西白令海夏季狭鳕肝脏异尖线虫感染特性研究

Parasitic characteristics of Anisakis sp.in the liver of Gadus chalcogrammus in the Western Bering Sea during summer

为探究狭鳕(Gadus chalcogrammus)肝脏内寄生虫的寄生特性,对2018年夏季采自西白令海域狭鳕肝脏内的异尖线虫(Anisakis sp.)进行收集统计,并探究其感染强度对狭鳕生长造成的影响。结果显示,狭鳕肝脏感染异尖线虫的感染率较高且感染强度较大,60尾狭鳕样本中共发现异尖线虫864条,93%的狭鳕肝脏被感染;异尖线虫感染强度随寄主体长、肝重的增加而增加,寄主肥满度与感染异尖线虫的强度不显著相关。研究结果为掌握狭鳕肝脏寄生虫的感染特性提供了基础信息,为进一步研究北太平洋重要鱼种与寄生虫之间的寄生关系提供了科学参考。

Walleye pollock Gadus chalcogrammus plays a primary ecological role in the North Pacific ecosystem and is also an important commercial fish species in this region.It feeds on a variety of fishes,copepods and cephalopods can be an intermediate/paratenic host of some helminthes.Anisakis sp.is a common parasite in Gadus chalcogrammus,however limited studies are concerned on it in the Western Bering Sea.In order to explore the parasitic characteristics of parasites in the liver of Gadus chalcogrammus,this study collected and counted the Anisakis sp.extracted from the liver of Gadus chalcogrammus in the Western Bering Sea in summer 2018,calculated the infection rate,infection intensity and fatness,and investigated the influence of its infection intensity on the growth of Gadus chalcogrammus.The detected Anisakis sp.were yellowish-white,cylindrical,translucent,with immature lips.The infection rate and the infection intensity of Anisakis sp.were high in Gadus chalcogrammus.A total of 864 Anisakis sp.were found in 60 individuals,and 93%of livers of the samples were infected.The mean intensity of Anisakis sp.infection decreased with the increasing of the sexual maturity stage of Gadus chalcogrammus.There was a significant correlation between the infection intensity and the host’s body length and liver weight.The number of Anisakis sp.increased gradually with the increasing of body length.The number of Anisakis sp.increased gradually with the increasing of liver weight.There was no significant correlation between the host fatness and the infection intensity.This suggests that host growth is related to not only the parasite,but to other factors such as food,climate,and differences in fish body can also cause changes in the fatness of fish.This study provides basic information for understanding the infection characteristics of Anisakis sp.in Gadus chalcogrammus,and provides scientific reference for further study on the parasitic relationship between important fish species and parasites in the North Pacific Ocean.