''Auxis'' is a genus of ocean-dwelling

ray-finned Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilag ...

in the family

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 butterfly ...

, and tribe Thunnini, also known as the tunas. ''Auxis'', commonly and collectively called the frigate tunas, is one of five genera of tunas which comprise the Thunnini tribe.

Species

There are four species in the genus ''Auxis'', which were formerly regarded as two polytypic species, each with two

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

. In 2021, the species ''Auxis koreanus'' was described from South Korea. * ''

Auxis brachydorax ''Auxis brachydorax'' is a species of tuna in the family Scombridae. It is a pelagic marine species native to the eastern Central Pacific, where it has been reported from mainland Ecuador, the Galápagos, Mexico, Panama, Peru, and the United State ...

'' Collette & Aadland, 1996 * ''

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 species rea ...

'' Collette & Aadland, 1996 * ''

Auxis koreanus ''Auxis'' is a genus of ocean-dwelling ray-finned bony fish in the family Scombridae, and tribe Thunnini, also known as the tunas. ''Auxis'', commonly and collectively called the frigate tunas, is one of five genera of tunas which comprise th ...

'' Nam et al., 2021 * ''

Auxis rochei The bullet tuna, ''Auxis rochei'', is a species of tuna, in the family Scombridae, found circumglobally in tropical oceans, including the Mediterranean Sea, in open surface waters to depths of 50 m (164 ft). The population of bullet tu ...

'' Risso, 1810 (bullet tuna) * '' Auxis thazard''

Lacépède Lacepede can refer to: * Bernard Germain de Lacépède (1756–1825), French naturalist and politician. * Lacepede Bay, a bay in South Australia. * Lacépède, Lot-et-Garonne, a ''commune'' in France * Lacepede Islands, a group of four islands in t ...

, 1800 (frigate tuna)

Description

''Auxis'' can reach a length of . They have a strong, fusiform body with a sharpened head. The teeth are small and conical. The two dorsal fins are separated by a wide gap. The pectoral fins are short. They have a dark, blue-black back, the top of the head may be deep purple or almost black. The belly is whitish and without streaks or spots.

Distribution

These fishes are widespread in all tropical and subtropical seas and oceans, and both mentioned species are present in the Mediterranean Sea with their subspecies (''A. thazard thazard'' and ''A. rochei rochei).''

Ecology

''Auxis'' species are the predominant prey of pelagic gamefish off of the east coast of the United States.

As food

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

the two species in the genus are collectively called , and this is also the common genus name. In Japanese cuisine, these fish are processed into , a product much like , though not really used in fine-dining restaurants or as condiment, but as a fish stock ingredient at more budget type popular-dining places, e.g., noodle shops. Although fresh fish might be eaten as sashimi or grilled, it has a lot of dark-red meat (), so it is valued much less than the similar ' (

skipjack tuna The skipjack tuna (''Katsuwonus pelamis'') is a medium-sized perciform fish in the tuna family, Scombridae. It is otherwise known as the balaya (Sri Lanka), bakulan/kayu (North Borneo), tongkol/aya (Malay Peninsula/Indonesia), aku (Hawaii), cakal ...

). And it degrades quickly so shipment out to market is limited. The

frigate tuna The frigate tuna, frigate mackerel or alagaduwa (''Auxis thazard'') is a species of tuna, in the family Scombridae, found around the world in tropical oceans. The eastern Pacific population is now regarded as a separate species by some authoritie ...

() is considered superior between the two.

Fossil record

Fossils of ''Auxis'' have been found in the Pliocene of Italy and United States (age range: from 5.3 to 3.6 million years ago.).Paleobiology Database
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References

External links

*
MNHN
{{Taxonbar, from=Q287566 Scombridae Marine fish genera Taxa named by Georges Cuvier