Percorrer por autor "Duran, Ana Margarida Geadas"
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- Oceanographic insights from Apex Predators: The MAANTA NAUTILOS Tag for dissolved oxygen monitoringPublication . Duran, Ana Margarida Geadas; Fontes, José Miguel Rodrigues; Catry, PauloOcean deoxygenation is intensifying globally, yet its effects on apex predators such as elasmobranchs remain poorly understood. Within the framework of the NAUTILOS project (New Approach to Underwater Technologies for Innovative, Low-cost Ocean Observation), we developed and validated the MAANTA tag—a non-invasive biologging tool that records high-resolution dissolved oxygen (DO), temperature, and fine-scale movement data. Extensive laboratory and in situ tests, including comparisons with calibrated conductivity–temperature–depth (CTD) instruments and modelled environmental data from CMEMS, confirmed the tag’s accuracy, although regular post-deployment calibration remains essential to minimize sensor drift. Deployment on the Chilean devil ray (Mobula tarapacana) provided the first in situ characterization of its diving behaviour in relation to DO. The species occupied well-oxygenated waters (210–230 μmol/L), tolerated a broad temperature range (9–24 °C), and showed increased vertical activity in cooler, oxygen-rich waters, consistent with diel vertical migration. Descent speeds reached up to 5.41 m/s—among the fastest recorded in marine animals. These findings demonstrate the MAANTA tag’s effectiveness for simultaneous behavioural and environmental monitoring, offering novel insights into the oxygen and thermal ecology of the Chilean devil ray supporting the conservation of this critically endangered species in an increasingly deoxygenated ocean.