Southern bluefin tuna

Thunnus maccoyii

5: Avoid How we work out the ratings

What to check for

Location

Southern Ocean: All areas

Technical location

48 - Atlantic, Antarctic, 58 - Indian Ocean, Antarctic and Southern, 88 - Pacific, Antarctic, All areas, All areas, All areas

Caught by

Hook & line (longline), Hook & line (pole & line), Net (purse seine on aggregating devices or free-schooling fish)

Rating summary

Southern bluefin tuna is listed as Endangered on the IUCN Red List and therefore is a Fish to Avoid.Rating last updated January 2024

How we worked out this Rating

Southern bluefin tuna is listed as Endangered on the IUCN Red List. It therefore receives a Critical Fail and is a default red rating. It is still in a heavily overfished state, but is gradually recovering. It is not subject to overfishing.Southern bluefin tuna (SBT) is assessed and managed by the Commission for the Conservation of Southern Bluefin Tuna (CCSBT). It has been fished since the 1940s. During that time, the stock has continuously declined, reaching a low of around 10% of its unfished level in 2009. Since then, it is estimated that the stock has been increasing by 5% per year.The last stock assessment was carried out in 2023 using data up to 2022, and the next one is expected in 2026. In 2023, the stock was thought to be at 23% of unfished levels, and 85% of levels associated with Maximum Sustainable Yield (MSY). This is based on Total Reproductive Output (akin to Spawning Stock Biomass). It had therefore reached its interim stock rebuilding objective (20% by the year 2035). The new rebuilding objective is now to reach 30% of unfished levels by 2035, which is the level associated with MSY, estimated to be 33,207 tonnes. The Marine Conservation Society considers 20% of unfished levels to be equivalent to Blim. This means that the increases in abundance have led to the stock raising above Blim, however the stock is still at an increased risk of suffering reduced reproductive capacity. This means that while the increases in abundance are very encouraging, the stock is still at dangerously low levels. Catch in 2022 was 17,138 tonnes. This was equivalent to 46% of the level associated with MSY (F/Fmsy = 0.46). The stock is therefore not subject to overfishing. Stock projections indicate that SBT is on track to reach 30% of unfished levels by 2035 with a 51% probability. The Total Allowable Catch (TAC) was therefore increased by the maximum amount of 3000 tonnes, resulting in an increase from 17,647 tonnes per year in 2021- 2023 to 20,647 tonnes per year for 2024 – 2026. Fishing for juvenile SBT is common, especially by purse seiners, which then slowly tow the fish in large net pens back to the coast. Here, they are fattened for later sale on the sashimi market. Individual fish can fetch upwards of £100,000. Any reduction in fishing will increase the rate of stock rebuilding. The CCSBT scientific committee have noted that the benefits of reducing catches of juveniles could take around 8 years to show, because SBT are only fully mature around age 11.

References

Abraham, E., Richard, Y., Walker, N., Gibson, W., Daisuke, O., Tsuji, S., Kerwath, S., Winker, H., Parsa, M., Small, C. and Waugh, S., 2019. Assessment of the risk of surface longline fisheries in the Southern Hemisphere to albatrosses and petrels, for 2016. CCSBT-ERS/1905/17 prepared for the 13th Meeting of the Ecologically Related Species Working Group of the Commission for the Conservation of Southern Bluefin Tuna. Available at https://www.ccsbt.org/en/system/files/ERSWG13_17_NZ_Assessment_RiskOfSurfaceLonglineFisheries_SouthernHemisphere.pdf [Accessed on 09.12.2024].

ACAP, 2023. ACAP Review of mitigation measures and Best Practice Advice for Reducing the Impact of Pelagic Longline Fisheries on Seabirds. Reviewed at the Thirteenth Meeting of the Advisory Committee, Edinburgh, United Kingdom, 22 - 26 May 2023. Available at https://www.acap.aq/resources/bycatch-mitigation/mitigation-advice/4548-acap-2023-pelagic-longlines-mitigation-review-and-bpa/file [Accessed on 26.01.2024].

ACAP, 2022. Conservation Status of Albatrosses and Petrels and Advice on Reducing their Bycatch in CCSBT Longline Fisheries. CCSBT-ERS/2203/16 presented to the 14th Meeting of the Ecologically Related Species Working Group. CCSBT-ERS/2203/BGD 01. Online, 21 - 25 Mar 2022. Available at https://www.ccsbt.org/system/files/ERSWG14_16_ACAP_update_spp%20%26%20BPA_2022.pdf [Accessed on 26.01.2024].

ACAP & BirdLife International, 2019. An update on the status and trends of ACAP- listed albatrosses and petrels in the CCSBT area. CCSBT-ERS/1905/22 presented to the 13th Meeting of the Ecologically Related Species Working Group, 28-31 May 2019, Canberra. Available at https://www.ccsbt.org/en/system/files/ERSWG13_22_ACAP_StatusSummary_ACAPspp_2019.pdf [Accessed on 26.01.2024].

CCSBT, 2019. Shark Species of Relevance to the CCSBT. In: The Thirteenth meeting of the Ecologically Related Species Working Group of the CCSBT (ERSWG13). CCSBT-ERS/1905/06, Canberra, Australia. Available at https://www.ccsbt.org/en/system/files/ERSWG13_06_Shark%20Species%20of%20Relevance%20to%20the%20CCSBT.pdf [Accessed on 26.01.2024].

CCSBT, 2023. Annual Report on Members’ implementation of ERS measures and performance with respect to ERS. In: CCSBT - 14th Meeting of the Ecologically Related Species Working Group. CCSBT-CC/2310/05, Online. Available at https://www.ccsbt.org/system/files/2023-09/jp_CC18_05_AnnualReportOnMembersERSPerformance.pdf [Accessed on 26.01.2024].

CCSBT, 2023. Report of the Eighteenth Meeting of the Compliance Committee. 5-7 October 2022, Busan, Korea. Available at https://www.ccsbt.org/sites/default/files/userfiles/file/docs_english/meetings/meeting_reports/ccsbt_30/report_of_CC18.pdf [Accessed on 19.01.2024].

CCSBT, 2023. Report on the Twenty Eighth Meeting of the Scientific Committee. 1 September 2023, Online. Available at: https://www.ccsbt.org/sites/default/files/userfiles/file/docs_english/meetings/meeting_reports/ccsbt_30/report_of_SC28.pdf [Accessed on 19.01.2024].

CCSBT, 2023. Report of the Thirtieth Annual Meeting of the Commission for the Conservation of Southern Bluefin Tuna. 12 October 2023, Busan, Korea. Available at https://www.ccsbt.org/sites/default/files/userfiles/file/docs_english/meetings/meeting_reports/ccsbt_30/report_of_CCSBT30.pdf [Accessed on 19.01.2024].

CCSBT, 2024. Operational Resolutions and Other Important Documents. Available at https://www.ccsbt.org/en/content/operational-resolutions-and-other-important-documents [Accessed on 26.01.2024].

Collette, B.B., Boustany, A., Fox, W., Graves, J., Juan Jorda, M. & Restrepo, V., 2021. The IUCN Red List of Threatened Species 2021: Thunnus maccoyii. e.T21858A170082633. Available at https://dx.doi.org/10.2305/IUCN.UK.2021-2.RLTS.T21858A170082633.en [Accessed on 19.01.2024].