Coral Reefs

pp 1–11

Clarifying functional roles: algal removal by the surgeonfishes Ctenochaetus striatus and Acanthurus nigrofuscus

  • Sterling B. Tebbett
  • Christopher H. R. Goatley
  • David R. Bellwood
Report

DOI: 10.1007/s00338-017-1571-z

Cite this article as:
Tebbett, S.B., Goatley, C.H.R. & Bellwood, D.R. Coral Reefs (2017). doi:10.1007/s00338-017-1571-z

Abstract

The lined bristletooth, Ctenochaetus striatus, and the brown surgeonfish, Acanthurus nigrofuscus, are among the most abundant surgeonfishes on Indo-Pacific coral reefs. Yet, the functional role of these species has been the focus of an ongoing debate lasting at least six decades. Specifically, to what extent are C. striatus herbivorous like the visually similar A. nigrofuscus? To address this question, we used natural feeding surfaces, covered with late successional stage reef-grown algal turfs, to examine turf algal removal by the two species. Surfaces exposed to C. striatus in laboratory experiments exhibited no significant reductions in turf length or area covered by turfing algae. In marked contrast, A. nigrofuscus reduced turf length by 51% and area covered by turfing algae by 15% in 1 h. The gut contents of specimens from the reef revealed that A. nigrofuscus predominantly ingests algae (the dominant item in 79.6–94.7% of gut content quadrats), while C. striatus ingests detritus and sediments (dominant in 99.6–100% of quadrats). Therefore, C. striatus ingests detritus and sediment, leaving mature algal turfs relatively intact, while A. nigrofuscus directly removes and ingests turf algae. The function of C. striatus differs from cropping herbivorous surgeonfishes such as A. nigrofuscus. On coral reefs, C. striatus brush detrital aggregates from algal turfs, removing microorganisms, organic detritus and inorganic sediment. Confusion over the functional role of C. striatus may stem from an inability to fit it into a single functional category.

Keywords

Coral reef Herbivory Detritivory Epilithic algal matrix Algal turfs 

Supplementary material

338_2017_1571_MOESM1_ESM.docx (339 kb)
Supplementary material 1 (DOCX 338 kb)

Funding information

Funder NameGrant NumberFunding Note
Australian Research Council
  • DP140100122
  • CE140100020

Copyright information

© Springer-Verlag Berlin Heidelberg 2017

Authors and Affiliations

  • Sterling B. Tebbett
    • 1
  • Christopher H. R. Goatley
    • 1
    • 2
  • David R. Bellwood
    • 1
  1. 1.ARC Centre of Excellence for Coral Reef Studies and College of Science and EngineeringJames Cook UniversityTownsvilleAustralia
  2. 2.Function, Evolution and Anatomy Research Lab, School of Environmental and Rural ScienceUniversity of New EnglandArmidaleAustralia

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