Vibriosis of Swimming Crab Portunus trituberculatus in Larviculture

Since 1985, frequent mass mortalities due to a bacterial infection have occurred in zoeal larvae of swimming crab Portunus trituberculatus reared at the Tamano Station of the Japan Sea-Farming Association. A bacterium was predominantly isolated from diseased larvae and was demonstrated by experimental infection to be the causative agent of the disease. Based on morphological, physiological, biochemical, serological and genetic characteristics of the pathogen, it was thought to be a new species and tentatively named Vibrio sp. Zoea. Challenge experiments with the bacterium in several aquatic animals indicate that Vibrio sp. Zoea appears to be a pathogen specific for crustaceans.