top of page

Basic oyster biology

General facts

The oysters raised by Merritt Island Oysters are the species Crassostrea virginica, more commonly known as the eastern oyster.  Oysters are bivalves with the unique characteristic of irregular shell shapes. They can grow around objects or attach to one another. Oysters typically live in the intertidal zone in reefs or beds located in waters that can vary widely in terms of temperature and salinity. An adult oyster feeds by filtering plankton out of the water with reports of oysters pumping up to 50 gallons of water per day! The rate at which an oyster pumps water through its gills depends on the temperature and salinity, with rates increasing with temperature and decreasing with lower salinity. 

The Eastern Oyster: Crassostrea virginica.
Kennedy, Victor S., Roger I.E. Newell, and Albert F. Eble, eds.. 1996. UM-SG-TS-96-01. 75.00. 772 pp.


Oyster reproduction

Oysters reproduce by releasing eggs and sperm into the water column. Male oysters depend on temperature and food signals to release sperm (spawn), and once a female senses the release of sperm, she releases eggs. The gametes will only live a few hours unless the sperm are able to fertilize eggs. Planktonic larvae will form a shell in 12-24 hours, and survive for about 2-3 weeks in the planktonic stage, migrating vertically with the tide to remain in more protected waters. Larval mortality rates are approximated at 99%. The survivors will eventually find a clean substrate to cement themselves to grow into adulthood. Newly attached oysters are called, "spat". Oysters are typically harvested when they are 3 inches or about 3 years old. 


Information from: Nonnative oysters in the Chesapeake Bay. (2004). Washington DC: The National Academies Press.

bottom of page