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Coral communities in China's Great Bay Area (GBA) have experienced severe degradation, but only limited information is available about their community structure. We surveyed 20 sites across three regions (Daya Bay, Dapeng Bay, Wanshan Islands) in GBA to provide an updated baseline of these urban coral communities. Live coral cover varied substantially, with the lowest values (<2 %) found inside the highly urbanized Daya Bay, and highest values (40–47 %) from offshore islands that are less affected by human activities. The two sites with the lowest live coral cover had a high percentage of dead coral. Five groups of coral communities could be identified, with most of them characterized by dominance of massive and encrusting coral species. Both coral cover and generic richness were negatively correlated with dissolved inorganic nitrogen in the water column, indicating that nutrient pollution could potentially constrain the development of these urban coral communities. • We aimed to provide a baseline of coral communities along the coasts of Guangdong, China. • We surveyed 20 sites across Daya Bay, Dapeng Bay, and Wanshan Islands. • Live coral cover varied substantially from 1.3 % to 46.5 %. • Most sites were dominated by massive and encrusting coral species. • Coral cover and generic richness were negatively correlated with dissolved inorganic nitrogen. [ABSTRACT FROM AUTHOR]

We surveyed 41 sites to provide an updated baseline of Hong Kong coral communities. Five community types were identified, among them the most common one inhabited oceanic waters and dominated by both massive and upward-plating corals. The 41 sites had 2.1–⁠79% coral cover; among them 21 in the eastern waters had >40% coral cover. Corals in several sites showed signs of external bioerosion or bleaching-induced damage. Sites in the southern waters had low coral cover. Both coral cover and generic richness correlated negatively with several water quality parameters including total inorganic nitrogen concentration and turbidity, indicating the development of Hong Kong's coral communities is constrained by water quality parameters. Management actions are proposed to reduce bioerosion, and to monitor sites affected by bleaching. [ABSTRACT FROM AUTHOR]