Learn to distinguish between tuna species with this handy guide.
Nick Honachefsky
It can be very difficult to tell the difference between the bigeye and yellowfin tuna. The second dorsal and anal fin on a bigeye do not reach back as far as a large yellowfin tuna. The best way to tell the difference, however, is to look at the liver, which in a bigeye is striated. A yellowfin's liver is smooth. Bigeye grow to more than 400 pounds
The blackfin tuna is favorite target for light-tackle anglers from the Carolinas to Brazil. Blackfin are abundant off of south Florida, especially in the Keys where they are caught on trolled baits and lures. Commonly caught in the 20-pound range, blackfin do reach up to 40-plus pounds. The pectoral fins do not extend beyond the second dorsal fin.
Ranging in size from a few pounds to the 1,500-pound plus giant bluefin, tunas represent some of the top-fighting (and tasting) fish in the ocean. This identifier pinpoints the key characteristics of each species of tuna.
Called by many different names such as bonito and false albacore, the little tunny is the most abundant tuna in the Atlantic because it is not a valuable table fish. A favorite target for fly-fishermen because of their speed and power, this species also makes a terrific live bait for marlin and larger tuna. The broken, wavy stripes above the lateral line are its most distinguishing characteristic.
The dogtooth prefers to hunt along reef edges and structure in the Indo-Pacific region. Targeted with swimming lures and high-speed jigs, the dogtooth is a proven fighter and highly sought-after game fish. The dogtooth is noted for its wavy lateral line, lacking scales and large conical teeth.
The skipjack tuna is distinguished by the dark stripes on its belly and absence of markings on its back. It's a valuable commercial species and sold as canned "chunk light" tuna. It's also one of the most preferred live baits for heavy-tackle offshore anglers targeting marlin. It's silvery belly is also used to make strip baits.
The yellowfin tuna is a perennial favorite with big-game fishermen for its fight, beauty and delectable meat. Capable of reaching more than 420 pounds, the pectoral fins in a large yellowfin may reach more than halfway back to the tail in a crescent shape. It's also one of the more colorful tuna, with golden yellow fin tips.
