ABSTRACT
At the beginning of the 20th century, Schmidt (1922) conducted numerous expeditions and discovered that the spawning areas for both the European eel (Anguilla anguilla, Anguillidae) and the American eel (A. rostrata, Anguillidae) were located far offshore in the Sargasso Sea of the Atlantic Ocean. Approximately 70 years after Schmidt’s (1922) discovery, the spawning area of the Japanese eel (A. japonica, Anguillidae) was found in the North Equatorial Current to the west of the Mariana Islands, approximately 3000 km from their growth habitats in east Asia in 1991 (Tsukamoto 1992). Since this discovery, intensive investigations have been conducted almost every year for the last 20 years. The preleptocephali have been collected just after hatching (Tsukamoto 2006), and the eggs and maturing eels have been collected in the spawning area (Tsukamoto et al. 2011). These fi ndings have not been reported for 18 of the 19 anguillid eel species and such fi ndings and studies would further contribute towards understanding the life history, migration route and behaviour, and ecological involvement with other species for the other 18 eel species.
