A Diverse Vibrio Community in Ría de Vigo (Northwestern Spain)

The genus <i>Vibrio</i> is genetically and ecologically diverse, resulting in severe economic losses in aquacultural macroalgae and animals. Studies on vibrios will contribute to the conservation of aquatic aquaculture in Ría de Vigo (Spain), which is famous for its shellfish farming activity. However, limited research focused on the diversity and distribution of <i>Vibrio</i> spp. in Ría de Vigo has been reported. Here, a slight increase in the abundance of <i>Vibrio</i> spp. was recorded from inshore to the open sea by quantitative PCR (qPCR). Vibrios were more abundant in the free-living (FL) than in the particle-associated (PA) fraction, showing that FL might be their preferential lifestyle. <i>Photobacterium piscicola</i>, <i>Vibrio japonicus</i> and <i>Vibrio harveyi</i>, which are serious pathogens for fish and invertebrates in mariculture, were found to be the dominant species across all samples by high-throughput sequencing and analyses and were mainly affected by stochastic processes. More colony-forming units and species of vibrios were recorded at 16 °C (18 species) than at 28 °C (6 species), and five isolates (5.05% of the total isolates) showed low 16S rRNA gene similarity (<98.65%) to the known strains. The results indicate that culture conditions closer to the in situ temperature may help to isolate more <i>Vibrio</i> species. Our findings may contribute to local aquatic aquaculture research, providing background information and novel insights for management and pathogen prevention in aquaculture, and more studies should focus on Ría de Vigo to acquire novel or pathogenic microbes in the future.