Assessment of coral diseases in the shallow reefs of Aka-jima Marine Reserve (AMR), with a brief geographic perspective of disease occurrence throughout the larger Kerama-Shoto Marine National Park (KMNP), Okinawa, Japan

Abstract

This study reports on the observation of coral diseases within the shallow/intertidal water habitat of the Akajima Marine Reserve (AMR), located within the Keramashoto Marine National Park (KMNP) of Japan. Major coral genera and species assessed during the survey included Montipora spp., Porites spp., Isopora palifera, Acropora spp., as well as others. Observed diseases and health conditions included Black Band Disease (BBD) in Montipora as well as in Goniopora, Skeletal Growth Anomalies (GAs) in Acropora, Montipora, Porites, Isopora and Astreopora, Terpios hoshinota covering Acropora, Montipora and Seriatopora, as well as bleaching, discoloration, and other compromised health signs. This field study recorded the presence of GAs in the genus Leptastrea for the first time within the Japanese Archipelago. The novelty in this study is reporting unreported genera to be infested with certain disease conditions, further this study demonstrates how surveys in previously poorly studied areas or habitats can reveal important information pertaining to coral diseases, thus helping to fill existing knowledge gaps. Another important aspect of this study is, we provide a review of the distribution of coral diseases within the KMNP based on our results and previous reports. Being a rapid survey, the dynamics of these diseases were not assessed, while the major cause(s) of the diseases remains to be identified. In general, climate change-related aspects including rises in sea surface temperature, as well as other factors such as host density may be responsible for disease prevalences in the region.