English: Tongol (longtail tuna)
Latin: Thunnus tonggol
Size + Weight:  Average today abt 90 cm abt 15-20 kg
Biggest Angled Fish:  35,7 kgs Australia, 1982 Tim Simpson
Catching Areas:  65% Western Pacific, 35% Indian Ocean 
Catching Methods:  Mostly pole and line, Long Lines
Share of all Tuna Caught:  About 4 % or 125.000 m/t
Main Production Areas: Thailand, Indonesia
Major Markets:  United Sates
Popular Product Forms:  Canned (Light Tuna), FreshTongol or mostly popular for canning purposes. It is a very seasonal fish caught mostly by small vessels in the waters along the Malay and Burmese coast. Also around the Indonesian archipelago there are local catches. Product characteristics: The meat is quite tender and has an almost white color. It has not too much taste. It is by some more appreciated as a canned product then the somewhat drier albacore meat.

Future Supply: There is limited data available on the volume of the catch, and the status of the current stocks. One reason is that Tongol is mainly caught by small local vessels, which makes monitoring difficult. The general feeling is that tongol catches could increase slightly and still maintain a sustainable level. Availability tends to be very seasonal, and restricted to mainly Indonesia and Thailand.

Habitat :
The Tonggol tuna (also known as the long tail tuna) is an epipelagic, predominantly neritic species and are known to avoid very turbid waters and areas with reduced salinity such as estuaries. Long tail tuna may form schools of varying sizes.
Distinctive Features:
The Tonggol tuna is one of the smaller tuna species; the body is at its deepest near the middle of the first dorsal fin base. The second dorsal fin is longer than the first dorsal fin. The pectoral fins are short to moderately long in comparison to other species; the swim bladder is absent or rudimentary.

The lower sides and the belly of tonggol tuna are silvery white with colorless elongate oval spots arranged in horizontally oriented rows. The dorsal, pectoral and pelvic fins have a blackish color, the tip of the second dorsal and the anal fins have a washed yellow color; the anal fin is silvery; the dorsal and anal finlets are yellow with grayish margins; the caudal fin is blackish with streaks of yellowish green.
Size, Age, and Growth :
The maximum fork length of a Tonggol tuna is about 130 cm. In the Indian Ocean common fork lengths range between 40 and 70 cm. The all tackle angling record is a 35.9 kg fish of 136 cm fork length taken at Montagne Island, New South Wales, Australia in 1982.
Long tail tuna are yet another important species of which there is still very little known about the biology. It is known that they will reach a fork length of about 38 cm at the age of two, around 51 cm by the age of three, and with mature fishes being over 60 cm. Very little is known about the spawning habits of long tail tuna, but in some parts of the world there are two distinct breeding seasons.
The thunnus tonggol is currently not listed as an endangered species in the database of IUCN.