Analysis and identification of causative pathogen for skin ulcerative syndrome in Fujian sea cage cultured Apostichopus japonicus

In the winter of 2011, the sea cage cultured sea cucumber suffered from serious disease in many sea areas of Ningde in Fujian Province, accompanied by the phenomenon of death. The symptom displayed as anorexia, viscera ejection, general atrophy, and skin ulceration, the disease was tentatively termed as "skin ulcerative syndrome". The bacterium CS1 and CS2 were isolated from the focal area of the infected sea cucumber, and they were dominant amongst the isolates. Artificial infection test proved that they were the causative pathogen associated with the disease. In addition, a lot of Boveria sp. was found from the respiratory tree of sick sea cucumber. The bacterium CS1 and CS2 were identified as Vibrio splendidus and Pseudoalteromonas, respectively, by the means of morphological, biochemical tests, and 16S rDNA sequence analysis. This paper revealed for the first time that the causative pathogens leading to the "skin ulcerative syndrome" of the sea cucumber in the area, which will be helpful in the disease control and health management during sea cucumber cultivation.