Category: Fishes | Resource

Oblique-jaw thryssa, Thryssa purava (Hamilton, 1822)

Systematic position
Phylum: Chordata
Class: Actinopterygii (Ray-finned fishes)
Order: Clupeiformes (Herrings)
Family: Engraulidae (Anchovies)
Genus: Thryssa
Species: T. purava

Synonyms
Clupea purava (Hamilton, 1822)
Engraulis annandalei (Chaudhuri, 1916)
Engraulis kempi (Chaudhuri, 1916)
Engraulis purava (Hamilton, 1822)
Engraulis rambhae (Chaudhuri, 1916)
Thryssa megastoma (Swainson, 1839)

Common/local names
English: Oblique-jaw thryssa and Gangetic ancovy

Distributions: Bangladesh (Rahman, 1989 and 2005). East coast of India, possibly also Bangladesh and Myanmar (Talwar and Jhingran, 1991). Sea and estuaries of Sindh, both sides of India, also the Malay Archipelago (Day, 1958). Bay of Bengal, eastern area of Indian Ocean, Persia gulf, Pakistan, Malay etc. (Shafi and Quddus, 2003).

Conservation status: Not threatened in Bangladesh (IUCN Bangladesh, 2000).

Morphology: Body fusiform and deeply compressed. Keeled belly present. Abdominal profile more arched than that of dorsal. Snout pointed, projecting and tip of snout present few above of eye centre. Maxilla moderate and projecting slightly beyond the edge of operculum or reaches to halfway of pectoral fin base (that means tapering portion extends to roof of pectoral). It is also dialated above mandibular joint. Angle of mouth rather oblique. Both of the jaws contain fine teeth (Rahman, 1989 and 2005) or only lower jaw that is slightly enlarged contain teeth (Talwar and Jhingran, 1991) and 40 along ramus of lower jaw. Lower part of first gill arch contain 17 to 21 (usually 18 or 19) raker (Talwar and Jhingran, 1991), or 17 to 18 gill raker present on lower arm of first arch (Rahman, 1989 and 2005) and their serrae is uneven but clumped. Subcutaneous eyes present. Dorsal fin present more or less at the mid between tip of snout and base of caudal. Dorsal fin base starts from entirely in advance of origin of anal. Pectoral reaches to pelvic. Caudal fin forked and upper lobe is shorter than lower one.

Head 4.7-4.9 in standard; 5.8-5.9 in total length. Eye diameter 4.0, snout 0.7 and interorbital 1.0 (Rahman, 1989 and 2005). 15 t 17 + 10 or 11 (Talwar and Jhingran, 1991); 16 + 11 (Rahman, 1989 and 2005) scutes present. 46 scales present in lateral line.

Back of the fish is blue (Rahman,2005) or brownish (Talwar and Jhingran, 1991), flanks and belly silvery. A prominent dark spot present behind the upper part of gill opening and faint dark line along back. Fins are hyaline.

Fin formula:
D. 1/13; P1. 14; P2. 6; A. 42-47 (Rahman, 1989 and 2005)
D iii 9-12; A iii 38-44; P i 14; V I 6 (Talwar and Jhingran, 2001).

Maximum length: 11.6 cm TL (Rahman, 1989 and 2005) and 15.5 cm SL (Talwar and Jhingran, 1991).

Habitats: Marine, pelagic, mostly inshore and entering estuaries and brackish water (Talwar and Jhingran, 1991). Estuaries and tidal rivers (Rahman, 2 1989 and 005). Lives in coastal water (Shafi and Quddus, 2003). Recorded from river Rupsa, Khulna (Bangladesh) (Rahman, 1989 and 2005).

Food and feeding: Lives on plankton (Shafi and Quddus, 2003).

Fishery information: Common fish species and contributor in artisanal catches of clupeoids in the Chikla lake (Orissa) and the Hoogly estuary (West Bengal) (Talwar and Jhingran, 1991).

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REFERENCES

Chaudhuri BL (1916) Fauna of the Chilka Lake. Fish. Part I. Memoirs of the Indian Museum 5(4): 403-439.

Day F (1958) The Fishes of India: being a Natural History of the fishes known to inhabit the seas and freshwater of India., Burma and Ceylon. Reproduced in 1958 by William Dowson and Sons, London. 629 pp.

Hamilton F (1822) An account of the fishes found in the river Ganges and its branches. Edinburgh & London. An account of the fishes found in the river Ganges and its branches.: i-vii + 1-405, Pls. 1-39.

IUCN Bangladesh (2000) Red book of threatened fishes of Bangladesh, IUCN- The world conservation union. xii+116 pp.

Rahman AKA (1989) Freshwater Fishes of Bangladesh, 1st edition, Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000, pp. 244-245.

Rahman AKA (2005) Freshwater Fishes of Bangladesh, 2nd edition, Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000, pp. 268-269.

Shafi M and Quddus MMA (2003) Bangopshagorer  Matsho Shampad (in bengali), Kabir publication, Dhaka, Bangladesh p. 147.

Swainson W (1839) The natural history and classification of fishes, amphibians, & reptiles, or monocardian animals. Spottiswoode & Co., London. Nat. Hist. & Class. i-vi + 1-448.

Talwar PK and Jhingran AG (1991) Inland Fishes of India and Adjacent Countries, Vol. 1, Oxford & IBH Publishing Co. Pvt. Ltd. New Delhi-Calcutta, pp. 146-147.

 

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MS Student, Department of Fisheries, University of Rajshahi, Rajshahi-6205, Bangladesh. Email: smanaser@gmail.com; smanaser@bdfish.org. More...

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