People are Volunteering to Plant Oyster Gardens in an Attempt to Restore Coral Reefs

Students on a platform underneath their school's long pier gently shake their oyster garden's wire cages as they remove them out of the sea, clearing silt and algae that may be preventing water and nutrients from reaching newborn oysters clinging to those shells.

(Photo : Getty Images)

These Bay St. Louis kids are part of a volunteer team rearing oysters from transparent spat the width of a soda straw to hard-shelled bivalves that can help rebuild degraded reefs along the United States coasts.

Coastal Ecosystems

(Photo : Francesco Ungaro)

Coastal ecosystems rely heavily on oyster reefs. Each oyster filters 25 to 50 gallons of water each day (95 to 190 liters). The spat is attached to bigger oysters and grows there. The reefs safeguard shorelines while providing shrimp, crabs, and fish habitat.

There are over 1,000 oyster gardens in Maryland, Virginia, Mississippi, and Alabama alone, most of which are housed in wire cages suspended from private docks or open-topped floats linked to them.

Dennis Hatfield of Gulf Shores, Ala., said the quantity of crabs, fish, shrimp, sponges, and other species he removes from his cages on Little Lagoon each summer astounds him.

Yearly Oyster Harvests

An average of 37,400 tons of oysters were harvested yearly from brackish waterways across the United States in the 1950s. According to official data, overharvesting, pollution, parasites, suffocating sediment, and other issues caused U.S. oyster harvests to drop 68 percent to around 11,900 tons per year in the 1990s.

Oysters are grown near the surface by commercial growers throughout the nation because they mature quicker. After all, the water contains more of the plankton they feed, and predators are easier to remove.

On a lesser scale, oyster gardening employs the same strategies. On the other hand, the oysters aren't being raised for half-shell or deep-frying.

According to Bob Stokes, head of the Galveston Bay Foundation in Texas, "it's as much education as it is rehabilitation."

"Shrimp Baskets"

More than 20 large plastic "shrimp baskets" contained oysters when the Little Lagoon oysters were harvested.

They're currently on reefs being rebuilt for fishing or reserved to hold broodstock for future generations, with no harvest allowed, and they're big enough to spawn next spring.

Related Article: Most of Indian Ocean's Coral Reefs May be Destroyed in Next 50 Years

Extreme Weather

Heavy rains in the Mississippi Sound during the spring and summer were particularly severe on young oysters. In mid-November, most shells in cages placed out in late June at St. Stanislaus carried just silt, and surviving juveniles were typically less than an inch long.

Rayne Palmer, an Auburn University graduate student who manages the Mississippi-Alabama Sea Grant's gardening program, said, "When you discover one with an oyster, put it away, so you don't count them twice."

Letha Boudreaux, the leader of the marine biology department at St. Stanislaus, explained that empty shells also end up on reefs.

Recycled Shells

Spat-like oyster shells as a firm surface and entire artificial reefs are composed of recycled shells. The Galveston Bay program throws mesh bags containing recyclable shells into the water to attract spat and give them a head start.

Oyster gardening began in the late 1990s in the Chesapeake Bay area, where harvests had dropped by 90% in two decades.

The Mississippi-Alabama Sea Grant's oyster gardening program, fashioned after the Chesapeake Bay, began a master's thesis research in Alabama in 2001.

Kimberly Henderson Hedrick, who earned a Gulf Guardian Award in 2004 as leader of Alabama's Shellfish Restoration Project and now teaches in the Indiana agricultural town where she grew up, said, "It makes me really glad to see that it took off and people are still doing it" in Alabama.

In addition to other issues, the Chesapeake Bay oysters were plagued by two very fatal parasite infections. According to Chris Moore, senior ecosystem scientist for the Chesapeake Bay Foundation, declines in the second half of the 1900s followed an even more dramatic drop in the 1920s due to rampant overharvesting.

Similar Initiatives

(Photo : Photo by Matt Cardy/Getty Images)

According to Moore, gardeners from the foundation and its member organizations have introduced at least 15 million oysters to Maryland and 1 million to Virginia.

In Virginia, members of the Tidewater Oyster Gardeners Association raise oysters for both eating and planting. Although Tidewater hasn't collected statistics on reef donations, president emeritus Vic Spain estimates that it is at least 500,000 each year.

The Chesapeake Oyster Alliance has set a target of producing 10 billion more oysters by 2025.

According to spokesperson Helene Hetrick, dozens of schools and community groups across New York Harbor have similar initiatives as part of the Billion Oyster Project. The project isn't called "oyster gardens" since the oysters in the harbor are unhealthy to eat, and the purpose is rehabilitation, not food, she explained.

Oyster gardens are withdrawn from the water every week to ten days to remove vermin, protect oysters from growing through the cage mesh, and dry off and clean algae and seaweed growing on the wire.

In the Chesapeake, oysters take three to four years to reach adulthood, but it takes a year to 18 months in high cages.

Oysters may be ready to transplant in four to five months in Mobile Bay and Mississippi, according to P.J. Waters, an Auburn University extension associate professor who directs Mississippi-Alabama Sea Grant's oyster farming program in Alabama.

Colin Wood, one of two student interns who maintain the St. Stanislaus garden, gather statistics, and oversee other students - not for compensation, but for a credit on their transcripts - said the hands-on component appealed to him.

Also Read: How are Coral Reefs Adapting to Survive the Changes in the Climate

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