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 (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