Foraging and microhabitat use by crustacean‑feeding wrasses on coral reefs

Abstract

Crustaceans are an important component of coral reef ecosystems, occupying a broad range of microhabitats, but achieving the greatest biomass in dead coral and coral rubble. These 2 microhabitats are therefore hypothesised to be focal foraging locations for crustacean-feeding fishes. The present study investigated the relationship between foraging in wrasses (Labridae), a major group of crustacean predators, and 5 major microhabitats on a coral reef: live coral, dead coral, coral rubble, sand and the epilithic algal matrix (EAM). Although the greatest biomass of crustaceans typically occurs in dead coral and coral rubble, crustacean-feeding wrasses displayed positive selection for a more diverse range of microhabitats. In contrast, sand and live coral were not positively selected by any taxa. The relationships between crustacean predators and their prey appear to be more complicated than previously assumed, and may be mediated by habitat structure, preferred prey, predation risk and behavioural and morphological adaptations.