Euthynnus lineatus, the black skipjack tuna or black skipjack, is a species of ray-finned bony fish in the family Scombridae. It belongs to the tribe Thunnini, better known as the .
Description
E. lineatus has a total of 10-15 spines in its
with the anterior spines of the first dorsal fin being much taller than the middle spines which gives this fin a concave outline. The
anal fin has 11 - 12 soft rays and it has a vertebra count of 37. Its body is almost entirely scaleless except for the
lateral line and a "corselet", and there is no
swim bladder. It is generally iridescent blue in colour with black markings on its back made up of 3 to 5 horizontal stripes, as well as a variable amount of black or dark grey spots above the
pelvic fins. Occasional specimens have extensive longitudinal stripes of light grey on their belly while other individuals have few or no such markings.
After death, the lines are often no longer prominent, but can still be distinguished by the 2 or more spots over the pelvic fins.
E. lineatus can reach up to and a weight up to .
Distribution
Eastern tropical Pacific from San Simeon,
California to northern
Peru and the Galápagos Islands.
Fisheries
No targeted fishery exists for this species, though it is
Incidental catch in the course of other fishery operations.
[ Like the closely related little tunny, its meat is regarded as subpar due to it being very bloody and red, and is often thrown back.
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Biology
E. lineatus is a Pelagic fish and oceanodromous species which is rarely recorded where the surface temperature falls below . The larvae are most commonly found at temperatures higher than . It is generally distributed in surface waters which are no more than from land. E. lineatus will form multi-species schools other Scombridae like the yellowfin tuna and skipjack tuna. It shows opportunistic predatory behavior, sharing its feeding pattern with other tunas, as well as dolphins and other large predatory fish, with which it also competes.[ Like other , the fish breaths through ram ventilation, so it must continue swimming to intake oxygen.
]
The spawning of this species has a wide geographical and temporal distribution, and in the eastern tropical Pacific it has been shown to occur over a wide area from coastal to oceanic waters.[
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