Studying early life history of the Anguilla bicolor pacifica by otolith daily increments

The Japanese eel (Anguilla japonica) was listed in the IUCN red list in 2014 as an endangered species, forming the bottle neck of sustainable eel aquaculture industry. To slow down the resource pressure of the Japanese eel, it is an important work to develop a new aquaculture species. In recent years, the culture of exotic eel species become more and more popular, especially on A. marmorata and A. bicolor pacifica. Their glass eels are mostly imported from the Philippines. Understanding the life history of these species is very helpful for the resource management as well as the industry development of the eels. According to previous studies, A. bicolor pacifica may spawn at west of the Mariana Islands and their leptocephali are transported by ocean currents to Taiwan, Philippines, and Sulawesi Island of Indonesia. Otolith microstructure of A. bicolor pacifica were examined in glass eels collected from Taiwan, Philippines, and Sulawesi Island of Indonesia. We test this hypothesis that the more away from the spawning ground for glass eel, the longer mean larval duration it would have. Our results find that Sulawesi has unusually shorter mean larval duration than other sampling sites. Hence, A. bicolor pacifica may have more than one spawning areas in the western north Pacific.