Integrating migratory marine connectivity into shark conservation

Understanding migratory connectivity is important for the conservation of highly mobile marine species facing escalating threats. Establishing baseline information on migratory connectivity is important to identify species and regions requiring transboundary cooperation for their conservation. Despite efforts to track migratory sharks and rays, information on transboundary movements is limited and often inaccessible to managers and policymakers. Here, we synthesised multimethod movement data for Australian shark and ray species listed under the Convention on Migratory Species (CMS), investigating which species require international engagement to support their population recovery. Based on data from a systematic literature review, we built connectivity networks from telemetry and mark-recapture studies that provide a first transboundary connectivity baseline for Australian sharks and rays. Of the 29 CMS-listed shark and ray species reviewed, we identified 5 species linking the Australian Exclusive Economic Zone to other national jurisdictions via multispecies migratory connections through the Tasman Sea to New Zealand, through the Tasman and Coral Sea to New Caledonia, and north across the Timor Sea and Torres Strait. White sharks ( Carcharhinus carcharias ) and whale sharks ( Rhincodon typus ) were the most data rich, while 18 (62%) of species had no movement information. Of note, nearly two-thirds of Endangered or Critically Endangered migratory shark and rays had only one or no published studies. We also show the applicability of this framework to support (or not) listing of migratory species under CMS. We demonstrate that migratory connectivity baselines can support international reporting, direct international collaboration, and focus research efforts on critical knowledge gaps.