Pelagic Gooseneck Barnacle

Overview

The Pelagic Gooseneck Barnacle is a cosmopolitan crustacean commonly found drifting in tropical and subtropical open seas. Unlike rock-dwelling barnacles, this species leads a free-floating lifestyle by attaching itself to various buoyant objects, such as driftwood, seaweed, plastic debris, and the hulls of ships.

Appearance

This barnacle consists of two primary sections: a heart-shaped, flattened head called the capitulum and a long, flexible stalk known as the peduncle. The capitulum is protected by five smooth, translucent white plates that are often edged with scarlet or dark tissue. While the capitulum typically reaches about 5 cm in length, the tough, purplish-brown peduncle is highly variable and can grow significantly longer, sometimes exceeding 80 cm.

Biology & behavior

As a nonselective filter feeder, the barnacle extends feathery, brown appendages called cirri from between its plates to capture zooplankton, small crustaceans, and organic particles from the water column. It is a hermaphroditic species that utilizes a specialized organ for cross-fertilization. After internal incubation, the barnacle releases free-swimming larvae that eventually settle onto floating substrates to begin their adult life. These barnacles are often found in large clusters and are known to contribute to biofouling on maritime vessels.