But to create baby barnacles, they must be fertilized by a neighbor. A retractable tube containing sperm can reach outside the shell as far as several inches to fertilize a nearby barnacle. Courtesy of Bullfrog Films and the National Film Board of Canada. Newborn barnacles emerge from their parent's shells as one-eyed larvae. These larvae settle to the bottom, and begin feeling around for a new home, beginning the cycle all over again.
Barnacles feed on plankton they sweep from the water with their fan-like feet.
The blue mussel is a competitor for space, possibly outgrowing and smothering barnacles. Excessive growth of the algae rockweed can also overpower a colony of barnacles.