Tuna

Tuna are fast, streamlined open-water fish built for speed. In this app the group includes the yellowfin tuna, the kawakawa, and the little tunny.

Look for a large, fast-swimming, torpedo-shaped fish with a crescent tail and a line of small yellow finlets near the tail. Within the group, size and colour markings help tell members apart, since the largest tuna are far bigger than the small tunas and bonitos.

Tuna have a sleek, torpedo-shaped body with two dorsal fins on the back and a crescent-shaped tail with pointed tips. A row of small yellow finlets runs along the back and belly toward the tail. The back is dark metallic blue and the belly is silvery, which helps hide them from above and below. Sizes vary a lot: some species stay under a metre, while the Atlantic bluefin tuna can grow to 4.6 metres.

Tuna live in open water across the world's oceans, mostly in tropical and temperate seas rather than close to the reef.

Tuna are active, fast-swimming predators. Unlike most fish, they can keep parts of their body warmer than the surrounding water, which lets them swim fast and hunt in cooler water than other fish can handle.

• 

  Atlantic Bluefin Tuna

  Thunnus thynnus

• 

  Black Skipjack

  Euthynnus lineatus

• 

  Kawakawa

  Euthynnus affinis

• 

  Little Tunny

  Euthynnus alletteratus

• 

  Yellowfin tuna

  Thunnus albacares