Species of goose barnacles are characterized by their long, fleshy stalks and calcareous plates, which protects their body (2). Goose barnacles are sessile, attaching themselves to rocks in the intertidal or driftwood via glue secreted by a cement gland (1). They almost always found in patches with other goose barnacles with their cyprid stage attaching where adult goose barnacles are present (1)(2). Additionally, predation by seabirds contributes to the patchy distribution of goose barnacles (5). Goose barnacles frequently compete with California mussels for space (5). They are omnivores, feeding by extending their cirri, long feeding legs, into the water and waiting for particles to be entangled, where the cirri are brought back into the shell and scrapped clean by its mouth (4). Interestingly, while goose barnacles are hermaphrodites they do not self-fertilize (3).
(1) Allen, R. K. (1977). Common Intertidal Invertebrates of Southern California (Revised ed.). Palo Alto: Peek Publications.
(2) Gooseneck Barnacles. Cabrilo Marine Aquarium. Retrieved March 04, 2018
(3) Hilgard, G. H. (1960). A Study Of Reproduction In The Intertidal Barnacle, Mitella Polymerus, In Monterey Bay, California,. The Biological Bulletin, 119(2), 169-188.
(4) Howard, G. K., & Scott, H. C. (1959). Predaceous Feeding in Two Common Gooseneck Barnacles. Science, 129(3350), 717-718.
(5) Meese, R. J. (1993). Effects of predation by birds on gooseneck barnacle Pollicipes polymerus Sowerby distribution and abundance. Journal of Experimental Marine Biology and Ecology,166(1), 47-64.
(Photograph) Lovell and Libby Langstroth © California Academy of Sciences
- rocky intertidal