Intraperitoneal injection of hydrocortisone elevates plasma cortisol levels in Atlantic salmon. Dot blots of plasma cortisol concentration (ng/mL) in fish collected from different experimental groups (C.S, C.H, E.S, and E.H) in SGPV experimental infection trial at A 1-day post-exposure (dpe) and B 14 dpe. Each plasma sample is represented by a dot, and horizontal lines in the blot indicate the median per group. The Wilcoxon test was used to determine statistical significance between the groups with bars representing P-values. Differences between groups were considered statistically significant when P < 0.05.