Clues to the location of the spawning area and larval migration characteristics of Anguilla mossambica as inferred from otolith microstructural analyses

The spawning area location and the larval migration characteristics of Anguilla mossambica were studied through the examination of early life-history traits (ELHT) inferred from otolith microstructural analyses of 122 glass A. mossambica collected along the eastern coast of Madagascar, in the south-western Indian Ocean. Backcalculated hatching dates of leptocephali that recruited between November 2005 and February 2006 suggested that spawning was continuous from June to November 2005, although individual migration duration periods were variable. Larvae that exhibited the highest daily otolith growth rates had the shortest leptocephalus durations and total length (L-T) at recruitment, possibly because they reached the competence to metamorphose more rapidly and to recruit to fresh waters. Migration durations and L-T increased from north to south on the Malagasy eastern coast, supporting earlier suggestions that A. mossambica spawns north-east of Madagascar, west of the Mascarene Ridge in the Indian Ocean.