Southern bluefin tuna

| parent = Thunnus (Thunnus) | taxon = Thunnus maccoyii | authority = (Castelnau, 1872) | synonyms = *''Thynnus maccoyii'' Castelnau, 1872 *''Thunnus phillipsi'' Jordan & Evermann, 1926 | synonyms_ref = }}

The southern bluefin tuna (''Thunnus maccoyii'') is a tuna of the family Scombridae found in open southern Hemisphere waters of all the world's oceans mainly between 30°S and 50°S, to nearly 60°S. At up to and weighing up to , it is among the larger bony fishes.

Southern bluefin tuna, like other pelagic tuna species, are part of a group of bony fishes that can maintain their body core temperature up to above the ambient temperature. This advantage enables them to maintain high metabolic output for predation and migrating large distances. The southern bluefin tuna is an opportunistic feeder, preying on a wide variety of fish, crustaceans, cephalopods, salps, and other marine animals. Provided by Wikipedia