Bacterial communities associated with hydromedusa Gonionemus vertens in different regions in Chinese coastal waters

Bacteria communities in cnidarian jellyfish can be harmful to many important aquaculture species, as they can be key vectors of bacterial pathogens. However, our knowledge of bacterial communities associated with jellyfish in culture ponds and their potential roles in the regulation of aquaculture species remains unclear. In this study, sequencing based on the bacterial 16S rRNA gene was used to investigate the composition and variation of the bacterial communities associated with hydromedusa Gonionemus vertens in sea cucumber culture ponds and natural marine environment. The associated bacterial communities of G. vertens from the culture ponds in the Yellow Sea and Bohai Sea had significantly different compositions, when compared with those from ambient seawater environment. Furthermore, bacterial communities associated with G. vertens had similar diversity and composition in culture ponds and natural marine environment in the Yellow Sea. There were 31 unique bacterial biomarkers identified in three locations. The major communities were highly abundant in Kiloniellales, Octadecabacter, Polynucleobacter, and Polaribacter, and are related to the environmental information processing. Pathogen candidates such as Vibrionales and Chlamydiales had notably low relative abundances (