Species: Thunnus thynnus, Bluefin Tuna

Thunnus thynnus (Linnaeus, 1758)

Bluefin Tuna

Body robust, fusiform, moderately compressed; no fatty eyelid; teeth slender, conical; top of tongue with 2 cartilaginous ridges; 34-43 gill rakers; 2 dorsal fins, barely separated, XII-XIV + 13-15, first with prolonged spines anteriorly, giving a strongly concave outline; 2nd dorsal and anal fins not greatly elongated; 8-10 finlets after dorsal fin, 7-9 behind anal fin; pectoral fins very short (<80% of head length); a short, forked bony process between pelvic fins; 1 large + 2 small keels on tail base; tail fin deeply forked; indistinct corselet of larger scales on front of body, small scales cover body behind corselet; lateral line complete.

Back metallic dark blue, becoming silver below; lower sides of freshly caught fish with colorless transverse lines alternating with rows of colorless dots; first dorsal yellowish or bluish, second dorsal reddish brown; anal fin and finlets dusky yellow with dark edges; central keel black in adults.

Size: reaches ~330 cm; 679 kg.

Habitat: oceanic pelagic.

Depth: 0-580 m.

Both sides of the North Atlantic; Labrador to NE Brazil.