鲻鱼寄生蠕虫种群和群落组成分析

ANALYSIS OF HELMINTH POPULATION AND COMMUNITY COMPOSITION PARASITIC IN STRIPED MULLET (MUGIL CEPHALUS L.)

从 10 18尾鲻鱼 (MugilcephalusL .)体内获得各类寄生蠕虫 9种 ,共 2 13 3个虫体 ,其中复殖吸虫 8种 ,棘头虫 1种。寄生蠕虫总的感染率为 2 4 4 % ,感染强度 1～ 81,平均感染强度为 8 8,平均密度为 2 3。鲻长尾吸虫 (Elonginusmugilus)和双睾原单脏吸虫 (Prohaplosplanchnusdiorchis)的感染率随着宿主体长增加而下降 ,而楔形单脏吸虫 (Haplosplanchnuscuneatus)、长形单脏吸虫 (H .elongatus)、浦里单脏吸虫 (H .purii)、惠东拟囊腔吸虫 (Saccocoelioideshuidongensis)、粤东纵睾吸虫 (Tandemorchisyuedongensis)、单睾椭囊吸虫(Elliptobursasinglorchis)和圆颚针鱼新棘吻虫 (Neoechinorhynchustylosuri)的感染率与宿主体长相关不显著 (P>0 0 5 )。研究结果还表明 ,楔形单脏吸虫、长形单脏吸虫、惠东拟囊腔吸虫和浦里单脏吸虫的感染强度则随着宿主体长增加而增大 ,其余 5种寄生蠕虫的感染强度与宿主体长相关性不显著 (P >0 0 5 )。鲻鱼寄生蠕虫在不同月份的感染率和种群数量差异 ,除 10月与 11月及 8月与 9月不明显外 (P >0 0 5 ) ,其余月份之间的差异极显著 (P <0 0 1)。根据感染率和种群密度变化分析 ,优势种为惠东拟囊腔虫 ;通过模糊聚类分析 ,将鲻鱼体内寄生蠕虫组分群落分为 3个亚群 。

We reported ecological characters of the helminth community parasitic and relationship between them and Mugil cephalus L. (1 018 fish) along Yuedong area in Guangdong Province, China. We collected 2 133 indiulduals of helminthes from January to December in 1995. The results indicated that the hosts were infected by one to nine species of helminthes, including eight kinds of Digeneans and a classification of Acanthosentis. The component communities of helminth parasitic in the hosts were dominated by digeneans. The total prevalence was 24 4%, the range of intensity and mean intensity was 1～81, and 8 8 respectively. The total mean abundance was 2 3. The prevalances of Elonginus mugilus and Prohaplosplanchnus diorchis decreased with the increasing of body length of hosts (F>F 0 01 , F test), but the relationship between the body length of hosts and the prevalances of Haplosplanchnus cuneatus, H. elongatus, H. purii, Saccocoelioides huidongensis, Tandemorchis yuedongensis, Elliptobursa singlorchis and Neoechinorhynchus tylosuri was not obvious (F<F 0 05 , F \|test), and it was irregularly fluctuated. The results indicated that the intensity of infection of Haplosplanchus cuneatus, H. elongatus, Saccocoelioides huidongensis and Haplosplanchnus purii increased with the increasing of the body length of the hosts, the relationship between the intensity of other five species and the body length of the hosts was not apparent (P>0 05, F test). The prevalence of helminth parasitic in host depended on the body length group of hosts, which was arranged as following 70～90 mm, 90～110 mm, 110～130 mm, 50～70 mm, 130～150 mm, 150～170 mm and >170 mm。 The prevalance and abundance in different month was different (F>F 0 01 , P<0 01, F test), except in August and September, October and November (F<F 0 05 , P>0 05, F test). On the basis of the prevalance and abundance variety, Saccocoelioides hundongensis is the dominent population. The prevalence and population size of helminth parasitic in hosts arranged according to months of the year from the most to the least as follows: January, February, December, October, November, September, June, July, August, March, April and May. The helminth component community can be divided into 3 sub component communities according to fuzzy clustering analysis, each having its own composition features. The results showed that the number of mean species, dominance index, infection index, species diversity, mean abundance and intensity of infection in the subcomponent community of helminths parasitic in host of less 70 mm body length were relatively low, and that the characteristic value of subcomponent community of helminths parasitic in host of more than 70 mm body length increased with the increasing of body size, except the number of mean species.