Abstract

Reef fishes are an important component of marine biodiversity, and changes in the composition of the assemblage structure may indicate ecological, climatic, or anthropogenic disturbances. To examine spatial differences in the reef fish assemblage structure around Easter Island, eight sites were sampled during autumn and summer 2016-2017 with baited remote underwater video systems. To determine seasonal changes, quarterly (seasonal) sampling was conducted at five of those eight sites. Fifteen pelagic species of fishes were recorded during this study, some of which have not previously been recorded in scuba surveys, including the Galapagos shark (Carcharhinus galapagensis, Snodgrass & Heller, 1905) and tunas (Scrombidae). Significant spatial and seasonal differences were found in the fish assemblage. Fish assemblages from the south coast differed significantly from those along the west and east coasts, mainly due to the occurrence of top predators. Winter differed from other seasons, especially along the south coast where the island is more exposed to large oceanic swells and winds from Antarctica. Owing to the variety and high relative abundance of species recorded during this survey, baited remote underwater video systems seemed to be an effective method for studying top predators at Easter Island. The identification of priority zones for the protection of top predator species represents an important contribution of this study, in order to develop management and conservation strategies to be implemented in the newly created Rapa Nui multiple uses coastal marine protected areas.