Mackerel Tuna, Euthynnus affinis (Cantor 1850)

Other Names: Bonito, Jack Mackerel, Kababida, Kawa Kawa, Kawakawa, Little Tuna, Little Tunny

A Mackerel Tuna, Euthynnus affinis, in Tokyo Sea Life Park (Kasai Rinkai Suizokuen), Japan. Source: License: CC By Attribution-ShareAlike


A small dark blue tuna becoming silvery-white below, with distinctive pattern of dark wavy oblique stripes above the lateral line behind the middle of the first dorsal fin, and usually several dark spots above the pelvic fins. 

Video of Mackeral Tuna in an aquarium.

Cite this page as:
Bray, D.J. & Schultz, S. 2019, Euthynnus affinis in Fishes of Australia, accessed 16 Apr 2024,

Mackerel Tuna, Euthynnus affinis (Cantor 1850)

More Info


Shark Bay, offshore reefs of Western Australia, and Ashmore Reef in the Timor Sea, around the tropical north to Merimbula, New South Wales; also at Christmas Island in the eastern Indian Ocean, and Lord Howe Island in the Tasman Sea. Elsewhere the species is widespread and abundant in tropical and subtropical waters of the Indo-west Pacific - from the Red Sea, East and South Africa to New Caledonia and Tonga, and north to southern Japan. 

This pelagic, oceanodromous species usually stays close to shore in depths to 50 m, although it may be found in open waters. Juveniles sometimes enter bays and harbours.

Mackerel Tuna often form large schools of up to several thousand individuals with other similar-sized tunas and mackeral species. 


Dorsal fin XI-XIV + I, 11-15 followed by 8-10 finlets; Anal fin 11-15 + 6-8 finlets; Pectoral fin 25-29; Gill rakers (first arch) 29-34; Vertebrae 39. 

Body robust, elongate, fusiform; caudal peduncle very slender with a prominent lateral keel positioned between 2 small keels at the caudal-fin base. Teeth small, conical, in single series on both jaws. Swimbladder absent.

First and second dorsal fins close together, never more than one eye diameter width apart; pectoral fins short, tips never reaching interspace between the dorsal fins; 2 flaps (interpelvic process) between pelvic fins. 

Body naked except for corselet and lateral line scales.


To at least 100 cm and around 14 kg in weight.


Dark blue above becoming silvery-white below, with many dark, broken, oblique stripes above lateral line behind middle of first dorsal fin, and several dark spots usually present between pelvic and pectoral fins. 


A fast swimming opportunistic predator - feeds on small fishes such as clupeoids and atherinids, along with squids, crustaceans and zooplankton. Mackeral Tuna are preyed upon by sharks and marlins.


No data is available from Australian waters. In Philippine waters individuals of 40 cm fork length are mature, whereas individuals in the Indian Ocean are mature at between 50 and 65 cm fork length, representing an age of 3 years. The spawning season is uncertain as it greatly varies from region to region. Females captured in the Indian Ocean displayed size-related fecundity, with larger females (4.6 kg) able to spawn around 2.5 million eggs per year. Interestingly, the sex ratio in immature fish is 1:1, but males dominate the adult stage.


Taken mostly as by-catch in commercial fisheries throughout its range, although the dark flesh deteriorates rapidly following capture. Commercial landings in Australia are low.

Mackerel Tuna are a popular light-tackle gamefish, and are sought after as bait for large gamefish such as billfishes and larger tunas. The species is prey for billfishes and sharks.


IUCN: Least Concern

Species Citation

Thynnus affinis Cantor 1850, J. Asiat. Soc. Beng. 18(2): 1088. Type locality: Malacca Strait, eastern Indian Ocean.


Bray, D.J. & Schultz, S. 2019


Atlas of Living Australia

Mackerel Tuna, Euthynnus affinis (Cantor 1850)


Allen, G.R. 1997. Marine Fishes of Tropical Australia and South-east Asia. Perth : Western Australian Museum 292 pp. 106 pls. 

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

Allen, G.R., Steene, R.C. & Orchard, M. 2007. Fishes of Christmas Island. Christmas Island : Christmas Island Natural History Association 2 edn, 284 pp. 

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. 

Cantor, T.E. 1850. Catalogue of Malayan fishes. Journal of the Asiatic Society of Bengal 18(2): 983-1443 pls 1-14 See ref at BHL

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., Chang, S.-K., Fox, W., Juan Jorda, M., Miyabe, N., Nelson, R. & Uozumi, Y. 2011. Euthynnus affinis. The IUCN Red List of Threatened Species 2011: e.T170336A6753804. Downloaded on 12 July 2019.

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 

Grant, E.M. 1991. Fishes of Australia. Brisbane : EM Grant Pty Ltd 480 pp. 

Griffiths, S.P., Kuhnert, P.M., Fry, G.F. & Manson, F.J. 2009. Temporal and size-related variation in the diet, consumption rate, and daily ration of mackerel tuna (Euthynnus affinis) in neritic waters of eastern Australia. ICES Journal of Marine Science 66: 720-733.

Hobbs, J-P.A., Newman, S.J., Mitsopoulos, G.E.A., Travers, M.J., Skepper, C.L., Gilligan, J.J., Allen, G.R., Choat, H.J. & Ayling, A.M. 2014. Checklist and new records of Christmas Island fishes: the influence of isolation, biogeography and habitat availability on species abundance and community composition. Raffles Bulletin of Zoology Supplement 30: 184–202

Hutchins, B. 2004. Fishes of the Dampier Archipelago, Western Australia. Records of the Western Australian Museum, Supplement 66: 343–398 

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 

Hutchins, J.B. & Swainston, R. 1986. Sea Fishes of Southern Australia. Complete field guide for anglers and divers. Perth : Swainston Publishing 180 pp. 

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Johnson, J.W. 2010. Fishes of the Moreton Bay Marine Park and adjacent continental shelf waters, Queensland, Australia. pp. 299-353 in Davie, P.J.F. & Phillips, J.A. Proceedings of the Thirteenth International Marine Biological Workshop, The Marine Fauna and Flora of Moreton Bay. Memoirs of the Queensland Museum 54(3) 

Pepperell, J. 2010. Fishes of the Open Ocean a Natural History & Illustrated Guide. Sydney : University of New South Wales Press Ltd 266 pp. 

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Randall, J.E., Allen, G.R. & Steene, R. 1997. Fishes of the Great Barrier Reef and Coral Sea. Bathurst : Crawford House Press 557 pp. figs. 

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 

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Schaefer, K.M. 2001. Reproductive biology of tunas. pp. 225-270 in Block, B.A. & Stevens, E.D (eds) Tuna: Physiology, Ecology, and Evolution. Academic Press, San Diego, California.

Whitley, G.P. 1937. The Middleton and Elizabeth Reefs, South Pacific Ocean. The Australian Zoologist 8(4): 199-231 figs 13-14 (described as Wanderer wallisi) See ref at BHL

Yearsley, G.K., Last, P.R. & Ward, R.D. (eds) 1999. Australian Seafood Handbook. Hobart : CSIRO Marine Research 460 pp.

Quick Facts

CAAB Code:37441010

Conservation:IUCN Least Concern

Depth:0-50 m


Habitat:Pelagic, oceanadromous

Max Size:100 cm FL

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Species Maps

CAAB distribution map