Led by Dr. Austin Gallagher, the scientists of Beneath the Waves have been studying the sharks in the Bahamas for over a decade.
Estella and Arlyne are two female tiger sharks that have recently been tracked swimming over the deepest features of the Caribbean – the tongue of the ocean and the Exuma sound – and making dives to over 700 meters. The sharks spent a significant time at depth as well, with 20-30 minutes per dive spent in the twilight zone. This pinging on the satellite tracker was something the Beneath the Waves scientists had never seen before.
The incredible new-found behaviour sheds light onto the importance of deep water zones for sharks and shark conservation: “Sharks have been found to go to these depths before – but never in this region, nor have they gone to these depths with such frequency,” Dr. Gallagher states. “What is truly groundbreaking is that we had no idea that tiger sharks would be spending this much time in the twilight zone. This opens up a Pandora’s box of research questions and could reframe our conservation approach for this species.”
Exactly what were they doing down there? Future research missions are planned to help answer these questions, but early data from camera logging tags suggests there may be reproductive benefits to deep water habitat use. The tracks of Estella and Arlyne – both tagged just two months ago in the Bahamas Shark Sanctuary with high-resolution 45-day pop off archival tags – are profiled in the image below.
The tags collect depth temperature and location estimates and store them while attached to the animal. The attachment is minimally invasive and the tag will pop off after a pre-determined period, where the data is then transmitted to satellites in space and the scientists can access and download the information.
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