Thunnus obesus (Lowe, 1839)

English Name: Bigeye tuna
Family: SCOMBRIDAE
Local Name: Loabodu kanneli
Order: Perciformes
Size: Max. 2.1 m

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Distinctive Characters: Dorsal fins close together. First dorsal with 13- 15 spines, second dorsal and anal fins falcate, each followed by 8-10 finlets. Pectoral fins moderately long in larger specimens (over 1 .1 mfork length). Corselet of large and thicker scales developed but not very distinct. Ventral surface of liver striated; all three lobes of roughly equal in length.

Colour: Dark blue above, pale below. Dorsal and anal fins yellow. Finlets yellow with black edges. Roughly 8-10 near vertical, and more or less continuous pale lines on sides.

Habitat and Biology: Epipelagic and mesopelagic in oceanic waters from the surface to 250 m. Juveniles school with yellowfin and/or skipjack tuna. Feeds on fishes, cephalopods and crustaceans.

Distribution: World-wide in tropical and subtropical oceans.

Remarks: Thunnus ohesus is very similar to and frequently confused with yellowfin tuna (previous page). It differs in having a heavier, thicker-set body and shorter second dorsal and anal fins. The pattern of pale lines on the sides is different. In addition, the liver of yellowfin tuna has one lobe noticeably longer than the other two and is not striated. Bigeye tuna is widespread in the Indian Ocean but is deeper swimming than yeilowfin tuna, so rarely appears in normal Maldivian catches.