21856-1

Thunnus alalunga 

Scope: Europe
Language: English
Status_ne_offStatus_dd_offStatus_lc_onStatus_nt_offStatus_vu_offStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Actinopterygii Perciformes Scombridae

Scientific Name: Thunnus alalunga (Bonnaterre, 1788)
Regional Assessments:
Common Name(s):
English Albacore Tuna, Aáhi Taria, Albacore, Albacore Fish, Bastard Albacore, Bonito, Langvin Tuna, Long-finned Tuna, Longfin Tuna, Long-fin Tunny, Longfin Tunny, Tuna
French Ara Lunga, Bonette, Germon, Germon Atlantique
Spanish Alalunga, Albacora, Atún, Atún Aleta Larga, Atún Blanco, Atún de Aleta Larga, Bonito del Norte, Sierra
Synonym(s):
Germo germon ssp. steadi Whitley, 1933
Orcynus pacificus Cooper, 1863
Scomber alalunga Cetti, 1777
Scomber alatunga Gmelin, 1789
Scomber albicans Walbaum, 1792
Scomber germo Bennett, 1840
Scomber germo Lacepède, 1801
Scomber germon Lacepède, 1800
Thunnus germo (Lacepède, 1801)
Thunnus pacificus (Cuvier, 1832)
Thynnus alalonga (Bonnaterre, 1788)
Thynnus alalunga (Bonnaterre, 1788)
Thynnus pacificus Cuvier, 1832
Taxonomic Source(s): Eschmeyer, W.N. (ed.). 2015. Catalog of Fishes. Updated 7 January 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 7 January 2015).
Taxonomic Notes: This species is often confused with juvenile Thunnus obesus, which also has very long pectorals, but with rounded tips.

Assessment Information [top]

Red List Category & Criteria: Least Concern (Regional assessment) ver 3.1
Year Published: 2015
Date Assessed: 2015-01-26
Assessor(s): Collette, B., Fernandes, P. & Heessen, H.
Reviewer(s): Allen, D.J. & Polidoro, B.
Contributor(s): Acero, A., Amorim, A.F., Boustany, A., Canales Ramirez, C., Cardenas, G., Carpenter, K.E., Chang, S.-K., Di Natale, A., Die, D., Fox, W., Fredou, F.L., Graves, J., Guzman-Mora, A.G., Hinton, M., Juan Jorda, M., Masuti, E., Minte Vera, C., Miyabe, N., Montano Cruz, R., Nelson, R., Oxenford, H., Pires Ferreira Travassos, P.E., Restrepo, V., Salas, E., Schaefer, K., Schratwieser, J., Serra, R., Sun, C., Teixeira Lessa, R.P., Uozumi, Y., Viera Hazin, F.H., Yanez, E. & de Oliveira Leite Jr., N.
Facilitator/Compiler(s): Ralph, G.
Justification:
European Regional Assessment: Least Concern (LC)

Thunnus alalunga is widely distributed in tropical and temperate waters of all oceans, including the Mediterranean. It is an important commercial food fish, and managed through most of its range. In the northeastern Atlantic, it is managed as two separate stocks: a North Atlantic stock and a Mediterranean stock. Although the North Atlantic stock has been subject to overfishing in recent years, in 2009 catch quotas were adopted in line with scientific advice to end overfishing and recent stock assessments have suggested that spawning stock biomass is increasing.

In the Mediterranean, the first stock assessment was completed in 2012, but there is concern that landings have been under-reported. Declines in catches range from 28 to 31.5% over the past three generation lengths (18-21 years). However, there is evidence that the fishing mortality has decreased over this time period, and that the spawning stock biomass has increased. Therefore, T. alalunga is assessed as Least Concern. However, we recommend that the current monitoring and management measures remain in place.

Geographic Range [top]

Range Description:This is a cosmopolitan species in tropical and temperate waters of all the oceans including the Mediterranean Sea, but it is not found at the surface between 10°N and 10°S. In the Atlantic, this species is widely distributed between 60°N and 50°S.
Countries occurrence:
Native:
Cyprus; Greece (East Aegean Is., Greece (mainland), Kriti); Ireland; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Malta; Palestinian Territory, Occupied; Portugal (Azores, Madeira, Portugal (mainland), Selvagens); Spain (Baleares, Canary Is., Spain (mainland)); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia); United Kingdom (Great Britain, Northern Ireland)
FAO Marine Fishing Areas:
Native:
Atlantic – eastern central; Atlantic – northeast; Mediterranean and Black Sea
Additional data:
Continuing decline in area of occupancy (AOO):No
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:No
Lower depth limit (metres):600
Range Map:21856-1

Population [top]

Population:There are three stocks of Thunnus alalunga in the Atlantic Ocean: the North Atlantic, South Atlantic, and Mediterranean stocks (ISSF 2013). The overall population trend within the european region is decreasing.

North Atlantic Ocean
Catches of this species in the north Atlantic peaked at 65,000 tonnes in the mid-1960s, then declined to a low of 20,000 tonnes in 2008. This decline is partly due to reduced fishing effort by some surface and longline fisheries. The most recent stock assessment in 2009 indicated that recruitment in the fishery is highly variable, and that biomass since 1993 has been less than biomass at maximum sustainable yield (MSY). Currently, the stock is about 40% below the MSY level and spawning stock biomass is currently only 25% of the original biomass (ICCAT 2009). The MSY from the last stock assessment was estimated at 29,000 tonnes, and catches in four of the last ten years have exceeded this value.

This species stock in the North Atlantic was considered overfished (ISSF 2010). However, in 2009 catch quotas were adopted in line with scientific advice to end overfishing. The most recent stock assessment suggested that overfishing is no longer occurring (Fcurrent/FMSY = 0.72), however current biomass is still below the biomass required to obtain maximum sustainable yields (Bcurrent/BMSY = 0.94) (ISSF 2013).

The 2013 stock assessment for the North Atlantic stock shows a fluctuating but decreasing trend in spawning stock biomass (SSB), from peaks in the 1940's of almost 120,000 mt to about 15,000 mt in 2000. Since then SSB has increased to about 40,000 mt in 2012 (ICCAT 2013), however ICCAT SCRS consider that spawning stock is currently still overfished but close to the BMSY levels (SSB2012/SSBMSY=0.94), and that overfishing is not occurring (STECF 2014).

Mediterranean
The first stock assessment for T. alalunga in the Mediterranean was completed in 2012. The ratio of Fcurrent/FMSY is less than or equal to 1, suggested that overfishing is probably not occurring at this time (ISSF 2013). However, the ratio of Bcurrent/BMSY could not be estimated with the available data, so it is unknown if the stock is overfished (ISSF 2013). Catches have increased from about 500 mt from 1965 to the early 1980s, to about 4500 in the mid-1980s, and peaking in the 1990s at about 7,000-8,000 mt (ISSF 2013).

The Mediterranean albacore fisheries are characterized by high spatio-temporal variability in landings and fishing patterns. Albacore fishing is a traditional activity for a number of fleets including those of Cyprus, Greece, Italy, Spain, and Malta. ICCAT statistics, however, are considered quite incomplete due to unreported catches from several countries and the lack of data in some years from other countries. Fishing effort is not possible to estimate due to short time series and inadequate coverage of artisanal gears. Even though catches of Mediterranean albacore have been increasing for the past few years, there is a lack of general information on this stock and biological information is also limited (ICCAT 2010). Although many countries are not yet reporting any catch for this species, the Mediterranean stock does not show any general trend, and the mixing rate with the Atlantic stock appears to be insignificant (Nakadate et al. 2005, STECF 2007).

Montes et al. (2012) found that there appear to be two genetic groups of albacore in the Mediterranean (East and West); Tyrrhenian and Adriatic Sea samples were grouped together and could be differentiated from the Balearic Sea.
Current Population Trend:Decreasing
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:This is an epipelagic and mesopelagic, oceanic species, that is abundant in surface waters of 15.6–19.4°C. Deeper swimming, large albacore are found in waters of 13.5–25.2°C. Temperatures as low as 9.5°C may be tolerated for short periods. It is known to concentrate along thermal discontinuities (Collette and Nauen 1983).

This species forms mixed schools with Skipjack Tuna (Katsuwonus pelamis), Yellowfin Tuna (Thunnus albacares) and Atlantic bluefin tuna (Thunnus thynnus). These schools may be associated with floating objects, including sargassum weeds (Collette and Nauen 1983). It is a pelagic predator, feeding on fish, crustaceans and squid. In the Mediterranean Sea, this species feeds on paralepidids, Paralepis speciosa and P. coregonoides; crustaceans - hyperidean amphipods Phrosina semilunata; and cephalopods - Brachyscelus cruslculum (Consoli et al. 2008).

Use of combined Japanese and US tagging data confirm the frequent westward movement of young albacore and infrequent eastward movements in the North Pacific. This corresponds to albacore life history where immature fish recruit into fisheries in the western and eastern Pacific and then gradually move near their spawning grounds in the central and western Pacific before maturing (Ichinokawa et al. 2008).

Immature Albacore Tuna (<80 cm) generally have a sex ratio of 1:1 but males predominate in catches of mature fish. Maturity is attained at about 90–94 cm (FL) for females and 94–97 cm (FL) for males. Spawning occurs at sea surface temperatures of 24°C or higher. Fecundity increases with size but there is no clear correlation between fork length and ovary weight and number of eggs. A 20 kg female may produce between two and three million eggs per season, released in at least two batches (Collette 2010).

Longevity for this species may be as long as 13 years in the South Atlantic (Lee and Yeh 2007) and in the South Pacific (Labelle et al. 1993, Lee and Yeh 1993). Age of first maturity is estimated to be between five and seven years (Wu and Kuo 1993, Ramon and Bailey 1996). Based on age-structured data from the Atlantic and Pacific (Collette et al. 2011), generation length is conservatively estimated to be between 6–7 years.

The all-tackle game fish record is of a 39.97 kg fish taken off of Gran Canaria, Canary Islands in 1977 (IGFA 2014).
Systems:Marine
Generation Length (years):8-9
Movement patterns:Full Migrant
Congregatory:Congregatory (year-round)

Use and Trade [top]

Use and Trade: An important fishery exists for this species, which is mainly marketed as canned white meat tuna.

Threats [top]

Major Threat(s): This species is caught by long-lining, live-bait fishing, purse seining, and trolling. In the Eastern Pacific it is also a bycatch of swordfish fisheries. Albacore Tuna are caught by long-line gear in most of the North and South Pacific (but not often between about 10°N and 5°S), by trolling gear in the eastern and central North and South Pacific, and by pole-and-line gear in the western North Pacific. In the North Pacific about 60% of the fish are taken in pole-and-line and troll fisheries that catch smaller, younger Albacore Tuna, whereas about 90% of the albacore caught in the South Pacific are taken by long-line (IATTC 2008).

Catches of northern Atlantic Albacore Tuna are primarily made by pole-and-line (35%), trolling (28%), trawlers (17%) and longline (17%). The main fisheries are Spain, France, and Chinese Taipei. Surface fisheries concentrate mainly in the Bay of Biscay and the Azores and Canary Islands during summer and fall, taking young fish while longline vessels operate throughout the Atlantic year-round and target larger fish (ISSF 2010). For the south Atlantic stock, the main fisheries are longliners from Chinese Taipei (56%), pole-and-line from South Africa (18%) and from Namibia (13%). Surface fisheries operate mainly between October and May capturing juvenile and subadult fish (ISSF 2010).

Conservation Actions [top]

Conservation Actions: 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).

In the north Atlantic, a total allowable catch (TAC) of 28,000 tonnes was established for 2010 and 2011 for the northern stock. TACs are also in place for the southern Atlantic albacore fishery. For the south Atlantic, the TAC for 2009–2011 is 29,900 and adjustments are made to reduce the TACs in the following year if the actual catch exceeds the TAC in a given year (ICCAT 2009). The driftnet fishery for albacore has been banned since January 1st 2002 in the European Union countries and from 2004 in all the ICCAT Mediterranean countries, but it is known that illegal fishing activity still occurs in some areas (STEFC 2007).

Ongoing monitoring of population and harvests trends is required for this species (STECF 2014).

Thunnus alalunga was assessed as Least Concern globally (IUCN 2011) and in the Mediterranean (Abdul Malak et al. 2011).

Citation: Collette, B., Fernandes, P. & Heessen, H. 2015. Thunnus alalunga. The IUCN Red List of Threatened Species 2015: e.T21856A18208821. . Downloaded on 24 November 2017.
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