Environmental and acoustic drivers of fish recruitment along degraded coral reefs

The global degradation of coral reefs threatens the persistence of fish assemblages, and protection-based management strategies alone may be insufficient to support their recovery. A key shortfall lies in the limited understanding of how habitat conditions shape fish recruitment along degraded reefs. In this study, we investigated how substrate composition, substrate rugosity, adult fish assemblages, and underwater soundscapes influence recruit abundance and richness. We found that rugosity was a consistent positive predictor of recruitment across degradation gradients. In contrast, benthic dominance by turf algae or soft corals was negatively associated with recruitment. While no clear relationships were found between adult and recruit assemblages, louder nighttime fish choruses-indicative of a healthy reef environment-were positively associated with recruit richness in less degraded reefs. These findings underscore the need to move beyond protection alone and adopt multidimensional approaches that account for both habitat structure and ecological signaling in degraded reef ecosystems.