Skipjack Tuna, Katsuwonus pelamis (Linnaeus 1758)
A Skipjack Tuna, Katsuwonus pelamis, caught off Okinawa, Japan. Source: Krw130lm. License: CC by Attribution-Share Alike 3.0 Unported
A medium-sized metallic blue to purple tuna becoming silvery below, with 4-6 dark wavy broken stripes on the lower sides, a strong median keel on the caudal-fin base between two small keels, first and second dorsal fins very close together and followed by 7-9 finlets.
This the smallest and most abundant of the major commercial tuna species, supplying about 50% of Australia's canned tuna used for domestic consumption. Skipjack Tuna form large schools near the surface and are often seen in feeding frenzies involving birds, sharks and larger tunas.
Skipjack Tuna, Katsuwonus pelamis (Linnaeus 1758)
More Info
Distribution |
Found in all Australian states and territories, absent from Gulf of Carpentaria. Elsewhere, circumglobal in tropical seas, and along the oceanic coast of Europe and throughout the North Sea; absent from the Mediterranean and Black Seas. |
Features |
Meristic features: Dorsal fin XIV-XVI, 0, 0, 14-15; Anal fin 14-15; Pectoral fin 26-27; Gill rakers 53-63. First and second dorsal fin close together, never more than eye width apart. Pectoral-fin tips do not reach space between first and second dorsal fins. Second dorsal and anal fins followed by 7-9 and 7-8 finlets, respectively. Body fusiform, elongate and rounded. Small conical teeth forming a single series. Body naked except for corselet and lateral line. Caudal peduncle with well developed keel, flanked on each side by a smaller keel. Swim bladder absent. |
Size |
To at least 110 cm and 35 kg. |
Colour |
Dark metallic blue above, sides and belly silvery. Four to six dark stripes along belly and lower sides. |
Feeding |
Carnivore - feeds on fishes, crustaceans and cephalopods. A highly opportunistic predator that feeds primarily at dawn and dusk. Skipjack tuna are an important prey species for larger pelagic fishes and sharks. |
Biology |
Matures at around 45 cm fork length (FL). Fecundity increases with size, with a female of 87 cm FL producing up to 2 million eggs over a number of batch spawnings. Different fish stocks mature at different sizes, and also vary in fecundity at a given size. Spawning occurs year round in tropical waters, but the spawning season is restricted to the summer in non-tropical waters. Known to live to least 12 years of age. |
Fisheries |
Skipjack Tuna are mostly fished between December and March with purse seines and some pole and line fishers. Australia supplies about 50% of the World's canned Skipjack Tuna and the fishery is closely monitored. Daily catch limits apply only to recreational anglers in Tasmania, the Northern Territory and Victoria. No bag limits for Skipjack Tuna apply to recreational anglers in New South Wales, Queensland, Western Australia or South Australia. |
Remarks |
Like many other tunas, Skipjack Tuna have a specialised heat exchange system that allows them to maintain their body temperatures above that of the surrounding water. |
Species Citation |
Scomber pelamis 1758, Systema Naturae, 10(1): 297. Type locality: Pelagic, between the tropics ("in Pelago inter Tropicos"). |
Author |
Schultz, S. |
Skipjack Tuna, Katsuwonus pelamis (Linnaeus 1758)
References
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