Role of natural and man-made structures as nurseries for coral reef fish

Abstract Coastal habitats have long been recognised to be nurseries for many marine organisms. The nursery role of different habitats for various fish species was investigated on a range of reef and coastal habitats on a coral reef island. Barrier and fringing reefs, pinnacles, tall vegetation zones, coastal rush and grass zones, mangroves, seawalls, and beaches were surveyed during three months in 2021 on the tropical island of Bora-Bora. Predators were most present on man-made walls, where the juvenile density was lowest. However, while juveniles were abundant on mangroves, the species richness was low. Using these results, the impact of urbanisation on coral reef fish was investigated and the validity and relevance of commonly-used nursery criteria were discussed within the frame of coral reef management. The island-wide approach of this study sets the ground to define targets for the preservation of ecosystems that play a key part in the life cycle of marine reef organisms.