Green sweet tuna (scientific name: Thunnus tonggol) is a fish belonging to the genus Scombridae and tuna. The general body length is 30-40 cm, the weight is 1.5-2 kg, the larger is 1.4 meters, and the weight is 9-11 kg. Body fusiform; medium-sized head; tip of snout; medium-sized eyes, upper lateral position; 2 nostrils on each side; medium-sized mouth, anterior position, oblique cleft; upper and lower jaws are about the same length; vomer and palate have small dentitions; The gill hole and the back edge of the operculum are round; the body is covered with small round scales, the head has no scales, and the chest scales are extra large, forming a breastplate; the lateral line is complete and wavy; 2 dorsal knots; pectoral fins are longer, longer than the head , Sickle-shaped; pectoral position of the pectoral fin, located just below the base of the pectoral fin; crescent-shaped caudal fin; blue on the dorsal side of the body, lighter abdomen; several light-colored oval patches in the chest and abdomen. The pelvic fin is light-colored, and the remaining fins are black. Economic value: Green sweet tuna is a commercial species with delicious meat and enjoys a high reputation in the international market. In addition to fresh sales, canned and salty dried products can be made, as well as smoked, canned and frozen.

       Nutritional value: ①The content of water, ash, crude protein and crude fat of dry green tuna are 71.13%, 1.56%, 24.56% and 0.63% respectively, which is a high-protein and low-fat food; and the naked flesh of green dry tuna It is rich in mineral elements, and the content of heavy metal elements is lower than the national limit standard. ②The amino acid content of green-dried tuna is relatively high, accounting for 24.36% and 20.84% ??of the fresh quality respectively. The essential amino acid content is rich, and naked meat is a high-quality protein source. ③Green-dried tuna contains rich types of fatty acids, and they are rich in EPA and DHA, which are beneficial to human health, with a total of 32.59% and 28.53%.