A satellite-tracking study of 17 juvenile whale sharks, said to be the most comprehensive ever carried out in the Philippines, has shown that although highly mobile all the sharks remained within the country's waters during the tracking period.
This, say the researchers, demonstrates the importance of the archipelago for the species.
The Philippines hosts, and for the past 20 years has officially protected, the third largest known population of whale sharks in the world.
Globally the species is classified as Endangered to Extinction following a population decline of more than 50%, largely caused by continued exploitation particularly in South-east Asia.
More than 600 individual whale sharks have been identified in the Sulu and Bohol Seas in the Philippines. Their proximity to South China Sea fisheries makes it important to monitor their movements to establish whether the population is recovering or declining, and to identify conservation priorities.
The research was carried out by the Large Marine Vertebrates Research Institute Philippines (LAMAVE), Marine Megafauna Foundation (MMF) and Tubbataha Management Office (TMO).
The scientists were able to observe the whale sharks in near-real time using tethered satellite tags that transmitted a location whenever the whale shark neared the surface.
The whale sharks ranged in size from 4.5 to 7m and were 73% males. They were tagged in Southern Leyte, northern Mindanao and Palawan between April 2015 and April 2016.
One individual originally tagged in Tubbataha Reefs Natural Park covered 1550 miles as it swam through the Sulu and Bohol Seas into the Pacific. Another was found to be covering an average of 29 miles a day.
“This research highlights the high mobility of whale sharks, even juveniles, and the need for broader-scale management and conservation plans for this endangered species,” said lead author of the study Gonzalo Araujo.
The findings can be found in PeerJ, the Journal of Life and Environmental Sciences.