GenBank accessions for 18S rRNA gene amplicons from swab specimens collected in the Caribbean and Réunion (France) from May 2022 to Dec 2024

Investigating the cause of mass mortality of Diadema antillarum (urn:lsid:marinespecies.org:taxname:124332) identified the etiological agent as the Diadema antillarum Scuticociliatosis Philaster Clade (DaScPc). We sought to investigate the prevalence of this ciliate in sympatric reservoirs in the coral reef environment by targeted PCR using primers designed around this 18S rRNA sequence. We used swab sampling of corals, macroalgae, and other surfaces, followed by phylogenetic analyses, to identify the presence and diversity of this ciliate. We found that DaScPc could be found primarily in association with the coral Siderastrea siderea, and that changes in its prevalence could be explained by disease state of urchins, macroalgal density, and proximity to disease sites. This dataset contains the GenBank accession, sequencing, and collection metadata for the study.