Abstract
To clarify the early life period distribution and migration pattern of Ryukyu-ayu (Plecoglossus altivelis ryukyuensis), investigations were conducted around Sumiyo and Yakeuchi Bays, Amamioshima Island, southern Japan, from November-2001 to May-2002. Larvaeand juveniles (from ca. 10 mm SL; 10 dayold) were present in brackish water inlets and near coastal shorelines, their persistence and frequency in brackish waters being longer and greater, respectively, than in seawater areas (recorded for only a few days in latter). Therefore, it was concluded that brackish waters were more important as nursery grounds for larvae and juveniles of Ryukyu-ayu than seawater areas.
