Southern Bluefin Tuna (SBT) is a highly migratory species and is widely distributed throughout waters of the southern oceans, including the Australian Fishing Zone (AFZ).
Principal species: Southern Bluefin Tuna (Thunnus maccoyii)
Number of active vessels in 2011/12:
Farm sector: 4
Longline sector: 11
The key areas where SBT is caught are the Great Australian Bight and waters off south eastern Australia.
Southern Bluefin Tuna Fishery - SBT
SOUTHERN BLUEFIN TUNA
Around 96% of Australia’s Southern Bluefin Tuna quota is taken by about 5 purse seine vessels fishing in the Great Australian Bight. They catch Southern Bluefin Tuna weighing between 13 and 25 kg. These are towed alive back to static grow-out pontoons located off Port Lincoln in South Australia. These fish are grown out for up to 6 months before being harvested and exported, predominantly to Japan. Southern Bluefin Tuna is also a valuable and largely incidental catch for longline vessels operating in southern Australian waters. They are also taken in small amounts by pole and line, and trolling.
The standard Southern Bluefin Tuna fishing season runs from 1 December to 30 November in the following year.The majority of fishing by purse seine, for grow-out ranching, occurs from December to March. Longline fishing for Southern Bluefin Tuna occurs primarily in the winter months off NSW. These boats operate in the Eastern Tuna and Billfish Fishery.
Australia is a member of the Commission for the Conservation of Southern Bluefin Tuna (CCSBT), which is responsible for the international management of the global Southern Bluefin Tuna stock. The objectives of the CCSBT are to ensure, through appropriate management, the conservation and optimum utilisation of the global Southern Bluefin Tuna Fishery. Management arrangements agreed at the CCSBT are implemented in the domestic fishery through the SBT Plan and associated legislative instruments. At the Eighteenth Annual Extended Commission Meeting of the CCSBT in 2011, a Management Procedure was adopted that outlines a rebuilding strategy for the Southern Bluefin Tuna stock. The Management Procedure is used to guide the setting of the Southern Bluefin Tuna global Total Allowable Catch (TAC) for each year, according to the following parameters
FARMED SOUTHERN BLUEFIN TUNA
With a rapid decline in the availability of Wild caught Southern Bluefin Tuna, Australian tuna fishers established a Sustainable ranching programme designed to maintain SBT stocks. This industry was initiated in the early ‘90s and has developed into the largest farmed seafood sector in Australia.
Tuna ranching involves the capture of Wild SBT from the fishing grounds on the Continental Shelf in the Great Australian Bight. Using a purse seine net to capture the live fish, the SBT are transferred into a tow cage and towed back to the holding farms adjacent to Port Lincoln.
Commencing in January each year, Southern Bluefin Tuna (SBT) are caught in the Great Australian Bight, using the purse seine method.
The tuna are transferred to tow cages and towed back to
Port Lincoln where they are transferred into farm cages.
The captive tuna are grown out under controlled feeding techniques. Using a combination of high fat imported sardines, anchovies, mackerel, red bait, squid and locally caught high protein pilchards, each fish is grown to a premium condition, reaching an average weight of 30 to 40 kilograms. Artificial nutrition or chemicals are not used to supplement the diet of the tuna
Once the tuna have reached their optimum size and condition they are harvested. The harvest process includes the physical capture of each individual fish and within seconds, the killing, bleeding, gill and gutting before the fish are frozen.