Captivity and Clade Identity: Investigating Symbiodiniaceae Diversity in Wild and Aquacultured Coral Symbioses

Abstract

This study investigates how aquaculture conditions influence the symbiotic community composition of reef-building corals by comparing Symbiodiniaceae clade identity between wild and aquacultured coral samples. Using ITS2 sequencing and phylogenetic analysis, DNA was extracted, purified, cloned, and sequenced from four aquacultured brain coral fragments (Favia and Platygyra spp.) and one wild Diploria labyrinthiformis sample. Results revealed that the wild coral exclusively hosted Clade B symbionts (Breviolum sp.), while aquacultured corals consistently harbored Clade C symbionts (Cladocopium sp., primarily C1 subvariants). No evidence of mixed clade infections was found. These findings suggest that environmental history may influence symbiont acquisition under aquaculture conditions, although the potential role of host identity cannot be fully excluded based on this study. From a conservation perspective, maintaining or enhancing symbiont diversity in cultured corals could improve ecological flexibility for reef restoration efforts. Future research should focus on resolving subclade variation and conducting direct comparisons within the same coral species across wild and cultured environments.