Bigeye tuna
Thunnus obesus
- Saltwater
- Vulnerable
Max length98.5 in
Common length70.75 in
Length typeFork Length
Max weight463 lb 0 oz
Depth range0 - 4920 ft
Max age11 years
Water typeSaltwater
Water temperature55 - 84 °F
Fish info
Short description
Bigeye tuna are dark metallic blue on the back and upper sides and white on the lower sides and belly. The first fin on their back is deep yellow, the second dorsal and anal fins are pale yellow, and the finlets are bright yellow with black edges. Bigeye and yellowfin tuna look fairly similar but are distinguished by their noticeably larger eyes (hence the name), length of the anal fin and their finlets have black edges. The pectoral fins are very long, reaching back beyond the start of the second dorsal fin in juveniles and the space between the first and second dorsal fin in adults.
Habitat
They have a greater tolerance to lower temperature and oxygen levels than other tunas, therefore, they tend to occupy deeper waters.
Distribution
Bigeye tuna are found in the open waters of all tropical and temperate oceans, but not in the Mediterranean Sea. They are generally found in more southern waters of Australia's east and west coasts, preferring offshore areas.
Behaviour
Bigeye tuna feed near the top of the food chain, preying on fish, crustaceans and squid. They undertake a distinct diel shift in vertical behavior, generally descending at dawn to deeper, cooler waters and returning to shallower, warmer waters at dusk. During the day they can undertake vertical movements into waters of 300–500 m depth that can be as much as 20 °C cooler than surface waters. Individuals undertake thermoregulatory behavior whilst at depth, periodically returning from deeper, cooler waters to shallower, warmer waters to re-warm.
Edibility
Bigeye tuna is an excellent source of healthy, extra-lean protein and is sought after by Japanese for sushi and sashimi as it has superb eating qualities raw.
Lure suggestion
Tuna respond well to trolled skirted and diving lures. Skirt large and horse ballyhoo with an Ilander lure work well (the blue/white color pattern is popular). Good baits: pilchards, slimy mackerel, yellowtail, rigged mullet and squid.
Similar species
Other similar species
Juvenile Bigeye Tuna are often confused with Yellowfin Tuna of the same size, however, the size of the eye and length of the anal fin separates these species., Other tuna species