The Oyster
There is a lot to learn about oysters. Below, we touch on some highlights about different oysters around the world, as well as their ecological and nutritional impacts.
Types of Oysters
Many people think that all oysters make pearls, but that is not the case. Most molluscs that have shells can create pearls, but the highly valuable pearls we see as jewelry come from a specific variety of pearl oysters, the largest of which is Pinctada maxima. We sometimes find pearls in Eastern oysters, but they are usually quite small and misshapen. |
Anatomy and Biology
Oysters are protrandric, meaning that they begin life as males, however, as they grow older and larger, can switch sexes and becomes female. Eastern oysters are broadcast spawners, releasing eggs and sperm into the water column, where the eggs are fertilized. Embryos develop into the free-swimming larval stage. Some female oysters can produce as many as 100 million eggs in a single spawning event! Oyster larvae spend roughly two and a half weeks swimming, eating and growing before they attach to a hard substrate and go through metamorphosis. From this point onward, oysters are sessile, meaning they are fixed in one place. For more information on the life cycle of oysters, see Raising Oysters. |
Habitat and Ecosystem Services
Oysters are filter feeders and play a valuable role removing nitrogen, phosphorus, plankton, detritus, and dissolved organic material from the water. Their filtering capacity is tremendous, as high as 50 gallons per day, so oysters can be very important in maintaining or improving water quality. Oysters are reef-builders. Planktonic larvae are attracted to the calcium in the shells of adult oysters, so often gravitate towards locations where oysters already exist, forming large and intricate reefs. These reefs provide valuable habitat to other marine life such as fish, crabs, and benthic invertebrates, just to name a few. |
Oysters as Food
Oysters have many nutritional benefits, being rich in vitamins and minerals such as iron, zinc, magnesium, phosphorus, copper, selenium, and vitamin B12. Farmed oysters, as a protein source, are shown to have less environmental impact than the beef or chicken industry. It has been argued that if Americans swapped 10% of their meat consumption for oysters, greenhouse gas savings would be the equivalent of keeping nearly 11 million cars off of the road. Many great oyster recipes, festivals, tours, and experiences can be found here in Virginia and around the world. Virginia is for Oyster Lovers, Virginia Oyster Trail, Virginia Seafood Council, and Virginia's River Realm are good places to start in our local area! |