Skipjack tuna important prey species for sharks and large pelagic fishes and is often used as live bait when fishing for Marlin. It has no scales, except on the lateral line and the corselet (a band of large, thick scales forming a circle around the body behind the head). It commonly reaches fork lengths up to and a weight of . Its maximum fork length is and maximum weight is . Ageing skipjack tuna is difficult, and the estimates of its potential lifespan range between 8 and 12 years. Skipjack tuna is a batch spawner. Spawning occurs year-round in equatorial waters, but
Skipjack-class submarine the increased size of the "Thresher" and "Sturgeon" classes, which retained "Skipjack"s S5W power plant, plus the introduction of the "skewback" screw, which was quiet but mechanically inefficient. The "Skipjack"s saw service during the Vietnam War and most of the Cold War. The "Skipjack"-class submarines were withdrawn from service in the late 1980s and early 1990s except for , which sank on 5 June 1968 southwest of the Azores while returning from a Mediterranean deployment, with all 99 crewmembers lost. The gap in the hull-number sequence was taken by the two one-of-a-kind submarines and . Skipjack-class submarine The "Skipjack" class