Invasion of Hawaiian shores by an Atlantic barnacle

A largely vacant niche in the upper mid-littoral zone of sheltered Hawaiian shores is now occupied by Chthamalus proteus Dando & Southward, 1980 (Crustacea, Cirripedia), otherwise found in the Caribbean, the Gulf of Mexico and Brazil. The identity of the species was established by morphological details and confirmed by allozyme electrophoresis. Previously, chthamaline barnacles have rarely been found fouling hulls of ships; this is the first recorded instance of regular occurrence on ships as well as of remote dispersal in the genus. While the introduction of C. proteus apparently has had little impact so far, there is a need to step up monitoring programs so as to prevent rather than simply detect future introductions.