Recruitment and movement of larval ayu occurring in the surfzone of a sandy beach facing Tosa Bay.

To elucidate the recruitment and movement process of larval ayuin the surf zone of a sandy beach facing Tosa Bay, 31 collectionswere made with a small seine net at intervals of approximately 5days from November 1990 to April 1991. On the basis of seasonalvariations in larval abundance, size, age, duration of residence,and the occurrence patterns of ayu in the surf zone, larval ayuwere classified into two groups: short-term resident (< 30days in duration) and long-term resident (90–120 days).The former appeared in the surf zone abundantly from mid-Novemberto mid-December and resided there for about 1 month until they reachedapproximately 25 mm BL. It is likely that larval ayu (short-termresident), which recruit abundantly to the surf zone, expand their distributionoffshore at approximately 25 mm BL. In contrast, the lattergroup were found after mid-December, and the population size wasmarkedly small although they stayed continuously in the surf zonefor 3–4 months until they reached approximately 40 mmBL. [ABSTRACT FROM AUTHOR]