What’s that fish – Longfin Tuna

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Thunnus alalunga go by a few names, including Longfin tuna, ‘White Tuna’, ‘Binnaga’, ‘Tombo Ahi’, ‘German Bonito’, and perhaps most popularly, especially abroad, Albacore.

Feisty, strong, fast, tough, are all among the adjectives that we’ve come to associate with the tuna family, and Longfin certainly live up to the family reputation. Although not as prized as their larger yellowfinned cousin, Longfin are a formidable opponent to big game anglers and are very tasty as well – targeted by commercial fishers the world over.

Longfin are similar in appearance to other tuna in that they share that distinct and compact ‘torpedo’ shape that allow them to propel through water at spectacular speeds, powered by a strong tailfin.

What distinguishes it from other tuna, however, is also what gives it its name – its long pectoral fin The pectoral fi n is remarkably long and extends well beyond the front of the anal fin. Though the very long pectoral fi ns readily distinguish adult Longfin from other adult tunas, it should be noted that juvenile Longfi n might have shorter pectoral fi ns than similar sized Yellowfin tuna or Bigeye tuna. However, the Longfin can be differentiated from these species at any age by the lack of stripes or spots on its lower flanks and belly and by the presence of a thin, white trailing edge on the margin of the tail fin.

Also, the deepest part of the Longfin’s body is near the second dorsal fin, rather than near the middle of the first dorsal fin as in other tuna. As with other tuna Longfi n generally have a dark blue hue dorsally which fades to a silvery white on the belly area, while the liver is striated on the ventral surface.

The Longfin is a pelagic and migratory fi sh, found throughout the world’s tropical and temperate waters, including the Mediterranean Sea. In South Africa they are mostly found some distance off Cape Point, typically about 30 nm.

After spawning, Longfin grow quite quickly but they remain in the area where they were born for the fi rst year of their lives after which they begin to migrate. They have an expected lifespan of about 10 to 12 years and they reach reproductive maturity at around fi ve or six years of age. Size of Longfin usually ranges between 60 cm and 1.5 m, the bigger specimens weighing in at about 20 – 30 kg with some record catches reaching as much as 40 kg. The IGFA (International Game Fishing Association) All-Tackle record currently still belongs to one Siegfried Dickemann who caught his prize fi sh in Gran Canaria in the Canary Islands in 1977, landing a 39.97 kg fish.


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