Bigeye Tuna Fishing Guide

The bigeye tuna (Thunnus obesus) is the most commercially valuable tuna in the sashimi market after bluefin, prized for a higher fat content (particularly in the belly) than yellowfin tuna. The large eyes — largest relative to body size of any tuna — allow bigeye to see effectively at the lower light levels encountered at the considerable depths they regularly inhabit. Bigeye are frequently misidentified as yellowfin at the boat; key differences include a larger head with proportionally bigger eyes, shorter pectoral fins in large adults, and the lack of yellow fin margins. As bigeye mature, they become increasingly deep-water oriented, spending days below 500 feet and moving shallow to feed at night. Most bigeye in US waters are caught incidentally while targeting yellowfin or swordfish.

Bigeye Tuna is a saltwater species.

Habitat

Deep, tropical to temperate offshore waters of all major oceans; more cold-tolerant than yellowfin and found in deeper water, particularly during daylight hours. In US waters, the Atlantic Gulf Stream canyon fishery from Cape Hatteras to New England produces significant bigeye catches, particularly on nighttime swordfish trips.

Diet

Squid, deep-sea fish, and various pelagic prey at depth during the day; mackerel, flying fish, and small tunas near the surface at night. The depth range of bigeye feeding behavior means they encounter a wider variety of prey than surface-oriented tuna species.

Fishing Techniques

Best Seasons

Summer, Fall

Size & Records

Average weight: 100 lbs. World record: 392.6 lbs (Canary Islands, Spain (1996)).