Tuna are large, streamlined fish that range in size from the small, 10 cm (4 in) long kawakawa to the giant of the oceans, the 4 m (13 ft) long bluefin tuna.
Tuna are among the fastest-swimming fish, with some species capable of speeds of up to 80 kph (50 mph). Most species are blue-green on the upper sides and silvery on the underside.
Tuna are found in both temperate and tropical oceans worldwide, usually near the surface.
Tuna are also opportunistic predators, taking advantage of whatever food sources are available.
They typically feed on small fish, crustaceans, and squid. Some species, such as the bluefin tuna, are highly migratory, traveling thousands of kilometers each year in search of food.
Tuna are highly social, forming large schools of hundreds or even thousands of individuals. They are also capable of long-distance migrations, typically traveling to cooler waters in the summer and warmer waters in the winter.
In the open ocean, tuna typically swim just below the surface, but may dive to depths of 200 m (660 ft) or more.
Tuna are a diverse group of fish that belong to the Tribe, Thunnini, with more than 20 species found worldwide. These include the skipjack, albacore, yellowfin, bigeye, and bluefin tuna.
All species are heavily fished, and some, such as the bluefin tuna, are considered to be overfished and are listed as endangered by the IUCN. Conservation efforts to protect tuna populations are ongoing.