Bluefin tuna are highly migratory, fast swimmers capable of attaining speeds over 90 km / h (Ref. 88852), moving between cooler feeding grounds and warmer spawning areas (Ref. 88823). Trans-Atlantic movements related to feeding have been reported; juveniles originating from the Mediterranean Sea found in foraging grounds in the eastern coast of the USA (88870), conversely, juveniles originating from the western Atlantic have been found in foraging grounds in the central North Atlantic (88868). In the northeastern Pacific, they tend to migrate northward along the coast of Baja California and California, USA from June to September. Off the Pacific coast of Japan they migrate northward in summer and southward during winter. Large fish may enter the Sea of Japan from the south in early summer and move as far north as the Okhotsk Sea, most leave the Sea of Japan through Tsugara Strait, north of Honshu. Variations in the food spectrum are attributed primarily to behavioral differences in feeding: 'vigorous pursuit' would be required on small schooling fishes (anchovies, sauries, hakes) or on squids, while 'modified filter-feeding' is used to feed on red crabs and other less agile organisms (Ref. 168). Preyed upon by killer whales, Orcinus orca; mako sharks and pilot whales, Globicephala melaena. Parasites found were Hirundinella ventricosa, Hysterothylacium adunca, Hysterothylacium incurvum, Hysterothylacium reliquens, Anisakis simplex, Genitocotyle atlantica, Derogenes varicans, Caligus coryphaenae and Rhapidascaris camura (Ref. 5951).