18 000km later: Bheni the green turtle visits Yemen and Djibouti

Many of our turtle community have been keeping up with the exciting tracking updates of Bheni, a green turtle that underwent just over a year of rehabilitation at our Turtle Conservation Centre.

Bheni was rescued in December 2022 with an active infection on his carapace (top shell). Thanks to some much-needed care, rest, and medical treatment, he was finally released into the crystal waters of De Hoop Nature Reserve a year later. Since then, Bheni has been making waves, proving himself a world traveller!

Let’s hear more from Talitha Noble-Trull, Turtle Conservation Centre Manager…

Just 344 days ago, Bheni was released in De Hoop Nature Reserve, and his movements have been nothing short of remarkable.

While Bheni spent his first few days enjoying the coastal shallows and ample algae of the De Hoop Marine Protected Area, this didn’t last long before he set off on a grand adventure. He began by moving with the currents, where the Agulhas Current retroflects (turns back on itself) in the southeast Atlantic Ocean near Cape Town. Then, Bheni followed the Agulhas east before moving north into the Indian Ocean over the southwest Indian Ridge Line.

Most recently, Bheni has been travelling west towards the Somali coastline, where he spent some time in the offshore Somali eddies! We know that the Somali Current is a cold ocean boundary current that boasts a super productive upwelling system, meaning that the waters here are nutrient-rich! Bheni was most likely enjoying some delicious snacks in these eddies.

Shortly afterwards, Bheni caught the northward moving current into the Arabian Sea, passing the island of Socotra, a UNESCO World Heritage Site renowned for its abundance of endemic species! Arriving in the waters of Yemen, Bheni followed this coastline eastward for about two weeks. Then, he turned around and swam through the Gulf of Aden towards Djibouti – right now, he seems to be exploring the northern coastline of this sub-Saharan country.

To date, Bheni has travelled 18 000 km and averaged just over 52 km per day!

Let’s learn a little bit about turtles in Yemen and Djibouti:

Three out of the seven sea turtle species nest on the Yemen coastline and neighbouring islands: Loggerhead, green and hawksbill turtles. Loggerheads nest abundantly on the island of Socotra, and green turtles nest primarily on the mainland.

While Bheni travelled east along the Yemen coastline, he was moving past some key nesting sites for green turtles! Green turtle nesting takes place year-round on this stretch of coastline, with peak season between July and September. Over 1 000 nests are laid on the Yemen mainland every year. Djibouti has a few nesting sites for green and hawksbill turtles, but unfortunately, this region lacks data. The last figures from 2003 estimated about 100 nesting turtles.

In terms of the region’s environment, this area is wonderful for green turtles. There are lots of intertidal and subtidal seagrass beds where the famously vegetarian green turtles can munch while enjoying the warm 30°C waters! The primary threat to turtles in this region is fisheries, as they could be caught as bycatch. For nesting turtles, poaching is the main threat.

Our Turtle Conservation Centre team was itching to learn more about turtle tracking in this area – not only is this a unique opportunity to learn more about the area in which Bheni finds himself, but it also helps us to “zoom out” and get a global perspective.

To learn more about turtle tracks in this area and to zoom out and get a unique global perspective, we asked Sophie Baudel from CLS, the power behind Argos Services, to tell us more.

CLS' Argos Services provide smart environment solutions through the use of cutting edge technology such as real-time location and data collection via Kinéis’ global connectivity as well as access to Earth Observation data, modeling and Artificial Intelligence. Accessible around the world, Argos services help monitor wildlife and thanks to tailor-made dashboards, users can view animal migrations and access ocean, weather and environment data in one place. Argos ervices is available around the world for many different environmental and scientific applications. Let’s find out more from Sophie...

TCC: How many turtles are currently being tracked globally on the ARGOS platform?

Sophie: Last month (October 2024), we have tracked 736 turtles. Since 2007, we have tracked 26 500 turtles. Below, you can see all turtle platforms collected from October 2007 to October 2024.

TCC: How do Bheni’s tracks compare to other turtles? Do you often see sea turtles travelling such distances and with such directions?

Sophie: Yes, turtle migrations are amazing, crossing the Atlantic Ocean from east to west and from west to east, from Guyana to the Bay of Biscaye. In the Indian Ocean, they can go from the south (from Reunion Island, for instance) to the north following the Somali Current. We can see many of them entering the Arabic Gulf.

TCC: If we zoom in on the Arabian Sea and the Yemen coastline, are Bheni's tracks in line with what you have seen from other tracked individuals in the area?

Sophie: Yes, many of them are following the Yemen coast going eastward.

It is incredibly exciting for our Turtle Conservation Centre team to witness the whirlwind journey that Bheni is on! Thanks to satellite tagging technology and organisations like CLS ARGOS, we get to follow him, discover the biodiversity and ecosystems of new places and turtle populations, and get just a small glimpse into turtle movements on a global scale!