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 species, such as southern bluefin tuna, are close to extinction.
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