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
USS Skipjack (SS-184) until again undergoing overhaul at Mare Island in July and August 1941. "Skipjack" returned on 16 August and commenced patrols off Midway Island, Wake Island, and the Gilbert Islands and Marshall Islands. In October 1941, SubDiv 15 (then commanded by "Sunshine" Murray) was transferred to ComSubAsiatic Fleet, along with the tender "Holland", and Joe Connolly's SubDiv 16, as SubRon 2. When the Japanese attacked Pearl Harbor on 7 December, "Skipjack" was in the Philippines undergoing repairs at the Cavite Navy Yard. On 9 December, "Skipjack" (under the command of Charles L. Freeman) departed Manila on her first war patrol, with