[MARMAM] New Paper - UAV aerial surveys

[Amanda Hodgson]

Hello all

We have just published the following paper describing a trial of an
Unmanned Aerial Vehicle for surveying dugongs. The pdf of the paper can be
downloaded from the PLoS ONE link below.

cheers
Amanda


http://dx.plos.org/10.1371/journal.pone.0079556


Unmanned Aerial Vehicles (UAVs) for Surveying Marine Fauna: a Dugong Case
Study

Amanda Hodgson (1); Natalie Kelly (2,3); David Peel (2,3).

(1) Murdoch University Cetacean Research Unit, School of Veterinary and
Life Sciences, Murdoch University, Murdoch, Western Australia, Australia
(2) CSIRO Computational Informatics and Wealth from Oceans National
Research Flagship, Hobart, Tasmania, Australia
(3) Australian Marine Mammal Centre, Kingston, Tasmania, Australia

Corresponding author: a.hodgson at murdoch.edu.au

Abstract

Aerial surveys of marine mammals are routinely conducted to assess and
monitor species¹ 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 Œcertain¹ (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.