters." They mate by ejecting sperm and eggs into the water, after which free-swimming larvae form. But the larvae are very sensitive and need a hard surface to anchor themselves and begin growing.
According to George Waldbusser, a researcher at Oregon State University, shells are ideal for this because they contain calcium carbonate, a base that helps protect against acidic conditions to which larvae are especially vulnerable.
In fact, oyster remains act like a Tums for the ocean; they release base as they dissolve, a buffer against acidic conditions created when carbon dioxide disperses in the sea, Waldbusser told TakePart. Ocean acidification has hurt oyster production in the Pacific Northwest and elsewhere.
The project is the first large-scale oyster shell-recycling program in the state of Louisiana, Collis reports, and it's about time—every other state that produces large quantities of oysters has such programs. Moreover, Louisiana produces about one-third of the country's oysters.
Collis visited similar programs in Tampa, Florida, and Galveston, Texas, to prepare for the project. The Galveston oyster shell-recycling program returns about 80-to-100 tons of shells to the ocean each year, according to the Times-Picayune. Collis said her group hopes to collect even more than that.
So far, the restaurants produce one-to-two cubic yards of oyster shells per day, which is roughly equivalent to one ton of shells.
After the shells are collected, they will be placed in the sun for six months, allowing the sun to cure them and kill any bacteria that remains. Collis explains they will then be made into "cultch" and placed on one of several oyster reefs in coastal Louisiana.
This project is important because Louisiana currently has a shell deficit, which is why oyster growers have been known to put limestone and other hard materials onto the seafloor to foster regeneration. But according to Collis, the natural substrate is preferable.
Oyster reefs are vital to the area's economy and provide habitat for fish. The reefs are also called "living shoreline" because they can regenerate, and help to protect against erosion. They are important for protecting Louisiana's shore, and other areas of the Gulf Coast, from hurricanes, blunting the impact of storm surges and waves, Collis said.
"We're dreaming big and hopefully this project will catch on across coastal Louisiana," Collis said.
Do you think that programs like this one can potentially make a large enough difference in ocean acidification? Let us know in the Comments.
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