News
Cendrawasih’s whale sharks…. not such homebodies after all
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.
Since 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!
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.
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…
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.
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.
In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.
This month we’re taking a look at the Dusky Shark, a highly migratory species with a particularly slow growth rate and late age at maturity.
Dusky sharks are one of the largest species within the Carcharhinus genus, generally measuring 3 metres total length but able to reach up to 4.2 metres. They are grey to grey-brown on their dorsal side and their fins usually have dusky margins, with the darkest tips on the caudal fin.
Dusky Sharks can often be confused with other species of the Carcharhinus genus, particularly the Galapagos Shark (Carcharhinus galapagensis). They have very similar external morphology, so it can be easier to ID to species level by taking location into account as the two species occupy very different ecological niches – Galapagos Sharks prefer offshore seamounts and islets, whilst duskies prefer continental margins.
Hybridisation:
A 2019 study found that Dusky Sharks are hybridising with Galapagos Sharks on the Eastern Tropical Pacific (Pazmiño et al., 2019). Hybridisation is when an animal breeds with an individual of another species to produce offspring (a hybrid). Hybrids are often infertile, but this study found that the hybrids were able to produce second generation hybrids!
Long distance swimmers:
Dusky sharks are highly mobile species, undertaking long migrations to stay in warm waters throughout the winter. In the Northern Hemisphere, they head towards the poles in the summer and return southwards towards the equator in winter. The longest distance recorded was 2000 nautical miles!
Very slow to mature and reproduce:
The Dusky Shark are both targeted and caught as bycatch globally. We already know that elasmobranchs are inherently slow reproducers which means that they are heavily impacted by overfishing; it takes them so long to recover that they cannot keep up with the rate at which they are being fished. Dusky Sharks are particularly slow to reproduce – females are only ready to start breeding at roughly 20 years old, their gestation periods can last up to 22 months, and they only give birth every two to three years. This makes duskies one of the most vulnerable of all shark species.
The Dusky Shark is now listed on Appendix II of the Convention on the Conservation of Migratory Species (CMS), but further action is required to protect this important species.
Scientific Name: Carcharhinus obscurus
Family: Carcharhinidae
Maximum Size: 420cm (Total Length)
Diet: Bony fishes, cephalopods, can also eat crustaceans, and small sharks, skates and rays
Distribution: Patchy distribution in tropical and warm temperate seas; Atlantic, Indo-Pacific and Mediterranean.
Habitat: Ranges from inshore waters out to the edge of the continental shelf.
Conservation status: Endangered.
For more great shark information and conservation visit the Shark Trust Website
Images: Andy Murch
Diana A. Pazmiño, Lynne van Herderden, Colin A. Simpfendorfer, Claudia Junge, Stephen C. Donnellan, E. Mauricio Hoyos-Padilla, Clinton A.J. Duffy, Charlie Huveneers, Bronwyn M. Gillanders, Paul A. Butcher, Gregory E. Maes. (2019). Introgressive hybridisation between two widespread sharks in the east Pacific region, Molecular Phylogenetics and Evolution 136(119-127), https://doi.org/10.1016/j.ympev.2019.04.013.
3rd AUGUST 2024 – 1 or 2 WEEK PROGRAMMES
Daily water programme with Snorkelling & Scuba Diving.
Beginners or qualified, something for all.
Leave the kids with the Splash Team for days of Excitement, Fun & Adventure!
BOOK NOW: INFO@PHARAOHDIVECLUB.COM / TEL: +44 7598 329059 or +20 100 6822000
There are various options for accommodation with options for 2, 3, 4 or 5 guests.
Eco Huts provide accommodation for families of up to 4. The best option to enhance the adventure and closest to camping with basic facilities. For August we will provide central air cooling for all the Eco Huts.
Deluxe Chalets are only suitable for 2 guests. Fully air conditioned rooms with private bathroom and other facilities.
Boutique Rooms are available for families of up to 5.
Individual bespoke rooms fully air conditioned with private bathroom and other facilities.
Eco Huts: £675 per adult / £425 per child / Under 8 FREE of charge
Deluxe Chalet: £830 per adult / £505 per child / Under 8 FREE of charge
Boutique Room: £925 per adult / £550 per child / Under 8 FREE of charge
BOOK NOW: INFO@PHARAOHDIVECLUB.COM / TEL: +44 7598 329059 or +20 100 6822000
This is a truly unique opportunity to have a Family Desert Adventure totally away from it all! You will be based at the remote Roots Red Sea on the coast of the Egyptian Eastern Desert, 140km south of Hurghada city.
Red Sea Splash main focus is Snorkelling & Scuba Diving but that’s not all, we provide a rounded week of activities in support.
Pool& Field Games – Arts & Crafts
Marine Biology Workshops
Cultural Activities – Orienteering Adventures
Roots Red Sea have established strong links with the local communities of Hamerwain & El Quseir affording our guests to have a true taste of the local culture, SPLASH CAMP embraces this opportunity and bring in the local children to join in the fun with our adventure seekers.
During the day, families are welcome to take part in all activities together or the kids can be left with the SPLASH CAMP team while the parents enjoy the facilities or go diving themselves!
At the end of the day, its family time while the SPLASH CAMP team take a break. For those with the energy, there are family evening activities planned a few evenings.
Open Air Movie Night – Desert Star Gazing Walk & Talk
El Quseir Evening City Tour
The second week is very special, we head off on the Big Blue for a liveaboard safari around Fury Shoals.
BOOK NOW: INFO@PHARAOHDIVECLUB.COM / TEL: +44 7598 329059 or +20 100 6822000
U-8 Splash Club
Sadly we can’t offer Scuba Diving to the Splash Club but we can have lots of fun Snorkelling & Free Diving!
Splash Club includes:
Certified Snorkel Course – Marine ID Games – Intro to Free Diving
Arts & Craft Sessions – Adventure trails – Cultural Playtime – Pool Games
U-12 Explorer Club
In addition to an exciting snorkelling and Free Diving Programme in the Splash Club we can take you under the water on SCUBA to a whole new world of fun and wonder. If you are under 10 your first breath under water will be as a Bubblemaker and continue with daily Seal Team Missions. From 10 we will complete a Discover Scuba Diving experience in the amazing Red Sea. Alternatively we offer a full junior certification programme to become an international qualified Scuba Diver.
U-16 Adventurer Club
For qualified Scuba Divers regardless of age it’s the Adventurer Club and exploration of the local reefs and marine life. There will be 2 dives every day with the Open Ocean marine field station team who will introduce you to Red Sea marine life and workshops on marine research. Alternatively there are opportunities to continue your scuba diving certifications with our instructional team.
Parents are welcome to join the club activities and join the courses.
BOOK NOW: INFO@PHARAOHDIVECLUB.COM / TEL: +44 7598 329059 or +20 100 6822000
Big Blue might seem like the new kid on the block, but the team behind the highly acclaimed liveaboard is far from that. They have been running Red Sea safaris since the late 1980’s and were in fact part of the early pioneers who ventured out to the unknown on vessels that in today’s world, really shouldn’t have left the harbour! It’s that experience and the years of operating the award-winning Roots Red Sea resort which truly set Big Blue apart from the crowd!
Large lounge area, spacious sun deck and terrace deck.
Airy restaurant with five tables with up to six chairs per table, serving a varied and delicious menu with special dietary requirements catered for.
The spacious cabins have side by side beds and a large walk in wet bathroom.
Ample dive deck for divers & snorkelers.
Safety is everyone’s priority, whether you are relaxing on board, swimming, snorkelling or diving.
On board Big Blue is fitted with smoke alarms, emergency lighting and a fire alarm system. The lower corridor has a full-size door fire exit at the bow and open stairs to the stern. There are evacuation plans in each room along with life jackets, glass breaker tool and a fire extinguisher.
BOOK NOW: INFO@PHARAOHDIVECLUB.COM / TEL: +44 7598 329059 or +20 100 6822000
Red Sea Splash at Fury Shoals is a very rare opportunity to get involved with marine biology expedition for children and adults. Open Ocean biologists are on board to provide fascinating and entertaining facts about the marine life you will see. The team will provide workshops on marine life identification and survey methods both of which, should you wish, you will have the chance to put into practice during your safari.
The week is open to snorkelers, scuba divers and non divers too!
Fury shoals is perfect for first time mariners as it offers plenty of protection from the weather.
We board at Port Ghaleb on Saturday evening and prepare to set sail early on Sunday morning.
Heading south, our first day will be diving the reefs of Abu Dabbab before sailing overnight to reach our ultimate destination the Fury Shoals.
Here we will spend four days swimming, snorkelling and scuba diving amazing reefs. This includes guaranteed DOLPHIN encounters at Sataya Reef! After the last dive we haul anchor and head back to Abu Dabbab for our final two dives before disembarking our boat BIG BLUE.
Camp Extension Cost*
Adult £650 per adult
Under 16 £350 per child
BOOK NOW: INFO@PHARAOHDIVECLUB.COM / TEL: +44 7598 329059 or +20 100 6822000
FURTHER INFORMATION – INFO@PHARAOHDIVECLUB.COM
TEL: +44 7598 329059 or +20 100 6822000
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