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
USS Skipjack (SSN-585) Atlantic transit. Down in the subsurface calm, the crew were hardly even aware of the turbulence above them. After returning to Norfolk, "Skipjack" conducted several exercises with ASW aircraft flying from air bases in Virginia and North Carolina. In these exercises "Skipjack" played the role of a Russian submarine; ASW forces were to locate, track and conduct simulated attacks against the "Skipjack". During the exercise, "Skipjack" was placed under certain handicaps that would not have been present in normal operations; for instance, she was restricted to a designated operating area measuring 20 miles by 10 miles. Also, at that time,