The bullet tuna, ''Auxis rochei'', is a
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of
tuna
A 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 greatly, ranging from the bullet tuna (max le ...
, in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Scombridae
The mackerel, tuna, and bonito family, Scombridae, includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies. All species are in the subfamily Scombrinae, except the butter ...
, found circumglobally in
tropical
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in
the Southern Hemisphere at S. The tropics are also referred to ...
oceans, including the Mediterranean Sea,
[ in open surface waters to depths of 50 m (164 ft). The population of bullet tuna in the western Pacific was classified as a subspecies of ''A. rochei'', ''A. rochei eudorax'', but some authorities regard this as a valid species '']Auxis eudorax
''Auxis eudorax'' is a species of tuna in the family Scombridae. It is a pelagic marine species native to the Eastern Pacific, where it has been reported from mainland Ecuador, the Galápagos, Mexico, Panama, and the United States. The spe ...
''.dorsal fin
A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through c ...
, widely separated from the second dorsal fin, which, like the anal and