Coral and reef fish community recovery following the 2010 extreme ocean warming event (mass bleaching event) at Thailand

Reef fish play an important role in the community dynamics of coral reefs and maintaining healthy reefs. This study aimed to (1) assess coral recovery at reefs around Racha Yai Island after the 2010 mass coral bleaching event and (2) compare the fish community indices (Shannon diversity, evenness) and fish trophic functional groups between low (Patok Bay) and high (Khonkae Bay) environmental disturbance sites during 2013-2019. The fish surveys and the percent live coral covers from both bays during 2013-2019 were collected using the fish visual census method and a permanent quadrat method along 50-m transect lines. Our results showed that the percentage of live coral cover at both bays increased by 6-8%. At Khonkae Bay, there were 69 reef fish species and 10,684 individual fish belonging to 5 orders, with 27 families and 54 genera observed from 7 orders: Perciformes (91.03%), Tetraodontiformes (5.54%), Syngnathiformes (1.24%), Beloniformes (0.26%), Beryciformes (1.25%), Scorpaeniformes (0.70%), and Aulopiformes (0.06%). Fish community indices at Khonkae Bay increased during 2013-2019 and were composed of species richness (3.65-10.53), the Shannon index (0.653.49), and species evenness (0.49-0.91). At Patok Bay, there were 60 reef fish species and 10,362 individual fish belonging to 3 orders, with 22 families and 50 genera observed from 4 orders: Perciformes (93.04%), Tetraodontiformes (5.92%), Syngnathiformes (0.55%), and Anguilliformes (0.53%). Fish community indices at Patok Bay increased during 2014-2019 and were composed of species richness (4.69-8.62), the Shannon index (1.36-3.30), and species evenness (4.92-8.62). Our results suggested that the 2010 mass coral bleaching event had large impacts on both the coral and reef fish community at both low and high environmental disturbance sites with good recovery over nine years.