|En - American cupped oyster, Fr - Huître creuse américaine, Sp - Ostión virgínico.|
3Alpha Code: OYA Taxonomic Code: 3160700803|
|Shell solid, inequivalve left (lower) valve convex, right (upper) valve tending to be flat, though often bent sitting within the left; inequilateral, beaks and umbones not prominent, tending to be broadly oval in outline but often distorted. Ligament internal, attached to a central triangular pit, with lateral extensions. Sculpture of concentric ridges and lines with a few irregular radiating ribs on the left valve which do not normally meet or indent the margin. Hinge line without teeth in the adult. Shell margins smooth.
Colour white, dirty white or brown, sometimes with dark purple markings. Periostracum thin, dark brown; interior of shell white; adductor muscle scar near the posterior margin, a deep purple or red-brown.
|Western Atlantic Ocean from the Gulf of Mexico and Panama to South Maine, and in the Gulf of St. Lawrence. Imported in Europe (British Islands to to Bay of Biscay) prior to 1939, but the colonies seem to have some difficulties in proliferating. Caught occasionally, with bottom trawls and dredges, in the Adriatic Sea (Mediterranean Sea).|
|Habitat and Biology|
|Sessile (cemented to the substrate on its left valve).Oysters favor estuaries and sounds with salinities between 5 and 30% and are intolerant of prolonged exposure to fresh water or marine salinities.
Filter feeder.Also they are found in shallow areas of tidal to subtidal zones (between 0,5-75 meters),prefer a firm substrate (pilings, hard rock bottoms, and substrates firmed with the oyster shells of previous generations). The American oyster is an epibenthicsuspension feeder, ingesting a variety of algae, bacteria, and small detrital particles. Fecal and pseudofecal material is important in sediment production and deposition, providing sites for remineralizing bacterial action, and as food source for deposit feeders.Swimming larvae have positive phototaxis, which becomes negative with increased temperature.|
|Measuring to 25 cm cm from hinge-line to the opposite margin; common 8-18 cm.|
|Interest to Fisheries|
|American oysters are prominent members of the benthic community in Chesapeake Bay (USA) and contribute substantially to the economy of the region. Oysters have recently experienced severe declines in abundance. Intense fishing pressure, loss of habitat, and water quality degradation have been blamed for declines in the abundance of this species. Its meat is not highly sought after by European consumers. Resource very important in Gulf of Mexico (Tamaulipas, Veracruz and Tabasco). The total catch reported for this species to FAO for 1999 was 132 207 t. The countries with the largest catches were USA (89 714 t) and Mexico (39 268 t).|
American oyster ,
Blue points ,
Blue point oyster ,
Common oyster ,
Eastern oyster .|
Huitre creuse americaine .|
Amerikanische auster .|
Ostión americano ,
Ostión de placer ,
Ostión de manglar ,
Ostra virgínica .|
|Many enemies, diseases, and other calamities afflict this bivalve. It is preyed upon by sea stars, drills, crabs, flatworms, fishes (such as drums and rays), oyster-catchers, scoters, and other sea ducks as well as man. Sponges, boring clams, mud worms, and crabs also harm oysters. Various protozoans and microbes cause disease and many other species compete for space.|
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