It’s been a rough past few decades for the Chesapeake Bay. Over the years, rampant over-fishing and noxious diseases have threatened the estuary's oysters. The shellfish aren't just tasty seafood; they're also vital for keeping the bay's waters clear. According to the Chesapeake Bay Foundation, a single adult oyster filters and cleans up to 50 gallons of water per day.

However, oysters caught in the bay have dropped from some 15 million in the 1800s to about 900,000 in recent years, the Washington Post reports. So in an ambitious plan to restore the estuary's bivalve mollusk population, the state of Maryland recently completed the world’s largest man-made oyster reef. The reef, which stretches for 330 acres across the bottom of a tidal creek on the state’s Eastern Shore, contains more than one billion oysters—and no fishing is allowed there.

Organizations that lent a hand on the project include the Army Corps, the National Oceanic and Atmospheric Administration, and the Nature Conservancy, among other participants. However, the reef really gained its, ahem, sea legs thanks to scientists at the Horn Point Laboratory in Cambridge, Md.

Run by the University of Maryland’s Center for Environmental Science, the lab created new baby oysters, or “spat,” by coaxing parents into mating. Once the spat formed, they were placed into tanks and spoon-fed algae.

Eventually, spat need to attach on to a solid surface, like oyster shells, so they can settle and grow their own hard casing. One problem: Horn Point’s hatchery was producing billions of spat, and there weren’t enough oyster shells in the Chesapeake Bay area to go around. The Oyster Recovery Partnership of Maryland had to import oyster shells from Louisiana and collect them from restaurants across the mid-Atlantic before shipping them back to Cambridge.

The project began five years ago, and the last remaining oyster spat were recently deposited into Harris Creek, the Star-Democrat reports. There, the fledgling organisms will grow into adults, filter nitrogen from the water, re-populate other neighboring reefs, and hopefully help save the Bay.

In following years, Maryland and Virginia will continue to restore the native oyster bottom of other Bay tributaries. Their efforts might serve as a model for similar endeavors, like New York City's Billion Oyster Project—a campaign that's planning on releasing one billion of the mollusks into New York Harbor over the next two decades. In any case, if you're a marine conservationist, it looks like the upcoming years are shaping up to be your oyster.

[h/t Washington Post]