Oysters Emilie Blotiau Scientific Name • Oysters scientific name is Crassostrea madrasensis Physical Characteristics • Have a rough outer shell. • Inner shell is smooth from the erosion of sand. Anatomy • Oysters have gills like fish that filter the oxygen out of the water. • They are filter feeders, and use beating cilia to catch food. • They have a small three chambered heart that lies under the adductor muscle. • The mantle contains many small blood vessels which filter for oxygen in the water. Habitat • Live mostly in the intertidal zone. • Live between rocks and attached to hard substrates. • No preference to ocean temperature however they feed best at 50 degrees. • Reside mostly in brackish water. Oysters Diet • Oysters are filter feeders. • Plankton and other particles are caught by the beating cilia, and get stuck in the mucus membrane of the gills. – The gills transport the food to the stomach. Reproduction • One cannot determine if an oyster is male or female by their shells. – they are one sex or the other (not hermaphroditic). – Can change sex once or more during their lifetime. – It is almost impossible to tell the age of an oyster. Interesting Facts • Some types of oysters can produce pearls inside their shells. • They can grow to be about a foot long. • Oysters have blood and veins, their blood is colorless. • It is extremely hard to open a live oyster shell. You must use a knife. Pictures Find the oyster in the pictures!