Tracking our Turtles: The first update of 2025

Nobomvu, the loggerhead turtle

Nobomvu, our “Red Lady”, has been at sea for 416 days since her release off Cape Point after an arduous rehabilitation. In that time, she has travelled over 20 800km!

Instead of travelling in a straight line with a clear direction, Nobomvu has spent most of the last year meandering off the South African coastline. Her furthest point of exploration was 650km offshore.

While these movements may appear aimless at first glance, Nobomvu’s tracks actually show clear intention when overlaid with ocean productivity! She has been using surface currents to “go with the flow” while spending time in super-productive waters (see the red areas on the map below).

But what is ocean productivity? Microscopic algae (phytoplankton) in the ocean convert sunlight and nutrients into energy. This is the foundation of the marine food web and the baseline of nutrition for most ocean life.

The area of South Africa where Nobomvu has been spending time is an area of particularly high productivity, largely due to good water circulation and coastal upwelling bringing nutrient-rich water to the surface. This results in increased phytoplankton activity, which attracts shrimp, fish, sea birds, and larger marine animals. For food-motivated turtles like Nobomvu, this is a great place to be!

Nobomvu is likely using the surface currents to navigate through these high-productivity waters, enjoying a menu of jellyfish and salps (planktonic invertebrates), floating crustaceans, small squid, and fish. We are proud of Nobomvu for remembering that nutrition is key!

Bokkie, the green turtle

Our amputee green turtle, Bokkie, has been in the ocean for 102 days now. After just under a year of rehabilitation, she was released within the beautiful, warm water of iSimangaliso Wetland Park at the end of October 2024. We are grateful to Sustainable Trendsetters for supporting Bokkie’s journey back to the ocean. Since her release, she has travelled 520km, staying close to the coastline and moving in a northerly direction.

About a month ago, Bokkie moved into the Bay of Maputo in Mozambique, where she spent the last weeks hanging out in this warm (25 - 30°C) and shallow (10 - 20m) water. Mozambique is a hotspot for turtle activity, with five of the seven turtle species nesting along its coastline and islands. In the Bay of Maputo, green turtles nest on the beach. Nesting occurs over the summer, so Bokkie may be saying hello to all the nesting females!

The bay receives a fair amount of river runoff, especially in the rainy season. This makes the waters nutrient-rich and abundant in algae and seagrass, which is great for green turtles like Bokkie. This food availability, warm water, and presence of other turtles make this an ideal spot for Bokkie to hang out for a while. However, the bay poses a few threats too, like fishing pressure and pollution.

Perhaps Bokkie is just saying hello to some friends and fattening up before a big ocean adventure? We will have to wait and see!

Bheni, the green turtle

It is finally the end of our tracking journey with Bheni the green turtle, our grand ocean traveller. After 18 000km and 420 days of tracking, Bheni’s tag stopped transmitting at the end of December 2024.

Even though we cannot follow along, this does not mean the end of Bheni’s journey! It simply means that the satellite tag’s battery has run out or the tag itself has fallen off Bheni’s carapace (top shell). And what an incredible privilege it has been to watch Bheni navigate the ocean!

Bheni started his journey in the De Hoop Marine Protected Area before quickly catching the warm current moving into the Indian Ocean basin and tracking the Southwest Indian Ocean Ridge northward and over the equator. After a slower period of exploration between the Seychelles and Maldives, Bheni once again swam along the Carlsberg Ridgeline towards the Somali coast. It was amazing to watch him move even further north to the nesting beaches of Yemen before backtracking and heading into the Gulf of Tadjoura in Djibouti.

For the last few weeks of December 2024, Bheni was in Lake Ghoubet in Djibouti, an area that is known to host green turtles. While this lake is not known as a nesting beach, it is an area of feeding and shelter for green turtles. Connected to the Red Sea, Lake Ghoubet is a brackish lagoon with salinity slightly lower than seawater.

What a fascinating spot to end our tracking journey with Bheni – a journey that has been full of smart swimming, warm water, and discovering cool turtle habitats. Thank you for teaching us, Bheni! We wish this special turtle the best of luck as he continues to journey through the ocean.