Publication Date

12-2022

Series Number

FRR No. 329

ISBN

978-1-921845-32-1

ISSN

2202-5758

Abstract

This project trialled the use of remote cameras to monitor the relative abundance of Australian sea lions (ASLs, Neophoca cinerea) at three Western Australian (WA) breeding colonies. The research was undertaken by the Department of Primary Industries and Regional Development (DPIRD) to assess whether the analysis of camera footage could be used to estimate ASL relative abundance, providing an alternative to the traditional “boots on the ground” approach (hereon in “BoG”) of visiting colonies to count animals. This report outlines the strengths and limitations of this novel approach rather than providing an update on the population status of ASLs.

Remote cameras and associated infrastructure were installed at Buller Island, Haul Off Rock and Wickham Island in the second half of 2018, after which camera images were manually interpreted with the intention of capturing data over an 18-month period (i.e., approximately one reproductive cycle). Overall, counts of ASLs were obtained from the analysis of 563 days (~6,700 hours) of camera footage. These data comprised the number of ASLs identified within the field of view (FoV) of each camera which represented relative abundance estimates for each colony. Day to day variations in the relative abundance of ASLs were estimated for Buller Island and Wickham Island, with limited data on ASL abundance collected for Haul Off Rock due to camera outages. The time series analysis applied to the Buller Island data provides the most detailed information within a single reproductive cycle at a WA colony. To ‘value-add’ from the original aims of the study, remote piloted aircraft (RPA) operations were also conducted within the Recherche Archipelago to provide a greater understanding of the potential application of both methods for on-going monitoring.

In summary, the diversity and remoteness of ASL colonies in WA means that no single survey method is likely to be appropriate for the monitoring of all colonies. Installing and maintaining remote cameras at 32 known ASL breeding colonies would be cost-prohibitive and logistically impractical. Instead, camera monitoring at strategic ASL colonies would provide a realistic prospect of collecting long-term abundance data for hard-to-reach Western Australian colonies which remains a challenging prospect using BoG surveys. The ability to view live camera footage could assist with the scheduling of BoG surveys so that on-site surveys can be conducted regularly and safely. Such an approach would require more formal research arrangements to be established between the various state agencies responsible for managing wildlife and fisheries. This project has provided an extensive permanent digital library of camera images that can be made available for use in subsequent ecological and fisheries-related studies.

Number of Pages

78

Keywords

Digital cameras, novel monitoring tools, Australian sea lion, breeding colony

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