Inshore pelagic, found at depths from the surface to 50 m.
Mostly eats small fishes, particularly clupeids and atherinids, but also squids, crustaceans and zooplankton. Forms size segregated same species and multi-species schools. Maturity of Euthynnus affinis varies by region, off the coast of India, length at where 50% of individuals are mature is estimated at 49 cm FL and 49.7 cm FL for females and males respectively.1 In waters off Taiwan, age of first maturity is estimated at 2 years.2Euthynnus affinis migrate to waters off the coast of Taiwan, north of the Philippines for spawning.3 Spawning season occurs from April to August, peaking in July.2 Maximum age is estimated at 9 years.4
Caught in multi-species fisheries mainly by gill netting and surface trolling.
Bullet & Frigate tuna
Auxis spp. differs in having an interpelvic process of 2 short flaps, (vs. single, large); a wide interdorsal space (vs. narrow) and no spots between pectoral- and pelvic-fin bases (vs. usually 1–3 spots).
Katsuwonus pelamis differs in having 4–6 dark, longitudinal stripes on belly (vs. none); no markings on dorsal scaleless area (vs. a series of oblique dark stripes) and 53–63 gill rakers on the first gill arch (vs. 43–48).
Sarda orientalis differs in having 5–1 narrow dark horizontal stripes on upper sides (vs. a series of oblique dark stripes); body entirely covered in minute scales behind a scaled corselet (vs. dorsal area scaleless behind a scaled corselet) and 29–34 gill rakers on the first gill arch (vs. 8–13).
Deepti VI, Sujatha K. Fishery and some aspects of reproductive biology of two coastal species of tuna, Auxis thazard (Lacepede, 1800) and Euthynnus affinis (Cantor, 1849) off north Andhra Pradesh, India. Indian Journal of Fisheries. 2012;59(4):67–76.
Chiou W-D, Cheng L-Z, Chen K-W. Reproduction and food habits of Kawakawa Euthynnus affinis in Taiwan. 臺灣水產學會刊. 2004;31(1):23–38.
Chiou W, Lee L. Migration of kawakawa Euthynnus affinis in the waters near Taiwan. Fisheries science. 2004;70(5):746–57.
Abdussamad EM, Rohit P, Said Koya KP, Sivadas M. Status and potential of neritic tunas exploited from Indian waters. IOTC Second Working Party on Neritic Tunas, Malaysia. 2012;