ABOVE: © NASA/SVS
When it comes to telling manta rays apart, Asia Armstrong is an expert. The University of Queensland PhD student is studying populations of Mobula alfredi, the reef manta, in the Great Barrier Reef Marine Park off the northeast coast of Australia, and has spent countless hours poring over photos of the fish—snapped by citizen scientists as well as by Armstrong and her colleagues over several decades—with the aim of identifying individuals. “Manta rays have a unique spot pattern on their ventral surface—smudges, dots, stripes,” she explains. In a database of around 1,300 individual animals, “I’d probably recognize half of them now.”
For the past few years, researchers have been working under the assumption that local manta populations are split between two main regions, a northern one and a southern one, separated by hundreds of kilometers. But a video Armstrong received last June from a dive site off ...