Oysters

                                                                    

Oysters

 

                              Bivalves are marine animals which have two shells. They have one  on the top and one on the bottom. They are common in shallow, and warmer, ocean water.  Females can have five to fifty million eggs a year. The shell begins to form within a day after an egg is fertilized. Oysters swim about a few days after hatching. They attach themselves onto a rock or a submerged object, where they will spend the rest of their lives. Adult oysters usually are two to ten inches long.