Giant manta rays (Mobula birostris) are some of the most iconic fish in the ocean. Their pectoral fins, which look a lot like wings as they swim, can reach nine meters from tip to tip. These gentle giants have few natural predators, but overfishing has landed the species on the International Union for Conversation of Nature’s (IUCN) endangered species list. Females take 10 to 15 years to become sexually mature and then only breed every few years, producing one pup at a time, so population recovery is quite slow. In order to better protect the species, scientists need to know more about their behavior, data that can be difficult to collect given the great distances the fish regularly travel.
A study published this week in PeerJ revealed that the waters of Komodo National Park off the coast of Indonesia—where it has been illegal to fish for manta rays since 2013—are home to a large aggregation of these manta rays. Researchers were able to identify more than 1,000 individuals thanks to diving photos from scientists as well as tourists. The patterning on the underside of a manta ray is as distinct as a fingerprint, allowing the scientists to comb through thousands of such images and get more information about each ray’s movement and behavior. They were able to identify common locations for feeding and mating, which can inform guidelines to better protect them from human impact.