Talking About the Weather: The Feasibility of Using Very High-Resolution Optical Satellite Imagery to Monitor Live and Stranded Cetaceans Around the UK and UK Overseas Territories

Monitoring live and stranded cetaceans can be expensive and logistically challenging, resulting in knowledge gaps. Very high-resolution (VHR) optical satellites are considered a potential solution to addressing some of these gaps. Despite success at detecting live and stranded cetaceans, satellites have only been trialed on restricted spatiotemporal scales. This project presents a framework for assessing the feasibility of using VHR optical satellite-based monitoring of cetaceans at high temporal frequency and local to global scales, focusing on the UK and UK Overseas Territories as a case study. We assess the primary environmental conditions necessary for the successful application of this technology: cloud cover and wind speed. Five-year monthly median “Total cloud cover” and “10m wind speed” ERA5 global reanalysis data were analyzed to map the spatial feasibility of satellite monitoring. We found that for the United Kingdom, VHR optical satellites could complement existing monitoring methods to achieve greater spatial and temporal coverage of live cetacean surveys, particularly, offshore, during the boreal spring and summer. However, satellites cannot address gaps in UK live cetacean monitoring in winter due to high wind speeds reducing whale detection probability. Based on environmental conditions, the tropics hold the greatest promise for achieving year-round satellite-based cetacean monitoring. In the Falkland Islands, particularly, the remote, unpopulated coastlines of West Island, satellites have the potential to improve strandings monitoring, opportunistically complementing existing stranding monitoring efforts.

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