Oysters in Virginia

Oysters are the Chesapeake Bay's best natural filters. A single adult oyster can filter up to 50 gallons of water a day. Oysters also provide essential habitat for fish and other Bay creatures. The eastern oyster is one of the most iconic species in the Chesapeake Bay. For more than a century, oysters  made up one of the region’s most valuable commercial fisheries, and the oysters which are filter-feeders continues to clean our waters and offer food and habitat to other animals.

In the 1850s, more than 150 million oysters were harvested from the Bay each year; three decades later, this number jumped to 2,000 million. At the turn of the twentieth century, the Bay’s oyster fishery was one of the most important in the United States. However over-harvesting led to the demise of the Bay’s healthy reefs. Over the decades the reefs were scraped away by dredging, oyster beds were reduced to flat, thin layers of dead shell and live oysters spread over the Bay’s bottom. These damaged habitats offer less surface area for reef-dwelling oysters to inhabit, and can be easily buried by sediment. The result has been that many wild populations of oysters are now considered “functionally extinct” because of severe habitat losses.

There is good news. The University of Virginia researchers, in partnership with The Nature Conservancy, have just published a 15-year study that demonstrates that restored reefs can match natural reef oyster populations in about six years and continue to hold strong thereafter. Oyster reefs in nature are built by the hinge-shelled mollusks. The reefs form along sand bars and muddy tidal flats, molding to contours at water’s edge and serving as a bulwark against erosion. As sea levels rise, so do the reefs – if they are healthy.

The researchers at University of Virginia found that at 16 sites in coastal Virginia, composed of 70 reefs, the researchers studied the Crassostrea virginica variety of oyster. This species better known as the Eastern oyster or the Atlantic oyster is vitally important to the seafood economy found on the Eastern Seaboard. 

Where the reefs were spared or have recovered, waters are clearer and cleaner. The oysters and bivalve mollusks, suck in surrounding water, consuming plankton and any silt and debris, then eject the water back out, free of impurities. The scientists note the oysters ability to mitigate the impact of fertilizer seepage. Oyster reefs also provide habitat for crabs and fish, supporting coastal fisheries. The study also found that these ecosystem benefits that restored reefs provide can catch up with the natural reefs within a decade—meaning cleaner and clearer water as well as habitat that supports coastal fisheries.

 “Our study shows that restoration can catalyze rapidrecovery of an imperiled coastal habitat and help reverse decades ofdegradation,” said the study’s lead author, Rachel Smith, a postdoctoralresearcher in the Department of Environmental Sciences at UVA.

Now, the Nature Conservancy and scientis are working to manage harvests, establish sanctuaries, overcome the effects of disease and restore reefs with aquaculture -hatchery-raised seed in an effort to bring back the oyster. In 2010, Maryland and Virginia embarked on a tributary-based restoration strategy that will build, seed and monitor reefs in several Maryland and Virginia waterways. This commitment was incorporated into the Chesapeake Bay TMDL restoration plan. By 2015, six Chesapeake Ba tributaries had been selected for oyster restoration: Harris Creek and the Little Choptank and Tred Avon rivers in Maryland, and the Lafayette, Lynnhaven and Piankatank rivers in Virginia. Read more about thisprogram here.