Species composition and inshore migration of the tropical eels Anguillaspp. recruiting to the estuary of the Poigar River, Sulawesi Island

Abstract

In order to determine the species composition and inshore migration of the tropical eels Anguilla spp. migrating to an Indonesian river, we collected 21 633 glass eels at the mouth of the Poigar River, north Sulawesi Island, throughout 1997, and subjected these samples to both morphological examination and polymerase chain reactionrestriction fragment length polyrnorphism (PCR-RFLP) analysis. Three species, Anguilla celebesensis, A. marmorata and A. bicolorpacifica, were found throughout the season in fluctuating abundance, while the previously recorded A. borneensis was not recognized in the study. A. celebesensis constituted a dominant 88.3 % of all glass eels migrating to the Poigar River in 1997, and was seen throughout most of the year, with a peak in May and June. A. marmorata (11.3%) was also seen throughout most of the year, with peak occurrence in June. A. bicolorpacifica (0.4 %) occurred only in January, March, April, October and December. Inshore migrationConsiderable knowledge has been accumulated on the inshore migration and early life history of juveniles of numerous temperate anguillid species, such as

Tropical eels Anguilla spp. recruiting to Réunion Island in the Indian Ocean: taxonomy, patterns of recruitment and early life histories

“…Present data on the 4 Indian eels from literature and from present study 2001a). According to available data, insular recruitment of A. marmorata occurs throughout the year in its Pacific distribution area (Marquet & Lamarque 1986, Marquet 1987, Arai et al 1999b, with different seasonal peaks occurring locally in response to regional hydroclimatic conditions. In Indonesia and the Philippines, A. marmorata recruitment peaks in February to March (Tabeta et al 1976, Budimawan 1997, Arai et al 2002, while in French Polynesia 2 annual peaks occur, 1 in January to February and 1 in March to April (Marquet 1992).…”

Comparison of early life history between New Zealand temperate eels and Pacific tropical eels revealed by otolith microstructure and microchemistry

“…Total length, predorsal, preanal and ano-dorsal lengths of each specimen were measured to the nearest 0.1 mm, and pigmentation stages were determined according to Bertin (1956). All specimens were identified morphologically (Ege 1939, Tabeta et al 1976 and genetically (Arai et al 1999a).…”

“…In addition, the 3 tropical species studied here have been found to recruit into freshwater at the Poigar River, Sulawesi Island, Indonesia (Fig. 1), throughout the year in varying abundances, indicating almost year-round spawning for A. marmorata and A. celebesensis (Arai et al 1999a). The greatest abundance of A. marmorata and A. celebesensis during recruitment was in June, but that of A. bicolor pacifica was much more sporadic.…”

Recruitment mechanisms of tropical eels Anguilla spp. and implications for the evolution of oceanic migration in the genus Anguilla

“…Of the latter, 7 species/subspecies occur in the western Pacific around Indonesia: A. celebesensis, A. interioris, A. nebulosa nebulosa, A. marmorata, A. borneensis, A. bicolor bicolor and A. bicolor pacifica (Ege 1939, Castle & Williamson 1974, Arai et al 1999a). Recent mitochondrial DNA analysis has revealed that A. borneensis from Borneo Island is closest to the ancestral form among the 15 presently known species .…”