Understanding variability in coral reef soundscapes to enable tool development and early warnings of ecosystem change

Coral reefs harbor some of the highest biodiversity on Earth. Their rich soundscape is vital to inhabiting animals and can provide a means of tracking community health. Reefs are facing immense climate stressors and are declining rapidly. Passive acoustic monitoring can provide a powerful, scalable tool for stakeholders, but these data are not evaluated on actionably relevant timescales. Here we present results from a long-term (10-years) acoustic and ecosystem study of multiple coral reefs in the U.S. Virgin Islands. Acoustic measurements (including snap rates, sound levels in low-frequency fish, and high-frequency shrimp bands) were made in-tandem with traditional, diver-based benthic and fish visual surveys. These key baseline data over multiple spatial and temporal scales provide a means of examining how soundscape changes are driven by climate-related stressors, and an important testbed for developing new analyses and tools. Here, we show how physical changes (temperature, light, coral disease) can influence the cue rates of snapping shrimp and fish, and apply novel tools including real-time recorders and underwater robots listening for biodiversity. These initial steps were then implemented into a novel rapid acoustic assessment, a key step toward providing actionable information to stakeholders monitoring for habitat change and weighing resource management.