Category: Fishes | Resource

Bigeye ilisha, Ilisha megaloptera (Swainson, 1839)

Systematic position
Phylum: Chordata
Class: Actinopterygii (Ray-finned fishes)
Order: Clupeiformes (Herrings)
Suborder: Clupeoidei
Family: Pristigasteridae (Longfin herrings)
Subfamily: Pelloninae
Genus: Ilisha
Species: I. megaloptera

Synonyms
Clupanodon motius Hamilton, 1822
Clupea megalopterus Swainson, 1839
Clupea parva Swainson, 1839
Ilisha dussumieri (Valenciennes, 1847)
Ilisha motius (Hamilton, 1822)
Pellona dussumieri Valenciennes, 1847
Pellona megaloptera (Swainson, 1839)
Pellona russellii Bleeker, 1852
Platygaster macropthalma Swainson, 1839

Common name
English: Bigeye ilisha and Bigeye herring
Bangladesh: Chaukka (চৌখ্যা) and Peti chaukka (পেটি চৌখ্যা)
India: Phansa (West Bengal) (Talwar and Jhingran, 1991)

Distributions: Indian Ocean (Bombay to the Bay of Bengal) and Java Sea (Talwar and Jhingran, 1991).

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

Morphology: Body fusiform, deep moderately and compressed strongly. Dorsal profile is nearly straight and convex ventral profile present. Body depth is 2.6-3.5 times in standard length. Upper jaw contains distinct median notch, lower jaw included when mouth firmly shut. Maxilla extending to below the middle of the eye. Eyes are large and occipital converge slightly posteriorly an ridges on head. Teeth present in jaws, palate and tongue. 24-26 (Rahman,1989 and 2005); 21-25 (Talwar and Jhingran, 1991) gillraker present on the lower part of the first arch.

Head 4.0-4.4 in standard, 5.0-5.4 in total length. Height 3.2-3.5 in standard, 4.0-4.4 in total length. Eye 2.5-2.7; Snout 0.7 and interorbital 0.5 (Rahman,1989 and 2005). Median lateral series contain 45-47 scales and 16 rows before dorsal. 16-18  prepelvic, 8-9  post pelvic (Rahman,1989 and 2005).

Dorsal originates from nearer to snout than to caudal base. Pelvic small and slightly longer than yhe diameter of eye. Caudal fin forked and longer lower lobe present. Dorsal fin inserted or originate slightly before midpoint of the body. Anal fin origin under the hind part of dorsal fin base. Vertical stripe on scales present which traverses whole scale or overlapped across centre of scale. Swim bladder present in either side of haemal spine consisting two tubes passing back in the muscle.

Body silvery with mother of pearl reflections. Dorsal profile dark, upper flanks light brown. By removing scales from the side can help to show a burnished band. Dorsal and caudal orange in color with dark outer edges Un-branched pectoral ray present uniformly and tipped with black spot and first eight or nine fin-rays darkly pigmented towards their tip, remaining rays hyaline. Anal margin black and caudal fin dusted with dark pigmented. Dotted pre-maxillary and anterior part of maxillary present. Scales and fins contain minute dots.

Fin formula:
D. 2-3/12-14; P1. 13-15; P2. 7; A. 2-3/36-39 (Rahman,1989 and 2005; Siddique et al., 2007)
D. iii 14-15; A ii 46-52; P I 15-17; V I 6 (Talwar and Jhingran, 1991).

Maximum lengths: 7.4 cm (Rahman, 1989 and 2005), 27.5 cm (Talwar and Jhingran, 1991) and 28 cm (Huda et al., 2003).

Habitats: Inshore species found into the upper end of the tidal zone (Siddique et al., 2007). Fairly common  in river Meghna and its branches, especially during rainy season (Rahman,1989 and 2005). Available in the Sundarbans (Huda et al., 2003).

Food and feeding habit: Feeds on fishes, crustaceans, amphipods, occasionally polychaetes, tunicates and small amount of algae and diatoms.

Ecological role: Control water pollution by consuming detritus (Siddique et al., 2007).

Fishery info: It has a minor commercial importance and don’t fetch a good price in the market.

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REFERENCES

Bleeker P (1852) Bijdrage tot de kennis der ichthyologische fauna van Singapore. Natuurkundig Tijdschrift voor Nederlandsch Indië 3:51-86.

Cuvier G and Valenciennes A (1847) Histoire naturelle des poissons. Tome dix-neuvième. Suite du livre dix-neuvième. Brochets ou Lucioïdes. Livre vingtième. De quelques familles de Malacoptérygiens, intermédiaires entre les Brochets et les Clupes. Histoire naturelle des poissons. 19: i-xix + 1-544 + 6 pp., Pls. 554-590.

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.

Huda MS, Haque ME, Babul AS and Shil NC (ed.) (2003) Field guide to finfishes of Sundarban, Aquatic resources division, Sundarban, Boyra, Khulna, Bangladesh, p. 65.

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. 253-254.

Rahman AKA (2005) Freshwater Fishes of Bangladesh, 2nd edition, Zoological Society of Bangladesh, Department of Zoology, University of Dhaka, Dhaka-1000, pp. 277 -278.

Siddiqui KU, Islam MA, Kabir SMH, Ahmad ATA, Rahman AKA, Haque EU, Ahmed ZU, Begum ZNT, Hasan MA, Khondker M and Rahman MM (eds) (2007) Encyclopedia of Flora and Fauna of Bangladesh, Vol. 23. Freshwter Fishes. Asiatic Society of Bangladesh, Dhaka. p. 17.

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. 119-120.

 

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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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