Next Article in Journal
Multispectral, Aerial Disease Detection for Myrtle Rust (Austropuccinia psidii) on a Lemon Myrtle Plantation
Next Article in Special Issue
Estimating Mangrove Forest Volume Using Terrestrial Laser Scanning and UAV-Derived Structure-from-Motion
Previous Article in Journal
Thermal-Drones as a Safe and Reliable Method for Detecting Subterranean Peat Fires
Previous Article in Special Issue
Suggestions to Limit Geometric Distortions in the Reconstruction of Linear Coastal Landforms by SfM Photogrammetry with PhotoScan® and MicMac® for UAV Surveys with Restricted GCPs Pattern
Article Menu
Issue 1 (March) cover image

Export Article

Open AccessCommunication

A Rapid UAV Method for Assessing Body Condition in Fur Seals

School of Life and Environmental Sciences, Deakin University, Warrnambool, VIC 3280, Australia
CSIRO Health and Biosecurity, Townsville, QLD 4811, Australia
School of Life and Environmental Sciences, Deakin University, Burwood, VIC 3125, Australia
Author to whom correspondence should be addressed.
Drones 2019, 3(1), 24;
Received: 18 February 2019 / Revised: 5 March 2019 / Accepted: 5 March 2019 / Published: 6 March 2019
(This article belongs to the Special Issue Drones for Coastal Environments)
PDF [8588 KB, uploaded 8 March 2019]


Condition indices correlating body lipid content with mass and morphometric measurements have been developed for a variety of taxa. However, for many large species, the capture and handling of enough animals to obtain representative population estimates is not logistically feasible. The relatively low cost and reduced disturbance effects of UAVs make them ideal for the rapid acquisition of high volume data for monitoring large species. This study examined the imagery collected from two different UAVs, flown at 25 m altitude, and the subsequent georeferenced orthomosaics as a method for measuring length and axillary girth of Australian fur seals (Arctocephalus pusillus doriferus) to derive an index of body condition. Up to 26% of individuals were orientated correctly (prostrate/sternal recumbent) to allow for body measurements. The UAV-obtained images over-estimated axillary girth diameter due to postural sag on the lateral sides of the thorax while the animals are lying flat in the sternal recumbent position on granite rocks. However, the relationship between axillary girth and standard length was similarly positive for the remotely- and physically-obtained measurements. This indicates that residual values from the remotely-obtained measurements can be used as a relative index of body condition. View Full-Text
Keywords: body condition; axillary girth; Australian fur seals (Arctocephalus pusillus doriferus) body condition; axillary girth; Australian fur seals (Arctocephalus pusillus doriferus)

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Allan, B.M.; Ierodiaconou, D.; Hoskins, A.J.; Arnould, J.P. A Rapid UAV Method for Assessing Body Condition in Fur Seals. Drones 2019, 3, 24.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Metrics

Article Access Statistics



[Return to top]
Drones EISSN 2504-446X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top