Marine Animal Encyclopedia
Gooseneck Barnacle Pollicipes polymerus
So called because of its resemblance to a goose neck and head, the gooseneck barnacle forms dense colonies in crevices on rocky shores with strong waves. Barnacles anchor themselves to rocks by a tough, flexible stalk (peduncle), which also contains the ovaries. This is actually their “head” end. Once the gooseneck barnacle has attached itself to an object, it secretes a series of pale plates at the end of its stalk, forming a shell around its featherlike legs, which comb through the water for food. The legs face away from the sea, enabling the barnacle to feed by filtering out particles of detritus from returning tidal water as it funnels past them through cracks in the rocks. Gooseneck barnacles become sexually mature at about five years of age and may live for up to 20 years. The larval stage is free-living but depends on sea currents for its transport and survival. Colonies of gooseneck barnacles are susceptible to the damaging effects of oil pollution and they recover only slowly from disturbance.