In a remote archipelago off Australia’s Top End, scientists and Indigenous rangers are collaborating to gather knowledge about the region’s large marine animals, which are thought to be in decline. Story and photography by DAVID HANCOCK, narrated by HANNAH HARMS.

As part of the Ultramarine project we are diving into our archives and republishing some paid content for free. This audio content was created from a story originally published in issue 97 of Cosmos print magazine, in December 2022. You can read more amazing long reads if you subscribe now.