Anguilla bicolor, McClelland, 1844

Freyhof, JÖrg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, De Gruyter : 60

Anguilla bicolor

Common name. Shortfin Eel

Diagnosis. Distinguished from A. bengalensis by: ● dorsal origin slightly in front of anus / ● plain olive yellowish to dark-brown or black, silvery grey from jaw to anus. Size usually about 500–600 mm, rarely up to 1200 mm TL.

Distribution. In Arabian Peninsula, recorded from Yemen along Arabian Sea and Gulf of Aden but may occur elsewhere in coastal waters. Widespread in Indian Ocean from east coast of Africa to north-west Australia and Greater Sundaland.

Habitat. Mostly found in lowland and coastal areas, inhabiting estuaries, brackish waters, freshwater lakes, streams, ponds, and small rivers. In Malaysia, 75 % of adults have been found in freshwater, 20 % in coastal seawater, and 5 % in brackish water. Spawns in deep tropical and subtropical oceans.

Biology. Catadromous. Arabian eels not yet been extensively studied. Live up to 20 years, adults die after spawning. Very little known about marine phase. Leptocephali have never been found, and more information on spawning areas or early life history is needed. Believed to spawn during a broad, prolonged season (data from Sumatra). Migrates downstream in central Vietnam during storm season,

October–December. Feeds on small fish, crustaceans, and molluscs.

Conservation status. NT; due to decline in availability of both A. japonica and A. anguilla (species traditionally used for aquaculture and consumption), A. bicolor is next preferred species for plain eels, driving up demand for this species in East Asia. Although there are very little data available to estimate population changes, it is clear that number of glass eels exported worldwide is increasing rapidly to meet demand. Anguilla bicolor can be purchased online from many suppliers. If catches continue to increase at current rates, exploitation is likely to pose a significant threat to populations worldwide, and shortfin eel may soon be listed as an endangered species.

Remarks. Molecular data suggest that the Indo-West Pacific A. bicolor pacifica (from southern China, the Philippines, and the Indonesian islands of Borneo, Sulawesi, and New Guinea) may represent its own conservation unit or an independent species.

Further reading. Talwar & Jhingran 1992 (biology, identification); Pethiyagoda 1991 (habitat); Chino & Arai 2010 (occurrence in Indonesia); Crook & Nakamura 2013 (trade); Shiraishi & Crook 2015 (trade); Pike et al. 2020c (biology, distribution, conservation status).

Wadi Hadhramaut in Yemen, is the habitat of Anguilla bengalensis and several endemic species.