Thunnus atlanticus

Common Name

Blackfin Tuna

Year Described

Lesson, 1831


Dorsal Fin: XIII-XIV, 12-16, followed by 7-9 finlets
Anal Fin: 11-16, followed by 6-8 finlets
Pectoral Fin: 31-35
Gill Rakers: 19-28 (on first arch)
Vertebrae: 39

Body fusiform, robust, and oval in cross-section. Snout about twice eye diameter. Adipose eyelid absent. Jaw extends to anterior half of orbit. Teeth small and conical. Two interpelvic processes; shorter than pelvic fins. Dorsal fins separated by a very small gap. Spiny dorsal fin long, with a strongly concave margin. Second dorsal and anal fin small with tall anterior lobes. Pectoral fins long (extend to second dorsal fin origin but never beyond rearmost ray). Caudal fin semilunate. Corselet not obvious but present. Body covered in very small scales. Two small caudal keels with a larger median keel in between them. No striations on liver; right lobe longer than others.


Body silvery-gray with an abruptly blue-black back and a white belly. Sometimes with faint vertical white lines and spots on lower body. Upper fins and tail dusky to dull yellowish. Lower fins pale.


Maximum size to 100cm FL. Common to around 70cm FL.


Epipelagic in oceanic waters. Forms large schools.


New England to S. Brazil, including the Gulf of Mexico and the Caribbean Sea.


Collette, B.B. 2002. Scombridae (pp 1836-1857). In: Carpenter. 2002. The living marine resources of the Western Central Atlantic. Vol. 3: Bony fishes part 2 (Opistognathidae to Molidae), sea turtles and sea mammals. FAO Species Identification Guides for Fisheries Purposes. American Society of Ichthyologists and Herpetologists Special Publication No. 5.

McEachran, J.D. and J.D. Fechhelm. 2005. Fishes of the Gulf of Mexico. Volume 2: Scorpaeniformes to Tetraodontiformes. University of Texas Press, Austin. i-viii +1-1004.