The Potential of Satellite Imagery for Surveying Whales
A newly published paper sets out the stall of a collaboration of researchers, including HiDef, sister company BioConsult SH and British Antarctic Survey. The emergence of very high-resolution (VHR) satellite imagery (less than 1 m spatial resolution) is creating new opportunities within conservation. The advancement of sub-meter resolution imagery has provided greater confidence in the detection and identification of features on the ground. With advances in computational power and sensor resolution, the feasibility of broad-scale VHR ocean surveys using VHR satellite imagery with automated detection and classification processes has increased. Initial attempts at automated surveys are showing promising results, but further development is necessary to ensure reliability. A newly published paper discusses the future directions in which VHR satellite imagery might be used to address urgent questions in whale conservation.
The study of wildlife using satellite imagery commenced with the Landsat-1 satellite (80 m spatial resolution), initially launched in 1972 to monitor land cover, and later extended for habitat surveys and to map the distribution range of some species. Since then, there have been several technical developments, including improvements of optical sensors for an increased spatial resolution, with the development of VHR satellite allowing a sub-meter spatial resolution, allowing the detection of individual animals such as cattle, elephants, polar bears, grey seals, and albatrosses.
Monitoring whales using VHR satellite imagery was first attempted 2002; however, the 0.82 m spatial resolution provided by this satellite was not sufficient to make confident identifications. A change in US legislation in August 2014 increased the maximum spatial resolution for commercial satellite operators to 0.25 m. Rather than coarse imagery with rudimentary outlines of large objects, the greater spatial resolution of 0.25 m imagery allows the capture of more detail where smaller features can be identified with greater confidence. The launch of the WorldView-3 satellite in 2016, offering the highest commercially available spatial resolution of 0.31 m, is capable of capturing whale-defining features such as flukes, increasing the confidence in detections and making this satellite the most adapted for whale surveys.
Traditional cetacean surveys are challenging and expensive, often requiring dedicated research vessels or aircraft and are thus limited. Much of the ocean’s surface has not been surveyed for whales leaving large knowledge gaps that hinder efforts to make sound conservation decisions. VHR satellite imagery has the potential to fill knowledge gaps in whale research, allowing access to remote regions, as well as surveys of large spatial scope.
Further reading: https://www.mdpi.com/1424-8220/21/3/963/htm
Caroline Höschle, Hannah C. Cubaynes, Penny J. Clarke, Dr. Grant Humphries and Alex Borowicz.
BioConsult SH GmbH & Co.KG, Schobüller Str. 36, 25813 Husum, Germany
British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
Scott Polar Research Institute, Department of Geography, University of Cambridge, Cambridge CB2 1TN, UK
UK Antarctic Heritage Trust, High Cross, Madingley Road, Cambridge CB3 0ET, UK
HiDef Aerial Surveying Limited, 17 Silvermills Court, Edinburgh EH3 5DG, UK
Department of Ecology & Evolution, Stony Brook University, New York, NY 11794, USA