The aim of this study was to identify the causative agent responsible for low losses in cultured Russian sturgeon (Acipencer gueldenstaedtii) in Turkey. Two outbreaks occurred in the autumn of 2007 and 2008 after heavy rainfall accompanied by a sudden change in water temperature and increased suspended solids. The sturgeons displayed ulcerations, haemorrhage and superficial skin erosions especially on the ventral side including the pectoral and pelvic fins as reported in other studies. Affected fish were lethargic displayed excessive mucus secretion with skin lesions appearing as pale grey spots. Phenotypical characterizations were done according to standard protocols and supplemented with commercial APIZYM, API 20E and API 20NE kits. Sequencing of 16S rDNA PCR products were performed to genetically confirm the identity of the isolated organism.