Bigeye Tuna

Latin name: Thunnus obesus

Common name: Tuna

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Wild Caught

Imported, Eastern Australia, Western Australia

Note: Choose bigeye tuna from the Eastern Australian fishery if available. If you can’t be sure, or there is only bigeye tuna from the Western Australian fishery, or imported from overseas then choose a sustainable alternative below.

Key Facts

  • Bigeye tuna is a highly migratory species of tuna that is targeted by fishing vessels managed by a number of different countries.
  • Bigeye tuna are targeted in Australian fisheries off the eastern and western coast and in international waters.
  • Bigeye tuna populations are subject to overfishing across the Indian Ocean, and there is a risk overfishing is also occurring in the population fished off eastern Australia, though the relatively small Australian catch is not a major impact compared to international fishing pressure.
  • Bigeye tuna is listed as 'Vulnerable' on the IUCN Red list.
  • Video monitoring of fishing boats operating in the Australian tuna fisheries is a welcome advance, improving confidence in fishery log book reports.
  • Bigeye tuna are caught on longlines that also catch endangered wildlife, such as turtles, seabirds, whales and dolphins.
  • Reported interactions with turtles, seabirds, whales and dolphins have increased significantly in recent years, particularly in the larger eastern fishery, most likely as a result of the introduction of video monitoring in this fishery.
  • The eastern Australian fishery needs to do much more to protect critically endangered leatherback turtles and is likely to be red-listed in future if appropriate and immediate management action is not taken.

More information

  • Commonwealth Eastern Tuna and Billfish Fishery (1,378t in 2021) and Western Tuna and Billfish Fishery (26t in 2020)

Bigeye tuna is a highly migratory species of tuna that is targeted by fishing vessels managed by a number of different countries. Due to high demand for bigeye tuna, fishing pressure on the species is intense. Bigeye tuna is listed as ‘Vulnerable’ to extinction on the IUCN Red List.

Fishery reports that have assessed the stock status of the species at a regional level indicate that the Indian Ocean population fished in Commonwealth-managed WTBF in Western Australian waters are being subjected to overfishing.  The Pacific Ocean population fished by Commonwealth-managed ETBF off eastern Australia is likely slightly below healthy levels and is declining under increasing fishing pressure. This suggests that there is a significant risk of overfishing occurring.

Bigeye tuna are caught using longlines in Australian waters, which also catch a range of threatened species. Independent Video monitoring across the fishing fleet was rolled out in 2015. This welcome progress provides confidence in reporting of wildlife affected by the fishery.

However, video monitoring has identified that fishers were significantly under-reporting how much endangered wildlife was killed in the past, which means that the impact of this fishery is substantially higher than previously thought. Since cameras have been installed on boats, the number of turtles, seabirds, whales and dolphins recorded as caught has significantly increased.

Despite this, most current management arrangements for the ecological risks of the fishery to endangered species is based on unreliable information collected before the implementation of cameras, though there is now seven years of reliable, recent data available to the fishery. This does not represent sustainable management, and will result in the red-listing of this fishery in future if not urgently addressed.

The catch of turtles in particular has increased over the past decade. From 2018-2021, an average of 122  turtles were caught per year in the ETBF, compared to the 4-16 that were reported as caught annually in the three years before video monitoring was mandated on the fishing vessels. In previous years, a ‘trigger limit’ was in place which required fishery managers to take action if the rate of turtle catch exceeded a certain level. This trigger limit has since been removed, which means there are no measures in place to cap the number of turtles caught in the tuna fishery. The relatively very low level of fishing activity in the WTBF in recent years significantly reduces the risk that fishery poses to threatened and endangered bycatch species.

Of particular concern; the ETBF has reported bycatch of between 20-68 critically endangered leatherback turtles per year since 2018. There are only 1000 mature nesters thought to be left in the population impacted by the ETBF, and it is declining at around 6% annually. For context, and demonstrating adequate management, a US-managed longline fishery that impacts the same leatherback turtle population is closed when yearly bycatch reaches 16 leatherbacks. If not for lower leatherback catch since 2020, the fishery was likely to have been red-listed. Immediate implementation of measures to reduce leatherback turtle bycatch to safe levels is required to avoid a red-listing in future.

In contrast, better protection arrangements and obligations on the ETBF to protect seabirds have resulted in additional management that should effectively reduce the impact of the fishery. This is welcome.

Turtles, whales, dolphins and seabirds are at risk from multiple threats, including fishing. Given the small scale of the Australian tuna fishery relative to international tuna fisheries, it is unlikely that this fishery is the major driver of on-going population declines in these species of endangered wildlife.

Commonwealth marine parks were established in 2018, but in a form significantly delayed and weakened following sustained Australian tuna fishing industry lobbying. As such they confer only a fraction of the protection for threatened and endangered species of original government proposals.