Tourists scuba diving and snorkeling in the Maldives frequently take underwater pictures of the spectacular and docile whale shark, they said, and these publicly sourced photographs are suitable for use in conservation work.
Individual sharks can be identified by distinctive patterns of spots behind the gills, a unique marking serves as a "fingerprint" to tell the animals apart.
UCL researcher Tim Davies compared results using tourist images downloaded from image-sharing websites such as Flickr and YouTube with results based on surveys by marine researchers specifically aiming to track the sharks.
Individual whale sharks could be successfully identified in 85 percent of the vacation photos, he said.
"Globally, this outcome provides strong support for the scientific use of photographs taken by tourists for whale shark monitoring," Davies said in a university release Friday.
"Hopefully, this will give whale shark research around the world confidence in using this source of free data."
Although widely thought to be threatened or at least rare, the conservation status of the whale shark has long remained uncertain.
"Hopefully, as more data come in from tourists over the years and from further across the archipelago, we will be able to build up our understanding of the Maldives population and monitor its status closely," Davies said.