Question of the Week: What Role Do Oysters Play in the Bay's Health?

Welcome to this week’s installment of the BayBlog Question of the Week! Each week we'll take a question submitted through the Chesapeake Bay Program website and answer it here for all to read.

Alvina asked: “What role do oysters play in the heath of the bay? What role might oysters play in the Bay’s future?”

Every native species is vital to the health and survival of any ecosystem. The eastern oyster in the Chesapeake Bay is no exception.

One major role oysters play in the Bay is filtering the water. Oysters are filter feeders, meaning they pump large volumes of water through their gills to sift out plankton and other particles they need for nourishmnet. But this process serves a double purpose: As the oysters feed, they also filter out harmful pollutants from the Bay's waters, helping to keep the water clear and clean for bay grasses and other underwater life.

Oysters also provide habitat for many species in the Chesapeake Bay. By forming reefs, oysters create small ecosystems with nooks and crannies where tiny aquatic animals hide from predators. Reefs can create 50 times the surface area of a flat, muddy Bay bottom of the same size, which is vital to sponges, sea squirts, skilletfish and other organisms that live attached to a hard surface.

Chesapeake Bay oysters are also a food source for various other Bay creatures. Anemones and sea nettles depend on oyster larvae for survival, while flatworms and mud crabs feed on new oyster spat. Older spat and first-year oysters are consumed by blue crabs and some types of fish. Some adult oysters even end up as prey for shorebirds like oystercatchers.

The roles of this important species are dramatically affected by variations in the oyster population. A diminished oyster population is not the sole reason for the Bay's poor health, but it is certainly detrimental. One of the challenges of Chesapeake Bay restoration is to restore and maintain a healthy oyster population for ecological purposes while also supporting an oyster fishery.

The future of the Chesapeake's oyster population depends on restoration and management efforts today. For instance, Maryland just introduced a proposal to increase the amount of oyster sanctuaries to one-quarter of the remaining quality reefs in that state's portion of the Bay. Oyster sanctuaries are reefs where harvesting is off-limits, allowing the reefs to expand and provide the important ecological services.

As with every living thing in the Bay, there is a domino effect. Because of all their important roles in the Bay, if oysters suffer, other creatures do as well.

For more information, check out our pages on oysters and oyster management and restoration.

Do you have a question about the Chesapeake Bay? Ask us and we might choose it for our Question of the Week!