The back of the body is blue-black, the belly is silvery white, and the second dorsal fin, anal fin and all the fins are bright yellow, which is the most obvious feature, hence the name yellowfin tuna. It is widely distributed in the tropical and subtropical waters of the three major oceans, approximately in the waters between 40 degrees north and south latitude. The maximum body length can reach 200 cm and the weight can exceed 170 kg. The average body length is about 150 cm. The temperature range for its habitat is between 18 and 31 degrees Celsius, and the optimum water temperature is 19 to 26 degrees Celsius. It mainly inhabits shallow water thermocline and is closer to the surface at night than during the day. Taiwanese people call it yellowfin or yellowfin string. Its scientific name is Thunnus albacares. It is widely distributed in tropical and subtropical waters around the world. It is a shallow-water fish that can be often caught near the coast of Taiwan. It is considered a small fish and is mostly produced in spring and autumn in Taiwan.