贺江典型海弯水虱种群动态监测及生物防控

Population dynamics monitoring and biological control of parasitic Alitropus typus(Isopoda,Aegidae) in Hejiang River

2006-2010年通过"人工诱捕"和"天然捕获"的方法对贺江典型海弯水虱种群动态进行监测,评价生物防控的效果。结果显示:典型海弯水虱在4-6月的寄生数量最少;推测其生命周期为1a,6月是世代交替期,种群世代不重叠或重叠不明显;试验发现草鱼、青鱼、鲤能主动捕食典型海弯水虱。选择典型海弯水虱寄生数量最少的4-6月作为放流时间,于2007-2009年在贺江人工放流草鱼、青鱼、鲤156万尾;比较2006-2010年人工诱捕的典型海弯水虱的数量,发现从2008年开始,典型海弯水虱的数量逐年减少,2010年诱捕到的典型海弯水虱的数量比2006年减少85.1%;天然捕获贺江野生鲮和,发现在2009年9月至2010年8月,典型海弯水虱对鲮和的感染率、平均感染强度和平均密度均比2006年9月至2007年8月显著降低。以上结果初步表明生物防控取得了一定的效果。

To evaluate the effect of biological controlling of Alitropus typus,the seasonal variation of Alitropus typus population were monitored via two methods, the trapping way and gill net,in Hejiang River from 2006 to 2010. The results of the seasonal population dynamics indicated that the parasitic number of A. typus was the least from April to June,the life cycle of A. typus was presumed to be one year and the alternation of generations occurred in June annually. However the overlapping between generatations was not significant. In addition, the experimental results showed that Ctenopharyngodon idellus ,Mylopharyngodon piceus, Cyprinus carpio were able to prey A. typus, which suggested that these fishes could be potential factors that could biologically cotroll A. typus. For the lowest parasite rate of A. typus appeared from April to June, this period was selected to release C. idellus,M, piceus and C. carpio into Hejiang River each year from 2007 to 2009. A total 1.56 million fish were released into Hejiang River during three years. While the number of A. typus captured by the trapping way gradually decreased since 2008. The number of A. typus in 2010 decreased 85. 1% than that in 2006. Cirrhinus molitorella and Hemiculter leucisculus were sampled by gill net placed at the same location from September 2006 to August 2007 and from September 2009 to August 2010. The results indicated that prevalence,mean infection intensity and mean density of A. typus were dramaticallydecreased from September 2009 to August 2010. All the results showed that biological control measures were effective in Hejiang River.