Euthynnus pelamis, Katsuwonus pelamis
Capture method — Purse seine (FAD & Free School)
Capture area — Pacific, North West (FAO 61) and Central (FAO 71,77)
Stock area — Western and Central Pacific
Stock detail —
The latest stock assessment was undertaken in 2016 and results were very similar to previous assessments, indicating that the stock is not overfished nor being subject to overfishing. The skipjack catch in 2017 (1,624,162t) was the lowest since 2011, and below the 2012-2016 average of 1,835,751 t and below estimated maximum sustainable yield of 1,892,000t. The commission is looking to establish harvest strategies for key fisheries and stocks but has not yet completed this work and so, as of January 2018 adopted a bridging measure to manage bigeye, yellowfin and skipjack until harvest strategies are in place or February 2021. As part of this, the average spawning biomass for skipjack is to be maintained at the interim target of 50% of unfished levels (about current levels). There is no Total Allowable Catch (TAC) set for this stock, but as skipjack is caught alongside bigeye and yellowfin, primarily in purse seine fisheries (nearly half of which is set on FADs), the range of measures and capture method impacts listed for bigeye also apply to skipjack and includes limits on vessel days and 5months of closures for purse seine sets on Fish Aggregation Devices (FADs). 80% of the skipjack catch here is caught in purse seine fisheries: 36% from sets around floating objects (FADs), and 44% on free-schooling tuna. Juvenile tuna are often caught in purse seine fisheries and the method is also associated with bycatch of vulnerable species including sharks, turtles and other billfish. The proportion of this bycatch is higher in FAD-associated fisheries, which can also entangle species. Whilst the proportion of this bycatch compared with the total catch is very low, the high volume of tuna that is caught means that even a low proportion of this can still be relatively high in terms of total volume or individuals. Redistribution of effort from FADs to free schools has resulted in substantial reductions in estimated catches of silky shark (by 83%) and oceanic whitetip shark (by 57%). Observer coverage is 100% for purse seiners on the High Seas and between 20 N and S unless fishing exclusively in their national waters.
Commercial buyers should establish what measures the flag state and fleet relating to their source is taking to reduce impacts to vulnerable species and encourage development of a harvest strategy for skipjack. Large buyers should consider supporting such improvements. There are MSC certified fleets within the scope of this rating which represent the best choice and there is also is a Fishery Improvement Project (FIP) in place for some fleets which is making good progress at improving elements of the fishery. More info about this FIP is available from fisheryprogress.org
MCS advocates specifying the need for supplying vessels to register on the ISSF Proactive Vessel Register.
Tuna belong to the family Scombridae. They are large, oceanic fish and are seasonally migratory, some making trans-oceanic journeys. Skipjack tuna are found throughout the world’s tropical and warm temperate waters. During the day they school on the surface (often with birds, drifting objects, sharks, whales etc.) but at night can descend to depths of 260m. Skipjack tuna are a very fast growing species, maturing at 2 to 3 years old (40cm in length) and living for up to 12 years. They can grow up to 100cm and 34kg in weight but are rarely found larger than 80cm and 10kg. They spawn all year round and have a medium to high resilience to fishing.
Criterion score: 0 info
Western and Central Pacific
The Western and Central Pacific Ocean (WCPO) skipjack stock supports the largest tuna fishery in the World, accounting for approximately 38% of worldwide tuna landings. It is managed and assessed by the Western and Central Pacific Fisheries Commission (WCPFC).
Skipjack tuna catches in the WCPO increased steadily from 1970 onwards, roughly doubling during the 1980s. After stabilising at around 1,000,000t during the early 1990s, they increased to between 1.5 and 2 million t from 2007 and a record catch of around 2 million t was taken in 2014. The increase in fishing mortality since the 1980s has been due to the increase of catches of both juvenile and adult fish from both associated purse seine sets and the mixed gear fisheries in the Philippines and Indonesia. Biomass also increased from the early 1980’s, resulting from higher recruitments, then fluctuated and declined slightly up until 2012. Since then there appears to have been a strong increase in spawning biomass, peaking in 2013/2014 at levels just below the 1980s peaks.
The skipjack catch in 2017 (1,624,162t) was the lowest since 2011, and below the 2012-2016 average of 1,835,751 t. The latest stock assessment was undertaken in 2016, indicating that the stock is not overfished (Spawning Biomass, SB, at 2.56 Bmsy) nor being subject to overfishing (Fishing mortality, F, at 0.45 Fmsy). Recent levels of spawning biomass are well above the level that will support MSY, and while there has been a steady depletion of the stock over most of the assessment period, the stock is still estimated to be healthy, and is estimated to have been at approximately 50% of unfished levels for the past decade: well above the limit reference point of 20%. Projections were updated in 2018. Under recent fishery conditions (2017 catch level for longline and other fisheries and effort level for purse seine), the skipjack stock was projected to decrease for a short period as recent relatively high recruitments move out of the stock. Predicted F2019/FMSY = 0.47, SB2019/SBF=0 = 0.45, and SB2019/SBMSY = 1.67. In the longer term, assuming long term average recruitment, modest increases in the stock were projected.
The scientific committee advise that tagging data is a critical component of the skipjack stock assessment and recommend regular large-scale tagging cruises and complementary tag recovery work continue to be undertaken in a way that provides the best possible data for stock assessment purposes. Currently, pole and line CPUE is the major indicator of abundance for assessment purposes, which in 2017 represented around 8% of the catch and continues to shrink geographically. Pole and line catch in 2017 (123,132 t) was a 21% decrease from 2016 and a 23% decrease from the average 2012-2016 catch.
Criterion score: 0.5 info
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.
WCPFC has put in place a lower limit for the spawning biomass of bigeye, skipjack, and yellowfin tuna of 20 percent of unfished levels (SB/SBF=0, aka spawning biomass depletion ratio), below which the stock should not fall. For skipjack there is also an interim target of 50 percent of unfished levels, which was adopted in 2015 and has been reached. The scientific committee recommends reducing fishing mortality on juvenile bigeye and yellowfin in the tropics, through preventing increases in overall fishing mortality, until targets for these two stocks can be agreed. The commission is looking to establish harvest strategies for key fisheries and stocks but has not yet completed this work and so, as of January 2018, a bridging measure is in force to manage bigeye, yellowfin and skipjack - the measure lasts until harvest strategies are in place or until February 2021. As part of this, spawning biomass depletion ratios for bigeye and yellowfin are to be maintained at recent levels (the average from 2012-2015) and skipjack at 50 percent. The bridging measure includes a number of new measures and consolidates some pre-existing ones, and is outlined below.
In the tropical region, between 20 degrees North and 20 degrees South, the following applies:
The use and deployment of FADs is prohibited 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. In order not to undermine the effectiveness of this, countries cannot transfer effort into areas outside of this region.
To create an incentive to reduce the non-intentional capture of juvenile fish, to discourage waste and to encourage an efficient utilization of fishery resources, purse seiners must retain on board and then land or transship at port all bigeye, skipjack, and yellowfin tuna (also applies to national waters).
All purse seine vessels operating on the high seas or within national waters in this region must carry an observer. This also applies to purse seiners anywhere in the convention area fishing in waters under multiple countries’ jurisdiction or moving between the high seas and national waters.
The number and capacity of large (over 24m) purse seiners and longliners (with freezing capacity and ice-chilled) operating in this area is frozen to 2016 levels (excluding SIDs and Indonesia).
Other measures that apply to the wider convention area:
The number of drifting FADs with activated instrumented buoys deployed at any one time is limited to 350 per purse seine vessel.
Catch and/or effort limits apply for purse seining within national waters (both the type of limit and the amount vary by country).
There are country-specific limits on longline bigeye catch, and by 2020 hard limits for bigeye and a framework to allocate them amongst countries shall be developed.
Catches by other commercial tuna fisheries for bigeye, yellowfin or skipjack tuna (excluding those taking less than 2,000 tonnes) shall not exceed either the average level for the period 2001-2004 or the level of 2004.
There is a requirement to submit FAD management plans, including information on strategies used to implement closures and other measures for reducing mortality of juvenile bigeye. A number of aspects in the bridging measure have been brought forward from previous management measures, and 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.
Observer coverage on purse seiners is poor in areas not specified in the bridging measure and only 5% coverage is required on longliners greater than 20m in length. 20% is considered to be the minimum to be effective.
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.
Criterion score: 0.75 info
80% of skipjack catches in the WCPO are from purse seine vessels (36% on FADs and 44% on free schools) - a figure which has steadily increased over the last 30 years. Many juvenile fish are often caught in purse seine fisheries and the method is also associated with bycatch of sharks, turtles and dolphins (more so in FAD-associated fisheries, which can also entangle species). Whilst the proportion of this bycatch compared with the total catch is relatively low, the high volume of tuna that is caught means that even a low proportion of this can still be relatively high in terms of total volume or individuals. The widespread use of FADs is also of concern due to the unknown impacts such gear might have on natural species composition of tuna schools, migratory patterns, growth rates and predation rates of affected pelagic species. The scientific committee recommends more comprehensive data collection relating to FADs.
To reduce the entanglement of sharks, marine turtles or any other species, and reduce the amount of synthetic marine debris, countries are encouraged to use non-entangling, natural and biodegradable design and materials for FADs, in line with scientific advice. Stricter (i.e. binding) measures may be adopted in 2018. Vessels are prohibited from knowingly setting a purse seine around tuna schools associated with a live whale shark, marine mammal or turtle, and all reasonable steps are required to be taken to ensure the safe release of these animals and details of the interaction are to be recorded if accidentally encircled. In 2016, catches of silky sharks in the longline fishery were around three times higher than in the purse seine fishery. Redistribution of effort from FADs to free schools has resulted in substantial reductions in estimated catches of silky shark (by 83%) and oceanic whitetip shark (by 57%). Shark measures include: full utilisation of permissible sharks and retention of no more than 5% of fins to total shark weight; a prohibition to land silky and oceanic whitetip sharks; a prohibition on the use of shark lines. 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 to date only 2 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. In 2017 the scientific committee recommended guidelines for safe release of manta and mobulid rays, which were adopted by the WCPFC. The commission is also looking to develop guidelines for other rays and sharks, especially silky shark and oceanic whitetips, as well as develop stronger and more comprehensive management measures for sharks, but there is no stated deadline for this. It is recommended that target and limit reference points are established for pelagic sharks.
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
Herring or sild
Salmon, Atlantic (Farmed)
Salmon, Chinook, King Salmon
Salmon, Chum, Keta, Calico or Dog salmon
Salmon, Coho , Silver, White
Salmon, Pink, Spring , humpback
Salmon, Sockeye , Red Salmon, Bluebacks, Redfish
ReferencesFishery Progress, 2018. Fishery Improvement Project Directory. Available at https://fisheryprogress.org/ [Accessed on 05.12.2018].
ISSF, 2018. Status of the world fisheries for tuna: October 2018. ISSF Technical Report 2018-21. International Seafood Sustainability Foundation, Washington, D.C., USA. 103 pp. Available at: https://iss-foundation.org/about-tuna/status-of-the-stocks/ [Accessed on 06.12.2018].
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.
WCPFC, 2018. Conservation and Management Measures of the Western and Central Pacific Fisheries Commission. Available at https://www.wcpfc.int/conservation-and-management-measures [Accessed on 06.12.2018].
WCPFC, 2018. Estimates of Annual Catches in the WCPFC Statistical Area WCPFC-SC14-2018 ST-IP-01 for the Fourteenth 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, 8-16 August 2018, Busan, Republic of Korea. 34 pp. Available at https://www.wcpfc.int/meetings/14th-regular-session-scientific-committee [Accessed on 06.12.2018].
WCPFC, 2018. Summary Report of the Fourteenth 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, 8-16 August 2018, Busan, Republic of Korea. 34 pp. Available at https://www.wcpfc.int/meetings/14th-regular-session-scientific-committee [Accessed on 06.12.2018].