Atlantic Bluefin Tuna Identification Guide
Identify the Atlantic bluefin tuna by its massive muscular body, short pectoral fins, and black-edged yellow finlets.
Read the full Atlantic Bluefin Tuna encyclopedia entry →
Key identification features
- Massive, torpedo-shaped, heavily muscled body, exceeding 10 feet (3 m) in large adults
- Short, pointed pectoral fins that do not reach past the first dorsal fin
- Two dorsal fins, the first foldable into a body groove
- Row of yellow finlets edged in black along the back and belly near the tail
- Dark blue-black back fading to a silvery-white belly, with a stout caudal keel
Common look-alikes
- Bigeye tuna has a noticeably larger eye, pectoral fins that reach farther back, and finlets that are plain yellow without the black edging.
- Yellowfin tuna shows dramatically longer, sickle-shaped second dorsal and anal fins and a more slender body than the stockier bluefin.
- Albacore has very long pectoral fins that extend well past the second dorsal fin, unlike the bluefin's short, stubby pectorals.
Where you'll see one
Atlantic bluefin tuna range through open temperate and subtropical waters of the North Atlantic and Mediterranean Sea, undertaking extensive transoceanic migrations between spawning grounds and rich feeding areas. They are typically found well offshore in open water rather than near coastlines.
Frequently asked questions
How do I tell an Atlantic bluefin tuna from a yellowfin tuna?
Look at the fins: bluefin have short, stubby pectoral fins and modestly sized dorsal/anal fins, while yellowfin have dramatically longer, sickle-shaped second dorsal and anal fins.
What fin marking helps confirm a bluefin tuna identification?
A row of yellow finlets edged in black running along the back and belly toward the tail is a reliable field mark for bluefin tuna.