Northern Bluefin Tuna
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| Northern Bluefin Tuna Conservation status: Lower risk | ||||||||||||||
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| Thunnus thynnus |
The Northern Bluefin Tuna (Thunnus thynnus) is a species of tuna fish, living in both the Western and the Eastern Atlantic Ocean and extending into the Mediterranean Sea and the Black Sea. Although not native to the Pacific Ocean, it is cultivated off Japan. Northern Bluefin Tuna can live up to 30 years old. The typical size is 6.6 feet (2 m) at about 1100 pounds (500 kg). The largest recorded specimen was caught off Nova Scotia, and was recorded as weighing 1500 pounds (679 kg). They are caught by sports fishermen using a heavy-duty rod and reel. The record for the longest battle took place off of Liverpool, Nova Scotia in 1934, when 6 men, working in shifts, fought a 795-lb tuna in a terrific fight that lasted 62 hours. It is an important food fish.
The species is also known as the leaping tuna, tunny, shortfin tuna, ahi, and the great albacore. It is often referred to simply as the "bluefin" or "bluefin tuna", but this name is ambiguous as it is also sometimes used for the Southern Bluefin Tuna, Thunnus maccoyii, and the Pacific Bluefin Tuna, T. orientalis. However, even the preferred name, Northern Bluefin Tuna, is not unambiguous, because this is sometimes used for the Longtail Tuna T. tonggol.
The body of the Northern Bluefin Tuna is cigar-shaped and robust. The head is conical and the mouth rather large. The color is dark blue above and gray below. Northern Bluefin Tuna can easily be distinguished from other members of the tuna family by the relatively short length of their pectoral fins. Their livers have a unique and definitive characteristic in that they are covered with blood vessels (striated). In other tunas with short pectoral fins, such vessels are either not present or present in small numbers along the edges.
The Northern Bluefin Tuna is an important source of seafood, providing most of the tuna used in sushi. It is a particular delicacy in Japan where the price of a single giant tuna can exceed $100,000 on the Tokyo fish market [1] (http://www.msnbc.msn.com/id/7656726/). As a result, some fisheries of bluefin are considered overfished, and this problem is compounded by the bluefin's slow growth rate and late maturity. For these reasons, the bluefin species are listed as "Avoid" on the Monterey Bay Aquarium's Seafood Watch program.
The Northern Bluefin Tuna has been depicted on the following stamps:
- Maldives, 3L, 1973
- Cuba, 2, 1975
- Western Sahara, 28 pesetas, 1995
- Canada, 45 cents, 1997
External links
- Bluefin tuna stocks crashing, help sought (http://www.msnbc.msn.com/id/7656726/)
- FishBase entry for the Northern Bluefin (http://www.fishbase.org/Summary/SpeciesSummary.cfm?genusname=Thunnus&speciesname=thynnus)
- Monterey Bay Aquarium Seafood Watch article (http://www.mbayaq.org/cr/cr_seafoodwatch/sfw_factsheet.asp?fid=60) on all three species of bluefinno:Makrellstørje