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Revisiting the functional roles of the surgeonfish Acanthurus nigrofuscus and Ctenochaetus striatus


Marshell, A and Mumby, PJ, Revisiting the functional roles of the surgeonfish Acanthurus nigrofuscus and Ctenochaetus striatus, Coral Reefs, 31, (4) pp. 1093-1101. ISSN 0722-4028 (2012) [Refereed Article]

Copyright Statement

Copyright Springer-Verlag 2012

DOI: doi:10.1007/s00338-012-0931-y


Investigating the functional role of herbivorous fish species is important for understanding reef resilience and developing targeted management plans. Among the most abundant fish species on Indo-Pacific coral reefs are the surgeonfishes Acanthurus nigrofuscus and Ctenochaetus striatus. A. nigrofuscus is an herbivorous grazer that crops filamentous algae from the epilithic algal matrix, while C. striatus is detritivorous and was thought to ‘brush’ detritus from the surface of filamentous algae, causing little damage to algal strands. Although the foraging mechanisms and general diet of these surgeonfishes have been established, their grazing impact on epilithic algal turfs has been unclear. This is the first study to quantify the grazing impact of A. nigrofuscus and C. striatus on algal turfs. Through aquaria trials using epilithic algal turf grown on experimental tiles, we found that both A. nigrofuscus and C. striatus consistently fed more intensively upon sparse/short algal turfs even though the yield of algae per bite was greater for dense/long algal turfs. As there was no difference in the nutritional value of sparse and dense algal turfs, we hypothesise that A. nigrofuscus avoided dense turf due to its significantly greater sediment load than sparse turf, while C. striatus likely avoided dense turf as it would become entangled in their bristle-like teeth. Unexpectedly, despite its dental morphology, C. striatus removed significantly more algal turf per hour than A. nigrofuscus, irrespective of canopy height. The capability of C. striatus to remove significant quantities of algal turf through their foraging activity implies that this abundant and widespread species may substantially affect algal turf dynamics. If this is the case, the exclusion of detritivorous Ctenochaetus species from herbivorous fish functional groups used in resilience monitoring will need to be re-evaluated.

Item Details

Item Type:Refereed Article
Keywords:surgeonfish, herbivore, detritivore, functional groups, ecological role, algal turf
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Assessment and management of benthic marine ecosystems
UTAS Author:Marshell, A (Dr Alyssa Marshell)
ID Code:150927
Year Published:2012
Web of Science® Times Cited:39
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2022-07-06
Last Modified:2022-08-04

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