Tuna (assorted)

Wikipedia says tuna are saltwater fish of the tribe Thunnini, a subgrouping of the mackerel family Scombridae, with 15 species across five genera. This group entry covers sightings where the species was not recorded. The World Register of Marine Species (WoRMS) lists Scombridae as an accepted family; the tribe name rests on Wikipedia.

Wikipedia gives maximum lengths from 50 cm for the bullet tuna to 4.6 m for the Atlantic bluefin tuna, and describes a sleek, streamlined body with a metallic dark blue back and a silvery underside.

A conservation status is not given here, because this entry covers a whole group. Wikipedia says overfishing has left some tuna species, such as the southern bluefin tuna, threatened with extinction.

Wikipedia describes tuna as pelagic fish found in warmer seas.

Where Divers Find Them

In Tulamben, Bali, Blue Season Bali says that away from the wall at the Drop Off you will see tuna, and lists large tuna among the larger pelagics to look out for at Batu Kelebit, where it describes an upwelling of plankton-rich cooler water.

Wikipedia calls tuna active and agile predators and among the fastest-swimming pelagic fish, giving the yellowfin tuna as capable of up to 75 km/h. It says tuna are among the only fish able to keep a body temperature higher than the surrounding water.

Underwater Encounter Behavior

The sources cited here do not describe how tuna react to divers.