The southern bluefin tuna (Thunnus maccoyii) is a tuna 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 2.5 metres (8.2 ft) and weighing up to 260 kilograms (570 lb), it is among the larger bony fishes.
Southern bluefin tuna, like other tuna species, like the Atlantic or Pacific Bluefish Tuna, are part of a group of bony fishes that can maintain their body core temperature up to 10 °C (18 °F) 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.
Southern bluefin tuna is a gourmet food, which is in demand for use in sashimi and sushi. It has medium flavoured flesh and is regarded by both Japanese and Western chefs as the best raw fish to eat in the world.
By far the largest consumer of SBT is Japan, with USA coming in second, followed by China. Japanese imports of fresh bluefin tuna (all 3 species) worldwide increased from 957 tons in 1984 to 5,235 tons in 1993 . The price peaked in 1990 at $34 per kilogram when a typical 350 pound fish sold for around $10,000. As of 2008, bluefin was selling for $23 a kilogram.
The drop in value was due to the drop in the Japanese market, an increase in supply from northern bluefin tuna from the Mediterranean, and more and more tuna being stored (tuna frozen with the special “flash” method can be kept for up to a year with no perceivable change in taste).
The Tsukiji fish market in Tokyo is the largest wholesale market of SBT in the world. Tsukiji handles more than 2,400 tons of fish, worth about US$20 million, a day, with pre-dawn auctions of tuna being the main feature. No tourists are allowed to enter the tuna wholesale areas, which they say is for purposes of sanitation and disruption to the auction process. Higher prices are charged for the highest quality fish; bluefin tuna worth over $150,000 have been sold at Tsukiji. In 2001, a 202-kilogram wild Pacific bluefin tuna caught in Tsugaru Straight near Omanachi I Aomori Prefecture sold for $173,600, or about $800 a kilogram. In 2013, a 222-kilogram Pacific bluefin tuna was sold at Tsukiji for $1.8 million, or about $8,000 per kilogram.