Forbes Sea Star
Sea stars belong to a group called Echinoderms which means “spiny skin.” Scientists prefer to use the term ‘sea star’ and not ‘starfish’ because this animal is an invertebrate and not a fish. The Forbes sea star is also called the ‘common sea star.’ This star can reach about 5 inches in diameter and its coloration can be tan, brown, or olive with tones of red, orange and pink. The bright orange dot in the center of the body is called the madreporite. This organ pumps water into the sea star’s body. This pumping action creates suction at the end of hundreds of tube feet, located in paired rows on the underside of the arms. A sea star can move rapidly along the bottom by removing its grip, curling up its arms and drifting with the current or tide.When a sea star loses or damages an arm, it sheds the appendage at a point close to the center of its body and the cut skin begins to heal over. It then will regenerate a new limb. Sometimes a sea star will overcompensate and grow more than one replacement limb. On the end of each arm is a small pigment eye spot that is sensitive to light.
The Forbes sea star is found from the Gulf of Maine to Texas. It lives predominantly on rock, gravel, or sand bottoms and is commonly found during low tide on rocky surfaces.
The Forbes’ sea star is a carnivore that feeds chiefly on bivalve mollusks in the wild. In aquariums, this animal will eat nearly anything. When feeding, a sea star will wrap its five arms around its prey gripping it with its suction cup like tube feet. The stomach, which looks like a thin white membrane, then extends through the mouth to surround the prey. The stomach tissue secretes digestive juices that dissolve the prey, which is absorbed by the stomach membrane. When preying on an oyster or clam, the sea star grips the bivalve’s shell and applies strong pressure to force it open. By creating even a tiny gap, the sea star can squeeze its stomach inside the shell and digest the soft body tissue.
Sea stars breed in the spring, producing as many as 2,500,000 eggs. Females will feel plump and spongy when their arms are filled with eggs.
Sea stars are eaten by bottom-dwelling fish and crabs, as well as by sea gulls when low tides leave the sea stars exposed.