Turtle Barnacle

The turtle barnacle is a species of barnacle most commonly found attached to the shells of sea turtles, though it can also settle on the shells of crabs, on manatees, and occasionally on ship hulls and other hard surfaces. Its base is broad and flattened, allowing it to conform closely to the curved surface of a turtle's shell rather than growing as a tall, narrow cone like many rock dwelling barnacles. Unlike the whale barnacle, it is not restricted to one single host species, and readily settles wherever a suitably stable hard surface is available in warm coastal waters. Heavy barnacle growth on a sea turtle's shell can add drag and weight, and is sometimes used by researchers as one sign of an individual turtle's overall health and activity level. It feeds by filtering plankton from the surrounding water using feathery limbs extended from its shell whenever submerged. Its presence on turtles, crabs, and other slow moving marine animals reflects a broadly opportunistic attachment strategy rather than a specialized, host specific relationship.