Auxis

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 the Thunnini tribe.

In Japan the two species in the genus are collectively called sōdagatsuo (ソウダガツオ,宗太鰹), and this is also the common genus name. In Japanese cuisine, these fish are processed into sōdabushi, a product much like katsuobushi, 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., soba noodle shops.

Although fresh fish might be eaten as sashimi or grilled, it has a lot of dark-red meat (chiai), so it is valued much less than the similar katsuo (skipjack tuna). And it degrades quickly so shipment out to market is limited. The frigate tuna (hirasoda) is considered superior between the two.

Species
There are two species in the genus Auxis, each with two subspecies.:
 * A. rochei (Risso, 1810) (bullet tuna); marusōda (マルソウダ)
 * ssp.. A. rochei rochei (Risso, 1810), distributed tropic and subtropic oceans worldwide (Atlantic, Indian and Pacific: including the Mediterranean Sea.).
 * ssp. A. rochei eudorax Collette et Aadland, 1996, Eastern Pacific.
 * A. thazard (Lacepède, 1800) (frigate tuna); hirasōda (ヒラソウダ)
 * ssp. A. thazard thazard (Lacepède, 1800), distributed tropic and subtropic Atlantic, Indian and Pacific Oceans.
 * ssp. A. thazard brachydorax Collette et Aadland, 1996, Eastern Pacific.