Unmanned Aerial Vehicles (UAVs) for Surveying Marine Fauna: A Dugong Case Study
Open Access
- 4 November 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (11), e79556
- https://doi.org/10.1371/journal.pone.0079556
Abstract
Aerial surveys of marine mammals are routinely conducted to assess and monitor species’ habitat use and population status. In Australia, dugongs (Dugong dugon) are regularly surveyed and long-term datasets have formed the basis for defining habitat of high conservation value and risk assessments of human impacts. Unmanned aerial vehicles (UAVs) may facilitate more accurate, human-risk free, and cheaper aerial surveys. We undertook the first Australian UAV survey trial in Shark Bay, western Australia. We conducted seven flights of the ScanEagle UAV, mounted with a digital SLR camera payload. During each flight, ten transects covering a 1.3 km2 area frequently used by dugongs, were flown at 500, 750 and 1000 ft. Image (photograph) capture was controlled via the Ground Control Station and the capture rate was scheduled to achieve a prescribed 10% overlap between images along transect lines. Images were manually reviewed post hoc for animals and scored according to sun glitter, Beaufort Sea state and turbidity. We captured 6243 images, 627 containing dugongs. We also identified whales, dolphins, turtles and a range of other fauna. Of all possible dugong sightings, 95% (CI = 90%, 98%) were subjectively classed as ‘certain’ (unmistakably dugongs). Neither our dugong sighting rate, nor our ability to identify dugongs with certainty, were affected by UAV altitude. Turbidity was the only environmental variable significantly affecting the dugong sighting rate. Our results suggest that UAV systems may not be limited by sea state conditions in the same manner as sightings from manned surveys. The overlap between images proved valuable for detecting animals that were masked by sun glitter in the corners of images, and identifying animals initially captured at awkward body angles. This initial trial of a basic camera system has successfully demonstrated that the ScanEagle UAV has great potential as a tool for marine mammal aerial surveys.Keywords
This publication has 38 references indexed in Scilit:
- Estimating Distribution of Hidden Objects with Drones: From Tennis Balls to ManateesPLOS ONE, 2012
- Monitoring Winter and Summer Abundance of Cetaceans in the Pelagos Sanctuary (Northwestern Mediterranean Sea) Through Aerial SurveysPLOS ONE, 2011
- Informing Species Conservation at Multiple Scales Using Data Collected for Marine Mammal Stock AssessmentsPLOS ONE, 2011
- Chilean Blue Whales as a Case Study to Illustrate Methods to Estimate Abundance and Evaluate Conservation Status of Rare SpeciesConservation Biology, 2011
- Rapid Assessment of Risks to a Mobile Marine Mammal in an Ecosystem‐Scale Marine Protected AreaConservation Biology, 2008
- The influence of animal mobility on the assumption of uniform distances in aerial line-transect surveysWildlife Research, 2008
- NORTH ATLANTIC RIGHT WHALE DISTRIBUTION IN RELATION TO SEA‐SURFACE TEMPERATURE IN THE SOUTHEASTERN UNITED STATES CALVING GROUNDSMarine Mammal Science, 2006
- Aerial surveys and the potential biological removal technique indicate that the Torres Strait dugong fishery is unsustainableAnimal Conservation, 2004
- The Indo-Pacific Humpback Dolphin, Sousa chinensis (Osbeck, 1765), in Australian Waters: A Summary of Current KnowledgeAquatic Mammals, 2004
- An Experimental Evaluation of Dugong and Sea Turtle Aerial Survey TechniquesWildlife Research, 1989