Skipjack tuna addition, skipjack's livers were tested globally for tributyltin contamination. TBT is an organotin compound introduced into marine ecosystems through antifouling paint used on ship hulls, and has been determined to be very toxic. About 90% of skipjack tested positive for contamination, especially in Southeast Asia, where regulations of TBT use are less rigorous than in Europe or the US. Skipjack tuna is used extensively in Japanese cuisine, where it is known as . Besides being eaten seared () and raw in sushi and sashimi, it is also smoked and dried to make katsuobushi, the central ingredient in dashi (a common
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 The "Skipjack"-class submarines were withdrawn from service in the late 1980s and early 1990s except for , which sank on 5 June 1968 southwest of the Azores while returning from a Mediterranean deployment,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