鲻长尾吸虫种群生态研究

The Population Ecology of Elonginurus mugilus Parasite in Mugil cephalus in Guangdong Province, China

鲻鱼肠道内的鲻长尾吸虫（Ｅｌｏｎｇｉｎｕｅｕｓ ｍｕｆｉｌｕｓ Ｌｕ，１９９５）随着宿主体长的生长，其感染率的变动范围在２８．８９％～３１ ９３％之间，而感染强度和种群平均密度呈现不规则的变动；体长在４０～１０６ｍｍ 范围内，种群平均拥挤度，扩散性指标则随着体长的生长有逐渐增加的趋势，而负二项参数则逐渐降低；在不同的月份中，吸虫在宿主体内的感染率，感染强度和种群平均密度均呈不稳定的地动．吸虫种群在不同体长组和不同月份的宿主体内的时空分布类型均为聚集分布，而且聚集强度随着种群密度增加而增强，从吸虫种群在宿主体内的频率分布中，表明多数宿主不感染或只感染少量的吸虫，而较大数量的吸虫只寄生于少数的宿主。

The population ecology of Elenginurus mugilus Lu 1995, parasitic in the intestine of Mugil cephalus L. in Pinqinglake in Shanwei City of Guangdong Province was reported. It base on the infor- mation of field investigation of trematodes parasitic in hosts sampled from January to December 1993 in the lake. The results indicated that the prevalence fluctuated from 28. 89% to 31 .93%, but the relative intensity and the mean density of infection changed irregularly in host of different body length group. The population mean crowding, spreading index increased with the increasing of the body length between 40 and 160 mm, but the negative binomic exponent decreased with the increasing of the body length of host. The incidence, relative intensity and mean density of infection fluctuated irregularly in different month in a year.The frquency distribution of the trematodes population showed that the most hosts were not infected or infected with less parasites, and a large number of trematodes parasited in a small number of hosts. The population distribution of trematodes parasite in the host of different group of body length and in different seasons all showed aggregated distribution.The degree of aggregation increased with the increasing of mean density of their population.