Species: Thunnus obesus, Bigeye Tuna

Thunnus obesus (Lowe, 1839)

Bigeye Tuna

Body elongate, fusiform, deep, deepest under center of first dorsal base, moderately compressed; eye large; no fatty eyelid; teeth slender, conical; top of tongue with 2 cartilaginous ridges; 23-31 gill rakers; 2 dorsal fins, barely separated; 1st dorsal XIII-XV; 8-9 finlets after dorsal and anal fins; 2nd dorsal and anal fin without long front lobes; pectoral fins moderately long, in juveniles tip is pointed down and fin reaches past 2nd dorsal front lobe, reaches 2nd dorsal lobe in adult; short, forked bony process between pelvic fins; 1 large + 2 small keels on tail base; tail fin deeply forked; indistinct scaly corselet on front of body, small scales cover body behind corselet; lateral line complete.

Back metallic dark blue, lower sides and belly whitish; a lateral iridescent blue band running along sides of live fish; juveniles with wide, continuous white bars on rear half of body, larger fish without bars; first dorsal fin yellow; second dorsal and anal fins pale yellow; finlets bright yellow, edged with black; tail dark grey, no white rear border.

Maximum size, 250 cm; all-tackle world record 197.3 kg.

Habitat: oceanic pelagic.

Depth: 0-1800 m.

Circumglobal in tropical and temperate seas; Canada to Argentina.