Production site and histopathology associations with Atlantic salmon gill mucus microbiome

The Atlantic salmon gill is continuously in contact with the microbial rich surrounding water and is highly susceptible to infection by opportunistic pathogens which results in poor gill and overall fish health in the aquaculture industry. Mucosal microbiomes are a first line of defence against pathogens and fish inhabiting waters in different geographic locations may have differing gill mucosal microbiomes influenced by the environmental communities and conditions they are exposed to. Host selective mechanisms may also drive some shared taxa between geographically distinct populations, but this is not well understood. Additionally, the impact or association of the host gill microbiome with the presence or progression of gill disease is not well studied to date. In this study, 16S sequencing will be utilised to compare gill mucosal microbiomes of fish from different sites, and also between those with differing scores for gill health determined by histopathology.