Tracking our Turtles: Bheni is zooming along!

Green turtles Bheni and Turbo and loggerhead turtle Nobomvu have been making some excellent progress in the big blue! Each of the turtles' journeys is uniquely fascinating.

Let's hear more from Talitha Noble-Trull, Conservation Manager at the Turtle Conservation Centre...

Nobomvu

Nobomvu, the loggerhead turtle, has been back in the ocean for just over 200 days. In that time, she has travelled a remarkable 8 424km! Currently, our Red Lady is only 300km west of the Cape Peninsula, in water that is about 4km deep and 17°C.

When overlayed with currents, temperature, and food productivity, Nobomvu’s travels do not appear to have a clear motivation – she has been making some twirly patterns for a while. However, Nobomvu is a smart lady and is likely getting used to being back in the ocean. Meandering, rather than missioning, allows her to move to and through whichever part of the ocean she likes!

Let’s review some of the interesting spaces Nobomvu has travelled through thus far:

• Nobomvu has travelled around and through seven of South Africa’s 42 Marine Protected Areas. In particular, she swam right through the middle of South-East Atlantic and South-West Indian Seamounts. Seamounts are fantastically rich with marine life; the steep slopes interact with the currents and bring lots of nutrients to the surface. Nobomvu likely had some good meals here!
• Nobomvu has crossed in and out of South Africa’s Exclusive Economic Zone (EEZ) eight times. Within the boundary of our EEZ, South Africa has the right to utilise the marine resources and the responsibility to protect them. Areas outside the EEZs are known as the High Seas or International Waters.
• Nobomvu has crossed over the continental shelf five times. The continental shelf is a part of the continent that is submerged underwater. This area of the sea is quite shallow when compared to the open ocean. In South Africa, the continental shelf has a huge impact on the movement of our two big currents: The Agulhas and the Benguela.

Turbo

562 days into his travels at sea, our young green turtle Turbo has reached the 10 000km mark!

Looking back over Turbo’s movements, it seems like his first 10 months at sea were “recalibration” – his wandering movements were similar to Nobomvu’s. It seems as though he was simply enjoying his time back in the ocean and going with the flow.

However, in October last year, Turbo pursued a more direct path, heading up the Western coastline of South Africa and into Namibia. Turbo made it to the southern point of the Skeleton Coast before looping towards the Walvis Ridge in a South-Westerly direction. As we speak, he is a mere 15km away from the Walvis Ridge line! This area does not have any strong currents, nor is it particularly well-known for food productivity. This leads us to believe that Turbo may have a destination in mind!

Watch this space to see where Turbo ventures next!

Bheni

In just over 200 days, Bheni our adventuring green turtle has travelled 10 300 km – that is over 50km per day!

We can tell that Bheni was utilising the currents in the initial stages after release – the Agulhas Current retroflects (turns back on itself) in the southeast Atlantic Ocean near Cape Town. Using the movement of the water, Bheni followed the current east before moving north into the Indian Ocean over the southwest Indian Ridge line.

Currently, Bheni is just north of the Vema Trench (named after a research vessel that mapped and sampled much of this area in the 20^th century). This trench is one of the deepest in the Indian Ocean, with its greatest depths reaching 6000m!

Bheni is in a part of the ocean that is home to five of the seven sea turtle species! The water temperatures are almost 30°C and the surrounding islands are home to many turtle nesting sites and rich meadows of seagrasses.

Bheni is also saying hi to some of our colleagues in turtle rehabilitation on his grand adventure! Just a few weeks ago, he swam past Reunion Island, giving a high-flipper to our friends at Kelonia Sea Turtle Care Center. About 1 000km northeast of his current location are two of the Olive Ridley Project’s Turtle Rescue and Rehabilitation Centres.

I cannot help but wonder if Bheni is from these turtle-rich waters or if this is a pitstop on his ocean travels.

The travels of Nobomvu, Bheni, and Turbo provide invaluable insight and prompt interesting questions – what makes a turtle decide between meandering and missioning? Why is Nobomvu twirling in the Atlantic Ocean while Bheni makes a beeline across the Indian Ocean? All of this information adds to the database of turtle research and contributes to the future preservation of these species!