Effects of feeding on microbial community structure and pathogen abundance in marine aquaculture ponds

Microbial communities in aquaculture ponds play a vital role in regulating water quality, driving nutrient cycling, and maintaining ecological balance. In 2023, we conducted a study to evaluate how feeding affects microbial communities by comparing the microbial composition and water quality in both fed and unfed aquaculture ponds. Metagenomic sequencing indicated that feeding significantly elevated the relative abundance of bacteria within the microbial community. Ecological similarity analysis showed that bacterial community in the ponds predominantly originated from internal pond sources, rather than from adjacent coastal waters. Furthermore, the relative abundance of pathogenic bacteria was significantly higher in fed ponds, with Vibrio parahaemolyticus levels reaching 1.6 times those in unfed ponds. In addition, water quality assessments further showed that feeding elevated nutrient concentrations, leading to eutrophication. Analyses of redundancy and correlation showed a notable positive link (p < 0.05) between the levels of pathogenic bacteria and the concentration of organic nutrients. These results suggest that excessive feeding contributes to eutrophication, which promotes the growth of bacteria, including pathogenic strains, thereby increasing the risk of disease outbreaks in aquaculture systems.