Geomorphological drivers of deeper reef habitats around Seychelles

This study investigates the geomorphological factors influencing the distribution of mesophotic coral ecosystems (MCEs) and rariphotic habitats in the Western Indian Ocean, focusing on coral atolls around the Seychelles. Using high-resolution multibeam sonar and underwater video surveys, the research explores how terrain features such as depth, slope, and substrate complexity affect the occurrence and composition of reef assemblages at depths ranging from 30 to 250 meters.

The study’s key findings highlight that complex geomorphological structures, such as terraces and paleo-shorelines, serve as critical habitats for these deeper reef ecosystems. These structures support high densities of benthic assemblages and are vital for biodiversity and conservation efforts. The research also reveals the limited vertical connectivity between shallow and deeper reefs, emphasising the distinct ecological characteristics of deeper reef assemblages.

The paper concludes with recommendations for conservation, noting that deeper reef habitats should be considered priority areas for marine management in Seychelles, particularly given their potential role as refuges for commercially important species like groupers and snappers.