Impact of El Nino 1997/1998 on the Successful Recruitment and Recovery of the Tropical Glass Eels (Anguilla spp) in the Poigar River Estuary, North Sulawesi Island, Indonesia

Impact of El Nino 1997/1998 was recorded during recruitment of the tropical glass eels (Anguilla spp) in the Poigar River estuary, North Sulawesi Island, Indonesia.  The glass eels recruited in the estuary with peak in 1997 and drastically decreased in 1998 before gradually increased from 1999 to 2002. Three species of the tropical glass eels were identified to enter the estuary. Two species of the Pacific tropical eels (Anguilla marmorata and A. bicolor pacifica) and one species of the Indonesian native tropical eel (A. celebesensis). In 1997, A. celebesensis was the most dominant species (73.6%) and followed by A. marmorata (25.2%) and A. bicolor pacifica (1.3%), respectively. However, species dominancy was replaced by A. marmorata from 1998 to 2002 with small increasing of A. bicolor pacifica from 1997 to 2002. Since the EL NINO phenomenon in 1997/1998 was reported to resulting higher SST in the Pacific Ocean, it was triggering a great oceanic migration escapement of the Pacific tropical eel leptocephali from unconvinient environment into their recruitment area in the tropical estuaries. The decreasing of the Indonesian native tropical eel, A. celebesensis, into the estuary after a great recruitment in 1997 were reflecting a long impact of EL NINO phenomenon on the successful recruitment and recovery of the tropical anguillid eels in the region.