Wild

Atlantic Bluefin tuna

Thunnus thynnus

Common Name(s)

Bluefin tunny, Northern bluefin tuna ; French: Thon Rouge de l'Atlantique ; Spanish: Atún Aleta Azul

Medium Risk

Stable, not optimal but not poor status. AND Actions identified to reduce environmental impact and/or improve management or stock status. May be data deficient with stable catches.

Traditional Chinese

藍鰭吞拿魚, 'Nam Kei Tun Na Yu'

Japanese

Kuromaguro

Simplified Chinese

蓝鳍金枪鱼 / 大西洋蓝鳍金枪鱼

Certifications

Click Here

Date of Assessments

July 2020

Peer Reviewer

Pending

Assessment Organisation

The University of Hong Kong

SEASONAL AVAILABILITY

In the Mediterranean and the Eastern Atlantic, the period 26 May to 24 June marks the season where large vessels (purse seiners), are allowed to fish for bluefin tuna. Trapping in the Mediterranean starts in February and ends in July.

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Overview

  • Atlantic bluefin tuna (Thunnus thynnus) are found in the entire North Atlantic and its adjacent seas, primarily the Mediterranean Sea. ICCAT recognizes two stocks: Western Atlantic, and Eastern Atlantic and Mediterranean bluefin. There is considerable mixing between the two.
  • Average size and age at maturity is 115cm (Fork Length) and 4 years respectively.
  • Bluefin Tuna are known to be highly migratory, with individuals making long migrations every year. These migrations correspond with their spawning behaviour and with their food needs.
  • Atlantic bluefin tuna spawn in two widely separated areas. One spawning ground exists in the western Mediterranean, particularly in the area of the Balearic Islands. Their other important spawning ground is the Gulf of Mexico.
  • This species reproduces via broadcast spawning, where several females and several males release millions of eggs and sperm into the water column at the same time. Female Atlantic bluefin tuna produce up to 10 million eggs a year. Eggs hatch 2 days after being fertilized.
  • Atlantic bluefin tuna are top predators, feeding on fish such as herring and mackerel as adults.
  • Atlantic bluefin tuna are the largest tuna species. The Western Atlantic stock reaches a maximum length of 13 feet (4 m) and weight of 2,000 pounds (907 kg), while the Eastern Atlantic stock reaches a maximum length of 15 feet (4.6 m).
  • Atlantic bluefin tuna can live for 35 years, possibly longer.
  • Catches of Eastern Atlantic bluefin tuna in 2018 were about 27,800 tonnes, and Western Atlantic bluefin tuna about 2,000 tonnes, the latter being predominantly a sports fishery.
  • For the Eastern Atlantic bluefin tuna stock, purse seiners take 61% of the catch, followed by traps (17%), longline (15%), and a variety of surface gears, including pole-and-line, handline and trolling.
  • In the Mediterranean and the Eastern Atlantic, the period 26 May to 24 June marks the season where large vessels (purse seiners), are allowed to fish for bluefin tuna. Together with traps, purses seiners account by far for the biggest part of the EU quota (71 %).
  • Particular attention is given to the control of those gears that catch the fish alive for farming purposes. In 2018 the number of vessels authorized to fish bluefin tuna is 1,088 vessels (of which, 58 are purse-seiners) and 12 traps and the EU quota for 2018 has been set at 15,850 tonnes.
  • The Member States actively involved in the bluefin tuna fishery are Spain, France, Croatia, Italy, Greece, Portugal, Malta and Cyprus.
  • The bluefin tuna fishery is regulated by the International Commission for the Conservation of Atlantic Tunas (ICCAT) where the EU is a contracting party. In 2006, ICCAT adopted a multi-annual recovery plan for Bluefin tuna, which has been regularly modified based on stock assessment, control experiences and new technologies.

Purse seine

Purse seine nets are used as walls to encircle fish. After the fish are surrounded, the bottom end of the purse seine net is pulled up and closed to form a bag that traps the fish. Schooling fish such as sardine, salmon and yellowfin tuna are caught by this method. Can be unselective, particularly if used alongside Fish Aggregating Devices (FADs), where sharks, rays, turtles, dolphins and juvenile tuna can be caught.

Pelagic longline

Longlining, as the name suggests, involves long fishing lines which can be as long as 100 kilometres. Attached to them are shorter lines with baited hook tied at fixed intervals. Longlines can be set at different depths to catch different species. Pelagic longline is where the lines are set near the surface of the water to catch open water fish such as bluefin tuna, yellowfin tuna and swordfish. Bycatch is a major environmental issue in the longline fishery, especially impacting billfish, sea turtles, pelagic sharks, and seabirds.

Pole and line

Hook and line is one of the best methods of fishing with regards to sustainability. This can involve one person and a rod, or alternatively using a basic winch with a line of hooks. The hook and line fishing method has little impact on the surrounding environment and the catch can be selective. For example, any fish too small, or not the right species can be placed back into the water, with limited harm.

Almadraba traps

The almadraba traps are big nets anchored or held by pegs, open on the surface and provided with different systems to direct and trap the fish. They are usually divided into different chambers, which have nets at the bottom. The fishing season for the pasotype of almadraba traps takes place in spring and ends at the beginning of summer, and for the “return” type almadrabas, it begins at the end of summer and ends in autumn. All almadraba traps currently belong to the pasotype, because the quota is reached within the first few months. Currently the almadraba season begins in February and ends in July. The crew for the almadraba is made up of 40-45 people hired during this period.

  • Evidence of the catch certificate showing the following:
    • latin species name,
    • country sea area / RFMO area,
    • vessel flag,
    • name of vessel,
    • Unique Vessel Identifier,
    • capture method,
    • landing port
  • Is the fishery in a fishery improvement project?

FISHERIES IMPROVEMENT PROJECTS

No Known FIP

COUNTRY SPECIFIC RISK ASSESSMENTS

  • Bluefin tuna caught by fisheries in the Eastern Atlantic and Mediterranean can be considered to be a medium risk.
  • There is considerable uncertainty on the level of abundance of Atlantic Bluefin tuna. However, the Total Allowable Catch in place and strict controls have ended over-fishing (ISSF 2020).
  • The bluefin tuna fishery is regulated by the International Commission for the Conservation of Atlantic Tunas (ICCAT) where the EU is a contracting party.
  • Illegal fishing of bluefin tuna in the North Atlantic and Mediterranean remains an issue, due to bluefin tuna’s very high market value.