First documented coral spawning and coral spawn-slick observation in Seychelles

Information about the timing of tropical coral spawning is of ecological significance and impor- tance to local and regional marine managers. Observations of coral spawning have been abun- dant in certain regions of the Western Indian Ocean, but missing for Seychelles. In the current study, observations are presented on the maturation state and coral spawning event of four Acropora species at Airport Reef, Fregate Island, Seychelles (4°35’19S, 55°56’22N). In 2021, 2022, 2023 and 2024 colonies of the species Acropora abrotanoides, Acropora austera, Acropora muricata and Acropora digitifera participated in multi-species spawning during the third night following the full moon of October. Coral spawn slicks were also observed throughout the years during the night of the spawning and/or the following day after the spawning night. To the best of the authors’ knowledge, these findings represent the first observations of multi-species coral spawning events from reefs in Seychelles. Further research is needed to better understand coral spawning synchrony across species and to investigate the potential for multiple spawning events in the Seychelles region.