Presented by: Meagan Wright

 Scientific Name: Crassostrea virginica  Common Names: Eastern Oyster & American Oyster  Phylum Mullusca  Class Bivalva or Class Pelecypoda

 Has two shells which are unequal in size and shape.  Vary in length from 2 – 12 inches  The body is deep in the shells and surrounded by a tissue called mantle.  The mantle contains muscle, organs, and membranes.  The shell is held together by a centrally located adductor muscle.  When the oyster relaxes, the shell is opened up by a hinge-like ligament at the narrow end of the shell

 Oysters also have a pair of gills located under the mantle.  The gills are covered with hair like structure called cilia.  They are composed of layers of folded filaments, giving them a pleated look.  The gills are used for gathering food and respiration.  The front end of the gills contains the mouth  Oysters do not have heads or brains, they have two nerve centers.  One controls the mouth and mantle. The other controls the internal organs.

 Found in temperate and tropical oceans.  The American & Eastern Oysters are typically found around the Gulf of Mexico and Atlantic coast of North America.  Live attached to the bottom of the ocean on a hard surface. This area is called oyster beds.  The beds are typically located in estuaries, sounds, bays, and tidal creeks from brackish water to full strength seawater.

 Eat organic debris called detritus and plankton – microscopic animals and plants.  Create a current in the water with their cillia. The water enters their gills, and the particles in the water are caught in mucus.  The food is sorted by size. The smaller particles go to the mouth and the larger ones go to the edge of the mantle to be taken out.

 European and the Olympia oysters contain both egg and sperm in one.  The egg is fertilized within the body is kept in the gills until shell-bearing larvae is developed.  The American blue point oyster the sexes are separate.  The oysters spawn by releasing sperm and egg into the water to develop into swimming larva called veliger larvae.  In about 2 weeks, the larvae “cement” themselves to something hard where their will remain the rest of their lives.

 Each ring on an oyster shell tells how long it has lived.  There are 100 species of true oysters.  Oysters can change sex several times throughout their lives, but they are either male or female at any given time.  Oysters are considered a “keystone species” because they provide shelter and habitat for many other estuary organisms, improve water quality, and prevent erosion.

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