Investigating drivers of Mediterranean coralligenous fish communities using passive acoustic monitoring: the role of thermal environment, day length and moon phases

The Mediterranean coralligenous reef is a vital ecosystem that provides essential habitat for various marine species. However, it faces growing threats due to human activities and climate change, particularly rising sea temperature and marine heat waves. While the impact of thermal anomalies on habitat-forming species is well-documented, their effects on associated fish communities remain understudied. This study investigates the role of the thermal environment, day length, and moon phases in shaping the acoustic community of coralligenous fish using passive acoustic monitoring. Acoustic data collected from two coralligenous reefs in Sardinia, between June and August 2023, revealed seventeen distinct sound types, six of which were attributed to four known species. The Generalized Linear Latent Variable Model highlighted the significant influence of mean daily temperature, temperature variation, and heating events on the abundance of most sound types, with higher temperatures generally correlating with increased sound production. However, some species exhibited reduced vocal activity in response to elevated temperatures, indicating species-specific responses. The study also found that reduced day length and moon phases influenced sound production, even though the thermal descriptors were more important in explaining fish sound abundance. These findings underscore the importance of temperature in shaping the fish acoustic community of coralligenous reefs and provide insights for the potential impacts of climate change on this marine ecosystem. Moreover, the study highlights the need for further research on the effects of sea warming on coralligenous fish assemblages.