About This Fish

Longtail Tuna


The longtail tuna (Thunnus tonggol) is a ray finned fish which belongs to family Scombridae under Order Perciformes of Class Actinopterygii. It is also known as Blue-fin tuna, Indian long-tailed tuna, Northern bluefin tuna, and oriental bonito. The longtail tuna occurs mainly in the Indo-West Pacific Ocean, including the Red Sea, around the Arabian Peninsula, off the coast of East Africa across to the coast of New Guinea, north to the waters around Japan, and south to the coast of Australia.



The longtail tuna’s body is elongated, fusiform and slightly compressed. The longtail tuna is dark blue to black dorsally with silvery white belly and lower side. Colorless oval spots are found which are arranged horizontally along the belly. The dorsal, pectoral and pelvic fins are blackish while the tip of the second dorsal and anal fins is washed with yellow. The anal fin is silvery while the dorsal and anal finlets are yellow with grayish margins. The caudal fin is blackish with streaks of yellow green. The second dorsal fin is higher than first dorsal fin. The first dorsal fin has 12-15 spines and second dorsal fin with 14 -15 soft rays which is followed by 8 -9 finlets. Anal fin contains 13 - 14 rays which are followed by 8-9 finlets. Pectoral fin is short to moderately long and interpelvic process is small and bifid. Body is covered with very small scales and caudal peduncle is very slender which bears a strong lateral keel between 2 smaller keels on each side. It is an opportunistic predator which consumes a wide variety of prey items including various pelagic and damersal fish, squid, and small crustaceans. The longtail tuna reaches sexual maturity at lengths of around 60-70 cm. The longtail tuna breeds during the summer with a typical spawning period lasting five to seven months. It grows up to 145 cm in length and 49 kg in weight.


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Northern Territory