Indonesian Shortfin Eel, Anguilla bicolor McClelland 1844
An Indonesian Shortfin Eel, Anguilla bicolor, caught at Unawatuna, Sri Lanka. Source: Theo Modder / FishBase. License: CC By Attribution-NonCommercial
A large olive to dark bluish-brown freshwater eel with a paler belly, dark brown to blackish fins, and elongate, yellow nostrils tipped with orange that protrude forward above the mouth.
The Indonesian Shortfin Eel spends most of its life in lowland freshwater streams and pools before migrating to the sea to spawn.
Indonesian Shortfin Eel, Anguilla bicolor McClelland 1844
More Info
|
Distribution |
Crystal Creek, Warrender Hill, to near the Fortesque River in the Kimberley region, Western Australia; also Christmas Island in the eastern Indian Ocean. Elsewhere the species occurs in the tropical Indo-west Pacific. Mostly inhabits rocky pools in freshwater creeks. The species is also found in brackish estuaries and tidal flats, often buried in the muddy bottom. Individuals spend most of their lives in freshwater, before migrating to the sea to spawn. On Christmas Island, a single juvenilewas collected in a baited trap in a subterranean cave with an opening to the sea. Large adults are also commonly sighted in some shallow creeks. |
|
Features |
Dorsal fin 240-245; Anal fin 200-220; Vertebrae 106-114. Body elongate, tubular and snake-like, with a moderately small head, small eyes, and a moderately large, horizontal mouth reaching well beyond the posterior edge of the eyes. Jaws with fine teeth in a broad band on each side of both jaws and on vomer, vomerine patch much shorter than bands laterally in jaws; no toothless groove between teeth in front of jaw. Gill openings small, just in front of lower half of pectoral fin bases. Dorsal, anal and caudal fins confluent; dorsal fin origin just in front of, or just behind vertical line drawn through anus; ventral fins absent; pectoral fin small and fan-like. Scales tiny, elongate, embedded deeply in skin; lateral line straight, not associated with scales. |
|
Colour |
Dark brown, tan or whitish on belly; fins dark brown to blackish. |
|
Feeding |
Feeds on small fishes, crustaceans and molluscs. Tweddle & Skelton (2016) hypothesised that the striking and highly visible yellow nostrils function as lures to attract prey. |
|
Biology |
Adults may remain in freshwater environments for 20 years or more before migrating to the sea to breed and then die. Following spawning, the small pelagic eggs float toward the surface where they hatch into leptocephalus larvae. The larvae are transparent, elongate, compressed and leaf-like. Leptocephali are believed to be passively transported to the continental shelf by oceanic currents before metamorphosis to the glass eel stage. During metamorphosis to glass eel stage, a reduction in body length and width and loss of teeth occurs. Glass eels move shoreward into estuaries where they adapt to reduced salinities and develop rapidly into fully pigmented elvers with teeth and full stomach development. This is followed by a secondary upstream migration into freshwater. |
|
Fisheries |
Juvenile and adults life stages of freshwater eels are harvested in Southeast Asia, and traded globally for human consumption and for use in leather products. Adults migrating back to sea to spawn are vulnerable to fishing pressure. Wild-caught juvenile eels or glass eels, that form the basis of this trade, are exported in very large numbers, mostly to markets in East Asia, particular in Japan and mainland China. |
|
Conservation |
IUCN Red List of Threatened Species: Near Threatened. The species has been assessed as Near Threatened due to the international trade for human consumption, along with the use of freshwater eels for leather products. |
|
Remarks |
This species is known as Lanyi by the Bunuba language group in the Kimberley. |
|
Similar Species |
Anguilla bicolor is most similar to Anguilla obscura, and the two species can only be reliably separated by their vertebral count and/or genetic analyses (Watanabe et al. 2004). This is the only freshwater eel recorded form the Kimberley region of Western Australia. |
|
Etymology |
The specific name bicolor is from the Latin bi- (= two) and color = (colour, hue), in reference to the dark olive-green to brown colour above and whitish colour below. |
|
Species Citation |
Anguilla bicolor McClelland 1844, Calcutta J. Nat. Hist. 5(18): 178, 202, 209, Pl. 6 (fig. 1). Type locality: Sandoway, Malay coast, India. |
|
Author |
Gomon, M.F. & Bray, D.J. 2022 |
|
Resources |
Indonesian Shortfin Eel, Anguilla bicolor McClelland 1844
References
Allen, G.R. 1989. Freshwater Fishes of Australia. T.F.H. Publications, 240 pp.
Allen, G.R., Midgley, S.H. & M. Allen. 2002. Field Guide to the Freshwater Fishes of Australia. Western Australian Museum, 394 pp.
Arai, T. & Chino, N. 2019. Variations in the migratory history of the tropical catadromous eels Anguilla bicolor bicolor and A. bicolor pacifica in south-east Asian waters. Journal of Fish Biology 94(5): 752-758.
Arai, T. & Kadir, S.R.A. 2017. Diversity, distribution and different habitat use among the tropical freshwater eels of genus Anguilla. Scientific Reports 7:7593: 1–12.
Arai, T., Limbong, D., Otake, T. & Tsukamoto, K. 2001. Recruitment mechanisms of tropical eels Anguilla spp. and implications for the evolution of oceanic migration in the genus Anguilla. Marine Ecology Progress Series 216: 253–264.
Crook, V. & Nakamura, M. 2013. Glass eels: Assessing supply chain and market impacts of a CITES listing on Anguilla species. TRAFFIC Bulletin 25(1): 24-30.
Hobbs, J-P.A., Newman, S.J., Mitsopoulos, G.E.A., Travers, M.J., Skepper, C.L., Gilligan, J.J., Allen, G.R., Choat, H.J. & Ayling, A.M. 2014. Checklist and new records of Christmas Island fishes: the influence of isolation, biogeography and habitat availability on species abundance and community composition. Raffles Bulletin of Zoology Supplement 30: 184–202 See ref online
Hui, T.H., Maruse, T., Fujita, Y., Kiat, T.S. 2014. Observations on the fauna from submarine and associated anchialine caves in Christmas Island, Indian Ocean Territory, Australia. Raffles Bulletin of Zoology, Supplement 30: 406-418. See ref online
Kuroki, M., Aoyama, J., Wouthuyzen, S., Sumardhiharga, K.O., Miller, M.J., Minagawa, G. & Tsukamoto, K. 2007. Age and growth of Anguilla bicolor bicolor leptocephali in the eastern Indian Ocean. Journal of Fish Biology 70: 538-550.
Larson, H.K. & Pidgeon, B. 2004. New records of freshwater fishes from East Timor. The Beagle, Records of the Museums and Art Galleries of the Northern Territory 20: 195-198.
McClelland, J. 1844. Apodal fishes of Bengal. Calcutta Journal of Natural History 5(18): 151-226, Pls. 5-14.
Miller, J.M. & K. Tsukamoto. 2004. An introduction to leptocephali biology and identification. Ocean Research Institute, The University of Tokyo. 96 pp.
Minegishi, Y., Gagnaire, P-A., Aoyama, J., Bosc, P., Feunteun, E., Tsukamoto, K. & Berrebi, P. 2012. Present and past genetic connectivity of the Indo-Pacific tropical eel Anguilla bicolor. Journal of Biogeography 39: 408-420.
Morgan, D.L., Allen, M.G., Bedford, P. & Horstman, M. 2004. Fish fauna of the Fitzroy River in the Kimberley region of Western Australia – including the Bunuba, Gooniyandi, Ngarinyin, Nyikina and Walmajarii Aboriginal names. Records of the Western Australian Museum 22: 147-161. https://doi.org/10.18195/issn.0312-3162.22(2).2004.147-161
Pike, C., Crook, V., Jacoby, D. & Gollock, M. 2020. Anguilla bicolor (amended version of 2019 assessment). The IUCN Red List of Threatened Species 2020: e.T166894A176494582. https://dx.doi.org/10.2305/IUCN.UK.2020-3.RLTS.T166894A176494582.en. Downloaded on 27 August 2021.
Ringuet, S., Muto, F. & Raymakers, C. 2002. Eels: their Harvest and Trade in Europe and Asia. TRAFFIC Bulletin 19(2): 80-106.
Shiraishi, H. & Crook, V. 2015. Eel market dynamics: An analysis of Anguilla production, trade and consumption in East Asia. TRAFFIC, Tokyo.
Skelton, P.H. 1993. A complete guide to the freshwater fishes of southern Africa. Southern Book Publishers, Ltd.: i-xiii + 1-388.
Smith, D.G. 1999 Anguillidae. Freshwater eels. pp. 1630-1636 in Carpenter, K.E. & Niem, V.H. (eds.) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Vol. 3. Batoid fishes, chimaeras and bony fishes part 1 (Elopidae to Linophrynidae). FAO, Rome.
Sugeha, H.Y. & Suharti, S.R. 2008. Discrimination and distribution of two tropical short-finned eels (Anguilla bicolor bicolor and Anguilla bicolor pacifica) in the Indonesian Water. The Nagisa Westpac Congress: 1-14.
Teng, H.-Y., Lin, Y.-S. & Tzeng, C.-S. 2009. A new Anguilla species and a reanalysis of the phylogeny of freshwater eels. Zoological Studies 46(6): 808-822.
Tweddle, D. & Skelton, P.H. 2016. Could the elongate yellow-orange nostrils of Anguilla bicolor McClelland, 1844 function as fishing lures? African Journal of Aquatic Science 41(4): 495-497. http://dx.doi.org/10.2989/16085914.2016.1240065
