Oysters have a rough, irregularly shaped shell and live mainly in temperate or warm coastal or estuarine waters. Oysters (often eaten raw) are considered a seafood delicacy. Raw oyster consumption is occasionally associated with gastrointestinal disease. Oyster beds, often located adjacent to rural communities, must be carefully monitored to ensure that they have not been contaminated with polluted water, especially during periods of heavy rain. Many species of oysters are harvested in small numbers and marketed for retail as exotic speciality oysters.
