Hamilton’s Thryssa, Thryssa hamiltonii Gray, 1835

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

Synonyms
Engraulis grayi Bleeker, 1851
Scutengraulis hamiltonii (Gray, 1835)
Stolephorus hamiltonii (Gray, 1835)
Thrissocles grayi (Bleeker, 1851)
Thrissocles hamiltonii Gray, 1835

Common/local names
English: Hamilton’s Thryssa
Bangladesh: Ram phasa  (রাম ফ্যাসা)

Distributions: India-west pacific (Talwar and Jhingran, 1991); Sind, through seas of India to the Malay Archipelago (Day, 1958); Bay of Bengal, eastern area of Indian ocean, North-south Quinsland, Pakistan, Persia bay (Shafi and Quddus, 2003)

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

Morphology: Body fusiform and strongly compressed. Ventral and drsal profile about equally convex. Snout prominent and above level of eye centre, usually at the level of upper rim of eye. Maxilla moderate or short, dilated above mandibular joint and tapering posteriorly and extends to base of pectoral fin or reaches beyond edge of gill cover. Mouth large with fine teeth in a single row on both jaws and also in vomer, palate, pterygoid and tongue. Eyes subcutaneous and belly with 16 to 19+8 or 9 keled scutes present at isthmus to anus. Lower part of first arch contain 12-14 (Talwar and Jhingran, 1991); 11-12 (Rahman, 1989 and 2005) gillrakers. Dorsal originate from nearer to snout than to caudal base. Pelvics are less than half f pectoral. Both pelvic and pectoral contain auxiliary scales. Lower lobe of caudal is longer.

Head 4.0-4.4 in SL; 5.0-5.4 in TL; height 3.2-4.0 in SL and 4.0-5.0 in TL. Eye diameter 4.0, snout 0.7-0.9 and interorbital 1.0. Abut 44 scales present in lateral line where abdominal scutes contain 26, prepelvic 15-16 and postpelvic 10-11 (Rahman,1989 and 2005)

Back of the fish is silvery and dark. Dorsal edge black and scapular region with black venules, fins are yellow in color.

Fin formula:
D. 1/14-15; P1.12; P2. 7; A. 40-41 (Rahman, 1989 and 2005)
D iii 10-12; A iii 32-39; P i 11-12; V i 6 (Talwar and Jhingran, 1991).

Maximum length: 19 cm (Rahman,1989 and 2005)

Habitats: Marine, pelagic, inshore, enters estuaries (Talwar and Jhingran, 1991); Estuaries and bay of Bengal (Rahman, 1989); Lives in sea, found in shoal (Shafi and Quddus, 2003)

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

Fishery info: Of no interest to fishery (Talwar and Jhingran, 1991).

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REFERENCES

Bleeker P (1851) Over eenige nieuwe soorten van Pleuronectoïden van den Indischen Archipel. Natuurkundig Tijdschrift voor Nederlandsch Indië 1:401-416.

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 andSons, London. 625 p.

Gray JE (1835) Illustrations of Indian zoology; chiefly selected from the collection of Major-General Hardwicke, F.R.S., 20 parts in 2 vols. Illustrations of Indian zoology; chiefly selected from the collection of Major-General Hardwicke, F.R.S., Pls. 1-202.

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. 245-246.

Rahman AKA (2005) Freshwater Fishes of Bangladesh, 2^nd edition, Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000, pp. 269-270.

Shafi M and Quddus MMA (2003) Bangopshagorer  Matsho Shampad (in bengali), Kabir Publication, Dhaka, Bangladesh, p. 145.

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. 144-145.

 

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