Distinct patterns of coral lesion composition from national/quasi-national marine parks of Kerama and Yoron Islands, Ryukyu Archipelago

A wide variety of coral communities are found in the Ryukyu Archipelago in southern Japan. Although reports of coral diseases and lesions in this region have increased since the 2000's, the variations of coral diseases among islands are somewhat limited. In this study, we conducted surveys to reveal the coral lesion assemblage and patterns in the marine national park area of Kerama Island and the quasi-national park on Yoron Island. Both sites are located 150 km away apart in the Ryukyu Archipelago. In total, 12 gross lesions were found in 30 coral genera. Corals in Yoron Island had 22% greater gross lesion abundance than Kerama Island (13.40 ± 1.36%) with an overall mean lesion abundance of 16.83 ± 1.66% (mean ± SE). Each Island shows a distinct pattern and group of coral lesion compositions. The disease lesion group of 7.21 ± 1.37% was dominated by White Syndrome (WS) and Black Band Disease (BBD), which severely infected various coral genera in Yoron Island. Corals in Kerama Island were predominantly affected by non-disease group lesion (9.76 ± 1.33%), such as Chalinula nematifera (CN) sponge overgrowing on the coral surface. Corals in the genus Pachyseris were highly susceptible (17.79%) to the diseases on Yoron Island, while Acroporid corals were the most susceptible (8.32%) to the diseases on Kerama Island. In addition, Porites were affected by disease and non-disease lesions from all sites in both Kerama and Yoron. These findings highlight the emergence of potential threats to coral communities in these national/quasi-national marine parks in Kerama and Yoron Island, which may be a factor limiting the survival and growth of key Scleractinian coral taxa. In addition, immediate consideration of environmental monitoring may be required to prevent coral disease outbreaks in the future.