Auxis Cuvier, 1829
Body robust, elongate and rounded. Gillrakers on first arch 38-47. 2 dorsal fins, the first with 10-12 spines, separated from the second by a large interspace (at least equal to length of first dorsal fin base), the second fin followed by 8 finlets; anal fin followed by 7 finlets; pectoral fins short, 22-25 rays. Inter-pelvic process large and single. Body naked except for the corselet, which is well developed. A strong median keel on each side of caudal peduncle between 2 smaller keels. Bony keels on caudal peduncle vertebrae well developed. Swimbladder absent. Intestine straight, without folds. Right lobe of liver very long, extending the length of the body cavity, left lobe greatly reduced, prominent branches of the hepatic vein present on the ventral surface of the right and middle lobes. Cutaneous artery present but divided into separate dorsal and ventral branches, the ventral branch being very poorly developed. Vertebrae 20 + 19 = 39. Vertebral column with long pedicel or epihaemal process displacing the dorsal aorta ventrally. Colour of back bluish, turning to deep purple or almost black on the head; a pattern of 15 or more dark bars or wavy lines in the scaleless area above lateral line; belly white; pectoral and pelvic fins purple, their inner sides black.
Habitat: epipelagic in inshore waters and near islands. Forms large schools of similar sized individuals. Food: small fishes, especially clupeids; also crustaceans, especially megalops larvae and larval stomatopods; and squids. Reproduction: extended spawning period, November August. Eggs and larvae planktonic.
Distribution: widely distributed in the southern part of the area, except in the Black Sea. Rare north of the Iberian coast. Isolated records from the British Isles and coasts of Belgium and Scandinavia. Elsewhere, cosmopolitan in warm waters.
Species 2; in Clofnam area 1.
Recent revision: Fitch and Roedel (1963).
Species of this genus in the program:
Auxis rochei