Western Atlantic Bluefin Tuna

About the Species

U.S. wild-caught western Atlantic bluefin tuna is a smart seafood choice because it is sustainably managed under a rebuilding plan that allows limited harvest by U.S. fishermen.

Status

• The 2017 stock assessment (pages 111 through 114) indicated that the western Atlantic bluefin tuna stock is not subject to overfishing.
• Based on the information in the 2017 stock assessment, NOAA Fisheries has determined that the western Atlantic bluefin tuna stock has an unknown overfished status.
• Scientists estimate that the western stock’s spawning stock biomass (a measure of the amount of bluefin that are able to reproduce) has been increasing since about 2004, after two decades of stability.
• For the 2017 stock assessment, the scientists were unable to determine if the stock is rebuilt under the 20-year rebuilding plan. Based on this information, ICCAT adopted an interim conservation and management plan for the stock for 2018 through 2020.
• Despite the longstanding uncertainty in estimating future recruitment, catch levels have been set at a level that is expected to support the maximum sustainable yield.
• ICCAT selected a catch limit for 2018 through 2020 that is a 17% increase relative to the level in effect for 2015 through 2017. This level provides a buffer from the top end of the range in the scientific advice to ensure an additional layer of precaution given the uncertainties that are not fully accounted for in the assessment.
• The Gulf of Mexico is the only known spawning area for the western stock of Atlantic bluefin tuna, and protecting these fish during spawning can help the long-term rebuilding of the depleted bluefin tuna population.

Appearance

• Atlantic bluefin tuna have large, torpedo-shaped bodies that are nearly circular in cross-section.
• They are the largest of the tuna species and can reach up to 13 feet and 2,000 pounds.
• They have dark blue-black on the back and white on the lower sides and belly.
• Atlantic bluefin tuna have colorless lines alternating with rows of colorless spots on their lower sides.
• The second fin on their back (dorsal fin) is reddish brown, and they have short pectoral fins.
• These characteristics separate this species from other members of the tuna genus, Thunnus.

Biology

• Bluefin tuna grow more slowly than other tuna.
• They have a long lifespan, up to 20 years or more and generally don’t spawn until they are about 8 years old. 
• They spawn from mid-April to June, mainly in the Gulf of Mexico.
• Females can produce up to 10 million eggs a year.
• The eggs are fertilized in the water column and hatch in about 2 days.
• Bluefin tuna are top predators.
• Juveniles eat fish, squid, and crustaceans, and adults feed mainly on baitfish such as herring, bluefish, and mackerel.
• Sharks, marine mammals (including killer whales and pilot whales), and large fish feed on bluefin tuna. Bluefish and seabirds also prey upon juvenile bluefin tuna.

Where They Live

• In the western Atlantic, bluefin tuna are found from Newfoundland to the Gulf of Mexico.

Management

• Effective conservation and management of highly migratory species like bluefin tuna require international cooperation as well as strong domestic management.
• NOAA Fisheries, through the Atlantic Highly Migratory Species Management Division, manages the Atlantic bluefin tuna fishery in the United States, and sets regulations for the U.S. fishery based on conservation and management recommendations from the International Commission for the Conservation of Atlantic Tunas (ICCAT), consistent with applicable U.S. laws.
• Managed under the 2006 Consolidated Atlantic Highly Migratory Species Fishery Management Plan and amendments:
  • Commercial and recreational fishermen must have a permit to harvest bluefin tuna.
  • Annual quota and subquotas.
  • Gear restrictions.
  • Time/area closures.
  • Minimum size limits.
  • Federal management for Atlantic tunas applies to state waters as well, except in Maine, Connecticut, and Mississippi. NOAA Fisheries periodically reviews these states’ regulations to make sure they’re consistent with federal regulations.
• Regulations do not allow targeted fishing of bluefin tuna in the Gulf of Mexico, an important spawning area for the species.
• NOAA Fisheries published several new regulations that are expected to reduce and improve accounting for bluefin tuna dead discards, including gear restricted areas and individual transferable quotas in the pelagic longline fishery, modified quota category allocations, and enhanced monitoring and reporting.
• In 2000, the United States established the Dolphin-Safe Tuna Tracking and Verification Program to monitor the domestic production and importation of all frozen and processed tuna products nationwide, and to authenticate any associated dolphin-safe claim.