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Tagging a whale shark in Djibouti

Tagged whale shark (Rhincodon typus)Throughout the winter from November onwards, whale sharks are in the Gulf of Tadjoura, where there is a large concentration of plankton.

To protect them, we need to know more about them. This is why, since 2004, several eco-volunteers have taken part in an annual expedition lasting one or two weeks in the south west of the Gulf of Tadjoura. This event is organised by MEGAPTERA/Exagone to further their studies of the habits and movements of whale sharks, especially off the coast of Arta and in the Bay of Ghoubbet.

Ludwig COULIER, a shark handler at Nausicaa, joined the MEGAPTERA team for the 2017 tagging operation which took place from 16 to 23 December 2017 with three tags attached to whale sharks. 

You can follow the moves of tagged whale sharks on seaturtle.org

Djibouti Expedition 2017

The team carrying out the tagging was led by Daniel JOUANNET from MEGAPTERA. 

During this operation, Ludwig posted daily updates on the expedition on our Facebook page and our social networks. It will be possible to track the tagged shark’s movements through a site. Nausicaa will put previously unseen images of this tagging programme on display on the Nausicaa TV Set.

The tags will be used to study this iconic creature and its way of life, migration and reproduction, enabling us to study this species in great depth. Once attached, they will be used to collect various pieces of information about depth, temperature and light levels. During the expedition, scientists will be able to decode and analyse the collected data in order to monitor the creature’s behaviour and movements. This will aid efforts to conserve the species. 

The whale shark (Rhincodon typus) is the world’s largest fish, but also one of its least well-known fish. This giant of the seas, which is harmless to man, feeds mainly on plankton, algae and microscopic creatures which it absorbs through its wide mouth. It has a long and bulky body and greyish skin with a characteristic checkerboard pattern of markings. It grows to a length of up to 20 metres and lives in the open seas and tropical and warm oceans. 

The whale shark has been listed under Appendix II to CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) since 2003.

MEGAPTERA

MEGAPTERA is a French association which is dedicated to the observation, understanding and protection of marine mammals and the whale shark. The MEGAPTERA approach, which is based on research, education and sustainable conservation, arose out of a growing awareness of the richness and uniqueness of these populations in the Indian Ocean region and the lack of information about them. To deepen our understanding of the whale shark and protect it more effectively, MEGAPTERA carries out regular photo-identification, marking and tagging of these giants of the seas with support from Exagone, which is the main sponsor of these expeditions.  

Djibouti Expedition December, 2017 - Logbook by Ludwig - Shark handler at Nausicaa

Saturday 16 December 2017

The Djibouti 2017 expedition has got off to a very, very good start. We got on board the boat this morning. After our meal, we set off to see the whale sharks. 

After sailing for 2 hours in the Gulf of Tadjoura, we had 10 encounters with whale sharks and saw 6 different individuals; they were all males measuring about 4 metres.

This evening, we put spotlights at the back of the boat to attract plankton. Half an hour later, a really beautiful male measuring 4.5 metres came to see us. He stayed with the divers for over an hour. It was a magical moment!

We’re also thinking about attaching the tags at night. 

See you tomorrow for some new adventures.

Sunday 17 December 2017

Expedition – day 1

Requin-baleine (Rhincodon typus)At the same time as attaching 3 tags to whale sharks, we carry out photo identification during each encounter.

In the photos that were taken during the day, we can see the pattern of the different marks on the shark within a precise area just above the left pectoral fin, behind the gills. This pattern is their fingerprint.

This is how we can identify all of the individuals that we come across.

Monday 18 December 2017

Our third tag is in place!!

We got the job done during our morning dive. The sea was calm. We came across 2 sharks and decided to attach the tag to the larger of the two: a male measuring 4.5 metres.

This afternoon, we explored the eastern part of the Marine Protected Area (MPA) of Arta in the Gulf of Tadjoura to look for whale sharks.

We didn’t find any.

We headed back towards the west coast, as we had done on the previous days, to continue with the photo identification and had 3 encounters, including two with sharks which had been tagged the day before.

Tuesday 19 December 2017

Great news!

Our efforts have been rewarded. 

We had Internet access for a few minutes today: the 3 tags are working.

We’ve already received some information about the location of the 3 whale sharks!

Wednesday 20 December 2017

In the morning, we set off for the Gulf of Ghoubbet. 

At 7am, we went looking for sharks in this new area. 

We didn’t come across any there, so we decide to go back to “Ras Coraly”, the area where we had been since Saturday.

This afternoon, we started looking again and were successful.

We took the opportunity to use the laser measurement system: we were able to measure two tagged sharks (the ones we saw on the first day!) with great precision.

Today, we had 5 encounters with 3 different individuals.

Thursday 21 December 2017

We are still in the area of Ras Coraly where we tagged the sharks at the beginning of the week.

During our 7am dive, we had 4 encounters with 3 different individuals, two of which were tagged (we’ve named them Téria and SharkyDJ3).

With the laser system, we measured SharkyDJ3 – the only tagged whale shark which was missing this information.

This afternoon, we went out again. We had another 4 encounters with the same individuals.

Friday 22 December 2017

There were plenty of encounters on this final day too. We were again able to observe 3 whale sharks.
This Djibouti 2017 expedition has really lived up to all of our expectations: great encounters (about fifty in all), the 3 satellite tags were attached, laser measurements were obtained for the 3 tagged individuals, and we’ve already received confirmation that the tags are working properly because we’ve already received data.

 

Tuesday 26 December 2017

Position des trois requins-baleines au 26 décembre 2017

Within the first 48 hours of the expedition, we managed to attach the three tags to three males measuring between 4 and 6 metres. The three sharks were identified and named TERIA, AGNES and SHARKYDJ3. These three tags were programmed to detach themselves after 153 days. They will tell us about the development and behaviour of the sharks over this period: immersion depths, how long they dive for, the water temperature, the light level, and so on. 


The 2016 Expedition

The team responsible for tagging the shark was led by Daniel Jouannet from the MEGAPTERA Association accompanied by Ludwig COULIER and a number of ecovolunteers. Two tags have been attached to whale sharks, one of them as a result of the crowdfunding operation launched by Nausicaa at the end of 2015 on the Ulule website. More than one hundred people contributed to the project.

“It’s an incredible adventure to take part in this scientific expedition, said Philippe VALLETTE, Managing director at Nausicaa. Now that the sharks have been tagged, people will be able to monitor their travels on a website. Researchers will be able to study this emblematic animal’s lifestyle, migration and breeding habits in great detail, because the tags will collect a range of data about depth, temperature and light. To date, their migration habits are still much unknown. During the study, the data will be decoded and analysed by scientists to monitor the animal’s behaviour and movements. This will improve conservation of the species.” 

Nausicaa displayed original images of the operation in its TV studio.

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