|Yellowfin tuna, Thunnus albacares|
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of 70Â km/h (43Â mph). Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an oxygen-binding molecule, which tuna express in quantities far higher than most other fish. Some larger tuna species, such as bluefin tuna, display some warm-blooded adaptations, and can raise their body temperatures above water temperatures by means of muscular activity. This enables them to survive in cooler waters and to inhabit a wider range of ocean environments than other types of fish.
"Tuna" is akin to the Spanish word atÃºn, from Latin thunnus / Greek Î¸ÏÎ½Î½Î¿Ï‚, thynnos.
Maximum reported sizes of tuna species
There are over fifty different "tuna" species, the "tuna" designation often varying in accordance with local custom. The Thunnus genus has been attributed to the species:
Species of several other genera (all in the family Scombridae) have common names containing "tuna":