Southern Bluefin Tuna

Southern Bluefin Tuna. Image by David Muirhead.

Scientific name

Thunnus maccoyii

Status in NSW



The Southern Bluefin Tuna is a large silver-white fish with a blue-black upper body, silver underside and yellow tinged fins. It is long and muscular, with small scales covering the skin. The keels near the tail are yellow in juveniles and black in adults.

Species similar in appearance

Longtail Tuna (Thunnus tonggol) are similar in appearance to Southern Bluefin Tuna.


Southern Bluefin Tuna can reach a maximum length of 2.35 metres and can weigh around 200kg, but rarely exceed 100kg in Australian waters.


Southern Bluefin Tuna are highly migratory pelagic fish. In Australian waters they range from northern NSW around southern Australia to northwestern Australia. They tend to form large surface schools in offshore waters off southern Australia at certain times of the year.

Report a Southern Bluefin Tuna sighting


Southern Bluefin Tuna are found in oceanic waters normally on the seaward side of the continental shelf. They belong to the family Scombridae which also includes tuna, mackerel, bonito and wahoo. Worldwide the species is considered a single population. Southern Bluefin Tuna spawn at only one location in the tropical waters between Java and north-west Australia.

Why is the Southern Bluefin Tuna threatened?

  • Commercial fishing in both international and Australian waters for world sashimi markets;
  • Harvest of wild caught juveniles for aquaculture farming;
  • Recreational fishing can impact on the viability of this species, although to a much lesser extent than commercial fishing practices.
  • A reduction in spawning stock and fishing impacts on the population during spawning events are likely to affect recruitment and subsequently reduce an already low fecundity;
  • The species is naturally slow growing, with a long life span and a single spawning ground meaning that Southern Bluefin Tuna are particularly vulnerable to over-exploitation and are slow to recover.

More information