‘Habitat-associated soundscape’ hypothesis tested on several coral reefs within a lagoon (Bora-Bora Island, French Polynesia)

Coral reefs encompass diferent habitats that have their own living communities. The present study aimed to test the hypothesis that these diferent kinds of habitats were characterized by specifc soundscapes. Within the lagoon of Bora-Bora, acoustic recordings and visual surveys of substrate type and fish communities were conducted on four reef sites belonging to the three main geomorphological habitats (fringing reef, channel reef, barrier reef) from February to April 2021. Two acoustic parameters were measured for each site and month, during the day and at night: the peak frequency (Fpeak, in Hz) and the corresponding power spectral density (PSDpeak, in dB re 1 µPa2 Hz−1). Our results showed that each geomorphological unit could be characterized by these two parameters and therefore had a specifc acoustic signature. Moreover, our study showed that a higher living coral cover was signifcantly positively correlated with Fpeak in the low-frequency band (50–2000 Hz) during day-time. Although biodiversity indices based on visual surveys did not difer signifcantly, fsh communities and soundscapes were signifcantly diferent between sites. Overall, our study underlines the importance of passive acoustics in coral reef monitoring as soundscapes are habitat specific.