Tuna is a saltwater finfish, comprises 15 species across 5 genera, the sizes of which vary greatly, ranging from the Bullet tuna (max. length: 1.6ft (50 cm), weight: 4 lb (1.8 kg)) up to the Bluefin tuna (max. length: 15 ft (4.6 m), weight: 1,508 lb (684 kg)).
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 47 mph (75 km/h). Found in warm seas, it is extensively fished commercially, and is popular as a game fish in sport fishing.
About 68% of the catches are from the Pacific Ocean, 22% from the Indian Ocean, and the remaining 10% from the Atlantic Ocean and the Mediterranean Sea.
Skipjack tuna makes up about 60% of the catch, followed by Yellowfin tuna 24%, Big-eye tuna 10%, Albacore tuna 5%, Bluefin tuna and others occupy the remainder 1%.
Between 1940 and 1960s, the annual world catch of Tunas rose sharply from about 300 thousand tons to about 1 million tons. Nowadays, with the development of modern purse-seine nets, catches have risen to more than 4 million tons per year. As a result of over-fishing, stocks of some tuna species such as the Bluefin tuna have been reduced dangerously close to the point of extinction.