Oysters thrive in the brackish waters of our estuaries and marshes, living in water from the low ride line to 40 feet. Oysters are sessile, which means they do not move about. They permanently adhere themselves to a hard object, most often other oysters, forming oyster beds, also known as rakes.Oysters change their sex repeatedly throughout their lives, depending upon the needs of the bed. One female can spawn 100 million eggs at a time, but probably only 10 of those make it to adulthood.