Abstract
Aversive conditioning has been used with terrestrial predators to reduce conflict with humans by changing predator behavior or moving them away. Proving the effectiveness of this management tool for cryptic animals, however, can be challenging. In this study, we assessed the interaction between presence and sightability in Estuarine Crocodiles (Crocodylus porosus) after a period of aversive conditioning. Crocodiles > 2 m in length were subjected to aversive conditioning using two non-lethal beanbags fired from a 12-gauge shotgun. Traditional night-time surveys were conducted prior to and after aversive conditioning to determine any changes in crocodile sightability. To detect crocodiles underwater and their movement, we attached acoustic transmitters with a hand-held pole harpoon, which were monitored with an acoustic receiver array. This technique allowed for transmitter attachment without the need for capture. Immediately after aversive conditioning, there was a significant reduction in the sightability of larger Estuarine Crocodiles (> 2 m) using traditional spotlight survey, and a detectable change in the movement patterns of two of the three tagged individuals. The two tagged crocodiles resumed normal movement patterns soon after (42 h, 15 d) and no crocodiles left the area in response to the treatment. Aversive conditioning has limited use in moving crocodiles away from a discrete area; however, it did have a short-term impact on crocodile behavior and crocodiles became more challenging to detect by traditional spotlight survey. The reduced sightability may indicate an increased wariness of people, which in some circumstances may be an acceptable outcome for management.
| Original language | English |
|---|---|
| Pages (from-to) | 168-181 |
| Number of pages | 14 |
| Journal | Herpetological Conservation and Biology |
| Volume | 18 |
| Issue number | 1 |
| Publication status | Published - Apr 2023 |
Bibliographical note
Funding Information:Data was collected with support of the Queensland Government through the Department of Environment and Science (DES), and assistance from the Carpentaria Land Council Aboriginal Corporation Land and Sea rangers in Normanton. The project was undertaken in accordance with the Nature Conservation Act 1992, and the Code of Practice for Humane Treatment of Wild and Farmed Australian Crocodiles. The research was conducted under approval from the Animal Ethics Committee of the Charles Darwin University (approval number A18007). We would also like to thank Juergen Arnold of Melaleuca Crocodile Farm for assistance with captive tag attachment trials, and DES staff that assisted in the planning and collection of field data.
Publisher Copyright:
© 2023. Simon Booth All Rights Reserved.