Synonyms:
Siluris attu, Bloch, 1801
Silluris boalis Hamilton, 1822
Wallagonia attu Smith, 1945
Wallago attu Day, 1878
Wallago attu Shaw and Shebbeare, 1937
Wallago attu Bhuiyan, 1964
Wallago attu Qureshi, 1965
Common name: Boal
Local name: Boal
Taxonomy position:
Phylum- Chordata
Class- Oesteichthyes
Order- Siluriformes
Family- Siluridae
Genus- Wallago Bleeker
Fin formula:
D. 5; P1.1/13-14; P2. 10; A. 85-89. (Rahman, 2005)
D 5; A iii 74-93; P I 13-15; V i 7-9 (Talwar and Jhingran, 1991)
Description of the species:
Elongated body is laterally compressed. Eyes are small. Mouth wide, its gape extends posteriorly to beyond eyes. Barbels are two pairs; among them, maxillary pair is long and extend posteriorly to well beyond origin of anal fin and the mandibular pair is much shorter, about as long as snout. Dorsal fin is short. Pectoral spine is weak. Caudal fin is deeply forked. Body colour greyish or yellowish grey in above and whitish in below but the fins grey. (Rahman, 1989; Rahman, 2005; Mohsin, 2007; Talwar and Jhingran, 1991)
According to the Day (1889), the maximum length is about 1.86 meter. The species may attain 20 cm in total length and weight more than 45 kg (Talwar and Jhingran, 1991). Longest specimen in collection is 30 cm by author.
Habit and Habitat:
Wallago attu inhabit fast running as well as sluggish water of deep and shallow poois, beels, haors, rivers and streams of Bangladesh. It is voracious, carnivorous and predatory; it can not be stocked in pond with other fishes. It is also called fresh water shark an account of its vicious biting and feeding habits (Bhuiyan, 1964).
Economic importance:
This fish is a commercially important species and an important food fish in Bangladesh. Good price in the market throughout the year.
Status and Conservation:
This fish is available in Rajshahi area and not listed in IUCN Red book of threatened fish of Bangladesh by IUCN Bangladesh (IUCN Bangladesh, 2000). Siltation and drying up of rivers, beels, haors, and similar water-bodies, increased fishing effort and fishing by dewatering of habitats are the potential threats (Mohsin, 2007).
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References:
Bhuiyan, A. L. 1964. Fishes of Dacca. Asiatic Society of Pakistan, Dacca. p 51.
Bloch, 1801, Syst Ichth., p. 378.
Day, F. 1889. The fauna of British India including Burma and Ceylon. (London) Fish. 1: 548 pp; 2: 509 pp.
Day, F. 1878, The Fishes of India: being a Natural History of the Fishes Known to Inhabit the seas and fresh waters of India, Burma and Ceylon. Text and Atlas in 4 parts. William Dawson & Sons Ltd. London, p. 479.
Hamilton, F., 1822. An account of the fishes found in the river Ganges and its branches, Edinburgh & London, Fishes Ganges, p. 154
IUCN Bangladesh. 2000. Red Book of Threatened Fishes of Bangladesh. IUCN- The World Conservation Union. xii+116 pp.
Mohsin, A.B.M. 2007. Wallago attu (Schneider, 1801). In: Siddiqui, K.U., Islam, M.A., Kabir, S.M.H., Ahmed, M., Ahmed, A.T.A., Rahman, A.K.A., Haque, E.U., Ahmed, Z.U., Begum, Z.N.T., Hasan, M.A., Khondker, M., and Rahman, M.M. (eds.). Encyclopedia of Flora and Fauna of Bangladesh, Vol. 23. Freshwater Fishes. Asiatic Society of Bangladesh, Dhaka. p.129.
Qureshi, M. R. 1965. Common Freshwater Fishes of Pakistan. Karachi VIII. 61pp.
Rahman, A.K.A. 2005. Freshwater Fishes of Bangladesh (Second edition). The Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000. 394 pp.
Rahman, A.K.A. 1989. Freshwater Fishes of Bangladesh. The Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000. p 165.
Shaw and Shebbeare, 1937, The Fishes of Northern Bangal. Journal of Royal Asiatic Society of Bengal Science. p 84.
Smith, H.M., 1945 The fresh-water fishes of Siam, or Thailand. Bull. U.S. Natl. Mus. 188:633 pp.
Talwar, P. K. and Jhingran, A. G., 1991. Inland Fishes of India and Adjacent Countries. Volume 1. Oxford & IBH Publishing Co. Pvt. Ltd. New Delhi, Calcutta. p 590.
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