Metamorphosis and inshore migration of tropical eels Anguilla spp. in the Indo-Pacific

In order to determine the early life history and recruitment mechanisms of tropical eels Anguilla spp. in the Indo-Pacific, the timing of metamorphosi s and age at recruitment to freshwater habitats were established from otoli th microstructure and microchemistry analyses of juveniles of Anguilla cele besensis, A. marmorata and A. bicolor bicolor. Otolith increment width mark edly increased from the age of 124 +/- 12.0 d (mean +/- SD) in A. celebesen sis, 120 +/- 13.0 d in A. marmorata (Philippines), 120 +/- 15.6 d in A. mar morata (Indonesia) and 139 +/- 15.9 d in A. bicolor bicolor The timing of t hese increases was coincident with drastic decreases in otolith Sr:Ca ratio s in each species, indicating the onset of metamorphosis from leptocephalus to glass eel. The mean duration of metamorphosis was 17 to 18 d in each sp ecies. Age at recruitment (mean +/- SD) was 157 +/- 13.7 d in A. celebesens is, 154 +/- 13.5 d in A. marmorata (Philippines), 152 +/- 15.2 d in A. marm orata (Indonesia) and 177 +/- 16.4 d in A. bicolor bicolor. In all species examined, close Linear relationships were found between ages at metamorphos is and recruitment, suggesting that individuals which metamorphosed earlier were recruited to freshwater habitats at a younger age.