Northern Blue-Fin Tuna

Fact File:

Common Name(s): Northern Blue-Fin Tuna or Tunny

Scientific Name: Thunnus thynnus  (Linnaeus, 1758)

Usual Size:Over 300cm - although usual to 200cm

UK Record Weights from rod/line:



MAFF Minimum Size: Shore: Boat:

Largest of all the tuna species. Swim bladder present. Typical tunny shape and deep set from the middle of the first dorsal. Colour: Lower sides and belly silvery white with colourless transverse lines alternated with rows of colourless dots (these are more prevalent in adult fish and only visible on fresh fish - they dissipate on death). First dorsal fin yellow or bluish, second reddish-brown, anal fin and finlets dusky yellow and black edging. The keel is black in adult fish. Pectoral fin doesn't extend beyond the first dorsal.

Egg dispersal. Females attain maturing at the age of 4 to 5 years and this equates to a weight of between 270 to 300kg and may produce upwards of 10 million eggs per season

These are the most water tolerant of all the tuna species, and will tolerate waters of between 10/250C, and they are not known to migrate into a water mass of below 100C. Mainly an offshore species, although in the times of their fast feeding migrations are known to come occasionally inshore.

Small schooling fishes and squids, although they have an ability to eat crabs, and are known to be partial to Salmon, though mainly feeds on Herring, Scad and Mackerel.

In the Eastern Atlantic from The British Isles and North Sea down south to Canary Islands.

Additional Notes:
Historically known in the North Sea and still migrates around Western Ireland to Northern waters. Can exceed 1200lbs.


FAO Species Catalogue 2 - Scombrids of The World - Collette/Nauen

Fishes of the North-Eastern Atlantic and the Mediterranean - Whitehead, Bauchot, Hureau, Nielsen, Tortonese

Key to the Fishes of Northern Europe - Wheeler

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