Skipjack Tuna

The Skipjack Tuna, Katsuwonus pelamis, is a perciform fish in the Scombridae family and the sole member of its genus. It is also known as oceanic bonito or striped tuna. This streamlined, fusiform tuna commonly reaches a fork length of 80 cm (2 ft 7 in) and a mass of 8-10 kg (18-22 lb). Maximum recorded fork length is 108 cm (3 ft 7 in) and maximum mass is 34.5 kg (76 lb). Its body is largely scaleless, except for the lateral line and a corselet, a band of large, thick scales forming a circle around the body behind the head. It typically exhibits a dark purplish-blue dorsal surface, transitioning to silver on the flanks and belly, marked by four to six distinct dark longitudinal stripes along its underside. The common name "skipjack" refers to its habit of leaping clear of the water when chasing prey.

A cosmopolitan pelagic species, Skipjack Tuna inhabits tropical and warm-temperate surface waters, forming large shoals of up to 50,000 individuals. It ranges from the surface down to approximately 260 m (850 ft), though it is primarily observed in the upper 100 m. Divers frequently encounter these fast-swimming fish in open water, often near reef drop-offs or offshore pinnacles. Its diet consists of smaller fish, crustaceans, cephalopods, and molluscs. Skipjack Tuna is a significant prey item for larger pelagic predators, including sharks. With 68% of its total body mass dedicated to skeletal muscle for locomotion, it has the highest percentage among all animals. Lifespan estimates range between 8 and 12 years.

Skipjack Tuna are batch spawners. Spawning occurs year-round in equatorial regions, becoming more seasonal further from the equator. Individuals reach first spawning at a fork length of about 45 cm (18 in). It is the most fecund of the commercially important tunas. The global population is considered sustainable.