What Are the Main Sources of Tuna? A Complete Guide

Tuna has delicious, tender flesh and is rich in protein, minerals, vitamins and other nutrients, making it a highly praised healthy food today. So what are the sources of tuna?

1. Tuna Origins

Tuna is distributed throughout the world's tropical and temperate sea areas (between 40° north and south latitude), with the densest concentration in waters near the equator. In China, tuna origins are distributed in the Xisha, Zhongsha and Nansha Islands of the South China Sea, as well as the East China Sea.

2. Tuna Species

1. Yellowfin tuna: The body is spindle-shaped, slightly laterally compressed, with a small head, a long and slender tail, and pink flesh. The back is blue-green, the sides are light gray with a touch of yellow and dotted horizontal bands, and in adult fish the second dorsal fin, anal fin and the small fins behind them are all bright yellow. Yellowfin tuna is widely distributed in the equatorial waters of the three major oceans and is a representative species of tropical sea areas.

2. Bluefin tuna: The largest species among tunas, also known as blackfin tuna. The body is short and sturdy, with a conical, slender build and a forked caudal fin; the color from the belly to the sides is bright, the upper body is dark blue, the fins are dark, the small fins are slightly yellow, and the raised ridge of the caudal peduncle is black. It inhabits water layers from the surface down to 50 m, with an optimum water temperature of 10-20°C, and feeds mainly on herring, sardines, mackerel, squid and crustaceans.

3. Bigeye tuna: Also known as fat tuna and obeastuna, with a body length of about 1.5-2.0 m and a body weight of more than 100 kg in large individuals, generally 160-350 kg. The back is blue-green, and the sides and belly are silvery white. The flesh is pink and slightly soft. The pectoral fins are long, with very prominent tips reaching below the second dorsal fin; the second dorsal fin is also relatively narrow and similar in height to the first dorsal fin. The body is gray, plump, with a short tail, and a noticeably larger head and eyes. Bigeye tuna inhabits deeper water, down to 200-300 m, while sexually mature individuals inhabit the surface layer.

4. Albacore tuna: The back is dark blue, and the sides and flanks are silvery white, with uniform body color. The body length is 1-1.5 m, and the body weight is about 15 kg. Large individuals can reach 45 kg. The flesh is pink, and the pectoral fins are sword-shaped and extremely long, longer than the head, which is the most distinctive feature of this species. Albacore tuna is mainly distributed in the 90-150 m water layer during the day, sometimes deeper at 150-200 m, and near the surface in the evening. The suitable temperature range for albacore tuna is 14-20°C. It feeds mainly on sardines and crustaceans.

5. Skipjack tuna: Also known as true bonito, cigarette fish, small string, dried bonito and cigarette tiger, it is one of the species in the Scombridae family, suborder Scombroidei, order Perciformes, class Actinopterygii. It is distributed in warm waters of the world's major oceans. The body length is 40-70 cm. The maximum body length can reach 111 cm. The maximum body weight can reach 34.5 kg. The body is spindle-shaped, laterally compressed, with a dark back, white belly, and 4-10 or more dark blue longitudinal lines, a pointed snout, and mostly no scales. It lives in temperate and tropical waters and has seasonal migrations. It is an important food fish, mostly used for sashimi (raw fish slices) and fish floss.

There are many varieties of tuna, and they are also very nutritious, suitable for middle-aged and elderly people to eat. If conditions allow, you can eat a little more.