| DESCRIPTION |
Bigeye tuna have an enormous range, being distributed throughout all the world’s tropical and subtropical oceans. Bigeye hunt in relatively deep, dark water, preying on animals that associate with the water’s deep scattering layer. Their diet includes squid, fish, and crustaceans. The largest bigeye on record weighed 333 kg, although the average weight of individuals caught is 15-20 kg and cm in length. They are considered to sexually mature at 3-4 years and 100 cm in length, although there is uncertainty about these figures. Little work has been done to determine a validated maximum age for this species; the figure of 5-7 years cited by some industry sources is probably a serious underestimate.
Juvenile bigeye form mixed schools with yellowfin and skipjack tunas. These schools often associate with drifting objects, which makes juvenile bigeye vulnerable to purse seiners using fish aggregating devices (FADs). As bigeye mature, their attraction to floating objects appears to lessen.
Spawning takes place in tropical waters, and young fish migrate into temperate waters as they grow. Bigeye are known to breed in the tropical center of the Pacific and in the northern Indian Ocean. In 2001, management scientists began research to confirm that Atlantic bigeye breed in the Gulf of Guinea, near Ivory Coast.
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