Fig. 1
Experimental design overview. Information was pseudonymised for the experiment, with each hatchery identified by a number and each farm by a letter. (A) Gill microbiomes were sampled at 13 sites: 6 freshwater hatcheries and 7 seawater farms, across Scotland from S0 (Autumn 2018) and S1 (Spring 2019) inputs. Each of the seven cohorts were sampled at their hatchery then their corresponding seawater farm following transfer. Dark blue circles seen for all S1 sites indicates that surface unit water was sampled and filtered. Hatcheries 3S0 and 3S1 were the same site, sampled once for each seasonal input. (B) At each sampling point, four fish were sampled from Unit A and four fish from Unit B (n = 8 fish per site). (C) 2L of water was taken from the surface of each unit. The water was filtered through first through a 1.2 μm pore glass fibre filter (particle attached microbiome) and then a 0.22µm pore Sterivex filter (pelagic microbiome)