Description:
Bluefin tuna are bluish-black on their dorsal side with a silvery coloration on their ventral side. Bluefin tuna are warm-blooded (homeothermic) and can thermoregulate, which means they can keep their body temperature higher than that of the surrounding water temperature. Because of this, they are capable of great speeds up to 50 miles per hour.
Atlantic bluefin can reach lengths of about 9 feet and weights of up to about 1,500 pounds.
Classification:
- Kingdom: Animalia
- Phylum: Chordata
- Class: Actinopterygii
- Order: Perciformes
- Family: Scombridae
- Genus: Thunnus
- Species: thynus
Feeding:
Atlantic bluefin tuna eat smaller schooling fish, such as herring, mackerel, hake, and menhaden, and also squid and crustaceans.
A tuna's predators includes orcas (killer whales) and sharks.
Habitat and Distribution:
In the western Atlantic, bluefin tuna are found from Newfoundland, Canada, to the Gulf of Mexico. In the eastern Atlantic, they are found throughout the Mediterranean Sea and from Iceland down to the Canary Islands.
Although they live in the open ocean, tuna are often at the water's surface, and can be seen leaping as they chase after prey or when they are traveling quickly. Tuna tend to group together by size. Schools of tuna can be found by the splashing they make as they travel at the surface.
Bluefin tuna may migrate thousands of miles, and across the Atlantic.
Conservation:
Fishing for tuna didn't begin in earnest until the 1970's, when they were sought after for sushi and steaks, especially in Japan. At this time, a dramatic increase in fishing for tuna occurred. Overfishing, combined with a low reproduction rate, has contributed to a dramatic decline in the population. Management of tuna fishing is difficult as tuna migrate across international boundaries. Atlantic bluefin are managed internationally by the International Commission for the Conservation of Atlantic Tunas (ICCAT).
Sources:
- Bigelow, H.B. and W.C. Schroeder. 1953. TunaThunnus thynnus. (Online) Fishes of the Gulf of Maine. Accessed July 17, 2009.
- National Marine Fisheries Service/NOAA. Atlantic Bluefin Tuna (Thunnus thynnus). FishWatch-U.S. Seafood Facts. Accessed July 17, 2009.
- Thunnus thynnus, Atlantic Bluefin Tuna (Online) MarineBio.org. Accessed July 17, 2009.
