Tracking Bob: 2 months at sea!

Bob, the green turtle, has been doing loops in the Atlantic Ocean – showing off his super chilled nature as he floats with the currents. Let’s hear more from Talitha Noble, Conservation Manager at the Two Oceans Aquarium Foundation.

Bob’s journey so far:

Bob, the green turtle, was released in KwaZulu-Natal 77 days ago! That’s 77 days of wildness and exploration in the big blue ocean!

During this time, he averaged 58 km per day, covering a distance of 4 400 km! Bob has reached these impressive daily distances because of his smart swimming and willingness to go with the flow. This is a quality that the turtle team noticed from the start of his rehabilitation journey – Bob is a very chilled, savvy swimmer!

As you can see in the swirling patterns of his tracking progress, Bob is letting himself be carried by the circular currents. The water is quite calm at the centre of these currents, with little movement or wind. But as you move out of the central space, the current speed increases quite quickly and can reach speeds of 1.5 m/s. This is the same speed as the fast-moving Agulhas Current.

Now, Bob is exhibiting similar behaviour to when he was cruising down the Agulhas Current after his release. Bob, while not in the fastest part of the current, is swimming in a spot that substantially aids his speed and decreases the effort required. He has made three big loops in the last three weeks. Classic Bob…

However, these surface currents change direction and speed quite quickly, so it will be interesting to see if Bob continues to loop in the Atlantic Ocean or decides to move in a clearer direction.

Bob’s current “looping” behaviours are very similar to Caddy, a young loggerhead turtle released in July 2022. Caddy also zoomed down the current and made some ocean loops! 

Bob is currently 420 km offshore and in water that is 4600 m deep. This depth doesn’t refer to his diving depth but rather the depth of the water that he is swimming through. Adult green turtles can dive hundreds of metres deep, but they spend over 80% of their time in the top two meters of the water column.

We are super excited to see what Bob gets up to next. The battery life on his satellite tag won’t last forever, so we may not be able to track his movements for longer than a few years. Luckily, Bob is also equipped with an acoustic tag, thanks to the support of the Acoustic Tracking Array Platform (ATAP). Acoustic tags have an incredible battery life of 10 years! This means that we will be able to track Bob’s movements around southern Africa for another decade. 

Turtles doing rollercoaster current loops in the ocean are just the best! Well done, Bob, for having a good time! Stay in the loop to see what Bob gets up to next…

Bob stats:

Days since release: 78

Distance travelled: 4 400km

Distance from shore: 420km

Nearest town: Hout Bay

Water Depth: 4 600m

14 April 2023, by Talitha Noble (read more)


Learn more about Bob and Turtles

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