Pelagic fish Atlantic Ocean, the Gulf of Mexico and the Mediterranean Sea. The term highly migratory species (HMS) is a legal term which has its origins in Article 64 of the United Nations Convention on the Law of the Sea (UNCLOS). The highly migratory species include: tuna and tuna-like species (albacore, Atlantic bluefin, bigeye tuna, skipjack, yellowfin, blackfin, little tunny, Pacific bluefin, southern bluefin and bullet), pomfret, marlin, sailfish, swordfish, saury and oceangoing sharks, dolphins and other cetaceans. Essentially, highly migratory species coincide with the larger of the "large pelagic fish", discussed in the previous section, if cetaceans are added and some
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 The "Skipjack"-class submarines were withdrawn from service in the late 1980s and early 1990s except for , which sank on 5 June 1968 southwest of the Azores while returning from a Mediterranean deployment,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