Bigeye Tuna
(Thunnus obesus)

Size:
Length - Maximum of approx. 5 – 7 feet
Weight - Maximum of approx. 300 – 400 lbs.

Range:
Bigeye tuna broadly inhabit all tropical and temperate waters worldwide. However, the bigeye tuna does not utilize the productive Mediterranean Sea.

Habitat:
Bigeye tuna regularly forage in colder deeper, oxygen-starved waters. They are known to hunt in waters as cold at 4 degrees Celsius. It is thought that their repetitive diving in these cool waters to over 1500 feet is correlated to the distribution of the organisms on which they prey.

Diet:
These deep-diving predators feed on other finfish, cephalopods, and various crustaceans.

Life History:
Although bigeye tuna are quite similar to yellowfin, they tend to live nearly twice as long. Although their lifespan often exceeds 10 years, the bigeye tuna reaches maturity at just 3 years of age. Often spawning twice per year, females will release between 3 and 6 million eggs per spawn.

Importance to Fisheries and Aquaculture:
While bigeye tuna are less important to the commercial fishing industry than yellowfin, recreational demand for this deep-diving tuna generates great economic benefits in coastal communities through recreational charters, fishing tournaments, and related land-based activities. As bigeye tuna are threatened by overfishing, researchers aim to develop hatchery technologies.

Fun Fact:
Bigeye tuna possess a higher fat content than the yellowfin tuna and all other tropical tuna species. As such, the bigeye tuna is the highest valued of the tropical tuna species in the marketplace.

The largest bigeye tuna recorded was caught in the Canary Islands in 1996. This fish weighed in at 392 lb. 6 oz.