Abstract:Bacterial population and community structures were studied in cage culture environment in Xiangshangang Bay in January and October (2006),and the results were compared with those in cage′s adjacent non-cultured environment in Xiangshangang Bay. Bacteria quantitative distribution presented a series of characters in water and sediment: Higher bacterial number was observed in Oct. than that in Jan.,and the horizontal distribution of bacterial number displayed that Cage culture area>Reference site near cage>Reference site near bayhead>Reference site near baymouth. The number of heterotrophic bacteria and vibrios in cage culture water ranged from 1.0×106-7.2×107 CFU/L and 1.6×105-1.3×106 CFU/L,respectively. The number of heterotrophic bacteria and vibrios in cage culture sediment ranged from 5.9×102-6.1×105 CFU/g and 8.0×101-7.4×104 CFU/g,respectively. 89 strains of heterotrophic bacteria isolated from the cage culture water mainly belonged to 12 genera. Acinetobacter, Pseudomonas and Vibrio were the dominant genera.136 strains of heterotrophic bacteria isolated from the cage culture sediment mainly belonged to 10 genera. Pseudomonas, Vibrio, Bacillus and Acinetobacter were the dominant genera. Because of long-term drainage of abundant nutrients and organic matters,microbial diversity reduced in cage culture area and reference site near cage,some functional microbes became dominating bacterial colonies.This study demonstrated that the characters of bacterial quantitive distribution and community structures were closely related to self-pollution status of cage culture, and the effects to bacterial community induced by cage culture have spreaded to its adjacent area.