Movements of the reef manta ray (Manta alfredi) in the Red Sea using satellite and acoustic telemetry
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Red Sea Research Center (RSRC)
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AbstractPopulations of mobulid rays are declining globally through a combination of directed fisheries and indirect anthropogenic threats. Understanding the movement ecology of these rays remains an important priority for devising appropriate conservation measures throughout the world’s oceans. We sought to determine manta movements across several temporal and spatial scales with a focus on quantifying site fidelity and seasonality in the northern Farasan Banks, Red Sea. We fitted manta rays with acoustic transmitters (n = 9) and pop-up satellite archival transmitting (PSAT) tags (n = 9), including four with GPS capability (Fastloc), during spring 2011 and 2012. We deployed an extensive array of acoustic receivers (n = 67) to record movements of tagged mantas in the study area. All acoustically tagged individuals traveled frequently among high-use receiver locations and reefs and demonstrated fidelity to specific sites within the array. Estimated and realized satellite tag data indicated regional movements <200 km from the tagging location, largely coastal residency, and high surface occupation. GPS-tagged individuals regularly moved within the coastal reef matrix up to ~70 km to the south but continued to return to the tagging area near the high-occupancy sites identified in the acoustic array. We also tested the accuracy of several geolocation models to determine the best approach to analyze our light-based satellite tag data. We documented significant errors in light-based movement estimates that should be considered when interpreting tracks derived from light-level geolocation, especially for animals with restricted movements through a homogenous temperature field. Despite some error in satellite tag positions, combining results from PSAT and acoustic tags in this study yielded a comprehensive representation of manta spatial ecology across several scales, and such approaches will, in the future, inform the design of appropriate management strategies for manta rays in the Red Sea and tropical regions worldwide.
CitationBraun CD, Skomal GB, Thorrold SR, Berumen ML (2015) Movements of the reef manta ray (Manta alfredi) in the Red Sea using satellite and acoustic telemetry. Marine Biology 162. Available: http://dx.doi.org/10.1007/s00227-015-2760-3.
SponsorsThe authors thank J. Cochran for useful discussion of the data and management of the acoustic array; Dream Divers for logistical support; T. Sinclair-Taylor, M. Priest, J. Cochran, M. Khalil, P. De La Torre, and the Reef Ecology Lab at King Abdullah University of Science and Technology (KAUST) for assistance in the field. Financial support was provided in part by KAUST baseline research funds (to MLB), KAUST award nos. USA00002 and KSA 00011 (to SRT), and the U.S. National Science Foundation (OCE 0825148 to SRT and GBS). The manuscript was improved by feedback from B. Jones and S. Kaartvedt.