Global Tuna Fisheries: Trends, Status and Management.

Since the onset of large-scale commercial exploitation in the 1950s, global tuna catches have steadily risen, reaching 1 million tonnes in the mid-1960s, 2 million tonnes in the mid-1980s, 3 million tonnes in 1990, 4 million tonnes in the late 1990s, 5 million tonnes in 2014, and finally topping out at 5.4 million tonnes in 2019. The global tuna catch has been stable at around 5 million tonnes since then. In 2023, the latest available data, the global tuna catch was approximately 5.2 million tonnes. The majority of tuna catches are attributed to skipjack tuna (57 percent), followed by yellowfin tuna (31 percent), bigeye tuna (7 percent), albacore tuna (4 percent), and three species of bluefin tuna (1 percent). In terms of fishing methods, purse seining accounts for 66 percent of global tuna catches, while longlines (9 percent), pole-and-line (7 percent), gillnets (4 percent) and other miscellaneous gear (14 percent) make up the remainder (FIGURE E.1.1). Purse seine catches are further categorized into associated sets (38 percent), unassociated sets (25 percent), and dolphin sets (3 percent). In 2023 the Pacific Ocean yielded the highest catches of principal market tuna species, contributing approximately 66 percent of the total. This was followed by the Indian Ocean, which accounted for around 23 percent, and the Atlantic Ocean and adjacent seas, with a contribution of about 11 percent. Globally, based on the most recent stock status adopted by tuna RFMOs, 16 out of 23 stocks are not overfished and overfishing is not occurring, 5 stocks are overfished but overfishing is not occurring (i.e. are in a state of rebuilding), and 2 stocks are overfished and overfishing is occurring (TABLE E.1.1). Similarly, in relation to catch, 95 percent of the total catch comes from sustainable stocks–that is, stocks that are not overfished and where overfishing is not occurring. This is due to the fact that skipjack tuna stocks contribute more than half of the global catch of tunas, and all are in healthy conditions. In contrast, two bluefin tuna stocks, two bigeye tuna stocks and one albacore tuna stock are overfished; accounting for the 5 percent of the total catch that comes from overfished stocks (FIGURE E.1.1).

AO: Atlantic Ocean, AOE: Eastern Atlantic Ocean, AOW: Western Atlantic Ocean, AON: North Atlantic Ocean, AOS: South Atlantic Ocean, EPO: Eastern Pacific Ocean, PO: Pacific Ocean, PON: North Pacific Ocean, POS: South Pacific Ocean, WCPO: Western and Central Pacific Ocean, IO: Indian Ocean

The estimated maximum sustainable yield (MSY) of all tuna populations across the 23 commercial tuna stocks totals approximately 6.3 million tonnes. In 2023, the total catch from these 23 populations was 5.2 million tonnes. FIGURE E.1.2 illustrates the difference between the catch and MSY for each stock, with each stock represented by a rectangle: the colour indicates its status, while the size reflects the difference. The bigeye, yellowfin, bluefin and albacore tuna populations are fished at MSY levels, while skipjack tuna could in theory generate higher yields, particularly in the WCPFC. However, in the WCPFC, which is the region primarily responsible for the difference between total catch and potential total MSY level (e.g. there is a 1 million tonne difference between the catch and MSY of WCPFC skipjack tuna), a target reference point and management procedure for skipjack tuna has been established, and fishing is already occurring at that MSY level, meaning further increases would not be feasible under the current management regime. Additionally, since almost all skipjack tuna fishing is done with fish aggregating devices (FADs), an increase in skipjack tuna catches would likely lead to higher bigeye and yellowfin catches, which would be detrimental to these species. In conclusion, the current scenario implies a need to maintain yields, with limited prospects for increasing yields in the future. It appears that the maximum catch under the current tuna management framework has either been reached or is close to being reached; therefore, further increases in catches are not likely.

FAO uses different criteria to determine the stock status of fish populations compared to those used by tuna RFMOs. The FAO Blue Transformation roadmap aims to maximize opportunities within aquatic food systems to enhance food security andmaintaining fish stocks at levels capable of producing MSY. Thus, the FAO methodology’s targets focus on ensuring food security and maximizing catches at MSY. FAO criteria include a buffer around biomass corresponding to MSY. According to these criteria, when a stock is between 0.8 SSB/SSBMSY and 1.2 SSB/SSBMSY, it is considered “maximally sustainably fished”, meaning that production can be sustainably maintained but not grow. If it is greater than 1.2, the stock is classified as “underfished”, whether it is because of a deliberate management choice for precautionary reasons or because the fishery has not yet reached maximum sustainable production, and if it is less than 0.8, it is considered “overfished”. This difference in criteria explains potential discrepancies in stock status determination between FAO and this chapter (TABLE E.1.1). For the purpose of this report, the reference year for the assessments is 2021. However, this chapter presents the most up-to-date data on tuna populations as of 2024. In 2021, Pacific bluefin, Southern bluefin, and Mediterranean albacore tuna were all classified as overfished according to FAO criteria. By 2024, only Mediterranean albacore tuna remained in the overfished category. The status of the other tuna stocks remained unchanged, except for yellowfin tuna, which shifted from being classified as fished at a maximally sustainable level in 2021 to underfished in 2024, based on FAO criteria.

Tuna and tuna-like species are important socioeconomic resources as well as a significant source of protein for society (Pew, 2020; Guillotreau et al., 2017). Therefore, tuna fisheries play a crucial role in the global seafood industry, providing a vital source of food, employment and economic value to many coastal nations (FAO, 2024). Tuna are among the most commercially valuable fish, with millions of tonnes caught annually to meet the demand for fresh, frozen and canned products (FAO, 2024). These fisheries support livelihoods in both developed and developing countries, particularly in the Pacific, Atlantic and Indian Oceans (Bell et al., 2015). Effectively managing global tuna populations is challenging due to their high value that generates a strong economic incentive, which can lead to overfishing and illegal fishing practices. Additionally, climate change presents another challenge, as it affects the productivity and distribution of these highly migratory populations (Erauskin-Extramiana et al., 2019; Bell et al., 2021). Thus, international cooperation is key to ensuring sustainable fishing and compliance with regulations. There are seven major commercial oceanic tuna species, which are extensively harvested. These species are albacore (Thunnus alalunga, ALB), bigeye (Thunnus obesus, BET), yellowfin (Thunnus albacares, YFT), skipjack (Katsuwonus pelamis, SKJ), and the three species of bluefin tuna, Atlantic bluefin (Thunnus thynnus, BFT), Pacific bluefin (Thunnus orientalis, PBF) and southern bluefin (Thunnus maccoyii, SBT). These species can perform long migrations and their spatial distribution includes temperate and tropical regions of all oceans (Collette et al., 2001). Based on their distribution and habitat preferences, tunas are categorized into “temperate” and “tropical” species (Block and Stevens, 2001). The temperate tunas, including bluefins and albacore, can inhabit waters as cold as 10 °C but are also found in warmer tropical regions. Conversely, tropical tunas such as skipjack tuna and yellowfin tuna thrive in waters above 18 °C, while bigeye tuna exhibit intermediate habitat preferences (Korsmeyer and Dewar, 2001). The biological characteristics, migratory patterns and growth rates of these species directly impact fishery management strategies and stock assessments (BOX E.1.1). Various industrial fleets, along with artisanal fleets from coastal states, catch these species in the three oceans (ISSF, 2024). They are then landed and processed in multiple locations worldwide, traded on a global market, and ultimately consumed around the world. Over the past decades, tuna catches have exhibited a consistent upward trend, stabilizing in the early 2000s before resuming growth in recent years (FIGURE E.1.3). The global annual catches of commercial tunas have continuously increased over time since the beginning of their exploitation in the 1950s, reaching 1 million tonnes in the mid-1960s, 2 million tonnes in the mid-1980s, 3 million tonnes in 1990, 4 million tonnes in the late 1990s, 5 million tonnes in 2014, and finally topping out at approximately 5.4 million tonnes in 2019 (FIGURE E.1.3). The global tuna catch has remained stable at around 5 million tonnes since then. In 2023, the global tuna catch was approximately 5.2 million tonnes. The majority of tuna catches are attributed to skipjack tuna (57 percent), followed by yellowfin tuna (31 percent ), bigeye tuna (7 percent), albacore tuna (4 percent) and bluefin tuna (1 percent).

In 2023 the Pacific Ocean yielded the highest catches of principal market tuna species, contributing approximately 66 percent of the total. This was followed by the Indian Ocean, which accounted for around 23 percent, and the Atlantic Ocean and adjacent seas, which contributed the remaining 11 percent. In terms of fishing methods, purse seining accounts for 66 percent of global tuna catches, while longlines (9 percent), pole-and-line (7 percent), gillnets (4 percent) and other miscellaneous gear (14 percent) make up the remainder (FIGURE E.1.3). Purse seine catches are further categorized into associated sets (38 percent), unassociated sets (25 percent), and dolphin sets (3 percent). The relative contribution of each gear to total tuna catches has changed over time. In the 1950s, most catches were taken with trolling and pole-and-line gear, accounting for 20 percent and 40 percent of the total catch, respectively. However, their share declined rapidly with the expansion of longline fleets, which accounted for around 50 percent of catches by 1960. By that time, the contribution of trolling and pole-and-line gear had decreased to 7 percent and 25 percent, respectively. Purse-seine gear accounted for 15 percent of total catches at this time. From 1960 onward, longline contributions gradually declined to around 30 percent by 1970 and remained at that level until the mid-1980s. Meanwhile, pole-and-line maintained a 30 percent share until the early 1980s, while purse-seine contributions continued to rise, reaching 40 percent of total catches by the 1980s. The continuous increase in total catches since then has primarily been driven by the expansion of purse-seine fisheries. In recent years, purse-seine gear has contributed approximately 65 percent of total catches (FIGURE E.1.3). Longline catches increased steadily from 1950, peaking at about 0.7 million tonnes in 1993. Since then, they have fluctuated between 0.6 million tonnes and 0.7 million tonnes until 2007, and between 0.42 million tonnes and 0.55 million tonnes thereafter. Similarly, pole-and-line catches increased from 1950, reaching a record high of approximately 0.6 million tonnes in 1984, before declining to 0.4 million tonnes by 2014, where they have since remained. In contrast, purse-seine catches have steadily increased from 1950 to 2023, reaching an all-time high of around 3.6 million tonnes in 2019 (FIGURE E.1.3).

Regarding the contribution of different gears to the catch of temperate and tropical tunas, the temporal trend of gear use in tropical tuna fisheries closely mirrors the overall trend described above. However, for temperate tunas, the contribution of different gears has remained relatively stable since 1960. The primary gears targeting temperate tunas are longline and pole-and-line, though the contribution of purse seine has slightly increased in recent years, particularly for bluefin tunas. The increasing trend in total tuna catch is primarily due to the expansion of tropical tuna fisheries (FIGURE E.1.4). In fact, the tropical tuna catch has risen continuously since 1950, reaching the highest recorded level in the time series in 2019, at approximately 5 million tonnes. A similar increasing trend is observed for each tropical tuna species. For example, the yellowfin tuna catch peaked at around 1.5 million tonnes in 2003, then declined to 1.2 million tonnes in 2009 before rising again to a new record high of 1.6 million tonnes in 2023. Meanwhile, the skipjack tuna catch reached its highest level in 2019, with a total of about 3.2 million tonnes, and has remained at around 3 million tonnes since then (FIGURE E.1.4). However, bigeye tuna followed a different trend, with catches peaking at approximately 510 000 tonnes in 1997, then declining to around 400 000 tonnes until 2013 and stabilizing between 370 000 tonnes and 400 000 tonnes thereafter.

The catch history of temperate tunas differs from that of tropical tunas. Their catches also increased from 1950, reaching a peak of around 380 000 tonnes in 1999 (FIGURE E.1.4). Since then, however, they have followed a declining trend, reaching the third-lowest level since 1999 at approximately 270 000 tonnes in 2023. This downward trend is also observed in albacore and the three bluefin tuna species. For instance, the albacore tuna catch steadily increased until reaching a record high of 280 000 tonnes in 2002, then declined and has remained between 200 000 tonnes and 250 000 tonnes since. The three bluefin tuna species show a different historical pattern. Their catches increased until a record high of approximately 140 000 tonnes early in the time series in 1961, followed by a general decline until 1993. At that point, an upward trend began, reaching 100 000 tonnes in 2000. Since then, catches have decreased again, hitting a record low of 38 000 tonnes in 2013–the lowest level since 1951. However, since 2013 catches have been increasing due to population recovery, and in 2023 the total catch of the three species reached approximately 80 000 tonnes (FIGURE E.1.4). For management purposes, 23 stocks of oceanic tuna species are recognized. The Atlantic Ocean has three albacore tuna stocks: North Atlantic, South Atlantic, and Mediterranean. In the Pacific there are two albacore tuna stocks, one in the North Pacific and another in the South Pacific, while the Indian Ocean has a single stock. Atlantic bluefin tuna is divided into two stocks: a western stock and an eastern stock, which includes the Mediterranean Sea. Pacific bluefin tuna consists of a single stock, as does southern bluefin tuna, which inhabits the southern regions of all three oceans. For bigeye and yellowfin tunas, the Pacific Ocean is divided into two stocks–eastern and western– whereas both the Atlantic and Indian Oceans each have a single stock. Similarly, skipjack tuna is managed as two stocks in both the Pacific and Atlantic Oceans (eastern and western, respectively), while the Indian Ocean has a single stock (see BOX E.1.1). Given the economic and ecological significance of tuna, international organizations, such as the five tuna regional fisheries management organizations (RFMOs), manage tuna stocks to prevent overexploitation and achieve sustainable fishing practices (Allen, 2010; De Bruyn et al., 2013). Scientific committees within each tuna RFMO conduct annual stock assessments based on data related to abundance, fishing effort and environmental factors, and provide scientific advice for management decisions. Ultimately, the Commissions of these organizations adopt binding management measures that each member implements. The five tuna RFMOs are (FIGURE E.1.5):

„ TheInter-American Tropical Tuna Commission (IATTC), responsible for the management of tunas in the Eastern Pacific Ocean. „ The International Commission for the Conservation of Atlantic Tunas (ICCAT), responsible for the management of tunas in the Atlantic Ocean and Mediterranean Sea. 

„ The Commission for the Conservation of Southern Bluefin Tuna (CCSBT), responsible for the conservation of southern bluefin tuna in the southern Atlantic, Indian and Pacific Oceans. 

„ The Indian Ocean Tuna Commission (IOTC), responsible for the conservation of tunas in the Indian Ocean. 

„ The Western and Central Pacific Fisheries Commission (WCPFC), responsible for the management of tunas in the Western and Central Pacific Ocean. 

The purpose of this session is to review tuna catch by species and gear type, summarize the status of the stocks based on the most recent scientific assessments, and briefly describe the current management measures adopted by tuna RFMOs.This part is structured by ocean region to align with RFMO mandates to provide a comprehensive view of the fisheries operating across each region.

 

DATA AND METHODOLOGY 

 Stock status determination criteria 

The assessment of tuna stock status relies on two primary indicators, the spawning stock biomass (SSB), usually defined as the total abundance of the female population, and the fishing mortality or exploitation rate (F). Stock status is estimated using biological and fishing mortality maximum sustainable yield (MSY) reference points commonly used in most of the tuna RFMOs: SSB/SSBMSY defined as the spawning stock biomass (SSB) relative to the spawning stock biomass at MSY and F/FMSY defined as the fishing mortality (F) relative to the F at which MSY can be obtained. As such, when the abundance of each stock falls below SSBMSY, the stock is considered overfished in most tuna RFMOs and in this analysis. When the fishing mortality (F) exceeds FMSY, tuna RFMOs consider that overfishing is occurring with the stock being at risk of becoming overfished. Stock status is commonly represented by a Kobe plot, as produced by the scientific bodies of each tuna RFMO (FIGURE E.1.6). The Kobe plot represents SSB/SSBMSY and F/FMSY as references in a figure with four different zones, each representing a different stock status: (1) red zone, representing an overfished stock and that overfishing is occurring; (2) green zone, representing a situation where no overfishing is taking place and where the stock is not overfished; (3) orange zone, where overfishing is occurring while the stock is not overfished; and (4) yellow zone, where overfishing is not taking place but the stock is overfished.

Moreover, for comparison, the FAO stock status classification–based solely on population abundance or biomass – is also included in each species-specific stock status determination. Since the FAO Blue Transformation roadmap (FAO, 2022) aims to maximize opportunities in aquatic food systems to enhance food security, FAO determines the stock status of fish populations in relation to maximizing catches at MSY. FAO criteria include a buffer around biomass corresponding to MSY. According to these criteria, when a stock is between 0.8 and 1.2 SSB/SSBMSY, it is considered “maximally sustainably fished”. If it is greater than 1.2, the stock is classified as “underfished”, and if it is less than 0.8, it is considered “overfished” 

The annual tuna catch information in this document is sourced from the publicly available nominal catch data or the best available scientific estimates datasets from the respective tuna RFMOs, which are updated annually following each RFMO’s scientific committee meeting: „ CCSBT. Annual catch by flag or gear from 1952 to 2023 inclusive. SBT Data. 2024. https://www.ccsbt.org/en/content/sbt-data (last access in October 2024). „ IATTC. EPO total estimated catch by year, flag, gear, species. Public domain data for download. 2024.(last access in October 2024). „ ICCAT. Nominal catch Task 1 Excel. Access to ICCAT statistical databases. 2024. (last access in October, 2024). „ IOTC. Best scientific estimates of nominal retained catch data by species and gear. IOTC Available Datasets. 2025.  (last access in January 2025). „ WCPFC. Annual Catch Estimates 2023–data files. WCPFC Tuna Fishery Yearbook–Annual Catch Estimates. 2024. (last access in October 2024); ISC. ISC24 Annual Catch Table. Fisheriesstatistics. 2024. (last access in September 2024).

Catch data is presented by the following main gear type categories: purse seine, longline, pole and line, gillnet, and other. The nominal catch data for tunas used in this document covers up to the year 2023, as this is the most recent data currently available in publicly accessible tuna RFMO catch datasets. In terms of management, tuna RFMOs are increasingly embracing management procedures (MP) (also known as harvest strategies), tested using management strategy evaluation (MSE), as a modern and precautionary management tool to ensure the sustainability of their tuna stocks (Punt et al., 2016). The first tuna RFMO to adopt a management procedure was the CCSBT when it adopted one for the recovery of southern bluefin tuna in 2011 (Hillary et al., 2016). Since then, the other tuna RFMOs have adopted management procedures, or in some instances harvest control rules , for several of their tuna stocks. The use of management procedures differs between RFMOs. For instance, while some RFMOs have adopted some elements of the management procedures (e.g. the harvest control rule), others have adopted them in full, including the monitoring strategy and the revision of exceptional circumstances (BOX E.1.2). Thus, this chapter provides an overview of tuna stock status, global catches, and management strategies based on the most recent scientific assessments. It summarizes RFMO findings, highlighting stock-specific trends and conservation measures. The chapter is structured by ocean region to align with RFMO mandates, and catches are shown by different gear types. For the purpose of this report, the reference year for the assessments is 2021. However, this chapter presents the most up-to-date data on tuna populations as of 2024. In 2021, Pacific bluefin, Southern bluefin, and Mediterranean albacore tuna were all classified as overfished according to FAO criteria. By 2024, only Mediterranean albacore tuna remained in the overfished category. The status of the other tuna stocks remained unchanged, except for Atlantic yellowfin tuna , which shifted from being classified as fished at a maximally sustainable level in 2021 to underfished in 2024, based on FAO criteria