How to identify a Bigeye Tuna
The pectoral fins of the bigeye may reach to the second dorsal fin. The second dorsal and anal fins never reach back as far as those of large yellowfin tuna. The bigeye tuna has a total of 23-31 gill rakers on the first arch. The margin of the liver is striated and the two dorsal fins are close-set, the first having 13-14 spines and the second, 14-16 rays. The anal fin has 11-15 rays. On either side of the caudal peduncle there is a strong lateral keel between two small keels that are located slightly farther back on the tail. The scales are small except on the anterior corselet. The vent is oval or teardrop shaped, not round as in the albacore. The first dorsal fin is deep yellow and the second dorsal fin and the anal fin are blackish brown or yellow and may be edged with black. The finlets are bright yellow with narrow black edges. The tail does not have a white trailing edge like that of the albacore. Generally, there are no special markings on the body, but some specimens may have vertical rows of whitish spots on the venter.The bigeye tuna and the yellowfin tuna are similar in many respects, but the bigeye’s second dorsal and anal fins never grow as long as those of the yellowfin. In the bigeye tuna the margin of the liver is striated and the right lobe is about the same size as the left lobe. In the yellowfin tuna the liver is smooth and the right lobe is clearly longer than either the left or the middle lobe.
Where to catch Bigeye Tuna
The bigeye tuna can be found in warm temperate waters of the Atlantic, Pacific, and Indian Oceans. This schooling, pelagic, seasonally migratory species is suspected of making rather extensive migrations. Schools of bigeye tuna generally run deep during the day whereas schools of bluefin, yellowfin, and some other tuna species are known to occasionally swim at the surface, especially in warm water. The following list includes additional details on where to catch this fish: