FISHERIES RESEARCH INSTITUTE,MOA,TAIWAN

Three leptocephali of Japanese eel Anguilla japonica were collected in thepresumed spawning ground of 12o30(-14 o30(N and 131o30(-140o30(E, on 16 to 23August, 1995. It was the first time of such collection by Taiwanese researchers.Total lengths of the leptocephali were measured as 27.4, 28.8 and 31.4 mm,respectively. Their daily ages were estimated to be 46, 50 and 51 days bycounting otolith growth increments, and growth rates be 0.577-0.658 mm.d-1. Thedaily ages of these three leptocephali were back-calculated for birth dates beJuly 1 and 3, and the spawning dates were on June 2 and 4 of the lunar calendarwhich were in the period of new moon. This study confirms that Japanese eelspawns in summer. Based on the localities of collections and the westwarddirection of ocean current, the body lengths and the daily ages of these threeleptocephali are difficult to depict the spawning ground as previously known.Spawning ground is probably rather widely spread.