Pathogenicity of Vibrio harveyi to cultured marine fishes in Korea

Five Vibrio harveyi strains, originally isolated from diseased marine fishes, were virulent for the olive flounder, Paralichthys olivaceus and black rockfish, Sebastes schlegeli. The LD50 value to olive flounder and black rockfish were 2.48 × 105–8.76 × 107 and 2.0 × 104–2.52 × 106 cfu g− 1 fish, respectively. The extracellular products (ECPs) of the V. harveyi strain were also harmful to olive flounder and black rockfish, with LD50 value of 7.98–11.4 and 1.83–7.7 μg g− 1 fish, respectively. We analyzed the relationship between toxicity to marine fishes and various virulence factors of V. hareyi. V. harveyi FR2, which was the most pathogenic isolate, showed the maximal effects to the various factors involving the survival ability in the fish serum and fish skin mucus, biofilm formation, and siderophore production.