Publié le August 3, 2020

Djibouti Mission

Photo-identification and attaching beacons

to whale sharks

4 to 11 January 2020

NAUSICAA, the French National Sea Centre


© H-Al Qallaf-Megaptera

Every year more than 100 million sharks are killed, essentially for their fins. As a result of this, shark numbers are under threat and the whale shark population, in particular, is being reduced to a worrying degree. Whale sharks have been included in Appendix II of the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) since 2003.

In order to protect them and preserve biodiversity it is important that we have a better understanding of these animals.

This is why the MEGAPTERA association and his partner TERIA organises missions in the Gulf of Tadjoura to pursue their studies, by monitoring the habits and movements of whale sharks.

Ludwig COULIER, a biologist at Nausicaá, is going to join the MEGAPTERA team for the 2020 mission, which is being organised from Saturday 4 to Saturday 11 January 2020.

During the campaign, Ludwig will be posting news every day on the Nausicaá website: and on social media.

During this mission, MEGAPTERA will carry out a photo-identification operation and deploy satellite beacons for the telemetry monitoring of whale sharks, thanks to the TERIA company, these missions’ main sponsor.

Photo-identification makes it possible to identify individual sharks: identification sheets and ID cards are linked with the animals and they are used by the researchers to recognise and count the whale sharks. In order to recognise them, you just have to take a photograph of a precise area just above the left-hand pectoral fin to the rear of the gills.

The placement of beacons provides an additional source of data making it possible to gain a better understanding of these animals. The beacons will be used to study these iconic animals: how they live, migration, reproduction, all that’s needed to put this species under the microscope. Once the beacon has been attached to the shark it will make it possible to collect different types of information and especially satellite positioning. The data collected will be decoded and analysed by scientists to monitor the animal’s behaviour and movements.

The whale shark (Rhincodon typus) is the largest fish in the world, and also one of the least-well known. Inoffensive for man, this giant of the seas feeds mainly on plankton and small fish that it swallows through its wide mouth. It’s an animal with a long, massive body, characterised by a greyish skin with a chequered pattern. It can be as much as 15 metres long and lives in all the tropical and hot temperate zones (except the Mediterranean).


© Alexis Rosenfeld – Divergence


– You have already taken part in missions with MEGAPTERA on whale sharks. What makes is this important for Nausicaá?

“Nausicaá works closely with the MEGAPTERA association to gain a better understanding of the whale shark and to preserve its biodiversity. Besides broadening our knowledge of their living environment and movements, the mission also aims is to raise the public’s awareness of the disappearance of sharks in general and explain how we can change things.”


– What is the goal of this mission? What are you going to be observing in particular?

“This mission serves to accumulate data so we can study the behaviour, habits and movements of the whale shark which, despite its impressive size is still poorly known. During this one-week expedition, we will make the most of our dives to take photographs of the whale sharks in order to identify them.

The beacons we’re going to attach to the sharks will make it possible to transmit data by satellite when they come up close to the surface. This data indicates where the animal is and will tell us what the temperature of the water is in that location.” 

– How do you go about attaching a beacon to a whale shark?

“In order to be able to place a beacon on a whale shark, we dive with flippers, a mask and snorkel down a few metres below the surface so we can get close to them as discreetly as possible without disturbing them. We fasten the beacon precisely at the level of the dorsal fin with the greatest respect for the individual.”



To find out more, contact the Communication & Press Dept.

NAUSICAA, Centre National de la Mer – Boulogne-sur-Mer

Tel.: – Email:



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