The Skipjack Tuna is a medium-sized perciform fish in the tuna family of mackerels, Scombridae. It congregates in shoals of up to 50 000. It is otherwise known as the striped tuna, stripies, aku, arctic bonito, mushmouth, oceanic bonito, striped tuna, or victor fish.
It has scales, grows up to 1m in length and can grow to a wieght of 18kg. It is a streamlined, fast-swimming pelagic fish, common in tropical waters, where it inhabits surface waters. It feeds on fish, crustaceans, cephalopods and mollusks, and is an important prey species for large pelagic fishes and sharks.
The Skipjack is one of five varieties of tuna that has been harvested for centuries. Skipjack swim along the edges of warm underwater streams in search of food.
It is dark blue or purple on the back and silvery on its lower sides and belly. It has three to five prominent, dark longitudinal bands on its lower sides. It has fine, slender teeth, a strong median keel on the caudal fin base between two small keels, and barely separated first and second dorsal fins.
The global distribution of Skipjack Tuna includes all tropical and subtropical waters except for the eastern Mediterranean Sea and the Black Sea. It normally inhabits waters with surface temperatures of 20 to 30 °C. However, adults are sometimes present waters as cold as 15 °C. The Skipjack's depth range can be from surface waters to 260m during the day, but at night it is much shallower.
In tropical waters, reproductively active female Skipjack Tuna spawn almost daily. Ripe Skipjack eggs are about 1mm in diameter and transparent and buoyant. Estimates of the number of eggs released at each spawning range from about 100 000 eggs for the smallest mature females to 2-million for the largest fish. Skipjack eggs hatch after 1 to 1,5 days.