The catch of tuna in the Western and Central Pacific Ocean (WCPO).

 

About 51  percent of the world’s production of tuna is from the Western and Central Pacific Ocean (WCPO) – FAO Major Fishing Areas 61, 71 and 81. Provisional catches of skipjack tuna, yellowfin tuna and bigeye tuna in 2023 were 2 490 300 tonnes, a 2 percent decrease from 2022; and provisional catches of North Pacific albacore tuna, South Pacific albacore tuna and Pacific bluefin tuna were 120 000 tonnes, a 25 percent decrease from 2022. Note that despite catches of North Pacific albacore tuna, South Pacific albacore tuna and Pacific bluefin tuna occurring throughout the entire Pacific Ocean (i.e. in both the IATTC and WCPFC areas), they are reported under this section dealing with the WCPFC.

The catch of tropical tunas in the WCPO steadily and continuously increased by around half a million tonnes per decade since the 1960s, reaching 1 million tonnes in 1984, 1.5 million tonnes in 1994, and 2 million tonnes in 2005, before peaking at a record high of 2.7 million tonnes in 2014. Since then, total catches have stabilized at around 2.5 million tonnes (FIGURE E.1.10). Catches of North Pacific albacore, South Pacific albacore and Pacific bluefin tuna also steadily increased to 175 000 tonnes from 1950 to 1973, then decreased to 89 000 tonnes by 1991 (the third-lowest level in the time series). They then increased again, reaching a peak of 204 000 tonnes in 2002, before showing a decreasing trend, reaching around 120 000 tonnes in 2023 (FIGURE E.1.10). Average tuna catches for the last five-year period (2019–2023) were 2 747 415 tonnes. During this period, skipjack tuna accounted for 64 percent of the total catch by weight, followed by yellowfin tuna (26 percent), bigeye tuna (5 percent), North Pacific albacore tuna (2 percent), South Pacific albacore tuna (2.5 percent) and Pacific bluefin tuna (0.5 percent). Purse-seine vessels took 70 percent of the total catch, followed by longline (9 percent), pole-and-line (6.5 percent), and other gears (14.5 percent). The skipjack tuna catch continuously increased, peaking at around 2 million tonnes in 2019–the highest on record–before stabilizing at around 1.6–1.7 million tonnes since then. Meanwhile, the yellowfin tuna catch reached its highest level in 2021, totaling about 750 000 tonnes, and has remained at that level since (FIGURE E.1.11). However, bigeye tuna, South Pacific albacore tuna, North Pacific albacore tuna and Pacific bluefin tuna followed different trends, with catches peaking at different times: in the 2000s for bigeye tuna and North Pacific albacore tuna, in 2010 for South Pacific albacore tuna, and in 1956 for Pacific bluefin tuna. In all cases, catches have declined since their peak records in the time series.

BIGEYE TUNA Provisional bigeye tuna catches in 2023 were about 133 700 tonnes, a 7 percent decrease from 2022. Longline fishing dominated the catches by weight until the mid-1990s. However, the relative contribution of purse seine to the catch in recent years has increased. For example, in the most recent five years, the main fishing gears are purse seine and longline with 44 percent and 39 percent of the catch, respectively (FIGURE E.1.11). Bigeye catches in the WCPO by other gears were relatively minor, but have increased in recent years.

 YELLOWFIN TUNA Provisional yellowfin tuna catches in the WCPO in 2023 were about 737 400 tonnes, an 8 percent increase from 2022. Until about 1980, fishing was dominated by longline and pole-and-line vessels; however, since the early 1980s purse seine has been the main gear. In the last five years purse seiners caught around 55 percent of the total catch, while 31 percent of the catch was taken by a number of mixed gears in the Philippines and Indonesia, and 11 percent was taken by longliners (FIGURE E.1.11). Most of the catches are taken from the tropical region where the stock is considered fully exploited and there is little or no room for increased fishing pressure. 

SKIPJACK TUNA The WCPO skipjack tuna stock supports the largest tuna fishery in the world, accounting for 35 percent of worldwide tuna landings. Catches in 2023 were 1 619 100 tonnes, a 6 percent decrease from 2022. Purse seining, which accounts for 83 percent of the catches, has increased steadily over the past three decades. In contrast, pole-and-line fishing (about 8 percent) has been declining since the mid-1980s (FIGURE E.1.11). 

NORTH PACIFIC ALBACORE TUNA North Pacific albacore tuna provisional catches in 2023 were about 34 000 tonnes, a 31 percent decrease from 2022. Approximately 77 percent of the catch occurs in the WCPO and 23 percent in the EPO. The main fishing gears are longline (45 percent) and pole-and-line (31 percent), followed by trolling (19 percent) (FIGURE E.1.11). Catches by longline have shown a decreasing trend since 1999.

SOUTH PACIFIC ALBACORE TUNA South Pacific albacore tuna extends beyond the WCPFC Convention Area. However, the stock is assessed by WCPFC. South Pacific albacore tuna provisional catches in 2023 were about 67 700 tonnes, a 26 percent decrease from 2022 catches. Approximately 70 percent of the catch occurs in the WCPO and 30 percent in the EPO. The main fishing gear is longline, accounting for 95 percent of the catch. Relatively minor amounts are taken by other gears like trolling (FIGURE E.1.11). 

PACIFIC BLUEFIN TUNA Reported Pacific bluefin tuna provisional catches in 2023 were about 18 200 tonnes, a 3 percent increase from estimates available for 2022. Most of the catch (71 percent) occurs in the Western Pacific Ocean. About 52 percent of the Pacific-wide catch is made by purse-seine fisheries, followed by a variety of gears such as coastal set nets and troll (29 percent) and longline (18 percent) (FIGURE E.1.11)

BIGEYE TUNA In 2023, the Pacific Community (SPC) conducted an assessment that included some improvements and a more rigorous approach than the previous assessment in 2020. All models in the uncertainty grid indicated that the stock is above the biomass limit reference point as well as MSY-based reference points. Therefore, the stock is not overfished and overfishing is not occurring (TABLE E.1.3 and FIGURE E.1.12). 

YELLOWFIN TUNA The last yellowfin tuna assessment was conducted in 2023. The results were in general less optimistic compared to previous assessments. All models in the uncertainty grid indicate the stock is above the biomass limit reference point as well as MSY-based reference points. Therefore, the assessment results indicate that the stock is not overfished and overfishing is not occurring. However, the current (2023) catches are larger than the median MSY, estimated to be 700 400 tonnes. 

SKIPJACK TUNA The last skipjack tuna assessment was conducted in 2022. Stock status was determined over an uncertainty grid of 18 models. There were several new developments and improvements to the stock assessment compared to the 2019 assessment, including the application of a new approach to estimate fishing mortality, the inclusion of an alternative growth model, and the use of new free-school indices of abundance. The results of the assessment indicate that the stock is not overfished and overfishing is not occurring. 

NORTH PACIFIC ALBACORE TUNA The last North Pacific albacore tuna stock assessment was conducted in 2023 (ISC, 2023) and the results indicated that the stock is not overfished and overfishing is not occurring. However, the stock assessment showed that increasing fishing effort is unlikely to result in higher yield. 

SOUTH PACIFIC ALBACORE TUNA The last full assessment was conducted in 2024 and indicated the stock is not overfished and that overfishing is not occurring. 

PACIFIC OCEAN BLUEFIN TUNA In 2024, a benchmark stock assessment was conducted. All aspects of the model were critically reviewed, and some modifications were made to improve the model. The assessment estimated that the SSB was 23.2 percent of the unfished level, having achieved the second rebuilding target set by the WCPFC and the IATTC in 2021. The point estimate of the depletion level is now above the biomass depletion-based limit reference point of 20 percent of the unfished stock biomass set by the WCPFC. Although the assessment indicated that the stock is overfished, overfishing is likely not occurring. Pacific bluefin tuna was heavily overfished but has now rebuilt to interim rebuilding targets. Management has been implemented to rebuild the stock towards higher target reference points that are currently being estimated.

BIGEYE TUNA AND YELLOWFIN TUNA There is ongoing work under a mixed fishery framework that involves developing stock-specific management procedures for skipjack, yellowfin, bigeye and South Pacific albacore tunas, in line with the agreed WCPFC harvest strategy workplan. The interaction of these management procedures, as well as their impact on yellowfin tuna, would then be evaluated using a combined mixed fisheries evaluation framework. 

SKIPJACK TUNA The skipjack tuna in the WCPO is managed through a management procedure CMM 2022-01. The management procedure applies to the catch and effort of purse-seine and poleand-line fisheries, and other commercial fisheries referred to in CMM 2022-01 taking more than 2 000 tonnes of tropical tunas (bigeye, yellowfin and skipjack tuna) in the exclusive economic zones and areas beyond national jurisdiction. The objectives of the management procedure ensure that the spawning potential depletion ratio of skipjack tuna is maintained on average at a level consistent with the target reference point; and the spawning potential depletion ratio of skipjack tuna is maintained above the limit reference point with a risk of the limit reference point being breached of no greater than 20 percent; in a manner that achieves the objective of relative stability in fishing levels between management periods and in the longer term. 

NORTH PACIFIC ALBACORE TUNA The IATTC (IATTCRes. C-23-02) and the WCPFC (Harvest Strategy 2023-01) adopted a full management procedure, including a harvest control rule, in 2023, which was applied for the first time in 2024 based on the latest stock assessment performed. The IATTC/ WCPFC management procedure is aligned and its objectives are defined as follows: 

„ Maintain spawning stock biomass (SSB) above the limit reference point, with a probability of at least 80 percent over the next ten years. The risk of breaching the limit reference point based on the most current estimate of SSB shall be no greater than 20 percent. 

„ Maintain depletion of total biomass around historical (2006–2015) average depletion over the next ten years. „ Maintain fishing intensity (F) at or below the target reference point with a probability of at least 50 percent over the next ten years. 

„ To the extent practicable, management changes (e.g. catch and/or effort) should be relatively gradual between years. The limit reference point is set at 14 percent of the dynamic unfished SSB and the target reference point at the fishing intensity (F) level that results in the stock producing 45 percent of spawning potential ratio. 

SOUTH PACIFIC ALBACORE TUNA There is no management procedure adopted for South Pacific albacore tuna in either the IATTC or in the WCPFC. However, various components of the management procedure, such as the target reference point and limit reference point, have been adopted. PACIFIC BLUEFIN TUNA There is no management procedure adopted for Pacific bluefin tuna in either the IATTC or in the WCPFC. However, various components of the management procedure, such as the target reference point, limit reference point and a harvest control rule for its rebuilding plan, have been adopted.

TROPICAL TUNAS The main binding conservation measure for bigeye, yellowfin and skipjack tuna established by the WCPFC is CMM 2023-01. 

For the 2024–2027 period, it calls for: 

„ A one-and-a-half-month closure (July to mid-August) of fishing on FADs in EEZ waters and on areas beyond national jurisdiction between 20° north and 20° south. 

„ Extension of the FAD closure for one additional month in areas beyond national jurisdiction, with some exemptions for Kiribati- and Philippines-flagged vessels. 

„ Fully non-entangling FADs without netting in their construction. 

„ A limit of 350 drifting FADs at any one time per purse-seine vessel. 

„ A limitation on the number of vessel days in EEZs (i.e. a vessel day scheme). 

„ Limitation of purse-seine effort on the high seas for non-Small Islands Developing States (SIDS) members. 

„ A full-retention requirement for all purse-seine vessels regarding bigeye, skipjack and yellowfin tunas between 20° north and 20° south. 

„ Flag-specific catch limits for non-SIDS longline fleets for bigeye tuna. These catch limits may be increased by up to 10 percent if linked to a proportional increase of observer coverage (achieved by human and/or electronic monitoring). 

This conservation and management measure (CMM) is complex, with many “either/or” choices, exemptions or exclusions and decisions yet to be made with respect to some measures, which makes it difficult to predict the outcomes in terms of actual future catch and effort levels. 

NORTH PACIFIC ALBACORE TUNA The main binding conservation measure for North Pacific albacore tuna established by the WCPFC is CMM 2019-03, which calls for members not to increase fishing effort for North Pacific albacore tuna in the Convention Area north of the equator and not to increase fishing effort directed at North Pacific albacore tuna beyond 2002–2004 annual average levels. In the IATTC, Resolution C-05-02 calls for members not to increase fishing effort directed at North Pacific albacore tuna beyond the “current level”. 

SOUTH PACIFIC ALBACORE TUNA The main binding conservation measure for South Pacific albacore tuna, established by the WCPFC, is CMM 2015-02, which aims to limit fishing mortality by capping the number of vessels fishing for South Pacific albacore tuna per Commission member, with some exemptions for SIDS. This capacity limitation prevents the number of vessels from exceeding the 2005 level or the 2000–2004 average. The IATTC adopted Resolution C-24-04, encouraging collaboration and alignment with the WCPFC in South Pacific albacore management. 

PACIFIC BLUEFIN TUNA WCPFC CMM 2024-01 establishes management measures to rebuild the Pacific bluefin tuna spawning biomass to its historical median level (the median point estimate for the 1952–2014 period) by 2024 with at least 60 percent probability. This CMM limits total fishing effort north of 20° north to below the average 2002–2004 levels. It also establishes catch limits per member for Pacific bluefin tuna less and larger than 30 kg, and allows members to use part of their juvenile catch limit (<30 kg) to catch adults (>30 kg). Members with less than 10 tonnes of catch during 2002–2004 are allowed to increase catch up to 10 tonnes. Any overcatch or undercatch on the catch limit will be deducted from or added to the following year’s TAC, with a maximum undercatch that can be carried over in any given year not exceeding 17 percent of its initial annual catch limit. An overall combined total commercial catch limit of 12 585 tonnes for the 2025–2026 period was set by IATTC in Resolution C-24-02. IATTC Resolution C-23-01 describes the objectives for both rebuilding periods, establishes harvest control rules for the second rebuilding period and the subsequent period after the second objective is met, sets overand under-harvest limits, and calls on the Commission to collaborate with the WCPFC Northern Committee to develop candidate reference points and harvest control rules.