Distribution and migration of Japanese flounder Paralichthys olivaceus around western Wakasa Bay, the Japan sea, evaluated from tag, release and recapture experiment

A tag-release and recapture experiment of wild Japanese founder Paralichthy s olivaceus was conducted in western Wakasa Bay in order to evaluate their distribution and migration. A total of 599 immature and 278 adult fish were tagged and released in spring and early summer during the period from 1993 to 1998. Most of the immature fish were recaptured within 40 km from the r elease site until August. The number of recaptured immature fash near the r elease site (< 40 km) decreased after August, although some immature fish w ere recaptured. Some of the immature fish migrated westward more than 100 k m from the release site. No eastward migration was observed. On the other h and, most of the adult fish were recaptured within 40 km from the release s ite with a few exceptions in which fish migrated westward in winter or nort heastward in summer from the release site. The recapture of adult fish occu rred all year around in western Wakasa Bay. Those results suggest that imma ture flounder spend spring and summer inside western Wakasa Bay, then some of them migrate westward in autumn and winter, whereas most of the adult fl ounder stay in the Bay for the whole year around.