Acorn, Thatch, Volcano, Buckshot...known by all simply as BARNACLES, these ubiquitous seashore creatures are often overlooked.

This is especially true early in their life. Like many invertebrates found at Haystack Rock, barnacles start out as microscopic larvae (pictured below), swimming freely in the water, searching for a place to call home.

To a barnacle, a suitable home is one that is close to other barnacles. This ensures that they will be able to reproduce when the time comes. The larvae are able to detect the presence of other barnacles through chemical recognition. The larvae will land on a rock or other surfaces and crawl around in ever-tightening spirals until it detects evidence of other barnacles. Then, it secretes a special adhesive (glue) from glands on its head and begins the process of building its hard, volcano-shaped shell.

Once constructed the barnacle lives out its life stuck head-first to the rock, using it's feet to bring food (microscopic plankton) into its shell and to its mouth.

The barnacle has two larval stages: Nauplius (below left) and Cypris (below right). Both images from www.microscopy-uk.org