Mackerel Tuna, Euthynnus affinis (Cantor 1850)

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

Mackerel Tuna, Euthynnus affinis. Source: Australian National Fish Collection, CSIRO. License: CC BY Attribution-Noncommercial


A medium sized tuna species, the Mackerel Tuna is a predominantly tropical species, but can be found ranging into temperate waters in summer. It is a sought after bait species for large gamefish such as tunas and marlins.

Cite this page as:
Schultz, S., Euthynnus affinis in Fishes of Australia, accessed 20 Jul 2019,

Mackerel Tuna, Euthynnus affinis (Cantor 1850)

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Found throughout the tropical and sub-tropical waters of the Indo-West Pacific. In Australian waters this species is known to occur along the northern half of the country, from Shark Bay (WA) to Merimbula (NSW).

An oceanic species, neritic and epipelagic. Usually found schooling in surface waters where the temperature is higher than 20 degrees, often with similar sized individuals of other tuna species. Schools can range on size from a few hundred to many thousands of fish.


D X-XV, 12-13; A 0, 13-14; P 25-29.

First and second dorsal fins close together, never more than eye width apart. Pectoral fin tips do not reach space between first and second dorsal fins. Second dorsal and anal fins followed by 8-10 and 6-8 finlets, respectively. Body robust and elongate. Very small, conical teeth, 40-55, on each side of both jaws. First gill arch with 29-33 gill rakers. Body naked ventrally behind the anterior corselet. Upper half of body covered with small scales. Caudal peduncle with well developed keel, flanked on each side by a smaller keel. Swimbladder absent.


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


Dark blue-greenish dorsally, belly silvery-white. Dark spots in area between pelvic and pectoral fins. Many dark, broken, oblique stripes above lateral line, from below first dorsal fin to caudal peduncle.


An opportunistic predator, known to feed on fishes, cephalopods and crustaceans.


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.


Commercial landings of this species are low due to rapid deterioration in meat quality after death making it difficult to market. The Mackerel tuna is a popular recreational species, particularly as bait for gamefishing. In NSW the recreational catch is estimated to be higher than the commercial catch, but less than 50 tonnes per annum.



Species Citation

Thynnus affinis Cantor 1850, J. Asiat. Soc. Beng. 18(2): 1088 [106], Sea of Penang (as Pinang), Malaysia.


Schultz, S.

Mackerel Tuna, Euthynnus affinis (Cantor 1850)


Carpenter, K.E.; Niem, V.H. (eds). FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 6. Bony fishes part 4 (Labridae to Latimeriidae), estuarine crocodiles, sea turtles, sea snakes and marine mammals. Rome, FAO. 2001. pp. 3381-4218.

Collette, B.B. and C.E. Nauen, FAO species 1983, catalogue. Vol. 2. Scombrids of the world. An annotated and illustrated catalogue of tunas, mackerels, bonitos and related species known to date. FAO Fish.Synop., (125)Vol.. 2: 137 p.

Hoese, D.F., D.J. Bray, J.R. Paxton, & G.R. Allen. 2006. Fishes. in Beesley, P.L. & A. Wells. (eds) Zoological Catalogue of Australia. Volume 35. ABRS & CSIRO Publishing: Australia. parts 1-3, pages 1-2178.

 Masuda, H., K. Amaoka, C. Araga, T. Uyeno & T. Yoshino (eds). 1984. The Fishes of the Japanese Archipelago. Tokai University Press, Tokyo, Japan.

Scandol, J, K. Rowling & K. Graham. 2008. Status of Fisheries Resources in NSW 2006/07. NSW Department of Primary Industries, Cronulla, 334 pp.

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CAAB Code:37441010

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