Bob is out there somewhere swimming freely but where, we no longer know because her satellite transmitter has stopped; this is what it means…
Cape Town, South Africa (10 November 2023) – In the early hours of the morning on the 3rd of October, came the end of a chapter as beloved green turtle Bob’s satellite tag stopped transmitting. As all satellite tags eventually do, Bob’s tag must have fallen off her shell while she was swimming. Luckily, this is not the end of her story.
It was a momentous occasion on 27 January 2023 when the Two Oceans Aquarium Foundation’s Turtle Conservation Centre team bid Bob the green turtle “go well” into the warm waters of KwaZulu Natal (KZN). This was an incredible moment for turtle conservation as, after eight long years of rehabilitation, Bob was fitted with three tags to track her progress.
Talitha Noble, Conservation Manager at the Two Oceans Aquarium Foundation’s Turtle Conservation Centre, reminisces:
“I remember it so clearly: those first moments of Bob being released into the warm ocean in KwaZulu Natal. As the thrill and adrenaline of her long-awaited release started to wear off, I began to feel some maternal concern about whether she would be okay.”
“I am grateful to say that the concern quickly faded as we marvelled at Bob’s exciting journey, watching with pride as she navigated the east coast of South Africa, riding the Agulhas Current, staying on the inside of the continental shelf, and hanging out in Marine Protected Areas (MPAs) wherever possible,” she explained.
One of the benefits of tagging Bob is being able to track her through the various MPAs along her journey. The value of MPAs to marine life hit home in a new way as we could all watch Bob’s journey, taking a collective sigh of relief each time she entered the boundaries of a safer, more protected piece of ocean.
On the 3rd of October at 07:07, Bob’s satellite tag stopped transmitting. The last transmission point was 300km west off the coast of Hondeklipbaai.
“We had the great privilege of tracking Bob for 249 days (about eight months), 12 656 km, and through over half of South Africa’s 42 MPAs!” said Laura du Toit, Content Marketing Coordinator at the Two Oceans Aquarium.
Why did Bob’s tag stop?
Green turtles like Bob are known to be challenging to tag: their shells, as well as being softer than those of other turtle species, excrete oil that makes it hard for satellite tags to grip over a long period. This had led the Two Oceans Aquarium Foundation team to suspect that the tag has fallen off Bob’s carapace. Generally, they have been able to track other turtle species for much longer, like loggerhead turtle Yoshi who travelled over 40 000 kilometres after her release!
Complete freedom is the ultimate reward for eight years of difficult rehabilitation, so although they are disappointed to have lost contact with Bob’s satellite tag, the team are thrilled that her journey is continuing!
What’s next for Bob?
The important thing to note is that whilst this tracking chapter is closed, the journey with Bob still promises much excitement ahead!
In May this year, it was discovered with certainty that Bob is a female! This means that at some point in the future, she will return to the beach where she hatched to lay clutches of her own offspring. Before her release, the veterinary team took genetic samples from Bob – these will be crucial in determining the region of the world she is originally from. As turtles imprint on the beaches of their birth, these genetic samples will produce ground-breaking insight into where Bob might return to breed.
Bob was not only satellite-tagged but also acoustic and flipper-tagged. The acoustic tag faces the same retention challenges with green turtles’ oily skin as it is attached to Bob’s shell. However, the flipper tags (attached to Bob’s front flippers) will likely keep their position for many years.
Flipper tagging is a reliable and commonly used tracking method for turtles – a small, unobtrusive metal or salt-resistant alloy device is attached to the turtle’s flipper. Despite being relatively basic, this tag identifies the turtle and provides scientists with important information, such as the date it was tagged and the place of release. These details are stamped onto the tag by way of a numeric code. So, Bob’s flipper tag (labelled ZA0497) tells anyone who encounters her in her future travels exactly where she came from!
The anticipation is high in the wait to see where Bob takes to the beaches to lay her eggs while showing us her beach of origin.
In the meantime, work in turtle conservation is ongoing, and networking and fundraising events are coming up for you to join.
Turtle Events to look forward to!
Bob-voyage – looking back at the life and travels of Bob the green turtle with the Two Oceans Aquarium Foundation’s Turtle Conservation Centre team. Speakers: Talitha Noble, Alexandra Panagiotou, Ayesha Cornelius.
Venue: Two Oceans Aquarium – buy your regular entry ticket for the Two Oceans Aquarium or come in on your annual membership card and attend in person.
Date: Monday 13 November 2023, Wednesday 15 November 2023, Friday 17 November 2023
Charting Conservation: A Night for Sea Turtles – This fundraising event is a wonderful opportunity to learn about the incredible work of the Turtle Conservation Centre. We’ll share heartwarming stories about our sea turtle rescue, rehabilitation, and release program, highlighting the dedication and passion that goes into saving these majestic creatures.
Venue: Royal Cape Yacht Club
Date:24 November 2023