|Scientific Name:||Thunnus albacares|
|Species Authority:||(Bonnaterre, 1788)|
Neothunnus albacora Lowe, 1839
Neothunnus catalinae Jordan & Evermann, 1926
Neothunnus itosibi Jordan & Evermann, 1926
Orcynus subulatus Poey, 1875
Scomber albacares Bonnaterre, 1788
Scomber albacorus Lacepède, 1800
Scomber sloanei Cuvier, 1832
Semathunnus guildi Fowler, 1933
Thunnus albacora (Lowe, 1839)
Thunnus allisoni Mowbray, 1920
Thunus albacares (Bonnaterre 1788)
Thynnus albacora Lowe, 1839
Thynnus argentivittatus Cuvier, 1832
Thynnus macropterus Temminck & Schlegel, 1844
|Taxonomic Notes:||Although several geographic populations have been named as species, morphological and genetic data show there is one world-wide panmictic species (Gibbs and Collette 1967, Scoles and Graves 1993).|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Collette, B., Acero, A., Amorim, A.F., Boustany, A., Canales Ramirez, C., Cardenas, G., Carpenter, K.E., Chang, S.-K., de Oliveira Leite Jr., N., Di Natale, A., Die, D., Fox, W., Fredou, F.L., Graves, J., Guzman-Mora, A., Viera Hazin, F.H., Hinton, M., Juan Jorda, M., Minte Vera, C., Miyabe, N., Montano Cruz, R., Masuti, E., Nelson, R., Oxenford, H., Restrepo, V., Salas, E., Schaefer, K., Schratwieser, J., Serra, R., Sun, C., Teixeira Lessa, R.P., Pires Ferreira Travassos, P.E., Uozumi, Y. & Yanez, E.|
|Reviewer(s):||Russell, B. & Polidoro, B.|
This species is fast-growing, widely distributed and highly productive. It is important in commercial fisheries around the world. It is being effectively managed throughout the majority of its range. All stocks are being fished below current maximum sustainable yield (MSY). However, more definitive data are needed for the Indian Ocean stock, as some model runs project that 2009 fishing mortality may have been above FMSY. Based on weighted declines of biomass or spawning stock biomass (SSB) across all stocks, there has been an estimated 33% decline globally over the past 10 years (1998–2008), or three generation lengths. This species is listed as Near Threatened, primarily as population declines would be much greater if it were not for the catch quotas that have been implemented. Although model projections are variable, concerns however remain about possible overfishing in recent years in the Indian Ocean. This species should be reassessed in the next five years, primarily because catches in the Indian Ocean region have declined substantially in 2009 (and possibly also in 2010) partly due to Somali-based piracy, which has shifted fishing effort to the Atlantic Ocean.
|Range Description:||This species is found worldwide in tropical and subtropical seas. Tagging data show that trans-Atlantic migrations occur, and the Yellowfin Tuna from the entire Atlantic are considered to be part of a single stock. In the eastern Pacific, this species ranges from southern California and the southwest and central eastern parts of the Gulf of California to Peru, including all of the oceanic islands. It may occur off Oregon and Washington during El Niño years (K.Schaefer pers comm 2008).|
Native:American Samoa (American Samoa); Angola (Angola); Anguilla; Antigua and Barbuda; Aruba; Australia; Bahamas; Bangladesh; Barbados; Belize; Benin; Bermuda; Bonaire, Sint Eustatius and Saba (Saba, Sint Eustatius); Brazil; Brunei Darussalam; Cameroon; Cape Verde; Cayman Islands; Chile; Christmas Island; Cocos (Keeling) Islands; Colombia; Comoros; Congo; Congo, The Democratic Republic of the; Cook Islands; Costa Rica; Côte d'Ivoire; Cuba; Curaçao; Djibouti; Dominica; Dominican Republic; Ecuador; El Salvador; Equatorial Guinea; Fiji; French Guiana; French Polynesia; Gabon; Gambia; Ghana; Grenada; Guadeloupe; Guam; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; Hong Kong; India; Indonesia; Iran, Islamic Republic of; Jamaica; Japan; Kenya; Kiribati; Liberia; Madagascar; Malaysia; Maldives; Marshall Islands; Martinique; Mauritania; Mauritius; Mexico; Micronesia, Federated States of ; Montserrat; Morocco; Mozambique; Myanmar; Namibia; Nauru; Netherlands Antilles (Bonaire); New Caledonia; New Zealand; Nicaragua; Nigeria; Niue; Norfolk Island; Northern Mariana Islands; Oman; Pakistan; Palau; Panama; Papua New Guinea; Peru; Philippines; Pitcairn; Portugal; Puerto Rico; Réunion; Saint Helena, Ascension and Tristan da Cunha; Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Vincent and the Grenadines; Samoa; Sao Tomé and Principe; Senegal; Seychelles; Sierra Leone; Singapore; Sint Maarten (Dutch part); Solomon Islands; Somalia; South Africa; Spain; Sri Lanka; Suriname; Taiwan, Province of China; Tanzania, United Republic of; Togo; Tokelau; Tonga; Trinidad and Tobago; Turks and Caicos Islands; Tuvalu; United Arab Emirates; United Kingdom; United States; United States Minor Outlying Islands; Vanuatu; Venezuela, Bolivarian Republic of; Viet Nam; Virgin Islands, British; Virgin Islands, U.S.; Wallis and Futuna; Western Sahara; Yemen
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – northeast; Atlantic – northwest; Atlantic – southeast; Atlantic – southwest; Atlantic – western central; Indian Ocean – eastern; Indian Ocean – western; Pacific – eastern central; Pacific – northwest; Pacific – southeast; Pacific – southwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
FAO reported worldwide landings show a gradual, but variable increase from 110,879 tonnes in 1950, to 1,130,605 tonnes in 2006 (FAO 2009). Landings data have exponentially increased over the last 50 years (400%). There are four stocks that are globally managed for this species. As of 2004, the stocks in the Atlantic, Indian Ocean, and Eastern Pacific are considered Fully Exploited, and the Western and Central Pacific stock is considered Fully to Over-exploited (Majkowski 2007).
Yearly catch levels have declined in the Atlantic Ocean since the peak catch of 194,000 tonnes in 1990. A steady decline occurred between 2001–2007, followed by an increase in 2008. These trends in part reflect changes in the number of purse seiners operating in the Atlantic Ocean (ISSF 2010). Recent trends have differed between the western and eastern Atlantic, with the overall catches in the west declining by 26% since 2006. In the eastern Atlantic, on the other hand, catches have increased by 23% since 2006, mainly due to substantial increases in purse seine effort (SCRS ICCAT 2010).
The most recent stock assessment for Yellowfin Tuna in the Atlantic was conducted in 2008 (ICCAT 2009), which showed that biomass is currently somewhat less than BMSY, but fishing mortality is also less than FMSY (ISSF 2010, ICCAT 2009). Based on linear regression of the middle values of Model 5 and Model 10 in the latest stock assessment (ICCAT 2009), spawning stock biomass (SSB) has declined approximately 22% over the past 10 years (1998–2007). These models suggest that only catches of 130,000 tonnes or less are sustainable.
Eastern Pacific Ocean
From 1976–2005 the total catch fluctuated from 100,000 to 443,000 t per year (IATTC 2008). The average annual retained catch of Yellowfin Tuna in the Eastern Pacific during 1991–2005 was 276,000 t, with a peak in 2002 of 443,000 t, the greatest on record. However catch decreased substantially in 2005 to 288,019 t, and in 2006 to 174,780 t (the lowest since 1984). Current maximum sustainable yield (MSY) is estimated to be about 273,000 t (IATTC 2009, ISSF 2010). Additionally, the average weights of the Yellowfin Tuna caught in 2006 were significantly lower than those of the previous five years (STECF 2007).
The most likely causes of the lesser catches are declines in recruitment, effort in the dolphin-associated fisheries, and catchability (IATTC 2008). The recruitment of Yellowfin Tuna to the fisheries in the Eastern Pacific varies seasonally and in response to regime shifts in productivity. The most recent stock assessment analysis and previous analyses have indicated that the Yellowfin Tuna population has experienced two, or possibly three, different recruitment productivity regimes (1975–1982, 1983–2002, and 2003–2008). The productivity regimes correspond to regimes in biomass, e.g., higher-productivity regimes producing greater biomass levels. Average annual catch of Yellowfin Tuna in the eastern Pacific Ocean was 233,000 t (100,000 to 301,000) during the period from 1975–2001. Variations in part reflect changes in fishing effort and regime shifts in productivity over up to three levels of recruitment. Changes in measures of fishing effort include changes in the proportion of purse seine catch by set type, as well as changes in the overall level of fishing effort, which occur in part in compliance with management action (M.Hinton pers comm 2011).
According to the most recent stock assessment in the Eastern Pacific conducted in 2009 (Maunder and Aires-da-Silva 2010), if the fishing mortality is proportional to the fishing effort and the current patterns of age-specific selectivity are maintained, the current (average of 2006–2008) level of fishing is below FMSY. The spawning stock biomass is also estimated to be above SSBMSY. Based on linear regression of the spawning stock biomass ratio (SBR) reported in the most recent stock assessment (Maunder and Aires-da-Silva 2010), there has been an estimated 49% decline in SBR over the past 10 years (1998–2007).
The catches of Yellowfin Tuna show a strong seasonality with high catches during the northern winter months and usually low catches from May–June to September–October. The Yellowfin Tuna stock assessment work in the Indian Ocean is an extremely difficult task because of the conflicting trends in the basic data, total yearly catches and abundance indices used based on the longline catch per unit effort (CPUE): the observed trends in Yellowfin Tuna catches and CPUEs are not consistent with production-model dynamics, or really with any known theory of fishing (IOTC 2009).
However, a stock assessment conducted in 2008 (Nishida 2008) indicated that recent levels of fishing mortality are at an historical high level and the stock has experienced a period of overfishing at least during 2003–2006 (e.g., Fcurrent > FMSY). Biomass based reference points also varied with the assumed level of steepness. For the lowest value of steepness (0.60), spawning biomass in 2007 was estimated to be below the MSY level (SB/SBMSY <1); i.e., the stock is in an overfished state. For higher values of steepness, biomass in 2007 was above the MSY level (SBcurrent > SBMSY) and the stock is not in an overfished state. The model estimated that recent recruitment has been lower than average, and on this basis total and spawning biomass could be expected to decline further over the next few years (IOTC 2008, IOTC 2009).
A size-based, age- and spatially-structured population model (Multifan-CL, MFCL) for the Yellowfin Tuna in the Indian Ocean initially carried out in 2008 was updated in 2009. Based on linear regression of estimated adult biomass (IOTC 2009), estimated SSB has declined approximately 45% over the past 10 years (1999–2008). Depending on the shape of the stock-recruitment relationship, current catches are likely to be higher than the estimated MSY, which ranges from 250,000 to 300,000 t. For example, total annual catches averaged 434,800 t over the period 2003 to 2007 (IOTC 2008), and 372,200 t over the period 2005 to 2009 (IOTC 2010). However, more recently catches in the Indian Ocean have declined substantially (in 2009 and possibly also in 2010) partly due to Somali-based piracy in the region.
Western and Central Pacific Ocean
Since 2000, the total Yellowfin Tuna catch in the Western and Central Pacific Ocean (WCPO) has varied between 370,000 and 440,000 mt. Purse seiners harvest the majority of the Yellowfin Tuna catch (53% by weight in 2007), with the longline and pole-and-line fisheries comprising 16% and 4% of the total catch, respectively (Langley et al. 2009). Longline catches in recent years (70,000–80,000 mt) are well below catches in the late 1970s to early 1980s (which peaked at about 110,000 mt), presumably related to changes in targeting practices by some of the larger fleets (Langley et al. 2009).
Estimated current biomass exceeds the biomass MSY, and current fishing mortality is below FMSY, indicating that the Yellowfin Tuna stock in the Western and Central Pacific Ocean is not in an overfished state. Depletion has increased steadily over time, reaching a level of about 60% of unexploited biomass (a fishery impact of 40%) in 2004–2007 (Langley et al. 2009). However, depletion is considerably higher in the equatorial region 3 (e.g., Philippines/Indonesia) where recent depletion levels are approximately 0.35 and 0.30 for total and adult biomass, respectively (65% and 70% reductions from the unexploited level). The stock in this region may be fully-exploited (ISSF 2010).
Overall SSB is estimated to have declined about 21% over a 10 year period (1999–2008), based on linear regression of SSB in the most recent 2009 stock assessment in the Western and Central Pacific (Langley et al. 2009).
|Habitat and Ecology:||
This is an open-water pelagic and oceanic species occurring above and below the thermocline to depths of at least 400 m. This species schools primarily by size, either in monospecific or multi-species groups. Larger fish frequently school with porpoises and are also associated with floating debris and other objects. It feeds on fishes, crustaceans and squids. It is sensitive to low concentrations of oxygen and therefore, is not usually caught below 250 m in the tropics, and is found in waters between the temperatures of 18–31°C.
The primary Atlantic spawning grounds are in the Gulf of Guinea, and to a lesser extent in the Gulf of Mexico. Spawning occurs throughout the year in the core areas of distribution at sea surface temperatures of 24°C or higher, but peaks are observed in the northern and southern summer months respectively. Spawning occurs almost entirely at night between 2200 and 0600 hrs (Kailola et al. 1993, Schaefer 1998).
In the Indian Ocean, longevity is at least seven years (Romanov and Korotkova 1988), although very few individuals live past four years. Estimated maximum age in the Eastern Pacific is 4.8 years (Wild 1986), in the Western Pacific is 6.5 years (Lehodey and Leroy 1999), and in the Atlantic is eight years (IGFA 2001). Smallest mature individuals in the Pacific off the Philippines and Central America are in the 50–60 cm size group at an age of 12–15 months. Length at 50% maturity in the eastern Pacific was 69 cm for males and 92 cm for females corresponding to an age of 2.1 years (Schaefer 1998). Batch fecundity estimates in the eastern Pacific ranged from 162,918 oocytes for a 1,180 mm female to 8,026,026 oocytes for a 1,460 mm female (Collette 2010). Based age-structure data across all stocks (Collette et al. 2011), generation length is estimated to be between 2.2 and 3.5 years.
Maximum Size is 200 cm fork length (FL). The all-tackle game fish record is of a 183.7 kg fish caught in Magdalena Bay, Baja Sur, Mexico (International Angler 2011).
|Use and Trade:||Yellowfin Tuna are caught in commercial fisheries around the world, and are the second most important species of tuna for canning.|
This species is primarily caught by the purse-seine fishery, but is also taken by longlines and pole-and-line fishing.
In terms of yield, Yellowfin Tuna is the most important tuna species in the Eastern Pacific, where an important proportion of the Yellowfin Tuna catch is harvested in association with dolphins, in free schools and increasingly under fish aggregating devices (FADs). In the Western and Central Pacific purse seiners harvest about 50%, while longline and pole-and-line fleets comprise 15% and 3% respectively.
In the Indian Ocean, over 40% of purse seine Yellowfin Tuna catches are taken in log-schools along with Skipjack Tuna and Bigeye Tuna. One of the driving forces behind recent changes in the purse seine fishery has been the impact of piracy in the western Indian Ocean, which has led to a decrease of the nominal effort (number of boats, total carrying capacity, number of fishing and searching days, total number of sets) as well as changes in the fishing behaviour due to the new security measures in place (boats working in pairs with military personnel on board, restriction on fishing areas, etc.) (IOTC 2010).
Fisheries exist for this species in the eastern Atlantic between Portugal and South Africa, and in the western Atlantic between the Gulf of Mexico and southern Brazil; longline fisheries occur throughout the entire tropical and temperate Atlantic. The main gears used to catch Yellowfin Tuna in the Atlantic are: purse seines (58%), longline (22%), and pole-and-line (13%) (ISSF 2010). The purse seine fishery is the major contributor to total catches of this species. Landings from baitboats and purse seiners generally declined between 2001–2007 (STECF 2009). The nominal effort in the purse seine fishery had been declining through 2006. As an indicator, the number of purse seiners from the European and associated fleet operating in the Atlantic had declined from 44 vessels in 2001 to 24 vessels in 2006 (last year’s data included during the assessment), with an average vessel age of about 25 years. Since then, however, the number of purse seiners has increased by 50% to 36, as vessels have moved from the Indian Ocean to the Atlantic. At the same time, the efficiencies of these fleets have been increasing, particularly as the vessels which had been operating in the Indian Ocean tend to be newer and with greater fishing power (ICCAT 2009).
This species is listed as a highly migratory species in Annex I of the 1982 Convention on the Law of the Sea (FAO Fisheries Department 1994).
Conservation measures imposed in 2004 for the Eastern Pacific under resolution C-04-09 (IATTC 2008) are predicted to maintain the stock at about the Average Maximum Sustainable Yield level, slightly higher than would otherwise be the case. Three month closures have been proposed by the Inter-American Tropical Tuna Commission (IATTC) and Mexico, which has one of the largest fisheries for this species.
In the Western Pacific, there was a two month closure of the FAD fishery in 2009, and three months in 2010 with an objective of achieving a 30% reduction of fishing effort.
In the Indian Ocean, the Indian Ocean Tuna Commission's (IOTC) Working Party on Tropical Tunas (WPTT) recommends that catches of Yellowfin Tuna in the Indian Ocean should not increase beyond 300,000 t in order to bring the stock to biomass levels that could sustain catches at the MSY level in the long term. If recruitment continues to be lower than average, catches below MSY would be needed to maintain stock levels (IOTC 2010).
In the Atlantic, the International Commission for the Conservation of Atlantic Tunas Standing Committee on Research and Statistics (ICCAT-SCRS) recommended that increased harvest of Yellowfin Tuna could have negative consequences for Bigeye Tuna in particular, and other species caught together with Yellowfin Tuna in fishing operations taking more than one species. The same group also continues to recommend that effective measures be found to reduce fishing mortality of small Yellowfin Tuna to increase long-term sustainable yield. ICCAT-SCRS noted that catch levels in recent years have been held in check, despite increasing efficiencies of individual vessels, by a continued decline in the number of purse seine vessels in the eastern Atlantic. The Scientific, Technical and Economic Committee for Fisheries (STECF) agrees that a continuation of the recent movement of additional newer vessels from the Indian Ocean into the Atlantic, with a corresponding increase in fishing mortality should be monitored closely to avoid adverse impacts on stock status (STECF 2009).
ICCAT recommendation 04-01 implemented a small closure for the surface fishing in the area 0–5ºN, 10–20ºE during November in the Gulf of Guinea for purse-seine and pole-and-line vessels. Although this regulation is intended to reduce small Bigeye Tuna catches, the Committee recognizes that its implementation and the change from the previous moratorium to the current regulation will potentially impact Yellowfin Tuna catches. Given the relatively small time-area coverage of the closure, any reduction in juvenile mortality is expected to be minimal (ICCAT 2009).
|Citation:||Collette, B., Acero, A., Amorim, A.F., Boustany, A., Canales Ramirez, C., Cardenas, G., Carpenter, K.E., Chang, S.-K., de Oliveira Leite Jr., N., Di Natale, A., Die, D., Fox, W., Fredou, F.L., Graves, J., Guzman-Mora, A., Viera Hazin, F.H., Hinton, M., Juan Jorda, M., Minte Vera, C., Miyabe, N., Montano Cruz, R., Masuti, E., Nelson, R., Oxenford, H., Restrepo, V., Salas, E., Schaefer, K., Schratwieser, J., Serra, R., Sun, C., Teixeira Lessa, R.P., Pires Ferreira Travassos, P.E., Uozumi, Y. & Yanez, E. 2011. Thunnus albacares. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 16 September 2014.|
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