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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13331

Effects of the cleaner fish Labroides dimidiatus on grazing fishes and coral reef benthos

Alexandra S. Grutter*, Sonia Bejarano, Karen L. Cheney, Anne W. Goldizen, Tane Sinclair-Taylor, Peter A. Waldie

*Corresponding author:

ABSTRACT: Territorial and roving grazing fishes, which farm algae and feed on algae, sediment, or detritus, exert differing influences on benthic community structure and are common clients of cleaner fish. Whether cleaners affect their diversity and abundance and, indirectly the benthos, was tested using reefs maintained free of cleaners (Labroides dimidiatus) for 8.5 years (removals) compared with controls. We quantified fish abundance per grazing functional group, rover foraging and cleaning rates, reef benthos composition, and fouling material on settlement tiles. Abundances of intensive and extensive territorial farmers, non-farmers, parrotfishes and Acanthurus spp. surgeonfishes were lower on removal than control reefs, but not for indeterminate farmers and Ctenochaetus striatus surgeonfish. Foraging rates of Acanthurus spp. and C. striatus individuals were not affected by cleaner presence, nor cleaning duration. This suggests some robustness of grazers’ foraging behaviour to loss of cleaners. Acanthurus individuals foraged predominantly on sediment and detritus, whereas C. striatus and parrotfishes grazed over algal turfs. Nevertheless, reef benthos percent cover and amount of organic and inorganic material accumulated over 3.5 months on tiles were not affected by cleaners. Thus, despite greater abundances of many roving grazers, and consequently higher grazing rates being linked to the presence of cleaners, the benthos was not detectably affected by cleaners. This reveals that the positive effect of cleaners on fish abundance is not associated with a subsequent change in the benthos as predicted. Rather it suggests a resilience of the benthic community structure to cleaner fish loss, possibly related to multiple antagonistic effects of different grazer functional groups.