ABSTRACT: Habitat selection processes in highly migratory animals such as sharks and whales are important to understand because they influence patterns of distribution, availability and therefore catch rates. However, spatial strategies remain poorlyunderstood over seasonal scales in most species, including, most notably, the plankton-feeding basking shark Cetorhinus maximus. It was proposed nearly 50 yr ago that this globally distributed species migrates from coastal summer-feeding areas ofthe northeast Atlantic to hibernate during winter in deep water on the bottom of continental-shelf slopes. This view has perpetuated in the literature even though the Œhibernation theory¹ has not been tested directly. We have now tracked basking sharksfor the first time over seasonal scales (1.7 to 6.5 mo) using Œpop-up¹ satellite archival transmitters. We show that they do not hibernate during winter but instead undertake extensive horizontal (up to 3400 km) and vertical (>750 m depth) movements toutilise productive continental-shelf and shelf-edge habitats during summer, autumn and winter. They travel long distances (390 to 460 km) to locate temporally discrete productivity Œhotspots¹ at shelf-break fronts, but at no time were prolonged movementsinto open-ocean regions away from shelf waters observed. Basking sharks have a very broad vertical diving range and can dive beyond the known range of planktivorous whales. Our study suggests this species can exploit shelf and slope-associatedzooplankton communities in mesopelagic (200 to 1000 m) as well as epipelagic habitat (0 to 200 m).