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Shark Project Update
May 31, 2024
Protect
Summary of activities and preliminary conclusions
The Conservation team was delighted to host project partners from the Darwin-funded Human-Shark Conflict Project, a collaboration between the University of Exeter, the Zoological Society of London and the University of Windsor, from March to May 2024. During their visit, the team maintained, collected data and redeployed a range of acoustic and oceanographic instruments.
In addition to the field work, the team engaged with the community through presentations detailing the project’s progress and sharing initial findings. Field activities, which took place from March to May, also included acoustic tagging of additional sharks to expand monitoring efforts.
After data from these instruments were collected, the acoustic receivers, ADCPs (which measure water current direction and speed) and temperature loggers were retrieved, maintained and redeployed. Data downloaded from the receivers show the movements of 34 acoustically tagged sharks, including silky and Galapagos sharks, from 2023 to 2024. Preliminary findings show that approximately 85% of Galapagos sharks show very high local residency on the islands, while intermittent residency for silky sharks indicates departures from the islands over several months with occasional returns. Hotspots of general shark activity were identified around the islands (Figure 1). Thermoclines and water temperatures were recorded throughout the year (Figure 2), with some evidence linking shark movements to changes in water temperature. Blood and fin samples are currently being processed in the University of Exeter laboratory, with early isotope analysis suggesting that Galapagos and silky sharks have similar diets.
Figure 1 Shark activity hotspots around the island
Figure 2 Example of water temperature captured from a data logger
Future plans for the acoustic array include continuing to collect data for the next 12 months, which will be recovered and analyzed as part of a larger PhD project in March 2025. Further analysis will help continue to understand the oceanographic impacts and fine movements of sharks around Ascension Island.
For more information, please contact Daniel Simpson at daniel.simpson@ascension.gov.ac or visit us at the Festival of Oceans event.
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