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Atlantic Bluefin Tuna: (Thunnus thynnus)

Atlantic bluefin tuna population levels are low. International overfishing is occurring.

  • Atlantic bluefin tuna is a highly migratory species that requires high levels of international cooperation for effective conservation and management.
  • Bluefin is low in sodium and is a very good source of vitamins A, B6, and B12, selenium, niacin, and phosphorous. For more on nutrition, see Nutrition Facts. (USDA)
  • Atlantic bluefin tuna is the highest valued Atlantic tuna species in the market. The United States is responsible for almost 5% of the global Atlantic bluefin tuna catch (2009). Over half of the U.S. commercial catch is exported to foreign markets, primarily Japan. The United States also imports bluefin tuna, mainly from Spain and Canada, among several other countries.
  • Life History and Habitat:

    Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is assessed and managed. Bluefin tuna are late to mature, slow-growing, and long-lived, making them more vulnerable to fishing pressure than species that grow rapidly such as tropical tuna species.

    Geographic range: The entire North Atlantic and its adjacent seas, including the Mediterranean Sea. In the western Atlantic, bluefin are found from the Gulf of Mexico to Newfoundland; in the eastern Atlantic, they are found from roughly the Canary Islands to south of Iceland, and throughout the Mediterranean Sea.

  • Habitat: Surface and subsurface temperate waters but also frequently dive to depths of 500 to 1,000 meters.
  • Life span: Long - about 40 years.
  • Food: Bluefin tuna are voracious carnivores that feed on fish, squid, and crustaceans.
  • Growth rate: Relatively slow compared to other tuna species.
  • Maximum size: Can grow to over 9.8 feet and reach more than 1,400 pounds.
  • Reaches reproductive maturity: Late – western Atlantic bluefin tuna are assumed to spawn around age 9 and are believed to take longer to reach maturity than eastern Atlantic bluefin tuna, which are assumed to spawn around age 4.
  • Reproduction: Females produce up to 10 million eggs a year.
  • Spawning season: From mid-April to June in the western Atlantic.
  • Spawning grounds: Principally in the Gulf of Mexico and in the Florida Straits.
  • Migrations: Bluefin tuna can migrate thousands of miles. Large bluefin tuna are adapted for migration to colder waters. Tagging of bluefin tuna has indicated that they move across the east/west boundary in the Atlantic.
  • Predators: Marine mammals, including killer whales and pilot whales, feed on bluefin tuna. Other predators include sharks and large predatory fishes. Juvenile bluefin tuna are also preyed upon by bluefish and seabirds.
  • Commercial or recreational interest: Both
  • Distinguishing characteristics: The bluefin tuna has a large, torpedo-shaped body that is nearly circular in cross-section. The fish is dark blue-black on the back and white on the lower sides and belly. On live bluefin, colorless lines alternate with rows of colorless spots on the lower sides. The second dorsal fin is reddish brown. The color of the dorsal fin, the number of gill rakers on the first arch, and the very short pectoral fins separate this species from other members of the tuna genus, Thunnus.
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    Information On Each Species:

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