大亚湾网箱养殖水体弧菌种类组成及变化

Vibrio Variations in Caged-Culture Waters and Its Neighboring Region in Dayawan Bay

研究了海水网箱养殖海域弧菌数量变化、种类组成及其相关因素．探讨弧菌数量的变化与鱼病的关系。结果表明：网箱内水体弧菌数量为390-230mL^-1．平均为20．6×10^2mL^-1,网箱外水体为130～1450mL^-1，平均为530mL^-1．非养殖对照海区为10-390mL^-1．平均为190mL^-1。养殖海区弧菌数量呈现明显的季节性变化．尤其是网箱水体．对照海区只在9月数量较高．其他时间变化不大。平均数量网箱内大于网箱外．网箱外大于对照海区。水体中出现的弧菌种类有河流弧菌Vibrio fluvialis．创伤弧菌Vibrio vulnif gicus．霍乱弧菌Vibrio cholerae．副溶血弧菌Vibrio parahaemolyticus．溶藻弧菌Vibrio alginolyticus．美人鱼弧菌Vibrio damsela．拟态弧菌Vibrio mimicus和好利斯弧菌Vibrio hollisae，美人鱼弧菌、溶藻弧菌和霍乱弧菌占有较大优势。弧种数量与海水温度、盐度及营养盐有相关性．但其相关性因不同种和不同点而不同。检测期间．网箱养殖鱼类无明显流行病发生．但弧菌的高峰期明显与报道的鱼病高峰期相吻合。

Quantitative and compositional variations of vibrios in the caged-culture waters and its neighboring region in Dayawan Bay were studied, and the relationship between fish diseases and vibrio quantity was investigated. Results showed that, variation of vibrios ranged from 390 to 8 230 CFU/mL, with average value of 2 060 CFU/mL inside the cages, 130-1450 CFU/mL with an average of 300 CFU/mL outside the cages and 10-390 CFU/mL with an average 190 CFU/mL in the compared region. Seasonal variations of vibrios in the farmed waters were obvious, especially inside the cages whereas in the compared region the drastic seasonal variations were not noticed except that vibrios density was at the highest rate in September. Vibrios in the waters were composed of Vibrio fluvialis , Vibrio vulni f gicus ,Vibrio cholerae ,Vibrio parahaemolyticus , Vibrio alginolyticus , Vibrio damsela , Vibrio mimicus and Vibrio hollisae. Vibrio damsela , Vibrio alginolyticus and V cholerae were 3 dominant species. The vibrio density snowed certain relationship with temperature, salinity and nutrients, but the relationships varied depending on different species and locations. In the period of study, no obvious epidemic occurred in caged fish, nevertheless the peak time of vibrios obviously matched the epidemic period of fish diseases reported previously.