Balanus glandula: a new alien barnacle from the west coast of North America, established on the northeast coast of Japan

摘要: A common littoral barnacle, Balanus glandula Darwin, 1854, (Crustacea, Cirripedia) from the west coast of North America was first reported in Mar del Plata port, Argentina 1974 (Bastida et al., 1980). Further studies showed that this species established along shore between 37 S and 47 (Vallarino Elias, 1997, Elias Vallarino, 2001, Rico Orensanz 2002). The also found opposite side Pacific; zone 38 30’N 42 40’N on northeast Honshu, Japan (Kado, 2003). It seems interesting B. introduced late 1960s or afterwards two regions. In case Japan, vectors for introduction were inferred to be cargo-ships carrying lumber NW US, From present (probably less than 30 years), successfully zone, especially big commercial ports. both regions have some ecological superiority over native communities. however, distribution is not continuous harbours, population densities do always correlate with distances invaded harbours. At locations common, even far these These new facts suggest local spread does depend only its larval dispersal. This study reports properties investigates role barges, tugboats similar vessels within as likely further spread.