A tuna (also called tunny) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max. length: 50 cm (1.6 ft), weight: 1.8 kg (4 lb)) up to the Atlantic bluefin tuna (max. length: 4.6 m (15 ft), weight: 684 kg (1,508 lb)). The bluefin averages 2 m (6.6 ft), and is believed to live up to 50 years.
Tuna, opah, and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish – the yellowfin tuna, for example, is capable of speeds of up to 75 km/h (47 mph). Found in warm seas, it is extensively fished commercially, and is popular as a game fish. As a result of overfishing, stocks of some tuna species, such as the southern bluefin tuna, are close to extinction.
Any of several species of fish of the genus Thunnus in the family Scombridae.
The edible flesh of the tuna.
The prickly pear, a type of cactus native to Mexico in the genus Opuntia.
The fruit of the cactus.