Gooseneck Barnacle
Pollicipes polymerus

 

Physical Description

  • Crustacean with long, fleshy, flexible stalk permanently attached to hard surface.
  • Stalk, or neck, ranges from reddish-brown to brownish-black in coloration.
  • Many hard, pearlescent plates at top, protecting the body and internal organs.
  • Tiny feathery feet, called cirri, project from plates, and are used to both feed and breathe.
  • As they grow, they produce more plates.

Range

  • From southern Alaska to Baja California, Mexico.

Habitat

  • Found on rocky cliffs in the splash zone.
  • Often in high-energy, high wave environments because their fleshy necks can survive it well.
  • Often in crevices to avoid direct sunlight and limit drying out.
  • Often in colonies of other gooseneck barnacles.
  • Also found floating on marine debris in the open ocean.

Reproduction

  • Gooseneck barnacles reach maturity around age 5.
  • Although almost all other crustaceans have separate sexes, barnacles are hermaphrodites (each has both male and female organs).
  • Will only self-fertilize if no other gooseneck barnacle within 8 inches.
  • Since they are stationary, they have a very long, extendable penis (about seven times as long as their body diameter).
  • Eggs are brooded in the mantle cavity.
  • Newborn barnacles extend as one-eyed larvae that feed on plankton and molt several times until they look like miniature shrimp.
  • When the planktonic larva settles out of the plankton, it crawls around to find other gooseneck barnacles before permanently settling. They must be near other barnacles for future reproduction.

Diet

  • Filter-feeders.
  • Eat plankton, cypris larvae, small clams, hydroids, and amphipods.

Predators

  • Glaucous-winged gulls, sea stars, whelks.
  • Humans eat as a delicacy.

Interesting Facts

  • These are such a delicacy in Spain and Portugal, where they are often steamed and then dipped in hot, melted butter, that they can go for 100 Euros per plate! 
  • Though their long stalk looks like a goose’s neck, their name actually comes from a medieval belief that this is where baby geese actually hatched from! 
  • One of the most common organisms found on floating marine debris, their length can be used to give a minimum amount of time the item has been floating out at sea, as their length is proportional to their age.

Sources: AtlasObscura; Cabrillo Marine Aquarium; AnimalDiversity.org; animals.net

Photo: Kevin Lee