Acoustic diversity of photic and mesophotic coral reefs of the Caribbean collected during the expedition DEEPLIFE

Passive acoustic monitoring is an effective tool for assessing the ecosystem diversity and ecology of soniferous species. Compared to traditional methods, it offers lower materials costs and the ability to record continuously under various conditions, including more difficult-to-reach habitats. This thesis aims to assess the acoustic diversity of coral reefs in Guadeloupe and test statistical differences between the levels of the factor depth and the levels of the factor period (day and night). A total of eight days of continuous recordings from the coral reefs of Guadeloupe at depths of 6, 50 and 120 meters were subsampled at 4kHz, as fish are known to vocalize at those frequencies. The recordings were visually and acoustically inspected. Sound-types from fish and invertebrates were classified, but invertebrate sounds were excluded from the statistical analyses, due to difficulties in distinguishing them. The abundance, richness and Shannon diversity were calculated, and differences among depths and periods were tested. A total of 110 distinct sound-types were identified, 42 of which were common across all investigated depths, suggesting a degree of continuity between populations at these levels, other than the unique species and ecological behaviors typical of each depth. Statistical analyses revealed significant differences between the three depths investigated, in line with previous studies, but no statistical differences between day and night have been detected. This could be attributed to the limited sample size, the period of recordings or site-specific factors. This thesis represents the first assessment of the acoustic diversity of photic and mesophotic coral reefs in Guadeloupe. Further research is necessary to expand knowledge on these ecosystems and enrich the acoustic bibliography of the Caribbean Islands. Additionally, more studies carried out with the same methods are needed to ensure comparability and consistent classification of sound-types.