The number of heterotrophic bacteria and vibrios in shoal for Bullacta exarata rearing fluctuated mainly within 1.25×10 4～7.21×10 4 cfu·g -1 and 0～1.08×10 4 cfu·g -1 ,respectively. 173 strains of bacteria, mainly belong to 13 genera were isolated. The predominant genera were composed of Bacillus,Photobacterium,Pseudomonas,Vibrio and some genera of Enterobacteriaceae . The number of bacteria changed in line with the alteration of the temperature,and was especially affected by the organic matter content after the use of pesticide. The predominant genera such as Bacillus were closely related with the environmental deterioration of rearing shoal.
s 107 strains of bacteria was isolated from crop,stomach and intestine of the Bullacta exarata and 85% of them were Gram_negative rod. The microflora of digestive tract was composed of eleven genera. The predominant genera were composed of Photobacterium , Vibrio , Bacillus, and Pseudomonas. The results indicate that predominant microflora was relatively steady in digestive tract of Bullacta exarata growth period. There were a great variety of bacteria in crop. The digestive tract may play a special role for regulating and controlling the microbial community.
