Algae associated with coral degradation affects risk assessment in coral reef fishes

McCormick, Mark I., Barry, Randall P., and Allan, Bridie J.M. (2017) Algae associated with coral degradation affects risk assessment in coral reef fishes. Scientific Reports, 7. 16937.

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Habitat degradation alters the chemical landscape through which information about community dynamics is transmitted. Olfactory information is crucial for risk assessment in aquatic organisms as predators release odours when they capture prey that lead to an alarm response in conspecific prey. Recent studies show some coral reef fishes are unable to use alarm odours when surrounded by dead-degraded coral. Our study examines the spatial and temporal dynamics of this alarm odour-nullifying effect, and which substratum types may be responsible. Field experiments showed that settlement-stage damselfish were not able to detect alarm odours within 2 m downcurrent of degraded coral, and that the antipredator response was re-established 20-40 min after transferral to live coral. Laboratory experiments indicate that the chemicals from common components of the degraded habitats, the cyanobacteria, Okeania sp., and diatom, Pseudo-nitzschia sp.prevented an alarm odour response. The same nullifying effect was found for the common red algae, Galaxauria robusta, suggesting that the problem is of a broader nature than previously realised. Those fish species best able to compensate for a lack of olfactory risk information at key times will be those potentially most resilient to the effects of coral degradation that operate through this mechanism.

Item ID: 51892
Item Type: Article (Research - C1)
ISSN: 2045-2322
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Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit

Funders: ARC Centre of Excellence for Coral Reef Studies, Australian Research Council (ARC)
Projects and Grants: ARC CoE EI140100117, ARC Discovery grant DP170103372
Research Data:
Date Deposited: 27 Dec 2017 07:42
FoR Codes: 31 BIOLOGICAL SCIENCES > 3103 Ecology > 310305 Marine and estuarine ecology (incl. marine ichthyology) @ 75%
41 ENVIRONMENTAL SCIENCES > 4101 Climate change impacts and adaptation > 410102 Ecological impacts of climate change and ecological adaptation @ 25%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 75%
96 ENVIRONMENT > 9603 Climate and Climate Change > 960399 Climate and Climate Change not elsewhere classified @ 25%
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