长江安庆段刀鲚寄生线虫群落结构及感染特征

为理清刀鲚(Coilia nasus)洄游时间与体内寄生线虫的关系,于2018年4—7月在长江安庆段调查了刀鲚寄生线虫的感染情况及群落结构。结果显示,刀鲚线虫感染率为96.0%,平均感染强度为8.06±7.26,平均感染丰度为7.74±7.29。经ITS分子标记共鉴定出7种线虫,其中异尖属2种,宫脂属4种,针晶蛔属1种,均为海水性寄生虫,可作为刀鲚有海水生活经历的生物标记。其中派氏异尖线虫(Anisakis pegreffii)的感染率最高,为84.5%,其次为内弯宫脂线虫(Hysterothylacium aduncum)(31.0%),二者的感染强度和感染丰度也较高,其中平均感染强度分别为6.40±6.08和2.81±2.49,平均感染丰度分别为5.41±6.05和0.87±1.90;派氏异尖线虫感染丰度和感染强度在洄游早期呈上升趋势,到6月下旬稍有降低但不显著(P>0.05),内弯宫脂线虫感染丰度和强度则均表现为下降趋势。刀鲚寄生线虫的群落结构在不同洄游时间也有所差异,其中刀鲚感染线虫的平均物种丰富度和Brillouin多样性指数均呈下降趋势,但优势物种一直是派氏异尖线虫,...

COMMUNITY STRUCTURE AND INFECTION CHARACTERISTICS OF NEMATODES IN THE COILIA NASUS IN ANQING SECTION OF THE YANGTZE RIVER

Coilia nasus is an anadromous fish, and the parasitic nematodes are a confirmation of its habitat history. In order to understand the relationship between the migration time of C. nasus and its nematodes, the infection and community structure of nematodes in C. nasus were investigated from April to July 2018 in Anqing section of the Yangtze River. The results showed that the infection rate of C. nasus was 96.0%, the average intensity was (8.06±7.26), and the average abundance was (7.74±7.29). A total of 7 species were identified by ITS molecular markers, including 2 species of Anisakis, 4 species of Hysterothylacium and 1 species of Raphidascaris. All of them are marine parasites and can be used as evidence that C. nasus has seawater life. Anisakis pegreffii (84.5%) had the highest infection rate, followed by Hysterophylaxium aduncum (31.0%). The average intensity and abundance were also high. The average intensity were (6.40±6.08) and (2.81±2.49), and the average abundance were (5.41±6.05) and (0.87±1.90), respectively. The average intensity and abundance of A. pegreffii showed an upward trend in the early stage of migration, and decreased slightly but not significantly in late June (P>0.05), while the H. aduncum showed a downward trend. The community structure of C. nasus nematode varied at different migration times. The richness, mean richness and the Brillouin index showed a downward trend, but the dominant species has always been A. pegreffii, and the number in the intestinal and pyloric caecum accounts for 46.13% and 30.02% respectively. The study will provide a reference for the later development of impact of nematode parasitism and population supplement, and also provide a new method for using parasite markers to study the migratory ecology of C. nasus.