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

Marshell, A. and Mumby, P.J. (2012) Revisiting the functional roles of the surgeonfish Acanthurus nigrofuscus and Ctenochaetus striatus. Coral Reefs, 31 4: 1093-1101. doi:10.1007/s00338-012-0931-y


Author Marshell, A.
Mumby, P.J.
Title Revisiting the functional roles of the surgeonfish Acanthurus nigrofuscus and Ctenochaetus striatus
Formatted title
Revisiting the functional roles of the surgeonfish Acanthurus nigrofuscus and Ctenochaetus striatus
Journal name Coral Reefs   Check publisher's open access policy
ISSN 0722-4028
1432-0975
Publication date 2012-12
Sub-type Article (original research)
DOI 10.1007/s00338-012-0931-y
Volume 31
Issue 4
Start page 1093
End page 1101
Total pages 9
Place of publication Heidelberg, Germany
Publisher Springer
Collection year 2013
Language eng
Formatted abstract
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.
Keyword Surgeonfish
Herbivore
Detritivore
Functional groups
Ecological role
Algal turf
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Published online: 04 July 2012

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Biological Sciences Publications
 
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Created: Fri, 14 Sep 2012, 10:37:51 EST by Gail Walter on behalf of School of Biological Sciences