Almost 11,000 kilometres. That’s how far one white shark swam while travelling from South Africa to Western Australia, before turning around and returning home.

In the waters off southern Australia, school sharks can cover up to 3,000 kilometres while crossing the Tasman Sea to New Zealand.

Many shark and ray species embark on mammoth migrations. But to protect these species, we need to know not only how far an animal moves, but whether it crosses national borders.

Our new study analysed 30 years of shark and ray movement studies. We uncovered major gaps in our understanding of where these species go during their migrations.

Sharks and rays move for many reasons. These species may travel to find food or give birth to young. They may also migrate to waters where the temperature or salinity levels suit them better.

Body size and maturity also affect how far animals travel – older, larger animals generally travel further. Depth, ocean currents and access to suitable habitat can shape the paths taken by sharks and rays.

These factors influence each species differently. Some species are confined to particular estuaries, while others can cross entire ocean basins.

Whale sharks, for instance, gather seasonally at Ningaloo........

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