A Proposed Method for Assessing the Spatio-Temporal Distribution of Carcharhinus melanopterus (Quoy and Gaimard, 1824) in Shallow Waters Using a UAV: A Study Conducted in Koh Tao, Thailand DOI Creative Commons

Andrea Di Tommaso,

Sureerat Sailar,

Francesco Luigi Leonetti

et al.

Diversity, Journal Year: 2024, Volume and Issue: 16(10), P. 606 - 606

Published: Oct. 1, 2024

In this study, we propose a method for assessing the temporal and spatial distribution of Carcharhinus melanopterus in shallow waters using unmanned aerial vehicles (UAVs). Aerial surveys were conducted Tien Og Bay (Koh Tao, Thailand) thrice daily (morning, afternoon, evening) along 360 m transect at 30 altitude. Environmental factors, including cloudiness, sea conditions, wind, tide, anthropogenic disturbance, recorded each time slot. We developed Python/AppleScript application to facilitate individual counting, correlating sightings with GPS data measuring pixel-based length. Abundance varied significantly across slots (p < 0.001), strong morning preference, was influenced by tide = 0.040), favoring low tide. Additionally, abundance related disturbance 0.048), being higher when activity absent. Spatial analysis indicated time-related, sector-based differences 0.001). Pixel-based length converted Total Length, identifying juveniles. They exhibited sector preference 0.001) irrespective day. Juvenile remained relatively stable throughout day, constituting 94.1% afternoon observations. Between 2020 2022, an underwater video survey determine sex ratio individuals. Only females juveniles sighted bay.

Language: Английский

A Proposed Method for Assessing the Spatio-Temporal Distribution of Carcharhinus melanopterus (Quoy and Gaimard, 1824) in Shallow Waters Using a UAV: A Study Conducted in Koh Tao, Thailand DOI Creative Commons

Andrea Di Tommaso,

Sureerat Sailar,

Francesco Luigi Leonetti

et al.

Diversity, Journal Year: 2024, Volume and Issue: 16(10), P. 606 - 606

Published: Oct. 1, 2024

In this study, we propose a method for assessing the temporal and spatial distribution of Carcharhinus melanopterus in shallow waters using unmanned aerial vehicles (UAVs). Aerial surveys were conducted Tien Og Bay (Koh Tao, Thailand) thrice daily (morning, afternoon, evening) along 360 m transect at 30 altitude. Environmental factors, including cloudiness, sea conditions, wind, tide, anthropogenic disturbance, recorded each time slot. We developed Python/AppleScript application to facilitate individual counting, correlating sightings with GPS data measuring pixel-based length. Abundance varied significantly across slots (p < 0.001), strong morning preference, was influenced by tide = 0.040), favoring low tide. Additionally, abundance related disturbance 0.048), being higher when activity absent. Spatial analysis indicated time-related, sector-based differences 0.001). Pixel-based length converted Total Length, identifying juveniles. They exhibited sector preference 0.001) irrespective day. Juvenile remained relatively stable throughout day, constituting 94.1% afternoon observations. Between 2020 2022, an underwater video survey determine sex ratio individuals. Only females juveniles sighted bay.

Language: Английский

Citations

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