Oysters are a bivalve mollusk common all over the world. As adults, they live their entire lives in a shell rooted to one place underwater. They are filter feeders, meaning they suck in water over their gills. The gills have tiny hairs called cilia and are covered in mucus that catches plankton and other particles. The cilia then transport the nutrients to the oyster’s mouth. They also catch sediments, nutrients and algae that is in the water. The food that they catch gets digested in the stomach, and the water is expelled from the shell. The average oyster can filter up to 10 liters of water an hour – that’s 50 gallons a day.
They are a very important species for keeping many saltwater and freshwater ecosystems healthy. They help to keep the water clean by filtering out things that could make other animals sick. They live in large groups that form beds, or reefs. This also provides a habitat for fish, sea anemones and barnacles.
•Oysters are related to scallops, clams and mussels.
•Oyster reefs protect the coast by blocking large waves that could cause erosion and flooding.
•Oysters are carnivores.
•Their shells are made of calcium.
•There are four main groups of oysters. Some are popular for food. Pearl oysters produce pearls. There are also thorny oysters and saddle oysters.
•Each group contains many different species.
•There are 150 species of oyster.
•Pollution and rising acidity in the ocean threaten many oyster beds.
•Oysters are not large animals They range in size from 1.2 inches to 6 inches.
•Humans, sea turtles, fish and marine mammals, including otters, all eat oysters.
•Pearls are created when an irritating piece of sand, rock or parasite gets stuck inside a pearl oyster’s shell.
•The oyster excretes a fluid called nacre that coats whatever is stuck in the shell. This is supposed to make it less bothersome.
•Over time, the layers of nacre build up, creating a pearl.
•Pearls are made of the same material as an oyster’s shell: calcium carbonate.
•Most pearls today are created by freshwater mussels and pearl oysters