Zoological Studies

Vol. 57, 2018

(update: 2018.06.27; 07.18) 

Reproductive Ecology and Biodiversity of Freshwater Eels around Sulawesi Island Indonesia

Jun Aoyama1,*, Sam Wouthuyzen2, Michael J. Miller3, Hagi Y. Sugeha2, Mari Kuroki4, Shun Watanabe5, Augy Syahailatua6, Fadly Y. Tantu7, Seishi Hagihara3, Triyanto8, Tsuguo Otake4, and Katsumi Tsukamoto3


1International Coastal Research Center, Atmosphere and Ocean Research Institute, The University of Tokyo, Otsuchi, Iwate 028-1102, Japan
2Research Centre for Oceanography, Indonesian Institute of Sciences, Ancol Timur, Jakarta 14430, Indonesia. E-mail: swouthuyzen@yahoo.com (Wouthuyzen), hysugeha@gmail.com (Sugeha)
3Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan. E-mail: michael.miller@nihon-u.ac.jp (Miller), hagihara.seishi@nihon-u.ac.jp (Hagihara), tsukamoto.katsumi@nihon-u.ac.jp (Tsukamoto)
4Department of Aquatic Bioscience, The University of Tokyo, Bunkyo, Tokyo 113-8657, Japan. E-mail: mari.kuroki@aqua.fs.a.u-tokyo.ac.jp (Kuroki), otake@aqua.fs.a.u-tokyo.ac.jp (Otake)
5Department of Fisheries, Kindai University, Nara 631-8505, Japan. E-mail: swpc@nara.kindai.ac.jp
6Centre for Deep-Sea Research, Indonesian Institute of Sciences, Poka, Ambon 97233, Indonesia. E-mail: augy.syahailatua@lipi.go.id
7Kampus Bumi Tadulako Tondo Palu, Tadulako University, Palu, Indonesia. E-mail: ftantu_wallacea@yahoo.com
8Research Center for Limnology, Indonesian Institute of Sciences, Bogor, Indonesia. E-mail: triyanto@limnologi.lipi.go.id

(Received 13 December 2017; Accepted 4 May 2018; Communicated by Hin-Kiu Mok)

Jun Aoyama, Sam Wouthuyzen, Michael J. Miller, Hagi Y. Sugeha, Mari Kuroki, Shun Watanabe, Augy Syahailatua, Fadly Y. Tantu, Seishi Hagihara, Triyanto Trie, Tsuguo Otake, and Katsumi Tsukamoto (2018) Sulawesi Island of north-central Indonesia is located in a region where at least 6 species of tropical anguillid eels are present, but the reproductive ecology and biodiversity of these eels in each area of the Indonesian archipelago remains poorly understood. Some information about these species was obtained from collections of their leptocephalus larvae made during several times of the year and from year-round collections of their recruitment-stage glass eels at a few locations. A sampling survey of anguillid leptocephali was conducted in March 2010 in both the Celebes Sea and Tomini Bay of Sulawesi Island to learn about the biodiversity and reproductive ecology of the eels in the region. Twenty-eight anguillid leptocephali were collected at 13 different stations, with genetic identification indicating that 3 species of eels had spawned in the two areas. Larvae were more abundant in the Celebes Sea (N = 21; 16.0-52.1 mm TL) than in Tomini Bay (N = 7; 9.6-54.8 mm). The abundant 16-21 mm size-class of Anguilla bornensis in the Celebes Sea indicated that species had recently spawned there, and spawning had also occurred in Tomini Bay by A. celebesensis (17.4 mm). These data and previous life history information suggest that A. celebesensis may have two spawning seasons in the Celebes Sea, but only one main spawning season in Tomini Bay. Anguilla borneensis may spawn at several times of the year in the Celebes Sea. Anguilla marmorata and A. biocolor pacifica spawn outside the Indonesian Seas, with A. marmorata recruiting in large numbers in the Sulawesi Island region during much of the year. Other spawning locations of A. celebesensis and A. interioris likely exist in Indonesian waters. Therefore, further research is needed to understand the reproductive ecologies and biodiversity of the tropical anguillid eels in each region of Indonesia in relation to geographic and climatic factors.

Key words: Freshwater eels, Reproductive ecology, Spawning area, Leptocephali, Sulawesi Island.

*Correspondence: E-mail: jaoyama@aori.u-tokyo.ac.jp