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Using drones to reveal the distribution and population abundance of threatened dasyatid rays at a nursery site in Seychelles

Bullock, Robert, Fermor, Daisy, Pouponeau, Dillys, Moulinie, Ellie, Grimmel, Henriette (2024) Using drones to reveal the distribution and population abundance of threatened dasyatid rays at a nursery site in Seychelles. Drones, 8 (2). Article Number 48. ISSN 2504-446X. (doi:10.3390/drones8020048) (KAR id:104997)


Drones are becoming increasingly valuable tools for studying species in marine environments. Here, a consumer-grade drone was used to elucidate the distribution and population abundance of two threatened dasyatid rays, Pastinachus ater and Urogymnus granulatus, in a remote marine protected area in the Republic of Seychelles. Over six weeks in March and April 2023, a total of 80 survey flights, covering an area of 3.2 km2, recorded 1262 P. ater and 822 U. granulatus. Findings revealed previously unresolved high-use areas for both species, which almost exclusively used sandy areas within the habitat and were found in greater abundances in areas closer to the shoreline. Spatial patterns in abundance were strongly correlated between species, with both often found in mixed-species groups. The site was shown to support large populations of both species with total population abundance estimates of 2524 (2029–3019 95% CI, 0.1 CV) for P. ater and 2136 (1732–2539 95% CI, 0.09 CV) for U. granulatus. This study highlights the applicability of drones in acquiring highly useful data for delineating critical habitats and informing the adaptive management of marine protected areas.

Item Type: Article
DOI/Identification number: 10.3390/drones8020048
Uncontrolled keywords: unmanned aerial vehicles; habitat use; Pastinachus ater; Urogymnus granulatus; elasmobranch; ray; Dasyatidae
Subjects: H Social Sciences
Divisions: Divisions > Division of Human and Social Sciences > School of Anthropology and Conservation > DICE (Durrell Institute of Conservation and Ecology)
Funders: University of Kent (
SWORD Depositor: JISC Publications Router
Depositing User: JISC Publications Router
Date Deposited: 15 Feb 2024 12:22 UTC
Last Modified: 16 Feb 2024 09:38 UTC
Resource URI: (The current URI for this page, for reference purposes)

University of Kent Author Information

Fermor, Daisy.

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