Scad Mackerel, Grammatorcynus bilineatus (Rüppell 1836)

Other Names: Doublelined Mackerel, Double-lined Mackerel, Shark Mackerel

A Scad Mackerel, Grammatorcynus bilineatus, at a cleaning station in southeast Asia, 2012. Source: Keith Wilson / Flickr. License: CC by Attribution-NonCommercial


A slender metallic bluish-green mackerel becoming silvery below, with no spots on the belly, a relatively large eye, and a divided lateral line with the lower part curving down behind the pectoral fin and running along the lower side to the caudal peduncle.

Cite this page as:
Bray, D.J. & Schultz, S. 2017, Grammatorcynus bilineatus in Fishes of Australia, accessed 20 Jul 2024,

Scad Mackerel, Grammatorcynus bilineatus (Rüppell 1836)

More Info


Port Hedland and offshore reefs of Western Australia, and Cartier Reef, Timor Sea, to about Yeppoon, Queensland; also reefs in the Coral Sea. Elsewhere the species is widespread in the tropical Indo-west-central Pacific from the Red Sea to Oceania.

Forms dense schools around reefs, often near outer reef walls or over deep clear-water slopes.


Dorsal fin XI-XIII, 0, 0, 10-12+ 6 finlets ; Anal fin 11-13 + 7 finlets; Pectoral fin 22-26; Gill rakers 19-24.

Dorsal fins separated by a narrow space. Pectoral fins stout. Body elongate and slightly compressed. Slender conical teeth forming a single series in each jaw, 20-30 in each jaw. Body covered in moderately small scales, no prominent corselet present. Two lateral lines. Caudal peduncle with well-developed keel, flanked on each side by a smaller keel. Swimbladder present.


To at least 100 cm and 10 kg.


Metallic blue-green dorsally, similar for sides, fading to silvery white with golden tinge on belly. Belly lacks spots.


Known to feed on small fishes and crustaceans.


Recreational fishers catch this species while trolling lures. This species is not highly sought after as the flesh is oily and not considered good eating.


Similar Species

G. bilineatus differs from the closely related G. bicarinatus in having no spots on the belly, a larger eye (4.0 to 6.0% vs 3.1-4.6% FL), more gill rakers (18-24 vs 12-14), and in its smaller size (60cm vs 110cm FL). The two species also differ in a number of osteological characters.


The specific name bilineatus is Latin meaning "double-lined" in reference to the divided lateral line.

Species Citation

Thynnus bilineatus Rüppell 1836, Fische des Rothen Meeres: 39, Pl. 12 (fig. 2), Massawa, Eritrea, Red Sea.


Bray, D.J. & Schultz, S. 2017


Australian Faunal Directory

Scad Mackerel, Grammatorcynus bilineatus (Rüppell 1836)


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Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp. 

Allen, G.R. & Russell, B.C. 1986. Part VII Fishes. pp. 79-103 in Berry, P.F. (ed.) Faunal Surveys of the Rowley Shoals, Scott Reef and Seringapatam Reef, northwestern Australia. Records of the Western Australian Museum, Supplement 25: 1-106 

Allen, G.R. & Swainston, R. 1988. The Marine Fishes of North-Western Australia. A field guide for anglers and divers. Perth, WA : Western Australian Museum vi 201 pp., 70 pls. 

Auster, P.J. 2008. Variation in search and predatory attack strategies of Shark Mackerel Grammatorcynus bicarinatusJ. Mar. Biol. Assoc. UK 88: 847-849. 

Collette BB. 1983. Recognition of two species of double-lined mackerels (Grammatorcynus, Scombridae). Proc. Biol. Soc. Washington 96: 715-718.

Collette, B.B. 2001. Scombridae. pp. 3721-3756 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 6 pp. 3381-4218. 

Collette, B., Chiang, W., Di Natale, A., Fox, W., Juan Jorda, M. & Nelson, R. 2011. Grammatorcynus bilineatus. The IUCN Red List of Threatened Species 2011: e.T170358A6768577. Downloaded on 17 September 2017.

Collette, B.B. & Gillis, G.B. 1992. Morphology, systematics, and biology of the double-lined mackerels (Grammatorcynus, Scombridae). Fishery Bulletin (U.S.) 90: 13-53, 27 figs 

Collette, B.B. & Nauen, C.E. 1983. FAO species catalogue. Scombrids of the world. An annotated and illustrated catalogue of tunas, mackerels, bonitos and related species known to date. Fisheries Synopsis No. 125, Vol. 2. Rome : FAO. 137 pp. 81 figs 

Fraser-Brunner, A. 1950. The fishes of the family Scombridae. Annals and Magazine of Natural History 12 3(7): 131-163 figs 1-35 

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Hutchins, J.B., Williams, D.McB., Newman, S.J., Cappo, M. & Speare, P. 1995. New records of fishes for the Rowley Shoals and Scott/Seringapatam Reefs, off north-western Australia. Records of the Western Australian Museum 17: 119-123 

Kuiter, R.H. 1992. Tropical Reef-Fishes of the Western Pacific, Indonesia and Adjacent Waters. Jakarta : PT Gramedia Pustaka Utama 314 pp. pls. 

Lewis, A.D., Chapman, L.B. & Sesewa, A. 1983. Biological Notes on Coastal Pelagic Fishes in Fiji. Fisheries Division (MAF), Fiji Technical Report 4.

 McPherson, G. 1984. Two species of double-lined mackerel (family Scombridae) in Queensland waters. Queensland Dept. Primary Industries Leaflet.

Oxley, W.G., Emslie, M., Muir, P. & Thompson, A.A. 2004. Marine surveys undertaken in the Lihou Reef National Nature Reserve, March 2004. Townsville : Australian Institute of Marine Science i-vii, 1-67 pp. 

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Randall, J.E., Allen, G.R. & Steene, R. 1990. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 507 pp. figs. 

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Rüppell, W.P.E. 1836. Neue Wirbelthiere zu der Fauna von Abyssinien gehörig. Fische des Rothen Meeres. Frankfurt Vol. 2, pp. 29–52, pls 8–14. 

Russell, B.C., Larson, H.K., Hutchins, J.B. & Allen, G.R. 2005. Reef fishes of the Sahul Shelf. The Beagle, Records of the Museums and Art Galleries of the Northern Territory Supplement 1 2005: 83-105

Quick Facts

CAAB Code:37441028

Conservation:IUCN Least Concern

Depth:15-50 m

Habitat:Pelagic, inshore

Max Size:60 cm FL

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