RECRUITMENT MECHANISM OF THE TROPICAL GLASS EELS GENUS ANGUILLA IN THE POSO ESTUARY, CENTRAL SULAWESI ISLAND, INDONESIA

Abstract

In order to understand recruitment mechanism of the tropical anguillid glass eels in the Poso Estuary, Central Sulawesi Island, Indonesia, a year quantitative sampling field was conducted from May 2008 to April 2009. About 11181 specimens of glass eels were fished using line transects method of two triangular scoop nets through 13 times of new moon and 1761 specimens were preserved for examined in the laboratory. It was found that recruitment of glass eels occurred almost throughout the year of investigation and peak of recruitment occurred in August. Anguilla celebesensis and Anguilla sp. nov 1 were recruited in dry season, A. marmorata recruited in dry and rainy seasons, while A. interioris, A. bicolor pacifica and Anguilla spp. nov 2 recruited only in rainy season. Anguilla celebesensis (69.17%) was the most dominant species recruited in the estuary followed by A. marmorata (23.54%), Anguilla spp nov 1 (4.99%), Anguilla spp nov 2 (2.03%), A. interioris (0.14%) and A. bicolor pacifica (0.04%). The onset of recruitment as well as fluctuation of abundance of the tropical anguillid glass eels into Poso estuary were strongly associated with seasonal and circadian rhythmic as well as tidal and lunar cycles that occurred in the central Indonesian regions.