Cendrawasih’s whale sharks…. not such homebodies after all

Capture4.jpg

For the past five years, Cendrawasih Bay’s friendly whale shark population has been attracting a lot of attention, primarily because of the near-certainty of having outstanding (and lengthy!) whale shark encounters during a visit to the region. Unlike many of the other known whale shark aggregations in the world (such as Ningaloo, Isla Mujeres, Belize, Galapagos and Donsol), which are highly seasonal, we now know with certainty that Cendrawasih has whale sharks present in the bay year round. Indeed, based on our observations combined with photos submitted by visitors to our BHS whale shark database, some highly-recognizeable individuals seem to be present throughout the year. Of course, one of the surest ways to confirm this is to monitor individual animals’ movements through satellite tagging – which is exactly what we’ve been doing in collaboration with the Cendrawasih Bay National Park Authority and Pak Bram Maruanaya and his local Kalilemon homestay in Kwatisore.

Capture3

Capture5Since June 2015, we’ve been able to tag 15 male whale sharks (ranging in size from 3 to 7 m in length) from Cendrawasih, using custom-made fin-mounted satellite tags by Wildlife Computers. These fin-mount tags have extended battery life which we hope will provide data for up to two years, and we’ve been delighted with their performance to date. All but one of the tags has been transmitting data very regularly (on average every 2-5 days) – basically each time one of the tagged sharks spends enough time on the surface for the tag to uplink to the ARGOS satellite network.

As previously reported back in November, the initial data received from June through October 2015 seemed to confirm what many suspected – that Cendrawasih whale sharks are largely “homebodies”, preferring to stay close to shore and feed upon the abundant ikan puri baitfish schools that abound in the coastal bays and estuarine areas of the southern and eastern coastlines of Cendrawasih. Which of course is a great thing for BHS marine tourism, as it means visitors can pretty much plan a trip any time of the year and have a very good chance of excellent whale shark interactions.

By December, however, we started to observe some very different behaviours that indicate Cendrawasih’s whale sharks might not be such homebodies after all! Just before Christmas, four of the sharks almost simultaneously moved towards the small exit to the bay between the eastern tip of Yapen Island and the Papuan mainland. Though two soon turned back, both “Jude” and “Wally” proceeded down the coastline towards Jayapura. Jude eventually turned back and returned to Kwatisore, but Wally continued down the coast – becoming the first of our tagged sharks to become an international visitor when he crossed into PNG waters in early January. While he appeared at one point to be returning to Cendrawasih (making it as far west as Jayapura), he’s since returned to the Wewak region of PNG (near the Sepik River outlet) and seems to be happily enjoying an extended vacation there!

Capture6

Similarly, one of our most recently tagged whale sharks, Ke’Opulupulu, headed almost immediately north into the center of the Bay (near the Auri Islands and atolls), then navigated to the south coast of Biak and Supiori Islands, where he’s remained for the past few weeks.

Capture7Capture8Capture9

Capture10

But horizontal movements are only part of the excitement we’ve recently recorded. The past 3 months have also seen a dramatic increase in deep-diving behaviour of many of our tagged sharks. While we did previously report a 672m deep diving record in October, we’ve now seen four of our sharks venture below 1000m depth, with the aptly-named “Moby” smashing the depth record (but fortunately not his tag’s depth gauge!) at 1416m!!! Even the “wee” 3m “Fijubeca” has dived to 700m depth. It’s still not clear why the sharks have shown such deep diving behaviour over the past few months – perhaps the El-Nino warmed surface waters are not providing enough food and they are searching for deeper plankton…

Capture11

Overall, we’re delighted to see these fin-mount tags proving so successful at divulging some of the secrets of Cendrawasih’s whale sharks. Its particularly noteworthy that the first 5 months’ of data seemed to simply confirm our scattered direct observations, but the past 4 months have revealed numerous exciting behaviours we didn’t expect. Who knows what the next few months’ data might reveal? Stay tuned and we’ll happily report back as the data keeps flowing in. And please remember – you too can contribute to our expanding knowledge and understanding of the charismatic megafauna of the Bird’s Head by contributing your photo IDs and observations of whale sharks and manta rays in the region to the databases maintained by our site.

Capture12

Mark Erdmann is Conservation International’s Vice President of Asia Pacific Marine Programs. Though now based in New Zealand after 23 years in Indonesia, he is still intimately involved with the Bird’s Head Seascape and frequently disappears into its remote corners for weeks on end….

Shawn Heinrichs is an Emmy Award-winning cinematographer, photographer and marine conservationist. An independent filmmaker, he is the founder of Blue Sphere Media, a production company specializing in underwater, adventure and conservation media. His work was recently featured in the film Racing Extinction.

A special thanks to Audrey, Shannon and Dennis Wong, Sally Timpson, and the management and guests of the True North expedition vessel for generously sponsoring the fin-mount whale shark satellite tags reported here, to Patti Seery and her amazing staff and crew of the Si Datu Buah liveaboard for hosting our most recent deployment expedition, and to OceanMax for continuing to support the tagging program with PropSpeed silicone foul-release coating for our satellite tags.

birdsheadseascape.com

Mark Erdmann

Mark Erdmann

Dr. Mark Erdmann's work largely focuses on the management of marine protected areas, as well as research on reef fish and mantis shrimp biodiversity, satellite tracking of endangered sharks and rays, and genetic connectivity in MPA networks.Mark is the Vice President of CI’s Asia-Pacific marine programs, tasked with providing strategic guidance and technical and fundraising support to focal marine programs in CI's Asia Pacific Field Division, including especially the Bird's Head Seascape and Pacific Oceanscape initiatives, as well as marine programs in China, the Philippines, Timor-Leste, Papua New Guinea, New Caledonia, Samoa and the Coral Triangle Initiative (CTI). Mark is a coral reef ecologist (Ph.D. University of California, Berkeley) who has recently moved to New Zealand, and previously lived and worked in Indonesia for 23 years. During his time there he launched and directed the Bird’s Head Seascape initiative for over a decade, developing it into one of CI's flagship marine programs globally. Mark is an avid diver and has logged over 10,000 scuba dives while surveying marine biodiversity throughout the region, discovering and describing over 150 new species of reef fish and mantis shrimp in the process.He has published over 140 scientific articles and four books, including most recently the three-volume set "Reef Fishes of the East Indies" with colleague Dr. Gerald Allen, and has been a scientific advisor to numerous natural history documentary films for the BBC, National Geographic and NHK. Erdmann was awarded a Pew Fellowship in Marine Conservation in 2004 for his work in marine conservation education and training for Indonesian schoolchildren, members of the press, and the law enforcement community. Though his work is now largely focused on the management of marine protected areas, his continuing research interests include reef fish and mantis shrimp biodiversity, satellite and acoustic telemetry of endangered elasmobranch species, and genetic connectivity in MPA networks. In recent years Mark has devoted significant time to supporting the Indonesian government in its efforts to improve conservation and management of its sharks and rays, including the designation of the world’s largest manta ray sanctuary in 2014. Mark maintains a research associate position with the California Academy of Sciences, supervises several Master's and PhD students at the University of Auckland, and is active on the boards of a number of NGOs working in the Coral Triangle, including Yayasan Kalabia, Reef Check Indonesia, and Manta Trust. Mark and his wife Arnaz and three children (Mica, Brahm and Cruz) live in Auckland, where he maintains a deep personal commitment to do whatever is necessary to ensure his children will be able to enjoy the same high-quality underwater experiences that continue to provide the inspiration for his dedication to the marine environment.

scroll to top