Growth and opportunities for drone surveillance in pinniped research

Abstract

Pinniped species undergo uniquely amphibious life histories that make them valuable subjects for many domains of research. Pinniped research has often progressed hand‐in‐hand with technological frontiers of wildlife biology, and drones represent a leap forward for methods of aerial remote sensing, enabling data collection, and integration at new scales of biological importance. Drone methods and data types provide four key opportunities for wildlife surveillance that are already advancing pinniped research and management: 1) repeat and on‐demand surveillance, 2) high‐resolution coverage at large extents, 3) morphometric photogrammetry, and 4) computer vision and deep learning applications. Drone methods for pinniped research represent early stages of technological adoption and can reshape the field as they scale towards the full potential of their techniques.

An unmanned aerial vehicle pipeline to estimate body volume at scale for ecological monitoring

“…We expect GSDs less than 0.8cm px -1 would further improve the percentage success rate of reconstructing seals so their volumes can be estimated and the accuracy of these estimates. However, we were limited to surveying at an altitude ≥ 40 m to ensure seals were not disturbed (Pomeroy et al, 2015; Larsen & Johnston, 2023) and by the resolution of off-the-shelf, affordable UAVs.…”

“…Figure B2 (Box 2) presents an overview of our pipeline, and the five stages of the pipeline are described in more detail throughout the Methods section. Key insights include that a UAV that can survey at a GSD of 0.8 cm px -1 whilst at ≥ 40 m in altitude (ensuring no disturbance to animals; Pomeroy et al, 2015;Larsen & Johnston, 2023) is optimal for resolving the trade-off between data quality and the cost of data collection for species the size of UK grey seals. In addition, using a transect survey pattern instead of a radial pattern obtains volume estimates on a much wider-scale (e.g., population vs small group).…”

“…We launched missions from land or boat depending on the accessibility of landing sites at a safe distance from seals. We maintained an in-flight altitude of ≥ 40 m when surveying and took-off and landed UAVs > 50 m from seals to avoid disturbance (Pomeroy et al, 2015; Larsen & Johnston, 2023). Seal and seabird behaviour were monitored during flights to ensure no disturbance.…”

“…We tested GSDs of 0.8 cm px -1 (40 m altitude with DJ Mavic 2 Enterprise Advanced; n = 154 adults, 88 pups), 1.0 cm px -1 (50 m; n = 178 adults, 27 pups), 1.2 cm px -1 (60 m; n = 87 adults, 59 pups), and 1.4 cm px -1 (70 m; n = 18 adults, 9 pups) (Table 1). We did not test altitudes lower than 40 m to avoid disturbing seals (Pomeroy et al, 2015; Larsen & Johnston, 2023). All 23 missions from the Isles of Scilly and one mission from the Farne Islands were analysed here.…”

“…UAVs have diverse applications in ecology and conservation biology, ranging from crop monitoring to assessing forest health (Anderson & Gaston, 2013;Maimaitijiang et al, 2020;Sun et al, 2021;Ecke et al, 2022;Larsen & Johnston, 2023). Recent advancements have made UAVs suitable for collecting continuous state demographic data (e.g., body size) from populations that would otherwise be challenging to study (Krause et al, 2017;Shero et al, 2021;Christiansen et al, 2022).…”