ABSTRACT
Parrotfishes are commonly classified into three main feeding modes, or functional groups, based largely on differences in the osteology and myology of the oral and pharyngeal jaws: excavators, scrapers, and browsers. These functional groups have provided a useful framework for assessing the disturbance impact of parrotfish assemblages of the reef substratum, however such approaches often obscure important variation among species. This chapter explores how the disturbance impacts (or effects) of parrotfish feeding on benthic reef communities vary among species, and with body size and temperature. The chapter starts by describing differences in the morphology of the feeding apparatus of parrotfishes and relate these to differences in feeding rate and feeding impact among species. It then explores the influence of body size on the rate of feeding, and the disturbance of individual bites on the reef surface, both among and within species. The evidence presented in this chapter reveal the overwhelming effect of body size on the amount of material that is scraped or excavated from reef surfaces, and questions the commonly accepted functional classification of this group. The chapter concludes that incorporating species- and size-specific metrics of feeding, together with the influence of environmental conditions (e.g., temperature) and nutrition will greatly expand our understanding of the causes and consequences of feeding among parrotfishes
