Behaviour of mesopredatory coral reef fishes in response to threats from sharks and humans

A. Asunsolo-Rivera*, E. Lester, T. Langlois, B. Vaughan, M. I. McCormick, S. D. Simpson, M. G. Meekan

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

3 Citations (Scopus)

Abstract

Both sharks and humans present a potentially lethal threat to mesopredatory fishes in coral reef systems, with implications for both population dynamics and the role of mesopredatory fishes in reef ecosystems. This study quantifies the antipredator behaviours mesopredatory fishes exhibit towards the presence of large coral reef carnivores and compares these behavioural responses to those elicited by the presence of snorkelers. Here, we used snorkelers and animated life-size models of the blacktip reef shark (Carcharhinus melanopterus) to simulate potential predatory threats to mesopredatory reef fishes (lethrinids, lutjanids, haemulids and serranids). The responses of these reef fishes to the models and the snorkelers were compared to those generated by three non-threatening controls (life-size models of a green turtle [Chelonia mydas], a PVC-pipe [an object control] and a Perspex shape [a second object control]). A Remote Underwater Stereo-Video System (Stereo-RUV) recorded the approach of the different treatments and controls and allowed accurate measurement of Flight Initiation Distance (FID) and categorization of the type of flight response by fishes. We found that mesopredatory reef fishes had greater FIDs in response to the approach of threatening models (1402 ± 402–1533 ± 171 mm; mean ± SE) compared to the controls (706 ± 151–896 ± 8963 mm). There was no significant difference in FID of mesopredatory fishes between the shark model and the snorkeler, suggesting that these treatments provoked similar levels of predator avoidance behaviour. This has implications for researchers monitoring behaviour in situ or using underwater census as a technique to estimate the abundance of reef fishes. Our study suggests that, irrespective of the degree to which sharks actually consume these mesopredatory reef fishes, they still elicit a predictable and consistent antipredator response that has the potential to create risk effects.

Original languageEnglish
Article number6714
JournalScientific Reports
Volume13
Issue number1
DOIs
Publication statusPublished - 25 Apr 2023

Bibliographical note

Funding Information:
We thank the staff at the Lizard Island Research Station and fieldwork assistance from Blair Bently, Ellen D’Cruz, Isla Davidson, Melinda Keighron, Harry Harding, and Tim Lamont. Jordan Goetze provided expertise for analysis of videos. We thank Brooke Gibbons and Diego Barneche for their help with data analysis. The project was funded by the Keiran McNamara World Heritage Scholarship and the Australian Institute of Marine Science.

Funding Information:
We thank the staff at the Lizard Island Research Station and fieldwork assistance from Blair Bently, Ellen D’Cruz, Isla Davidson, Melinda Keighron, Harry Harding, and Tim Lamont. Jordan Goetze provided expertise for analysis of videos. We thank Brooke Gibbons and Diego Barneche for their help with data analysis. The project was funded by the Keiran McNamara World Heritage Scholarship and the Australian Institute of Marine Science.

Publisher Copyright:
© 2023, The Author(s).

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