Which fish is traditionally used in sushi more than any other?

Tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary from the bullet tuna to the Atlantic bluefin tuna, which averages 2 m (6.6 ft) and is believed to live up to 50 years.