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 shad is necessary to keep turbidity and siltation levels down, as this species will only live in waters that are clear to moderately turbid. Sampling of skipjack shad has been performed through the use of gillnetting and electro fishing. These methods are best utilized beneath impoundments over sand or gravel substrates around spawning time each spring, where they are most abundant. Sampling should be done across the entire native range to document its abundance in different locations and human induced changes. For now, skipjack shad have a stable abundance in the southern part of its distribution, and need more management plans