Thunnus maccoyii

Common Name

Southern Bluefin Tuna

Year Described

Castelnau, 1872


Dorsal Fin: XIII-XIV, 12-16, followed by 8-10 finlets
Anal Fin: 11-16, followed by 7-9 finlets
Pectoral Fin: 30-36
Gill Rakers: 31-40 (on first arch)
Vertebrae: 39

Body fusiform, robust, and rounded in cross-section. Snout about twice eye diameter. Adipose eyelid absent. Jaw extends to anterior half of orbit. Teeth small and conical. Two interpelvic processes; shorter than pelvic fins. Dorsal fins separated by a very small gap. Spiny dorsal fin long, with a strongly concave margin. Second dorsal and anal fin small with tall anterior lobes. Pectoral fins very short (20-23% of FL). Caudal fin semilunate. Corselet not obvious but present. Body covered in very small scales. Two small caudal keels with a larger median keel in between them. Liver striated.


Body silvery-gray to white with an abruptly dark blue back. A bluish sheen often apparent. Dorsal fins brown to yellowish-brown. Anal fin and both sets of finlets yellowish. Median caudal keel yellow.


Maximum size to 225cm FL. Commonly to 200cm FL.


Epipelagic in cold oceanic waters. Forms schools.


Southwestern Atlantic: S. Brazil to Argentina. Also Indian and S. Pacific Ocean.


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