Southern Bluefin Tuna Identification Guide

Key identification features

• Large, deep-bodied, torpedo-shaped tuna reaching over 6 feet
• Dark blue-black back fading to a silvery-white belly
• Short pectoral fins, noticeably shorter than the distance to the second dorsal fin
• Small, low first dorsal fin, often yellowish
• Second dorsal and anal fins relatively short compared to yellowfin, colored dusky yellow
• Yellow finlets with narrow black margins running along the back and belly toward the tail

Common look-alikes

• Pacific Bluefin Tuna: nearly identical in shape and range does not overlap much, but Southern Bluefin has a slightly slimmer body and different liver structure used in dockside identification
• Bigeye Tuna: has a larger eye and slightly longer pectoral fins reaching closer to the second dorsal
• Albacore: has very long pectoral fins that extend past the anal fin, far exceeding Southern Bluefin's short fins

Where you'll see one

Southern Bluefin Tuna inhabit cool temperate waters of the Southern Hemisphere, ranging across the southern Indian, Pacific, and Atlantic Oceans, with a single known spawning ground south of Indonesia and broad feeding migrations toward Australia, New Zealand, and South Africa.