Occurrence of Caligus lalandei Barnard, 1948 (Copepoda, Siphonostomatoida)on amberjacks (Seriola spp.) in the western North Pacific

Caligus lalandei Barnard, 1948 (Caligidae, Siphonostomatoida) is redescribe d based on the materials occurring in the waters of East Asia. This parasit ic copepod is so far known only from the amber-jacks (Seriola spp.) outside of the western North Pacific. However, in 1989 it was discovered on "mojak o" (juveniles) of Seriola quinqueradiata collected off Azuma-cho and Yamaka wa-cho in Kogoshima Prefecture, Japan. In 1998 it appeared on Seriola lalan di caught in a set net installed off the coast near Kangreung, Korea and in the following year it was found parasitic on S. lalandi cultured in Tsukum i of Oita Prefecture, Japan. The possible origin of the occurrence of C. la landei in Japan and Korea is discussed; but, due to several unknown factors , it is inconclusive at this point of time whether the occurrence of C. lal andei in Japan and Korea is due to the "natural" or "artificial" process. H owever, the parasite has well established in its new habitat - the northern region of the western North Pacific.