Visualization and quantification of coral reef soundscapes using CoralSoundExplorer software

Despite hosting some of the highest concentrations of biodiversity and providing invaluable goods and services in the oceans, coral reefs are under threat from global change and other local human impacts. Changes in living ecosystems often induce changes in their acoustic characteristics, but despite recent efforts in passive acoustic monitoring of coral reefs, rapid measurement and identification of changes in their soundscapes remains a challenge. Here we present the new open-source software CoralSoundExplorer (https://sound-scape-explorer.github.io/docs/CSE/), which is designed to study and monitor coral reef soundscapes. CoralSoundExplorer uses deep learning approaches and is designed to eliminate the need to extract conventional acoustic indices. To demonstrate CoralSoundExplorers functionalities, we use and analyze a set of recordings from three coral reef sites, each with different purposes (undisturbed site, tourist site and boat site) located on the island of Bora-Bora in French Polynesia. We explain the CoralSoundExplorer analysis workflow, from raw sounds to ecological results, detailing and justifying each processing step. We detail the software settings, the graphical representations used for visual exploration of soundscapes and their temporal dynamics, along with the analysis methods and metrics proposed. We demonstrate that CoralSoundExplorer is a powerful tool for identifying disturbances affecting coral reef soundscapes, combining visualizations of the spatio-temporal distribution of sound recordings with new quantification methods to characterize soundscapes at different temporal scales. Author summaryTodays scientists are faced with the challenge of analyzing large amounts of data, such as those generated by passive acoustic monitoring of ecosystems. We have built CoralSoundExplorer (https://sound-scape-explorer.github.io/docs/CSE/), an efficient tool for analyzing large datasets of sound recordings, which transforms coral reef soundscape recordings into visual representations in 2D or 3D spaces. By spreading them across easy-to-explore acoustic spaces, CoralSoundExplorer enables the observer to quickly grasp the characteristics of soundscapes, their differences and similarities, and their organization on different temporal scales. These acoustic spaces and their temporal dynamics can be quantified, for example to account for the speed at which soundscapes change over time. In this study, we take the example of reef soundscapes from the island of Bora-Bora to illustrate the features and possibilities offered by CoralSoundExplorer. CoralSoundExplorer is open source and easy to use, even for non-specialists, thanks to an interface that requires no coding skills. We provide detailed instructions for installing and using CoralSoundExplorer to help users get started easily. CoralSoundExplorer needs to be installed on a computer to perform the analyses and calculations based on sound recordings. There is also an online interface (https://sound-scape-explorer.github.io/coral-sound-explorer/) enabling users to visualize data that have already been processed by CoralSoundExplorer.