Tuna, yellowfin

Thunnus albacares

Method of production — Caught at sea
Capture method — Longline
Capture area — Atlantic Ocean (FAO 21,27,31,34,41 and 47)
Stock area — Atlantic
Stock detail — All Areas
Picture of Tuna, yellowfin

Sustainability rating three info

Sustainability overview

Updated: December 2019 

Yellowfin and other tuna stocks in the Atlantic are assessed by the International Commission for the Conservation of Atlantic Tunas (ICCAT). A new stock assessment was carried out in 2019. Although there are large uncertainties, it found that the stock was not overfished (B2018:BMSY = 1.17) or undergoing overfishing - although fishing mortality was close to the threshold (F2018:FMSY = 0.96). This is an improvement from the previous assessment, when the stock was in an overfished state, but this is not owing improved data in the model, not sock recovery. Biomass has continuously declined throughout the lifetime of the fishery, while fishing mortality has been increasing since the mid-2000s.

Projections indicate that catch levels at or below 120,000t (the estimated Maximum Sustainable Yield) would maintain healthy biomass through to 2033. However, and catches have exceeded 120,000 t every year since 2015 (2018 catch was 135,689t), and if this continues the stock will decline. If catches remain around 140,000 tonnes, there is only a 20% probability that the stock will be above BMSY and below FMSY by 2030. Given that this is also in excess of Total Allowable Catch (110,000t), existing conservation and management measures appear to be insufficient, and the scientific committee recommends that they be strengthened. The estimated MSY may be below what was achieved in past decades because overall selectivity has shifted to smaller fish. A multi-annual management programme has been in place for bigeye and yellowfin since 2012 and a closure and restrictions on the purse seine fishery exist off the west coast of Africa to reduce juvenile catches of bigeye and yellowfin, but this has had little impact so in 2019 the closure was extended to cover the whole convention area.

About 11% of the catch is taken in pelagic longline fisheries, which is associated with significant bycatch of other billfish and vulnerable species such as sharks, turtles and seabirds. Whilst some mitigation measures are in place, they do not follow best practice, their effectiveness has not been evaluated, and better data collection & reporting is needed. Observer coverage is 5% on large longliners, increasing to 10% in 2022, yet this is not being complied with by several countries and 20% coverage is recommended.

Commercial buyers should establish what measures the flag state and fleet relating to their source is taking to reduce impacts to and improve reporting of interactions with vulnerable species. Large buyers should consider supporting such improvements.

Biology

Tuna belong to the family Scombridae. They are large, oceanic fish and are seasonally migratory, some making trans-oceanic journeys. Yellowfin are found throughout the world’s tropical and subtropical seas, except the Mediterranean. They often form large, size specific schools, frequently associated with dolphins or floating objects. Yellowfin is a large fast growing species, reaching maximum sizes of 240cm in length, 200kg in weight and an age of 8 years. They mature when 2 to 5 years old and mainly spawn in summer. Smaller fish are mainly limited to surface waters, while larger fish are found in surface and deeper waters, but rarely below 250m. Yellowfin has medium resilience to fishing.

Stock information

Criterion score: 0 info

Stock Area

Atlantic

Stock information

Yellowfin and other tuna stocks in the Atlantic are assessed by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Yellowfin tuna have been exploited by three major gears (longline, bait boat and purse seine fisheries) and by many countries throughout its range.

A new stock assessment was carried out in 2019. Although there are large uncertainties, it found that the stock was not overfished (B2018:BMSY = 1.17) or undergoing overfishing - although fishing mortality was close to the threshold (F2018:FMSY = 0.96). This is an improvement from the previous assessment, when the stock was in an overfished state. It is important to note that this is not owing to stock recovery, but because of improved data in the model. Biomass has continuously declined throughout the lifetime of the fishery, including between 2014 and 2018, while fishing mortality has been increasing since the mid-2000s.

Overall Atlantic catches declined by nearly half from their peak in 1990 (190,000t) to 109,000t in 2013, subsequently rising to an average of 140,000 tonnes from 2016-2018. 2018 catch was 135,689t, 75% of which was from the east Atlantic. Projections indicate that catch levels at or below 120,000t (the estimated Maximum Sustainable Yield) would maintain healthy biomass through to 2033. However, the most recent catch estimates suggest that overall catches have exceeded 120,000 t every year since 2015, and if this continues the stock will decline. If catches remain around 140,000 tonnes, there is only a 20% probability that the stock will be above BMSY and below FMSY by 2030. Given that this is also in excess of Total Allowable Catch (110,000t), existing conservation and management measures appear to be insufficient, and the scientific committee recommends that they be strengthened.

The majority of catches are from the east Atlantic purse seine fishery, about a third of which is on Fish Aggregating Devices (FADs). The scientific committee highlighted that increased catches of small yellowfin (and small bigeye, as they are caught together on FADs) will have negative effects on stock size and future harvest rates. Therefore, effective measures should be introduced to reduce fishing mortality on small yellowfin and bigeye tunas.

In the previous assessment, there were uncertainties in stock structure, natural mortality, and growth. As hoped, the ongoing Atlantic Ocean Tropical Tuna Tagging Programme (AOTTP) and Pacific yellowfin tagging studies were able to provide data to address a number of these uncertainties, highlighting the value of tagging programmes for managing tuna fisheries.

Management

Criterion score: 0.75 info

Most tuna stocks range across and are accessed by numerous coastal states, making harmonised and effective management of these individual stocks very difficult. To try and address this, intergovernmental Regional Fisheries Management Organisations (RFMOs) have been established. There are five main tuna RFMOs worldwide and it is their responsibility to carry out data collection, scientific monitoring and management of these fisheries. This stock is managed and assessed by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Whilst the RFMOs are responsible for the development of management and conservation measures, the degree to which they are implemented, monitored and enforced still varies significantly between coastal states. There remain large data deficiencies in most tuna and billfish fisheries, particularly with regards to fine scale spatial and temporal data for both target and especially for vulnerable bycatch species. For this reason, it is important to choose tuna that has been caught by vessels that are well regulated by their flag state.

The TAC (Total Allowable Catch) for yellowfin from 2012 onwards is 110,000 t, and keeping catches at 120,000t or less is expected to maintain healthy stock status through to 2033. However, in recent years the TAC has been exceeded by 17-37%, and if this level of fishing pressure is maintained the stock is projected to decline. In 2018 and again in 2019 the scientific committee suggested that existing conservation and management measures appeared to be insufficient and needed to be strengthened.

The following measures are in place for bigeye, skipjack and yellowfin:
There is a tagging programme to improve stock assessments for tropical tunas and gauge effectiveness of management measures for these species. This helped to improve the quality of the 2019 yellowfin assessment.
A multi-annual management programme has been in place for bigeye and yellowfin since 2012, and eastern skipjack since 2015. Fishing for these species using aggregation devices, including FADs, was prohibited from 1st January to 28th February in an area off the west African coast to reduce catches of juvenile bigeye and yellowfin, for the rest of the year vessels were limited to 500 FADs. This failed to reduce the mortality of juvenile bigeye and yellowfin tuna so in 2019, to address this, the number of FADs was reduced from 500 to 350 in 2020 and 300 in 2021. The FAD closure was extended to the full convention area, lasting 2 months in 2020 and 3 months in 2021.
Countries must have FAD Management Plans that improve understanding of FADs and limit their impacts on the ecosystem.
ICCAT maintains a list of vessels over 20m authorised to fish for these species, although other vessels may retain them as bycatch as long as the country sets limits on this and doesn’t exceed its quota.
Countries are encouraged to reduce discards.

Increased harvests on FADs may have negative consequences for adult yellowfin and bigeye tuna, as well as other by-catch species. The increasing use of fish aggregation devices (FADs) in skipjack fisheries since the early 1990s has changed the species composition of free schools. It is noted that, in fact, free schools of mixed species were considerably more common prior to the introduction of FADs. Furthermore, the association with FADs may also have an impact on the biology (growth rate, plumpness of the fish) and on the ecology (distances, movement orientation) of skipjack and yellowfin (the “ecological trap” concept). To increase long term sustainable yield, the scientific committee continues to recommend that effective measures be found to reduce FAD-related and other fishing mortality of small yellowfin tuna.

Other management measures of note include:
In 2019 ICCAT increased observer coverage: large purse seiners targeting tropical tunas must have 100% coverage year round rather than just during the FAD closures, and longline coverage will increase from 5% to 10% in 2022. However, the 5% coverage was not well complied with or enforced by some fleets (although others exceeded it), and even this increase falls short of recommendations for a minimum of 20% for accurate reporting of bycatch. However, standards for electronic monitoring are to be developed by 2021. Purse seine and longline vessels over 20m long are encouraged to increase their observer coverage from the required minimum, and some have. Vessel Monitoring Systems are required for all vessels over 24m.
In 2015 a working group was formed to look at ways to reduce juvenile catches of bigeye and yellowfin tuna caught in FAD fishing.
Drift nets are banned in the Mediterranean.
ICCAT maintains lists of vessels authorised to fish for tuna and tuna-like species in the ICCAT area, and those caught carrying out Illegal, Unreported or Unregulated activities.
At-sea transhipment is prohibited unless pre-authorised and the vessel has an observer on board.
In 2017 ICCAT banned the discarding of skipjack, yellowfin and bigeye.
In 2016 the Commission passed measures to strengthen and streamline its compliance assessment process and to develop a scheme of responses to non-compliance.

Capture Information

Criterion score: 0.75 info

Longline catches for yellowfin in the Atlantic have fluctuated since the 90s, but now account for about 11% of the total catch (around 15,000 tonnes in 2018). The longline fishery generally catches medium to large yellowfin compared to the purse seine and pole and line fisheries which target smaller fish. Pelagic longlining is associated with the bycatch of vulnerable species, including sharks, sea turtles and seabirds.

ICCAT aims to take an ecosystem-based and precautionary approach to fisheries management. In order to protect juvenile swordfish, a closure period applies to longline vessels targeting Mediterranean albacore from 1 October to 30 November each year.

For sharks: Countries are required to develop and submit National Plans of Action for the conservation and management of sharks. Sharks must be fully utilised (e.g. no removal of fins); must be released wherever possible (if not being directly targeted); and countries must try to minimise bycatch of sharks (although no gear-specific measures are identified). Catching silky sharks, hammerheads, oceanic whitetips, and bigeye threshers is prohibited, and catching other thresher species is discouraged. Shortfin mako, which is heavily overfished, can be caught and retained if over 180cm for males and 210cm for females, otherwise, they must be released unharmed. An updated assessment in 2019 indicated that shortfin mako is unlikely to recover to healthy levels until 2070, unless size restrictions combined with a fixed Total Allowable Catch were introduced. The maximum catch that would allow recovery by 2070 with a reasonable probability (60%) was 300 tonnes. Regardless of management measures, the stock will continue to decline until 2035. However, in 2019 ICCAT failed to reach agreement on measures to protect this species. Catch limits are now in place for both northern (39,102t as of 2016) and southern (28,923t as of 2016) blue sharks, with the northern TAC being allocated out to countries - a first for ICCAT shark stocks. If exceeded, the commission has committed to reviewing the effectiveness of its blue shark management measures (although preliminary catch of northern blue shark in 2016 was 42,117 t). Porbeagle is overfished throughout the Atlantic, significantly so in the northwest, and for the north Atlantic overall it is predicted to take at least 30 years to recover if there was zero fishing mortality. The main porbeagle-directed fisheries (EU, Uruguay and Canada) have closed, and ICCAT have a recommendation to release live porbeagle unharmed, but it is still caught incidentally and discarded, and also landed by other fleets. Currently there is not enough data to properly assess the status of many pelagic sharks (no assessments have been carried out for the Mediterranean).

For seabirds: There are particular concerns over the status of albatross and petrels. South of 20 degrees South, vessels must use bird-scaring lines. Swordfish vessels are exempt from this if they fish at night and weight their hooks. South of 25 degrees South, vessels must use 2 of the three measures (bird-scarers, night fishing or weighted hooks). In the Mediterranean, these measures are voluntary. However, recommended best practice is to use all three of the aforementioned measures for all longline vessels.

For turtles: Longliners must carry equipment and have training to enable them to safely release turtles that have been caught. Countries are required to research and trial circle hooks for longliners. The scientific committee recommends that longliners targeting swordfish and sharks must use either large circle hooks or finfish bait as mitigation, but as of 2019 this has still not been implemented.

Observer coverage was increased in 2019 (see Management) but is still inadequate for purse seiners targeting species other than tropical tunas, and all longliners.

Alternatives

Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.

Anchovy, anchovies
Arctic char
Herring or sild
Mackerel
Salmon, Atlantic (Farmed)
Salmon, Chum, Keta, Calico or Dog salmon
Salmon, Pink, Spring , humpback
Salmon, Sockeye , Red Salmon, Bluebacks, Redfish
Swordfish
Trout, Rainbow
Tuna, albacore
Tuna, skipjack
Tuna, yellowfin

References

EC, 2019. European Commission Press: Good news for tuna and blue sharks, 29.11.2019. Available at https://ec.europa.eu/fisheries/press/good-news-tuna-and-blue-sharks_en [Accessed on 09.12.2019].

ICCAT, 2019. Report of the 2019 ICCAT yellowfin tuna stock assessment meeting, 8-16 July 2019, Grand-Bassam, Cote d'Ivoire. Available at https://www.iccat.int/Documents/SCRS/DetRep/YFT_SA_ENG.pdf [Accessed on 09.12.2019].

ICCAT, 2019. Report of the Standing Committee on Research and Statistics (SCRS) of the International Commission for the Conservation of Atlantic Tunas, 30 September - 4 October 2019, Madrid, Spain. 459 pp. Available at https://www.iccat.int/Documents/Meetings/Docs/2019/REPORTS/2019_SCRS_ENG.pdf [Accessed on 09.12.2019].

ISSF, 2019. International Seafood Sustainability Foundation Blog: ICCAT Moves to Protect Atlantic Bigeye and Close Gaps in Monitoring and Data Collection, 4 December 2019. Available at https://iss-foundation.org/iccat-moves-to-protect-atlantic-bigeye-and-close-gaps-in-monitoring-and-data-collection/ [Accessed on 09.12.2019].

ISSF, 2019. Status of the world fisheries for tuna. Oct. 2019. ISSF Technical Report 2019-12. International Seafood Sustainability Foundation, Washington, D.C., USA. Available at https://iss-foundation.org/knowledge-tools/technical-and-meeting-reports/download-info/issf-2019-12-status-of-the-world-fisheries-for-tuna-october-2019/ [Accessed on 26.11.2019].

ICCAT, 2018. Resolutions, Recommendations and other Decisions. Available at http://www.iccat.es/en/RecsRegs.asp [Accessed on 11.12.2018].

IPNLF, 2012. Ensuring sustainability of live bait fish, International Pole and Line Foundation, London, 57 pp.

Restrepo, V., Dagorn, L., Itano D., Justel-Rubio A., Forget F. and Moreno, G., 2017. A summary of bycatch issues and ISSF mitigation initiatives to-date in purse seine fisheries, with emphasis on FADs. ISSF Technical Report 2017-06. International Seafood Sustainability Foundation, Washington, D.C., USA.