Thunnus obesus

Author: (Lowe, 1839)

Thunnus obesus (Lowe, 1839)

Status in World Register of Marine Species:
Accepted name: Thunnus obesus (Lowe, 1839) (updated 2009-06-25)

Diagnosis: a large species with robust, fusiform body, slightly compressed from side to side. Gillrakers 23-31 on first arch. Pectoral fins moderately long (22-31% of fork length) in large specimens (over 110 cm fork length), but very long (as long as in T. alalunga) in smaller specimens. Ventral surface of liver striated. Colour: first dorsal fin deep yellow, second dorsal and anal fins light yellow, finlets bright yellow edged with black. Size: 239 cm fork length (max.), 197 kg, common to 180 cm.

Habitat: epipelagic and mesopelagic in warm seas, generally below the thermocline to depths of 250 m. Schooling and migratory. Food: a wide variety of fishes, squids, and crustaceans. Reproduction: spawning period extended, perhaps year round in equatorial waters. Eggs and larvae planktonic.

Distribution: regularly taken around the Canaries, Madeira and the Azores. More or less numerous in the Bay of Spain and a few isolated catches in the Bay of Biscay. The northernmost record, from Concarneau in the Gulf of Gascogne, needs confirmation. Unknown from the Mediterranean Sea. Elsewhere, cosmopolitan in warm waters.

Eggs, larvae and young stages. Zhudova (transl. Klawe), 1969 (1970): 3, fig. 3 (larva).
Otoliths (sagitta). Fitch and Craig, 1964: 204.