The distribution of ayu larvae and juveniles from the Kagami River were investigated around Urado Inlet, into which the river flows, from October 2004 to June 2005. The downstream swept larvae were distributed over the inside of inlet, and were never found outside the inlet. Vertically, they tended to be dispersed from the surface to the bottom, and to be concentrated at the surface when more developed. The larvae (yolk-sac to flexion stages) of 4-10 days old (chiefly 4-6 days old) occurred. In shallow waters around Urado Inlet, the larvae and juveniles continued to occur from November to May, in particular were assembled in the Kagami estuary located in the bottom part of inlet in January and February. Their main stages were postflexion around 20 mm BL. These facts suggest that the ayu larvae born in the Kagami River immigrate to shallow waters of the inner part of inlet, where they are nursed until upstream migration, after pelagic life in the inlet without migration into the open sea. Consequently, it is presumable that they perform a homing.
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