Capture method — Longline
Capture area — Pacific, North West (FAO 61) and Central (FAO 71,77)
Stock area — Western and Central Pacific
Stock detail — All Areas
Updated: November 2020
The Western and Central Pacific Ocean (WCPO) yellowfin stock supports the second largest tuna fishery in the world. It is not overfished nor subject to overfishing. A Harvest Control Rule is yet to be developed for yellowfin. Until then, management measures are mainly aimed at limiting fishing effort by purse seiners, which is responsible for around 55% of the yellowfin catch. Observers, to verify catch and bycatch, are on 100% of purse seiners within the main fishing grounds, but are low for other areas and gear types at just 5%. There is not enough data to be sure that countries are complying with the management measures. Around 16% of Western Central North Pacific Ocean (WCPO) yellowfin catches are from longline. While longlining is unlikely to have habitat impacts, it can have a bycatch of highly vulnerable species such as sharks, turtles, and seabirds. Some mitigation measures are in place, but a number of Endangered and Critically Endangered species are still caught as bycatch in longline fisheries. Better data is needed. Mandatory observer coverage is very low, at just 5%. In general, 20% is scientifically recommended to ensure adequate monitoring of catch and bycatch. Unfortunately, owing to Covid disruption, ecosystem considerations were not discussed during the WCPFC’s meetings in 2020.
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. There are a number of Fishery Improvement Projects (FIPs) in the WCPO making improvements in longline fisheries for yellowfin. More information about these FIPs is available from fisheryprogress.org.
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.
Criterion score: 0 info
The yellowfin tuna fishery in the Western and Central Pacific Ocean (WCPO) is the second largest in the world after skipjack. It is not overfished and not subject to overfishing.
This stock is assessed and managed by the Western and Central Pacific Fisheries Commission (WCPFC). A new stock assessment was carried out in 2020 using data up to 2018. Fishing for this stock began in the 1950s and catches have steadily increased to peak in 2017 at around 700,000 tonnes. During this time, Fishing Mortality (F) increased until the early 2000s, when it stabilised for juveniles but carried on increasing for adults. The average F from 2014-2017 was 36% of levels associated with Maximum Sustainable Yield (MSY) (F2014-2017 / FMSY = 0.36). Meanwhile, Spawning Biomass (SB) continuously declined to around 50% of unfished levels in the mid-2000s, and has stayed relatively stable since then. In the latest stock assessment it is at 58% (SB2015-2018 / SBF=0 = 0.58). A limit Reference Point has been set for this stock of 20%. Below this level, the stock would be considered depleted. All models in the assessment indicated that the stock was above the LRP, and fishing mortality rates below FMSY, with 100% probability. Based on the results of this assessment, the yellowfin stock in the WCPO is not considered overfished, nor subject to overfishing. Preliminary catch in 2019 was 669,362t, a 5% decrease from 2018 and a 1% increase from the average 2014-2018.
Recruitment levels have declined over time as the stock size has declined, but have stabilized over the last 20 years and recently slightly increased. Overall, there has been a decline in the proportion of old (greater than age class 15) fish in the population since the 1970s. Levels of fishing mortality and depletion differ between regions, and fishery impact is highest in the tropical region, mainly due to the purse seine fisheries in the equatorial Pacific and the “other” fisheries within the Western Pacific. The scientific committee continues to recommend measures to reduce fishing mortality on juveniles and maintain current spawning biomass levels.
The 2020 assessment is more optimistic than the 2017 assessment, but the causes aren’t clear. MSY in the 2020 assessment (1,000,000 tonnes) is 63% higher than in 2017. There are some research needs to improve the assessment, including estimation of natural mortality rates using tagging data.
Criterion score: 0.5 info
The Western and Central Pacific Ocean (WCPO) yellowfin stock supports the second largest tuna fishery in the world. It is not overfished nor subject to overfishing. A Harvest Control Rule is yet to be developed for yellowfin. Until then, management measures are mainly aimed at limiting fishing effort by purse seiners, which is responsible for around 55% of the yellowfin catch. Observers, to verify catch and bycatch, are on 100% of purse seiners within the main fishing grounds, but are low for other areas and gear types at just 5%. There is not enough data to be sure that countries are complying with the management measures.
Most tuna stocks range across and are accessed by numerous coastal states, making harmonised and effective management of these individual stocks very difficult. As a result, 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. The tuna fisheries in the Western and Central Pacific Ocean (WCPO) are managed by the Western and Central Pacific Fisheries Commission (WCPFC). 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. For this reason, it is important to choose tuna that has been caught by vessels that are well regulated by their flag state. A significant proportion of West Pacific skipjack and yellowfin tuna is caught within the waters of the Parties to the Nauru Agreement (PNA). These South Pacific island nations have incorporated additional management measures, and pushed for improvements in the wider management of these stocks. In addition, around 50% of West Pacific purse-seine-caught skipjack and 70% of yellowfin is certified by the Marine Stewardship Council. There are also several fishery improvement projects for WCPO yellowfin, some of which are making improvements to management and fishing practices and seeing results on the water.
WCPFC is looking to establish harvest strategies for key fisheries and stocks but has not yet completed this work and so a bridging measure is in force to manage bigeye, yellowfin and skipjack. It lasts from 2018 until harvest strategies are in place, or February 2021. There is a limit reference point for the spawning biomass of bigeye, skipjack, and yellowfin tuna of 20% of unfished levels (SB/SBF0 = 0.2), below which the stock should not fall. Skipjack also has an interim target reference point of 50% of unfished levels, while bigeye and yellowfin are to be maintained at recent levels (the average from 2012-2015). Yellowfin stock has stayed fairly stable since 2010 and is currently above the limit reference point, at 58%. It is not overfished, nor subject to overfishing. However, the scientific committee recommends caution on interpreting this for management decisions. It recommends that fishing mortality on yellowfin tuna should not be increased from the level that maintains spawning biomass at 2012-2015 levels until the Commission can agree on an appropriate target reference point. It also notes that further increases in yellowfin fishing mortality would likely affect other stocks and species which are currently moderately exploited due to the interactions in WCPFC fisheries.
An evaluation of the bridging measure in 2019 found that it would achieve its targets if bigeye recruitment remains high, but if that declines, fishing mortality will double to above FMSY and biomass has a 20% chance of dropping below the limit reference point. For yellowfin, the measure will marginally fail its aims as SB will experience a small decrease. The bridging measure includes a number of new measures and consolidates some pre-existing ones. It isn’t clear how well they have been implemented, especially given the ongoing increases in total catch of skipjack. The scientific committee recommends more comprehensive data collection relating to FADs. It also recommends reducing fishing mortality on juveniles by preventing increases in overall fishing mortality. In the tropical region, between 20 degrees North and 20 degrees South, the following applies:
FADs are banned for 5 months of the year (3 months for Kiribati and the Philippines). VMS polling frequency increases to every 30 minutes during the FAD closure.
Effort limits (in vessel days) apply to purse seining on the high seas (excluding Small Island Developing States, SIDS). Limits vary by country. Effort shouldn’t be transferred into areas outside of the bridging measure. Large purse seine and longline vessel numbers and capacity are frozen to 2016 levels (excluding SIDs and Indonesia).
Purse seiners must retain and land all bigeye, skipjack, and yellowfin tuna. This is intended to incentivise reductions in bycatch of juvenile fish.
100% observer coverage is required for purse seine vessels. Outside of the areas covered by the bridging measure, observer coverage on purse seiners is poor. Only 5% coverage is required on longliners greater than 20m in length. 20% is considered to be the minimum to be effective.
Other measures that apply to tuna in the wider convention area:
Each purse seine vessel is limited to 350 drifting FADs at a time. Countries should have FAD management plans, with strategies to implement closures and other measures for reducing mortality of juvenile bigeye.
Catch and/or effort limits apply to purse seining within national waters (it varies by country). For bigeye, there are country-specific limits on longline catch. By 2020, limits for bigeye and a framework to allocate them amongst countries should be developed. Catches by other fisheries for bigeye, yellowfin or skipjack tuna (except those taking less than 2,000 tonnes) are frozen to either the average level for 2001-2004 or the level of 2004.
To help address IUU, the WCPFC maintains an IUU Vessel List, prohibits transhipments at sea between purse seiners (some exemptions apply) and requires all other transhipments to be documented and 100% observed as part of the regional observer programme.
In 2017 a Compliance Monitoring Scheme was introduced to assess and improve compliance with obligations, and penalise non-compliance.
The Parties to the Narau Agreement (PNA), which covers a number of South Pacific Islands and produces 25% of the world’s tuna, has a series of agreements in place to control access to tuna it is waters and increase economic benefits for South Pacific islanders. Their IUU aerial surveillance programme in 2017 covered 100% of the EEZs in their area. 90% of FAD sets in the WCPO were in PNA waters, and FAD density is high - 400-500 FADs in one degree square (roughly 110km sq.) per month. A recent PNA report estimated that 7% of FADs ‘beach’ (with concerns for pollution and navigation safety) and up to 52% were lost (drift outside the fishing ground of the company owning it, at which point the company is likely to abandon it). Therefore, ghost fishing is of concern where FADs have entangling elements. 98% of FADs have echo-sounders, allowing remote monitoring of the biomass near them. There are plans to develop this technology to distinguish between species to enable reduction of fishing mortality on bigeye.
Criterion score: 0.75 info
Around 16% of Western Central North Pacific Ocean (WCPO) yellowfin catches are from longline. While longlining is unlikely to have habitat impacts, it can have a bycatch of highly vulnerable species such as sharks, turtles, and seabirds. Some mitigation measures are in place, but a number of Endangered and Critically Endangered species are still caught as bycatch in longline fisheries. Better data is needed. Mandatory observer coverage is very low, at just 5%. In general, 20% is scientifically recommended to ensure adequate monitoring of catch and bycatch. Unfortunately, owing to Covid disruption, ecosystem considerations were not discussed during the WCPFC’s meetings in 2020.
In general, the effectiveness of the below mitigation measures has not been evaluated. Monitoring is deficient and the reporting of interactions with vulnerable species is poor. 100% observer coverage is required for purse seine vessels fishing for tropical tunas in the tropical region, between 20 degrees North and 20 degrees South. Outside of this and for other gears, observer coverage is poor. Only 5% coverage is required on longliners greater than 20m in length. 20% is considered to be the minimum to be effective.
Turtles: The five marine turtle species in the WCPFC Convention Area are threatened or critically endangered, and WCPFC does not hold sufficient information to quantify the severity of the threat posed by longline fisheries to sea turtle populations. Measures to mitigate turtle bycatch, from 2008, are: to safely recover and release captured turtles, for purse seiners to avoid encircling them, for longliners to carry cutters and dehookers for releasing them, and for shallow-set swordfish longliners to use circle hooks and whole finfish bait (some exemptions to the latter measure apply, e.g. if there is 10% observer coverage). Under this measure, less than 1% of Western and Central Pacific Ocean (WCPO) longline effort is subject to mitigation, even though approximately 20% of the WCPO longline effort consists of shallow sets. To improve current management measures, research into turtle bycatch mitigation is ongoing. Research includes, but is not limited to, the wider use in longline fisheries of large circle hooks and/or whole finfish for bait. Improvements in data collection on interactions with sea turtles are needed. Although interaction rates are higher in shallow-set longlines, mitigation for deep-set longlines would deliver greater reductions in total interactions because effort in deep-set longline fisheries is 4 times that of shallow sets. Similarly, introducing mitigation to deep-set longlines would deliver greater reductions in at-vessel mortality compared to shallow-sets, because sea turtles have a higher probability of asphyxiation in deep sets.
Sharks: Many sharks are deliberately targeted, and so RFMO management must cover active shark fisheries as well as bycatch in tuna fisheries. However, sharks are vulnerable to fishing pressure, being slow-growing and late to mature. Some are listed on Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Shark measures include: no shark finning; a prohibition to land silky and oceanic whitetip sharks; and a prohibition on the use of shark lines. Tuna often swim with whale sharks; deliberately setting a net on a whale shark is prohibited. The effectiveness of these measures are difficult to evaluate owing to lack of data. As of 2014, shark management plans are required where sharks are being targeted, although few countries have developed them. There are measures to improve recording of manta and mobula rays discarded and released, and to treat these species as key shark species for assessment and research. Guidelines for safe release of manta and mobulid rays were adopted in 2017. The commission is also looking to develop guidelines for other rays and sharks, and develop stronger and more comprehensive management measures for sharks, but there is no stated deadline for this. No limit reference points are in place for any Pacific sharks, and it is recommended that these be implemented.
Shark species of concern are:
Silky sharks, which are subject to overfishing. In 2016, catches of silky sharks in the longline fishery were around three times higher than in the purse seine fishery.
Pacific bigeye thresher, which seems likely to be experiencing overfishing, primarily from the bigeye tuna fleet.
Oceanic whitetip, which is heavily overfished, at just 4% of unfished levels. This is a very slight recovery from previous years, but it’s unclear if recovery will continue. Fishing pressure is high but has declined. The greatest impact on this species is bycatch from longline fisheries, with lesser impacts from purse seining. Further catch mitigation and improved handling and release practices are required. Reduced catch and retention has occurred as a result of the existing management measures, but this has reduced the amount of data coming in about the species.
Seabirds: The annual mortalities of seabirds in WCPFC longline and purse seine fisheries from 2015 to 2018 were estimated between 13,000 and 19,000 individuals - two thirds by longline fisheries north of 20 degrees N, one quarter by longline fisheries south of 30 degrees S, and negligible amounts from purse seining. A small area east of Tasmania and south of 40 degrees S is estimated to account for around 60% of the longline seabird bycatch south of 30 degrees S and 15% of the total seabird bycatch in the WCPFC Convention Area (this includes fleets targeting southern bluefin tuna as well as species managed by the WCPFC). The low or absent observer coverage in key longline fleets in high latitude areas (both north and south) prevents accurate estimation of seabird bycatch. In the Northern hemisphere, there is no clear evidence of decline in the affected seabird populations. In the south, according to the Commission for the Conservation of Antarctic Marine Living Resources, longline fisheries are the largest threat to some seabird species, notably albatrosses and petrels, which are threatened with global extinction. Of critical concern is Antipodean wandering albatross, which is expanding foraging range into tuna fishery areas and has experienced a high and sustained rate of decline - it is now in New Zealand’s “Nationally Critical” conservation status category. Countries are expected to implement the International Plan of Action for Reducing Incidental Catches of Seabirds in Longline Fisheries (IPOA-Seabirds) and report back on this. South of 30 degrees South and north of 23 degrees North, longliners must use at least 2 mitigation measures. In the area between, longliners need only use 1. The simultaneous use of 3 measures (weighted branch lines, bird scaring lines and night setting) remains the best practice approach. Further research is being done on hook shielding devices, and countries are encouraged to develop and refine measures to mitigate seabird bycatch, including safe release of seabirds captured alive. Scientific advice is to increase observer coverage and ensure compliance with existing regulations.
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, European anchovy
Anchovy, Peruvian anchovy
Herring or sild
Horse Mackerel, Scad
Salmon, Chum, Keta, Calico or Dog salmon
Salmon, Pink, Spring , humpback
Salmon, Sockeye , Red Salmon, Bluebacks, Redfish
Sardine, European pilchard, sardines
ReferencesACAP, 2019. ACAP Review and Best Practice Advice for Reducing the Impact of Pelagic Longline Fisheries on Seabirds, Reviewed at the Eleventh Meeting of the Advisory Committee of the Agreement on the Conservation of Albatrosses and Petrels, 13 - 17 May 2019, Florianopolis, Brazil. Available at https://www.acap.aq/en/bycatch-mitigation/mitigation-advice/3498-acap-2019-review-and-best-practice-advice-for-reducing-the-impact-of-pelagic-longline-fisheries-on-seabirds/file [Accessed on 29.11.2019].
Brouwer, S., Pilling, G., Williams, P., WCPFC Secretariat , 2017. Trends in the South Pacific albacore longline and troll fisheries, Document WCPFC-SC13-2017/SA-WP-08 for the Thirteenth Regular Session of the Scientific Committee of the Commission for the Conservation and Management of Highly Migratory Fish Stocks in the Western and Central Pacific Ocean, 9 - 17 August 2017, Rarotonga, Cook Islands. 70 pp. Available at https://www.wcpfc.int/meetings/sc13 [Accessed on 27.11.2017].
Dias, M. P., Martin. R., Pearmain, E., J., Burfield, I. J., Small, C., Phillips, R. A., Yates, O., Lascelles, B., Garcia Borboroglu, P. and Croxall, J. P., 2019. Threats to seabirds: A global assessment. Biol. Cons. 237, pp 525-537. https://doi.org/10.1016/j.biocon.2019.06.033 [Accessed on 29.11.2019].
IPNLF, 2012. Ensuring sustainability of live bait fish, International Pole and Line Foundation, London, 57 pp.
ISSF, IPNLF, 2019. Skippers’ Guidebook to Pole-and-Line Fishing Best Practices. Version 1.0 - April 2019. International Seafood Sustainability Foundation and International Pole & Line Foundation. Available at http://ipnlf.org/perch/resources/pl-guidebookipnlfissffinal.pdf [Accessed on 30.11.2020].
ISSF, 2020. Status of the world fisheries for tuna. Nov. 2020. ISSF Technical Report 2020-16. International Seafood Sustainability Foundation, Washington, D.C., USA. Available at https://iss-foundation.org/knowledge-tools/technical-and-meeting-reports/download-info/issf-2020-16-status-of-the-world-fisheries-for-tuna-november-2020/ [Accessed on 10.12.2020].
Phillip, N.B. and Escalle, L., 2020. Updated evaluation of drifting FAD construction materials in the WCPO. WCPFC-SC16-2020/EB-IP-03 presented to the Western and Central Pacific Fisheries Commission Scientific Committee 16th Regular Session, 11-20 August 2020, Online. Available at https://www.wcpfc.int/node/46724 [Accessed on 11.12.2020].
WCPFC, 2020. Summary Report of the Sixteenth Regular Session of the Scientific Committee of the WCPFC, 12-19 August 2020 (Reconvened on 10 September 2020), Online. Available at https://www.wcpfc.int/file/568072/download?token=hcPeql6u [Accessed on 10.12.2020].
WCPFC, 2020. Conservation and Management Measures of the Western and Central Pacific Fisheries Commission. Compiled 2 Nov 2020 - 09:46. Available at https://www.wcpfc.int/system/files/booklets/31/CMM%20and%20Resolutions.pdf [Accessed on 10.12.2020].
Vincent M., Ducharme-Barth, N., Hamer,P., Hampton, J., Williams, P. and Pilling, G., 2020. Stock assessment of yellowfin tuna in the western and central Pacific Ocean. WCPFC-SC16-2020/SA-WP-04 (Rev.3) presented to the Western and Central Pacific Fisheries Commission Scientific Committee 16th Regular Session, 11-20 August 2020, Online. Available at https://www.wcpfc.int/node/46611 [Accessed on 11.12.2020].