Marine Invertebrates Research

Barnacle, popular name for members of a subclass of sessile crustaceans. The name was originally applied to the barnacle goose of northern Europe, and its transfer to these crustaceans was due to the fable that the bird develops from the stalked, or goose, barnacle. Most barnacles are hermaphrodites (see Hermaphroditism). All inhabit salt water. The larvae are free-swimming, but the adults are always permanently attached to foreign objects, such as ship bottoms, wharf piles, rocks, floating timbers, whales, large fish, and shellfish. The subclass is divided into five orders, four of which are minute forms parasitic on other shellfish. The other order includes the acorn barnacles, common to temperate and cold waters, and the stalked barnacles, which are usually found in warm waters, but, because they attach themselves to ships, they are distributed throughout the world. Much expense is involved in the periodic removal of barnacles from the bottoms of ships. A method of controlling barnacle infestation by means of ultrasonic vibrations was introduced in 1955. The hull of the ship is fitted with thin metal plates that are vibrated by a generator at 25,000 cycles per second. The vibrations repel the barnacles. Scientific classification: Barnacles constitute the subclass Cirripedia, of the class Crustacea.