Bacterial Communities From Two Freshwater Aquaculture Systems in Northern Germany

Area of Science:

• Aquatic microbiology
• Environmental science
• Aquaculture science

Background:

• Aquatic microbiomes are crucial for aquaculture system health.
• Water quality, fish metabolism, feeding, and disease treatments impact these communities.
• Monitoring microbiome changes is essential for sustainable aquaculture and minimizing environmental discharge.

Purpose of the Study:

• To assess how fish farm activities affect water microbiome composition.
• To identify pathogenic bacterial species associated with fish diseases in aquaculture.
• To compare microbiomes in water entering and leaving aquaculture systems.

Main Methods:

• 16S rRNA gene amplicon sequencing was used to analyze microbial communities.
• Water samples were collected from the inflow and outflow of two fish farms.
• Abundance, diversity, and identity of microorganisms were evaluated.

Main Results:

• Proteobacteria (38.2%) and Bacteroidetes (31.3%) were the most abundant phyla.
• Microbiome composition changed after water passed through fish tanks, with shifts in taxa like Nitrospirae, Chloroflexi, Deferribacteres, and Cyanobacteria.
• Flavobacterium sp. and Pseudomonas sp. were identified as predominant potential pathogens and heterotrophic bacteria.
• Aquaculture systems were dominated by heterotrophic organisms, unlike the natural reservoir which contained chemolithotrophic bacteria and archaea.

Conclusions:

• Fish farm operations significantly alter the aquatic microbiome.
• The study identified key bacterial phyla and potential pathogens relevant to aquaculture health.
• Understanding these shifts is vital for optimizing aquaculture management and environmental stewardship.