has an almost global amphitemperate distribution, i.e. it is absent from the tropics; in the North Pacific, its niche is assumed by the salmon shark. It is found mostly within 30–70°N and 30–50°S latitudes. In the North Atlantic, the northern limit of its range extends from the Newfoundland Grand Banks off Canada, through southern Greenland, to Scandinavia and Russia; the southern limit of its range extends from New Jersey and Bermuda, through the Azores and Madeira, to Morocco. It is found in the Mediterranean Sea, but not the Black Sea. Normally, North Atlantic sharks only stray as far south as South Carolina and the Gulf of Guinea, but pregnant females from the western North Atlantic population are known to range into the Sargasso Sea, almost as far as Hispaniola, to give birth. In the Southern Hemisphere, the porbeagle apparently occupies a continuous band bound in the south by the Antarctic Convergence, and extending as far north as Chile and Brazil, the Western Cape province of South Africa, Australia to southern Western Australia and southern Queensland, and New Zealand. In New Zealand it is most common south of the Cook Strait. The porbeagle is thought to have colonized the Southern Hemisphere during the Quaternary glaciation (beginning around 2.6 Mya), when the tropical climate zone was much narrower than it is today. Offshore fishing banks are the favored habitat of the porbeagle, though it can be found from a depth of in oceanic basins to littoral (close to shore) waters less than deep, over the entire water column. A single, anomalous record was made of a juvenile in brackish water in Mar Chiquita in Argentina. A tracking study off the British Isles has found substantial variation in the short-term movements of this species, both between and within individuals. Vertical movements tended to increase with water depth and corresponding temperature stratification; in shallow, unstratified waters, sharks either showed no pattern in changing depth or made reverse diel movements, spending the day in shallow water and descending at night. In deeper, stratified waters, the sharks performed a regular diel migration, spending the day below the thermocline and rising towards the surface at night. The porbeagle has been reported across a temperature range of , with most records between . In a study that included 420 porbeagles caught in the northwest Atlantic off Canada, all were in water below and the majority between . Porbeagle