Marine megavertebrate migrations connect the global ocean

Animal migrations are extensive, ubiquitous, and in decline. To effectively protect migratory species, it is often crucial to identify the interconnected sets of sites they rely upon. Gaps between primary ecological research and synthesised information that is useful to policymakers has limited effective conservation of long-distance migrants, particularly in the marine realm. By synthesising 1304 references to identify 1787 sites and develop model migratory networks for 109 species, we show the minimum extent of marine megafauna connectivity across the global oceans. Our analyses underscore the importance of transboundary cooperation for migratory species conservation at scales larger than current regional structures afford and provide a free online system that will enable policymakers to efficiently summarise how marine migrants use and connect their jurisdictions.