HRAP Online Encyclopedia

Barnacles

Often confused as part of the rocks, barnacles are actually a member of the arthropod phylum along with crabs and shrimp. The outer shell protects the soft bodied animal within from predators. When underwater, the shells will open and the barnacle will extend its cirri - a fan like appendage - to catch plankton. Barnacles are upside down on the rocks! They’re attached to the rock at their head and feed using their modified legs (cirri). Like other arthropods, barnacles will shed their cirri exoskeletons periodically and these feather-like structures can be found in the tide pools or wrack line around Haystack. Most barnacles are hermaphrodites, having both male and female sex organs. This makes it easy to fertilize their neighbors while living in such close proximity. Each barnacle broods the eggs internally until the larva are released to settle somewhere else on their own. Barnacles grow on most of the rocks in the marine garden, when visiting please walk on the sand to avoid harming these little creatures.