Microbial community dynamics in a commercial RAS for production of Atlantic salmon fry (Salmo salar)

This study aimed to improve our understanding of microbial community dynamics in a RAS involving three production batches of Atlantic salmon fry during a period of 20 months. Water for analysis of microbiota was sampled at different positions in the RAS, and we also examined the effect of UV treatment on the water microbiota. Microbial communities were characterized by Illumina sequencing of amplicons representing the v3+v4 regions of the 16S rRNA gene and based both on DNA and RNA extracts. Water samples were taken from five positions in the RAS loop: directly upstream and downstream of the UV treatment unit and from three of the rearing tanks. In total 6 sampling events were made during a 20-month period, two from a spring batch in 2015, one from an autumn batch in 2015, and two from a spring batch in 2016.