Philippines archipelago provides vital habitat for juvenile whale sharks

Brooks Hays UPI 24 Jul 18;

July 24 (UPI) -- Satellite tracking data suggests the waters surrounding the Philippines archipelago are vital to endangered whale sharks.

In 2015 and 2016, researchers with the Large Marine Vertebrates Research Institute Philippines attached satellite tags to 17 juvenile whale sharks. The most recent analysis of the satellite data -- published this week in the journal PeerJ -- revealed the importance of the Philippines archipelago to whale sharks.

Scientists attached tracking devices that floated above the sharks, attached by a thin tether. The new types of satellite tags ensure the devices breached the surface more often, returning clear signals and delivering more data.

Over the course of the tracking period, all 17 whale sharks remained in the vicinity of the archipelago. Despite traveling up to 30 miles per day -- in the case of one fast-swimming male -- the whales never left the islands.

Whale sharks are protected in the Philippines, but in 2016, the International Union for Conservation of Nature upgraded the species from "vulnerable" to "endangered" as a result of the population's dramatic decline in the Indo-Pacific. Illegal fishing remains one of the largest threats to the whale shark, Rhincodon typus.

In addition to combating illegal fishing activities, scientists say habitat protection is essential to whale shark conservation. And efforts like the latest satellite tracking survey can help conservationists decide where protections would prove most beneficial.

"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," biologist Gonzalo Araujo said in a news release.


Satellite tracking reveals Philippine waters are important for endangered whale sharks
PEERJ EurekAlert 24 Jul 18;

A new scientific study published in PeerJ - the Journal of Life and Environmental Sciences has tracked juvenile whale sharks across the Philippines emphasising the importance of the archipelago for the species. The study is the most complete tracking study of whale sharks in the country, with satellite tags deployed on different individuals in multiple sites.

The Philippines is an important hotspot for whale sharks and globally hosts the third largest known population of whale sharks (whaleshark.org). While the species has been protected in the Philippines since 1998, globally the species was uplisted in 2016 to 'endangered to extinction' in the IUCN Red List of Threatened Species due to a population decline of more than 50%, largely caused by continued exploitation in the Indo-Pacific. Particularly in South East Asia, concerns remain due to continued fishing in regional waters; understanding the movements of whale sharks in the Philippines is vital if we are to identify conservation priorities for the species.

By attaching Wildlife Computers SPOT5 satellite tags to whale sharks, researchers from Large Marine Vertebrates Research Institute Philippines (LAMAVE), Marine Megafauna Foundation (MMF) and Tubbataha Management Office (TMO) were able to follow the movements of juvenile whale sharks in near real-time to gain an insight into their behaviour. The tags work by communicating with passing ARGOS satellites, transmitting a location when the wet/dry sensor is triggered when a tagged whale shark breaks the surface. To aid transmission tags were tethered to a whale shark by a 1.8-meter line to ensure the tags broke the surface more frequently.

17 individual whale sharks were tagged in three different locations in the Philippines: Panaon Island (Southern Leyte), northern Mindanao (Misamis Oriental and Surigao del Norte) and Tubbataha Reefs Natural Park (Palawan). Tagging took place between April 2015 and April 2016. All tagged whale sharks were juveniles, ranging in size between 4.5 - 7 meters and 73% of them were male.

In their paper, peer-reviewed and published in PeerJ - the Journal of Life & Environmental Sciences, the researchers discovered that the tracks from the tags showed that all whale sharks stayed within the Philippines over the tracking period, emphasising the importance of the archipelago for the species. The longest track observed was from a whale shark originally tagged in Tubbataha Reefs Natural Park, which appeared to swim through the Sulu and Bohol Seas and into the Pacific, a journey accumulating over 2,500 km in length. While whale sharks are not known for their speed, results revealed that one individual whale shark was averaging 47km a day, further emphasising the species' mobile tendencies.

Lead author of the study, Gonzalo Araujo stresses that "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."

Dedicated research by LAMAVE and citizen science has identified over 600 individuals in the Sulu and Bohol Seas, yet the proximity of this population to fisheries in the broader region (South China Sea) means it is vital to monitor this population as a whole to understand if this population is in recovery or continuing to decline. Identifying threats and mitigation strategies is a conservation priority for the species. LAMAVE continues to study whale sharks in five key areas in the Philippines, working with local and national governments as well as collaborating organisations to develop conservation strategies for this iconic species.

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Contact:

Sally Snow - s.snow@lamave.org

Media pack (including embargoed article, video and images): https://drive.google.com/drive/folders/1sFyHTLvwOK1y_iejy3G4IkNGxMES0Zm0

Video 1: Behind the Science: Tagging Whale Sharks in the Phillipines (link)

Images:

Image credit: A tagged juvenile whale shark swims through the waters of Panaon Island, Southern Leyte (Gonzalo Araujo)

Image credit: The team tag a whale shark, surrounded by barracuda in Tubbataha Reefs Natural Park (Steve De Neef)

Image credit: Tracks of whale sharks tagged in Tubbataha Reefs Natural Park, with park boundaries in orange. Araujo G, Rohner CA, Labaja J, Conales SJ, Snow SJ, Murray R, Pierce SJ, Ponzo A. (2018) Satellite tracking of juvenile whale sharks in the Sulu and Bohol Seas, Philippines. PeerJ 6:e5231 https://doi.org/10.7717/peerj.5231 (CC BY)

Link to the Published Version of the article (quote this link in your story - the link will ONLY work after the embargo lifts): https://peerj.com/articles/5231 your readers will be able to freely access this article at this URL.

Citation to the article: Araujo et al. (2018), Satellite tracking of juvenile whale sharks in the Sulu and Bohol Seas, Philippines. PeerJ 6:e5231; DOI 10.7717/peerj.5231

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