Indonesian Shortfin Eel, Anguilla bicolor McClelland 1844


Other Names: Bicolor Eel, Bicolour Eel, Freshwater Eel, Indian Ocean Eel, Indian Short-finned Eel, Northern Eel, Shortfin Eel

An Indonesian Shortfin Eel, Anguilla bicolor, caught at Unawatuna, Sri Lanka. Source: Theo Modder / FishBase. License: CC By Attribution-NonCommercial

Summary:

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.


Cite this page as:
Gomon, M.F. & Bray, D.J. 2017, Anguilla bicolor in Fishes of Australia, accessed 17 Nov 2018, http://fishesofaustralia.net.au/home/species/1424

Indonesian Shortfin Eel, Anguilla bicolor McClelland 1844

More Info


Distribution

Known from tropical waters of East and South Africa, across to the Western Indian Ocean; recorded in Australian waters from Crystal Creek, Warrender Hill to near the Fortesque River in the Kimberley region, Western Australia; also Christmas Island in the eastern Indian Ocean.

Mostly inhabits rocky pools in freshwater creeks. The species is also found in brackish estuaries and tidal flats, often buried in the muddy bottom.

The species is catadromous - individuals spend most of their lives in freshwater, before migrating to the sea to spawn.

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 of shortfin eel comprises two subpopulations: sometimes listed as the subspecies Anguilla bicolor bicolor (McLelland 1844), one subpopulation is found in the Indian Ocean from the east coast of Africa to northwestern Australia and greater Sundaland; while the other subpopulation, sometimes listed as the subspecies Anguilla bicolor pacifica, is found in the Indo-West Pacific from southern China, Philippines and the Indonesian islands of Borneo, Sulawesi and New Guinea (Schmidt 1923). The Indonesian Shortfin Eel is the only anguillid occurring in fresh waters of the Kimberly region of Western Australia.

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).

Anguilla bicolor is the only freshwater eel recorded form the Kimberley region of Western Australia.

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. 2017

Resources

Atlas of Living Australia 

Australian Faunal Directory

Catalog of Fishes  

OZCAM – Online Zoological Collections of Australian Museums

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.

Crook, V. 2010. Trade in Anguilla species, with a focus on recent trade in European Eel A. anguilla. TRAFFIC report prepared for the European Commission, 56 pp. PDF

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.

Jacoby, D., Harrison, I.J. & Gollock, M. 2014. Anguilla bicolor. The IUCN Red List of Threatened Species. Version 2015.2. . Downloaded on 15 August 2015.

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. & B. Pidgeon. 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., M.G. Allen, P. Bedford & M. Horstman. 2004. Fish fauna of the Fitzroy River in the Kimbeley region of Western Australia – including the Bunuba, Gooniyandi, Ngarinyin, Nyikina and Walmajarii Aboriginal names. Records of the Western Australian Museum 22: 147-161.

Ringuet, S., Muto, F. & Raymakers, C. 2002. Eels: their Harvest and Trade in Europe and Asia. TRAFFIC Bulletin 19(2): 80-106.

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. p. 1630-1636. In K.E. Carpenter and V.H. Niem (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., Y.-S. Lin & C.-S. Tzeng. 2009. A new Anguilla species and a reanalysis of the phylogeny of freshwater eels. Zoological Studies 46(6): 808-822.

Tweddle, D. & PH 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 Abstract

Quick Facts


CAAB Code:37056003

Biology:Migratory - catadromous

Conservation:IUCN Near Threatened

Fishing:Commercial species

Habitat:Freshwater/marine larvae

Max Size:1.1 metres TL

Species Image Gallery

Species Maps

CAAB distribution map