7 Oct 2014 - 2:36 PM  UPDATED 7 Oct 2014 - 2:36 PM

What species?

  • Southern Bluefin Tuna are farmed in ‘sea ranches’ off South Australia.
  • Southern Bluefin Tuna are a migratory fish. They are caught in nets when they are young and dragged and transferred to ‘sea ranches’ to be fattened up until they are big enough to sell.

What’s the catch?

  • Australian Commonwealth stock status reports classify Southern Bluefin Tuna as 'overfished'.
  • Current stock assessments have found that Southern Bluefin Tuna are at around 5% of their original level.
  • The International Union for Conservation of Nature and Natural Resources lists Southern Bluefin Tuna as ‘critically endangered’ on its Red List. 
  • However, because Southern Bluefin Tuna migrates across international borders they are fished in Australia, Japan, Taiwan and New Zealand. The fishing stocks of Southern Bluefin Tuna are managed by an international committee, the Commission for the Conservation of Southern Bluefin Tuna. 
  • If Australia were to stop fishing Southern Bluefin Tuna it would forfeit its place on this committee.
  • As a result, despite being classified as critically endangered, Southern Bluefin Tuna are still fished in Australia.
  • Southern Bluefin Tuna are vulnerable to overfishing as they are a slow developing large fish, living for up to twelve years.
  • Southern Bluefin Tuna are captured when they are juveniles and kept in sea ranches in South Australia, but are then fished before they are old enough to reproduce.
  • As a result they are unable to replenish their already dwindling stocks.
  • Southern Bluefin Tuna play an important role in the ecosystem as a top predator. If this species continue to be overfished this will potentially create an unbalanced ecosystem. Link to trophic cascade?
  • Farmed Southern Bluefin Tuna are not self-sufficient as they are a carnivorous fish and must be fed wild fish, including sardines.
  • Around 15-20 kgs of wild fish is required to produce 1 kg of Southern Bluefin Tuna, the worst feed conversion rate of any fish. 
  • Most of the Southern Bluefin Tuna are then exported to Japan where they are sold for a high price. An individual fish can be sold for hundreds of thousands of dollars.
  • The Australian Marine Conservation Society says to say no to eating Southern Bluefin Tuna and it is on Greenpeace Australia Pacific's Seafood Redlist.

What’s the solution?

For canned tuna, Greenpeace recommends choosing pole or line caught Albacore or Skipjack Tuna.
Switch to another fish – Matthew?

Whats the recipe?

Blackened skipjack tuna 

More information


View our Southern Bluefin Tuna infographic