Spatial extent, population size and demographics of Cycloseris distorta and C. fragilis within a large mesophotic mushroom coral bed off Ningaloo Reef, north-western Australia

Researchers have identified the largest known mesophotic mushroom coral bed, spanning 82 hectares off Ningaloo Reef in north-western Australia. This dense bed, composed primarily of Cycloseris distorta and C. fragilis, hosts an estimated 653 million individuals with densities exceeding 1100 corals per square meter at some sites. The bed is situated in a narrow depth range (35.5–40.7 meters), suggesting optimal environmental conditions or minimal competition from other benthic organisms. The study also revealed that dead corals constitute 58% by number and 34% by weight of the assemblage, highlighting potential vulnerabilities. While located within the Ningaloo Marine Park, the bed lacks full protection, prompting calls for enhanced conservation measures to safeguard this unique ecosystem.

Keesing, J. K., Bessey, C., Mortimer, N., Slatter, Z., Slawinski, D., & Crossing, R. (2026). Spatial extent, population size and demographics of Cycloseris distorta and C. fragilis within a large mesophotic mushroom coral bed off Ningaloo Reef, north-western Australia. Coral Reefs, 45(3), 1093–1104. https://doi.org/10.1007/s00338-026-02820-3