HABITAT

Common acorn barnacles make their homes on a variety of surfaces.  They, typically, attach to rocks but are also common on man-made surfaces such as pilings and boats.  On rocky shores they often look like a white band in the mid intertidal zone.  The lower edge of the band, probably, marks the upper limit of predators such as purple sea stars and wrinkled whelks.    

White barnacle band

Photo by Bill Austin, Marine Ecology Centre