Western Atlantic Bluefin Tuna

Atlantic Bluefin Tuna

Thunnus thynnus


    Tuna, Bluefin Tuna, Toro, Maguro, Giant Bluefin, Northern Bluefin Tuna


    U.S. wild-caught from Maine to Louisiana



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School of bluefin tuna

School of bluefin tuna


Three species of bluefin tuna are found around the world – Northern (or Atlantic) bluefin tuna (Thunnus thynnus), Southern bluefin tuna (Thunnus maccoyii), and Pacific bluefin tuna (Thunnus orientalis). Atlantic bluefin tuna is divided into two stocks. The western stock is harvested off the coast of North America by Canada, Japan, and the United States, and the eastern stock is harvested off the coast of Europe and Africa and in the Mediterranean Sea.

Fisheries for bluefin tuna date back thousands of years in the Mediterranean but didn’t emerge in the western Atlantic until the 1950s. Although today they’re widely known as the most prized species of tuna, there was no commercial market for western Atlantic bluefin tuna until the late 1950s. In fact, fishermen regarded giant bluefin tuna (greater than 310 pounds) as a nuisance because of the damage they caused to fishing gear. However, as sushi and sashimi markets developed in the 1970s and 1980s, the demand and prices for bluefin tuna increased and so did fishing pressure around the world.

Since bluefin tuna are late to mature, slow-growing, and long-lived, they’re especially vulnerable to fishing pressure compared to faster growing, more productive species. Many nations harvest bluefin tuna and effective conservation and management of this resource depend on strong international cooperation. The United States has taken many steps to conserve and manage U.S. fisheries for Atlantic bluefin tuna since the early 1980s. It is due in part to these measures and U.S. efforts internationally that Atlantic bluefin tuna are no longer subject to overfishing.

In 1981, through the International Commission for the Conservation of Atlantic Tunas (ICCAT) disclaimer the United States prohibited capture of bluefin tuna for the next fishing year and closed the Gulf of Mexico (the major spawning area for western Atlantic bluefin tuna) to directed bluefin fishing. In 1991, ICCAT further reduced the amount of bluefin that could be harvested and increased the minimum size of bluefin that could be retained. In 1998 ICCAT adopted a rebuilding plan disclaimer for the stock, with a goal of rebuilding the stock by 2019. Since the plan was adopted, population indices continue to improve.

Today, both U.S. and international fisheries for western Atlantic bluefin tuna are highly regulated. The most recent annual catch level set for 2015 and 2016 is expected to support continued growth and recovery of the stock. Strict measures are in place to ensure compliance – on the water, in port, and at the marketplace – through the implementation of the catch documentation scheme disclaimer, which allows trade tracking for individual shipments of fish.

Finally, because the western and eastern stocks mix, western Atlantic bluefin are also affected by fishing pressure in the eastern Atlantic. There was rampant overfishing in the eastern Atlantic/Mediterranean during the 1990s and early 2000s. However, in recent years, catches in the eastern Atlantic have been reduced to levels consistent with scientific advice, and new monitoring and control measures have been adopted to address illegal, unreported and unregulated (IUU) fishing on that stock. Scientists advise that improved stock conservation in the eastern Atlantic would likely benefit the western stock as well.

Looking Ahead

Under the Magnuson-Stevens Fishery Conservation and Management Act, the U.S. must meet many fisheries management objectives, including preventing overfishing and minimizing bycatch. In response to recent trends in the bluefin tuna fisheries, NOAA Fisheries adopted Amendment 7 to the 2006 Consolidated Atlantic Highly Migratory Species Fishery Management Plan to reduce and account for Atlantic bluefin tuna dead discards and enhance monitoring and reporting in bluefin tuna fisheries, among other fishery management measures such as gear restricted areas.



Northern, or Atlantic, bluefin tuna live throughout the entire North Atlantic and its adjacent seas, including the Mediterranean. In the western Atlantic, bluefin are found from Newfoundland to the Gulf of Mexico; in the eastern Atlantic, they’re found from south of Iceland to the Canary Islands, and throughout the Mediterranean Sea.

Bluefin tuna live near the surface in temperate waters but frequently dive to depths of 500 to 1,000 meters. Bluefin tuna are a highly migratory species – they can migrate thousands of miles across an entire ocean. Tagging studies have indicated that bluefin tuna move across the east/west boundary in the Atlantic. Although they’re highly migratory, they tend to spawn in the same areas in the Gulf of Mexico and Mediterranean.



Bluefin tuna grow more slowly than other tunas and have a long life span, 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 fishes feed on bluefin tuna. Bluefish and seabirds also prey upon juvenile bluefin tuna.



The bluefin tuna has a large, torpedo-shaped body that is nearly circular in cross-section. They are the largest of the tuna species and can reach up to 13 feet and 2,000 pounds. Bluefin tuna are dark blue-black on the back and white on the lower sides and belly. Live bluefin 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.



There are two stocks of Atlantic bluefin tuna: 1) western Atlantic and 2) eastern Atlantic/Mediterranean. The International Commission for the Conservation of Atlantic Tunas' (ICCAT) disclaimer scientific committee typically assesses the abundance of both the western and eastern Atlantic stocks every 2 to 3 years. Managers use the results of these stock assessments to develop new conservation and management measures as needed.



Scientists estimate the spawning stock biomass (a measure of the amount of bluefin that are able to reproduce) of the western Atlantic stock declined steadily between 1970 and 1992 and then fluctuated around 25 to 30 percent of the 1970 level for about the next decade. In recent years, however, spawning stock biomass appears to have gradually increased from 27 percent of 1970 levels in 2003 to an estimated 55 percent in 2013. Since 1998, when ICCAT adopted a rebuilding plan disclaimer, spawning stock biomass has increased by 70 percent. According to the 2014 stock assessment disclaimer, the western Atlantic bluefin tuna stock is no longer subject to overfishing. However, based on the information in the 2014 stock assessment  and continued uncertainty about population estimates, NOAA Fisheries has determined that the western Atlantic bluefin tuna stock remains overfished.



The United States supports research that concentrates on stock structure, migration, aging, spawning behavior, reproductive biology, and population modeling analyses. NOAA Fisheries also collects data on fishing effort and catch from the United States for bluefin tuna to support ICCAT stock assessments and reports.

NOAA Fisheries scientists continue to study the possible effects of the 2010 Deepwater Horizon oil spill on Atlantic bluefin tuna, as the Gulf of Mexico is one of the only known spawning grounds for the western stock of Atlantic bluefin tuna. Results of a recent study by NOAA and academic scientists indicate that crude oil can cause severe defects in large predatory fish like bluefin tuna. Because the spawning season of many of these fish coincided with the 2010 Deepwater Horizon oil spill, young fish were potentially in harm's way.


Harvesting Bluefin Tuna

U.S. fishermen harvest bluefin tuna with handgear (rod and reel, handline, and harpoon) and purse seines. They generally target schools of tuna, and these fishing gears are fairly selective and allow for the live release of any unintentionally caught species. Fishing gear used to catch bluefin tuna rarely contacts the ocean floor and therefore has minimal impact on habitat.

Although fishermen are not allowed to use pelagic longline gear to target bluefin tuna directly, strict regulations allow them to retain a limited number of bluefin tuna caught incidentally while fishing for other species such as swordfish and yellowfin tuna. NOAA Fisheries requires U.S. commercial fishermen who fish for yellowfin tuna, swordfish, and other species with pelagic longlines in the Gulf of Mexico to use “weak hooks,” a type of hook designed to reduce the incidental catch of Atlantic bluefin tuna. Fishing for bluefin tuna in two known hotspots—Cape Hatteras, North Carolina and the Gulf of Mexico—is strictly regulated. 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. Cape Hatteras is a feeding area for bluefin tuna.



Who’s in charge? Management of highly migratory species such as bluefin tuna is complicated because these species migrate thousands of miles across oceans and international borders and are fished by many nations. Effective conservation and management of these resources require international cooperation as well as strong domestic management. With Atlantic bluefin tuna, NOAA Fisheries' Atlantic Highly Migratory Species Management Division 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.

Current management:
International: Taking into consideration the results of the most recent stock assessment, ICCAT member nations develop new conservation and management measures as needed. ICCAT sets and allocates western Atlantic bluefin tuna quotas by country. Based on the 2014 stock assessment disclaimer, the total allowable catch is set at 2,000 metric tons annually for 2015 and 2016, which will provide for continued growth in spawning stock biomass and allow the strong 2003 year-class to continue to enhance the productivity of the stock. There has been a history of strong compliance with these quotas and other conservation measures in the western Atlantic.

ICCAT began to limit catches of eastern Atlantic and Mediterranean bluefin tuna in the mid-1990s. Unfortunately, limits were set in excess of scientific advice and compliance was poor for many years. However, adherence to individual quotas in the eastern Atlantic and Mediterranean has greatly improved in the past few years and catch limits are within the range of scientific advice and are expected to support continued growth, provided parties comply with the agreed limits. The United States does not fish in the eastern Atlantic; however, because the two stocks sometimes mix, management of the larger stock in the eastern Atlantic can have an impact on the western stock.

Domestic: 2006 Consolidated Atlantic Highly Migratory Species Fishery Management Plan

  • Annual quotas and limits on the amount of fish a vessel can keep per trip, seasons, gear restrictions, and minimum size limits are all designed to manage total U.S. harvests to conform to ICCAT recommendations.
  • Regulations prohibit directed fishing for bluefin tuna in the Gulf of Mexico due to the area’s value as an important spawning ground, but regulations allow for a limited number of incidentally caught bluefin tuna to be retained by the Gulf of Mexico pelagic longline fleet.
  • Pelagic longliners fishing for yellowfin tuna and swordfish have a strict limit on the number of bluefin tuna they can keep each year and must report their catches after each set. Electronic monitoring is in place to audit reporting. In the Gulf of Mexico, pelagic longline fishermen must also use “weak hooks” to reduce the number of bluefin tuna caught unintentionally. These regulations were designed to manage total U.S. catches consistent with ICCAT recommendations.
  • Vessels must have a permit to fish for, retain, possess, or sell Atlantic bluefin tuna and must report landings of all bluefin tuna. They can only sell to permitted dealers.
  • Management also regulates trade of Atlantic bluefin tuna – all fish dealers purchasing regulated Atlantic tunas from vessels holding an Atlantic tunas permit or an Atlantic Highly Migratory Species permit must obtain an Atlantic tunas dealer permit. An International Trade Permit is required for the international trade of all bluefin tuna.
  • NOAA Fisheries monitors the bluefin tuna fishery in all commercial and recreational fisheries and has the authority to take inseason actions (such as closing fisheries and adjusting retention limits) to ensure available quotas are not exceeded or to enhance scientific data collection from, and fishing opportunities in, all geographic areas.
  • 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.

Annual Harvest

More than half the global catch of bluefin tuna comes from the eastern and western Atlantic Ocean. ICCAT implemented harvest quotas for the western Atlantic bluefin tuna stock in 1982, and since then catch has been relatively stable. In 2013, U.S. commercial and recreational fishermen caught 659 metric tons of western Atlantic bluefin tuna (landings and dead discards). U.S. catch comprised 44 percent of total western Atlantic bluefin tuna catch and 4.4 percent of Atlantic-wide bluefin tuna catch (including the Mediterranean Sea) in 2013.  



Ex-vessel prices (the price fishermen receive for their catch) for bluefin tuna have declined 23 percent since 2012. The ex-vessel price depends on a number of factors, including the quality of the fish (e.g., freshness, fat content, method of storage), the weight of the fish, the supply of fish, and consumer demand. In 2012 and 2013, the annual ex-vessel revenue for the fishery was $10.8 million and $5.8 million, respectively (according to NOAA’s Bluefin Tuna Dealer Report database).

In 2013, 44 percent of U.S. Atlantic bluefin tuna catch was exported, mainly to the sushi markets in Japan. Exports of Atlantic bluefin tuna generally depend on the amount of commercial landings and Japanese yen/U.S. dollar exchange rates.



Recreationally caught Atlantic tunas may not be sold. Bluefin tuna must be larger than 27 inches to be retained. Depending on the recreational fishery, there is also a limit on the maximum size of bluefin that can be retained and a limit on the amount fishermen can keep per fishing trip. Regulations do not allow recreationally caught bluefin tuna to be retained in the Gulf of Mexico, an important spawning area for the species. All released bluefin tuna must be released in a manner that will maximize its survival, and without removing the fish from the water. For the latest information on current retention limits, visit the NOAA Fisheries HMS Permit Shop.

Recreational fishing for highly migratory species such as bluefin tuna provides significant economic benefits to coastal communities through individual angler expenditures, recreational charters, tournaments, and the shoreside businesses that support those activities.



Bluefin tuna flesh is the darkest and fattiest of any tuna. Because of its high fat content, bluefin tuna is especially prized for sushi and sashimi. A higher fat content in bluefin tuna is equated with a higher-quality product. Also, because of the high fat content, cooking is not advised as it produces a strong fish taste and odor when cooked.







Servings 1
Serving Weight 100 g (raw)
Calories 144
Protein 23.33 g
Fat, total 4.9 g
Saturated fatty acids, total 1.257 g
Carbohydrate 0 g
Sugars, total 0 g
Fiber, total dietary 0 g
Cholesterol 38 mg
Selenium 36.5 mcg
Sodium 39 mg

Western Atlantic Bluefin Tuna Table of Nutrition



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