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Tuna

2007 Schools Wikipedia Selection. Related subjects: Insects, Reptiles and
Fish

                   iTuna
   Yellowfin tuna, Thunnus albacares
   Yellowfin tuna, Thunnus albacares
         Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Actinopterygii
   Order:   Perciformes
   Family:  Scombridae
   Genus:   Thunnus
            South, 1845

                                   Species

   See text.

   Tuna, sometimes called tunafish, are several species of ocean-dwelling
   fish in the family Scombridae, mostly in the genus Thunnus.

   Tunas are fast swimmers (they have been clocked at 77 km/h (48 mph))
   and include several species that are warm-blooded. Unlike most fish
   species, which have white flesh, the flesh of tuna is pink to dark red.
   This is because tuna muscle tissue contains greater quantities of
   myoglobin, an oxygen-binding molecule, than the muscle tissue of most
   other fish species. Some of the larger tuna species such as the bluefin
   tuna can raise their blood temperature above the water temperature with
   muscular activity. This enables them to live in cooler waters and
   survive a wider range of circumstances.

   Tuna is an important commercial fish. Some varieties of tuna, such as
   the bluefin and bigeye tuna, Thunnus obesus, are threatened by
   overfishing, dramatically affecting tuna populations in the Atlantic
   and northwestern Pacific Oceans. Other populations seem to support
   fairly healthy fisheries (for example, the central and western Pacific
   skipjack tuna, Allothunnus fallai), but there is mounting evidence that
   overcapitalization threatens tuna fisheries world-wide. The Australian
   Government alleged in 2006 that Japan had illegally over-fished
   southern bluefin to the value of USD $2 billion, by taking 12,000 to
   20,000 tonnes per year instead of international agreed 6,000 tonnes.
   This has resulted in severe damage to stocks.

   Increasing quantities of high-grade tuna are entering the market from
   operations that rear tuna in net pens and feed them on a variety of
   bait fish. In Australia the southern bluefin tuna, Thunnus maccoyii, is
   one of two species of bluefin tunas that are kept in tuna farms by
   former fishermen. Its close relative, the northern bluefin tuna,
   Thunnus thynnus, is being used to develop tuna farming industries in
   the Mediterranean, North America and Japan.

   Due to their high position in the food chain and the subsequent
   accumulation of heavy metals from their diet, mercury levels can be
   relatively high in some of the larger species of tuna such as bluefin
   and albacore. As a result, in March 2004 the United States FDA issued
   guidelines recommending pregnant women, nursing mothers and children
   limit their intake of tuna and other types of predatory fish . However,
   most canned light tuna is skipjack tuna and is low in mercury. Further,
   the closely related tongkol has recently come to market as a
   low-mercury, less expensive substitute for canned albacore.

Species

   There are nine species:
     * Albacore, Thunnus alalunga ( Bonnaterre, 1788).
     * Yellowfin tuna, Thunnus albacares ( Bonnaterre, 1788).
     * Blackfin tuna, Thunnus atlanticus ( Lesson, 1831).
     * Karasick tuna, Thunnus karasicus ( Lesson, 1831).
     * Southern bluefin tuna, Thunnus maccoyii ( Castelnau, 1872).
     * Bigeye tuna, Thunnus obesus (Lowe, 1839).
     * Pacific bluefin tuna, Thunnus orientalis ( Temminck & Schlegel,
       1844).
     * Northern bluefin tuna, Thunnus thynnus (Linnaeus, 1758).
     * Longtail tuna, Thunnus tonggol ( Bleeker, 1851).

Pronunciation

   There are different ways to pronounce tuna. Many Americans say 'toona',
   while the British say 'choona' or 'tyoona'.

Methods of Capture

     * Almadraba is an arabic way of hunting using nets to creat a maze
     * big-game fishing

   Retrieved from " http://en.wikipedia.org/wiki/Tuna"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
