Dermo, or Perkinsus marinus, is a parasite that most often infects oysters during their second year of life, causing slowed growth rates and death. MSX was discovered in the region a decade later. In 1949, scientists discovered Dermo in the Bay. These damaged habitats offer less surface area for reef-dwelling critters to inhabit, and can be easily buried by sediment. Because these reefs have been scraped away by dredges, oyster beds are now often limited to flat, thin layers of dead shell and live oysters spread over the Bay’s bottom. At the turn of the twentieth century, the Bay’s oyster fishery was one of the most important in the United States.īut over-harvesting removed huge volumes of oysters from the Bay and led to the demise of the Bay’s healthy reefs. In the 1850s, more than 1.5 million bushels of oysters were harvested from the Bay each year three decades later, this number jumped to 20 million. Colonists first used hand tongs to harvest oysters, but by the 1800s, dredges were also in use. European settlers reported enormous oyster reefs that thrust up from the Bay’s bottom, posing navigational hazards to their ships. In the seventeenth century, huge numbers of oysters lived in the Bay. The severity of this decline is often illustrated in terms of its impact on water quality: in the late nineteenth century, the Bay’s oysters could filter a volume of water equal to that of the entire Bay in three or four days today’s population takes nearly a year to filter this same amount. The decline of the native oyster population can be attributed to several factors, including historic over-harvesting, disease, pollution and habitat loss. What caused the Chesapeake Bay oyster population to decline? Oysters have also added to the region’s historical and cultural heritage, inspiring the unique design of the skipjack and fueling countless bull and oyster roasts. Since the late nineteenth century, the oyster industry-including the catch, sale, shucking, packing and shipping of oysters-has contributed millions of dollars to the region’s economy. Shorebirds feed on adult oysters exposed on intertidal flats.Blue crabs and some fish feed on older spat and first-year oysters.Flatworms and mud crabs feed on new spat.Anemones, sea nettles and other filter feeders feed on oyster larvae.Oysters have a number of natural predators: With their countless nooks and crannies, these aquatic reefs provide habitat to hundreds of critters, from small fish and invertebrates seeking shelter to larger fish looking for food. Under certain conditions, one oyster can filter more than 50 gallons of water in a single day.Īs oysters grow, larvae settle on top of adults, forming layers of oysters that spread upward and outward. In doing so, oysters help keep the water clean and clear for underwater grasses and other aquatic life. This means they feed by pumping water through their gills, trapping particles of food as well as nutrients, suspended sediments and other contaminants. You don’t have to like eating this peculiar-looking bivalve to appreciate its vital role in the Chesapeake Bay ecosystem and its importance to people in the region. Why are oysters important to the Chesapeake Bay? Scientists and resource managers are working to manage harvests, establish sanctuaries, overcome the effects of disease and restore reefs in an effort to bring back the bivalve. But over-harvesting, disease, pollution and habitat loss have led to a severe drop in oyster populations. For more than a century, oysters have made up one of the region’s most valuable commercial fisheries, and the filter-feeder continues to clean our waters and offer food and habitat to other animals. The eastern oyster is one of the most iconic species in the Chesapeake Bay.
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