Show the difference in ISAV recovery percentages at different virus spiking concentrations for RT-qPCR and RT-ddPCR.

Two-fold serial dilutions of ISAV stock sample were used to spike different 1L natural seawater (1 dilution/each), and the spiked seawater samples were concentrated using MF-/buffer 1 concentration method. ISAV recovery percentages (%) and virus copy numbers/L are presented as mean ± standard deviation from four biological replicates. Student t-test was used to compare differences in ISAV recovery between RT-ddPCR and RT-qPCR assays.