Larger individuals are associated with cooler water bodies, while smaller individuals occur in warmer strata in the Atlantic. Albacore tend to concentrate along thermal discontinuities such as the Transition Zone in the north Pacific and the Kuroshio Front east of Japan because of richer forage organisms but poorer in oxygen content. Albacore migrate within water masses rather than across temperature and oxygen boundaries. Minimum oxygen requirements are probably about 2 ml/l. At least two stocks (northern and southern) are believed to exist in both the Atlantic and the Pacific. Feed during the day and at night (diurnal and nocturnal).The migration pattern of albacore in the south Pacific Ocean has recently been described (Ref. 30272). Juveniles move from the tropics into temperate waters and then eastwards along the subtropical convergence zone. At maturity, albacore return to the tropics but go back to temperate waters after spawning (Ref. 6390).In Australian waters, larvae are present on the North West shelf all summer, but are present off north-eastern Australia mainly between October and December (Ref. 30274). Juveniles are found off New South Wales from September to November, and during summer they follow the warmer waters of the East Australian Current southwards (Ref. 6390). Albacore may reach eastern Tasmanian waters by December, where they remain until about April (Ref. 6390). As autumn approaches and warm waters recede, the juveniles move northwards and are present again off New South Wales until May (Ref. 30278). Adult albacore travel in independent, small groups (Ref. 30273), and are common throughout much of the species' range (Ref. 6390). Also Ref. 26132.