Patterns of coral disease distribution, frequency, and host susceptibility along Oman’s northern coast

Coral diseases are emerging as a significant global threat; however, their distribution and species susceptibility patterns remain understudied in many regions, including Oman’s reefs. To address this gap, we surveyed ten northeastern Omani reef sites, and documented disease types, spatial patterns, their frequency, and genus-specific susceptibility. We found five disease types: black band disease (BBD), white syndromes (WS), endolithic hypermycosis (EH), growth anomalies (GA), and focal bleached patches (fBL). These diseases affected nine out of 21 recorded coral genera. Overall, disease abundance was low, averaging 0.17 cases/m² across all sites, with the highest abundance at Inner Island (1.2 cases/m²), followed by Fahal Island East (0.11 cases/m²). GA were the most common lesions (82%), followed by tissue loss (6%), fBL (5%) and BBD (3.6%). GA affected Porites, Acropora, and Platygyra, while BBD, and tissue loss affected Porites, and Goniopora. The most frequently observed diseases were Platygyra GA, Porites GA, and Porites WS, each at 50% of surveyed sites, followed by Astreopora GA (40%), Porites BBD, and Porites fBL (30% of sites). Relative disease susceptibility varied across coral genera, with Porites, Platygyra, and Acropora exhibiting vulnerability to five, three, and one disease types, respectively. This baseline study on coral disease in Omani waters provides the first quantitative baseline assessment of coral diseases in the country and serves as a critical foundation for ongoing monitoring and conservation programs.