Olfactory responses of coral-reef fishes to coral degradation and crown-of-thorns (Acanthaster planci)

Journal Publication ResearchOnline@JCU
Coppock, Amy G.;Gardiner, Naomi M.;Jones, Geoffrey P.
Abstract

Coral degradation is a major threat towards the biodiversity of coral-reef ecosystems, either through the physical effects of environmental change, or biological agents such as crown-of-thorns (Acanthaster planci). Coral loss is leading to significant declines in reef-fish assemblages, particularly those dependent on live coral as settlement sites. Most reef fishes use olfactory stimuli at settlement; however, their ability to detect chemical stimuli from degraded corals or A. planci is unknown. Here, olfactory responses of juvenile reef fishes to the presence of stressed corals and A. planci were tested. Juveniles of eight common coral-associated species were subjected to a series of pair-wise choice tests, where the period of time spent in two differing water sources was noted. All species demonstrated a significant attraction towards healthy coral (≥76%), avoiding cues emitted by stressed coral colonies. When given the choice between a control water (untreated reef water) and water containing chemical cues from A. planci, most species elicited no response. Finally, when given the choice between chemical cues derived from feeding A. planci or the control, all species avoided A. planci (≥70%). Our results indicated that juvenile reef fish are capable of distinguishing the state of coral health, but not directly from disturbance agents.

Journal

Marine and Freshwater Research

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Volume

67

ISBN/ISSN

1448-6059

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Issue

5

Pages Count

7

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Publisher

CSIRO

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EISSN

N/A

DOI

10.1071/MF14424