Tuna 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 speeds up to 45 mp and include several species that are warm-blooded.
Unlike most fish species, which have white flesh, tuna have flesh that is pink to dark red.
The red coloring comes from tuna muscle tissue’s greater quantities of myoglobin, an oxygen-binding molecule and does not effect the taste of the flesh.
Tunas are a popular target of recreational fisherman and make good table fare.
Further information on the following tuna species can be found on this site: