Flight response of the barber surgeonfish, Acanthurus bahianus Castelnau, 1855 (Teleostei: Acanthuridae), to spearfisher presence

Larissa J Benevides,Cláudio L S Sampaio,José De Anchieta C C Nunes,Tiego L A Costa

doi:10.1590/1982-0224-20150010

Abstract

ABSTRACT When confronted by predators, prey need to make an economic decision between continuing their current activity or flee. Flight Initiation Distance (FID), the distance at which an organism begins to flee an approaching threat, has been used to indicate an animal's fearfulness level and a way to examine factors influencing escape decisions. Here we investigated how the FID of the barber surgeonfish, Acanthurus bahianus, responds to the presence of spearfishers in a fishing site in northeast Brazil. Specifically, we examined whether the FID was influenced by body and group size; by the heterogeneity of species in groups formation; and the distance to shelter. Significant differences in FID were observed with increasing body size. We found no significant relationship of FID with size or group formation, neither with distance to shelter. Preferences in forming groups with A. bahianus were seen among some species, and a higher FID was associated with less sheltered substrates. Results obtained here support theories suggesting that spearfishers do influence fish behavior. We highlight that future research should focus on the indirect impacts of spearfishing on the structure of marine communities, emphasizing the anti-predator behaviour of juvenile and adult target fishes.

Highlights

Risk perception in animals can be a result of the evolution of prey defensive traits in response to predator hunting behaviour (Abrams, 2000)
Flight Initiation Distance (FID) varied between the main substrates (ANCOVA; F = 3.95, p = 0.028) (Table 1) with greater flight distances observed where there was a higher percentage of sand substrate (Fig. 3)
We investigated FID of Acanthurus bahianus when confronted with a spearfisher

Summary

Introduction

Risk perception in animals can be a result of the evolution of prey defensive traits in response to predator hunting behaviour (Abrams, 2000). Prey may adaptively respond to predators by becoming more vigilant and loosing foraging opportunities; remaining inactive and increasing the risk of capture (Brown et al, 2001), or by moving away (flee) from an approaching threat (Dill, 1974). The main metric used to test risk perception and escape responses in wild animals is known as Flight Initiation Distance or FID. This index estimates the shorter distance at which the prey begins to flee from the predator approach (Ydenberg & Dill, 1986; Cooper & Frederick, 2007). FID has been used to examine the vigilance levels in a number of taxa, including birds (Blumstein, 2006), ungulates (Stankowich, 2008), lizards (Cooper, 2009), anurans (Bateman & Fleming, 2014), and fishes, which have been specially studied in the context of fishing (Feary et al, 2011; Januchowski-Hartley et al, 2012)

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