丹江口水库鲤肠道寄生蠕虫群落结构与季节动态

COMMUNITY STRUCTURE AND SEASONAL DYNAMICS OF INTESTINAL HELMINTHS IN THE COMMON CARP FROM THE DANJIANGKOU RESERVOIR,CHINA

2004年2月到2005年11月在丹江口水库库区206尾鲤(Cyprinus carpio)肠道中检获蠕虫11种,其中复殖吸虫3种,线虫5种,棘头虫2种,绦虫1种。总体感染率为45.63%,平均感染丰度为4.23±12.65,平均感染强度为9.29±17.48,其中饭岛盾腹吸虫(Aspidogaster ijimai)的总感染率(25.24%)和平均感染丰度(1.76±6.46)最大,瓣睾鲫吸虫(Carassatrema lamellorchis)的感染强度(25.00±46.68)最大。除部分平均感染丰度较低的线虫如鲤带巾线虫(Cucullanus cyprini)外,其他蠕虫的分布类型均为聚集分布,蠕虫群落多样性指数为4.63,均匀度指数为0.60,对群落多样性的季节动态分析表明,各季节群落多样性和均匀度波动较大,并无明显变化规律。每尾鲤感染蠕虫种数多在1—4种之间,所有感染的11种蠕虫中优势种为饭岛盾腹吸虫;次优势种为日本侧殖吸虫(Asymphylodora japonica)、中华许氏绦虫(Khawia sinensis)、瓣睾棘吸虫和鲤长棘吻虫(Rhadinarhynchus cyprini);非优势种为对盲囊线虫(Contracaecum sp.)、鲤带巾线虫、鲤杆咽吸虫(Rhabdochona cyprini)、黄颡刺盖线虫(Spinitectus gigi)、毛细线虫(Capillaria sp.)和木村小棘吻虫(Micracanthorhynchina motomurai)。在种间协调关系方面,鲤杆咽线虫和瓣睾鲫吸虫、鲤长棘吻虫和饭岛盾腹吸虫、对盲囊线虫和木村小棘吻虫、鲤长棘吻虫和木村小棘吻虫之间分别存在显著正关联。对优势种和次优势种蠕虫中种群的季节动态分析表明,鲤寄生蠕虫各组分的感染率和平均感染丰度存在显著的季节差异,在秋、冬季节的感染水平普遍比较高,而到春夏则急剧下降,但中华许氏绦虫无显著季节变化。

Change of the environment by natural barriers （e.g. lakes, mountain ranges） and/ or human activities （e.g. major roads, agriculture, dam） can lead to the difference on diversity and change of seasonal dynamics of parasite communities by affecting population size and dispersal pattern of species in nature. In order to study the influence of characteristics on parasite communities in the Danjiangkou Reservoir Area, we investigated the infra- and component communities of intestinal helminths in the common carp Cyprinus carpio before the Middle Route of the South to North water Transfer Project was constructed in the Hanjiang River from February 2004 to November 2005. In investigation, a total of 11 species of intestinal helminths were recorded from 206 fish, including 3 digeneans, 5 nematodes, 2 acantho- cephalans and 1 cestode and the statistical analysis of infective status of helminth population and community were per- formed at the same time. The total prevalence was 45.63%, and the mean abundance of helminthes and the intensity of infection being 4.23±12.65 and 9.29±17.48 respectively. Among the 11 species sampled, Aspidogaster ijimai had the highest total prevalence （25.24%） and mean abundance （1.76±6.46）, while Carassatrema lamellorchi had the highest mean intensity （25.00±46.68）. The frequency distribution of helminths was over-dispersed in most of species as meas- ured by the variance to mean ratio except that in low infective abundance, i.e. Cucullanus cyprini. The species diversity index of helminths communities was 4.63 as measured by Shanon-Wiener Index, and the species equitability index was 0.60. The analysis of seasonal dynamics of helminth community diversity showed that it possessed a fluctuant and ir- regular seasonal changes about helminth species composition and number. In common, each fish was infected with 1 to 4 species of helminths. In the helminth component communities, Aspidogaster ijimai was the dominant species, and the subdominant species were Asymphylodora japonica, Khawia sinensis, Carassatrema lamellorchis and Rhadinarhynchus cyprini, which were measured by important value index. Interspecific association analysis measured by coordinate coef- ficient indicated that there were significant positive associations between Rhabdochona cyprini and Carassatrema la- mellorchi, Rhadinarhynchus cyprini and Aspidogaster ijimai, Contracaecum sp. and Micracanthorhynchina motomurai, Rhadinarhynchus cyprinid and Micracanthorhynchina motomurai respectively. The seasonal dynamics of prevalence and mean abundance of the dominant and subdominant species were measured by G-test of heterogeneity and Kruskal-Wallis H Test respectively. The result showed that most helminth species exhibited a very similar and signifi- cantly seasonal change pattern which had higher infection levels in autumn and winter and lower in spring and summer except Khawia sinensis which had no seasonal changes being found. The result of the present data showed that helminth infra-communities in common carp of the Dangjiangkou Reservoir Area would be relatively abundant, which reflected a relatively satisfactory survival environment including copious food and favorable water quality for fish hosts. While most of these infections focused on a few of the dominant and subdominant species and presented a distinguished sea- sonal dynamics, which revealed a nice subsistence strategy.