MEPS 411:299-302 (2010)  -  DOI: https://doi.org/10.3354/meps08660

ABSTRACT: Algal size has often been related to shifts in the susceptibility of algae to herbivores. Within coral reef systems, macroalgal assays have been widely used to quantify herbivory; however, the effect of macroalgal size has been largely overlooked. I used Sargassum polycystum assays that spanned the range of available heights (10 to 80 cm) and underwater video cameras to examine the effect of macroalgal height on the rates and agents of herbivory on an inner-shelf reef of the Great Barrier Reef. Rates of herbivory were high and displayed limited variation among heights, ranging from 86.4 to 95.2% 5h^–1. There was, however, significant variation in the species recorded feeding from S. polycystum of different heights. Naso unicornis dominated feeding on the shortest (10 cm) assays, while Kyphosus vaigiensis dominated feeding on the larger (20 to 80 cm) assays. This variation appears to be related to interspecific differences in foraging behaviour, and suggests that the roles of these fishes may change at different stages of benthic community succession.

KEY WORDS: Herbivory · Sargassum spp. · Algal succession · Resilience