Fertilization is external except for flat oysters. For at least 10, years at least oyster growers have placed structures cultch such as oyster shells in specific locations to catch the natural spawn of native oysters. Many times these structures are then moved to areas more favorable to accelerate oyster growth faster currents bringing more alga to eat.
Over the years it was discovered that oysters work much like humans; get the adult oysters into a hot tub and watch what happens. It turns out that raising the water temperature 10 Celsius per hour for several hours gets the oysters to release their gonadal material. Boys usually go first, emitting strong blasts of milky sperm. As the females filter the sperm they in turn release their eggs into the seawater.
Fertilization is external. In nature almost all the offspring die because when they settle to the bottom 10 to 14 days after spawning, the bottom does not have clean cultch for the oyster to set upon.
In hatcheries, oysters spawn in tanks of seawater where the tank either has bags of whole oyster shells or has ground shell on the bottom of the tank. With these optimal conditions the survival rates are greatly increased. Six male and six female oysters can produce over 15 million larvae in one day!
Sperm is taken into the female and she holds her seed until she thinks conditions are optimal. What are they doing?? This was the first question which attracted me to a career-long love affair with oysters. I still like to sit outside on a still evening and listen to the oysters spitting. An unexpected symphony often accompanied by snapping shrimp. Try it sometime.
In addition to being yummy and intriguing, oysters are critical to our coastal ecosystems. Oysters are to South Carolina estuaries what coral reefs are to the Florida Keys. Oysters build complex reefs which provide habitat for small critters such as juvenile fish, mud crabs and polychaete worms. Some fish such as blennies, gobies and oyster toadfish may live their entire lives on an oyster reef. Other larger fish and invertebrates are attracted to the abundant food supply on oyster reefs.
Many of our most important commercial and recreational species rely on oyster reefs at some point in their lives. Shrimp, crabs, red drum, flounder, kingfish, spotted seatrout, spadefish, croaker, and sheepshead are just a few of the species regularly found on oyster reefs. How do clams communicate? How do you make clams spit? Why do oysters produce pearls? How can you tell if clams are bad? Do clams poop? Were do clams come from? What do clams start out as? How do clams walk?
What is bigger clams or mussel? Are clams vegan? How clams avoid animals? Can clams scream? What is the difference between ocean and sea clams? Are little neck clams and steamer clams the same? How do you call a tasty dish with clams?
How many clams are there? Are clams edible? Do vegetarians eat clams? Are clams decomposers? Are clams unicellular or multicellular? Why is spit called spit? Can clams live in freshwater? What are clams adaptations to survive?
Do clams eat algae?
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