iki jime Fish Finder
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Also known as:

Northern Bluefin

Northern Bluefin Tuna


Common Group Name:

Mackerels and Tunas

Family Name:


Genus Name:


Species Name:

Thunnus tonggol

Dispatch Method:

The eating qualities of longtail tuna can be greatly improved if they are killed immediately by iki jime before placing them in an ice slurry after bleeding. A firm knock on the head may be required to stun larger fish first before attempting iki jime.

Fish Description:

  • Longtail Tuna are a smaller tuna species with a relatively long slender tail.
  • The upper surface is bluish/black while the lower sides and belly are silvery white with colorless oval spots. The anal fin and dorsal and anal finlets are yellow.
  • This species forms schools of varying size. Large schools of smaller fish around 6 kg occur in tropical regions while smaller schools of larger fish (1+ meter, 15+ kg) tend to forage in cooler waters.
  • This species matures at 60-70 cm fork length at 3-4 years old and spawning occurs when water temperatures exceed 24°C. They are relatively slow growing for a tuna and fish over 1 meter long may be up to 20 years old.
  • They feed mostly during daylight hours on smaller fishes, usually selectively feeding on small pelagic fishes like anchovies, sprats and sardines.

Fish Distribution:

  • Longtail tuna are a highly migratory species which can be found throughout the tropical and sub-tropical waters of the Indo-West Pacific from the red Sea to Japan and as far south as northern New Zealand.
  • In Australia they can be found offshore as well as anywhere throughout the inshore coastal waters of tropical Australia as far south as the south coasts of NSW and WA.
  • They do, however, tend to avoid very turbid waters and areas with reduced salinity.

Fish Size Common Length:

60-100 cm (24-40 inches), maximum size around 150 cm (5 feet) and 36 kg (80 lb). World record 35.9 kg (79 lb) from Montague Island, Australia.