Crustacean parasites of Leporinus affinis, an Anostomidae fish from the Brazilian Amazon

Abstract This study investigated the fauna of ectoparasitic crustaceans in Leporinus affinis from Reservoir Coaracy Nunes, in eastern Amazon (Brazil), as well as the parasite-host interactions. The mouth, gills and tegument of 50.9% of the fish examined were parasitized by Argulus chicomendesi, Ergasilus turucuyus and Excorallana berbicensis, and a total of 118 parasites were collected. The dominance was found for E. berbicensis and the higher infestation levels were caused by E. berbicensis on the body surface of the hosts, but E. turucuyus had the highest prevalence on the gills of this host. The cluster analysis revealed higher similarity in the infestations by E. berbicensis and A. chicomendesi in relation to infestation site in hosts. Host sex and relative condition factor (Kn) were not influenced by moderate parasitism, but the abundance of parasites presented negative correlation with weight and Kn of the fish. This is the first study on the parasites of L. affinis showing low species diversity, with moderate prevalence and low parasite abundance.

摘要 本研究针对巴西东部亚马逊地区科拉西·努内斯水库（Reservoir Coaracy Nunes）中的尖吻脂鲤（Leporinus affinis）外寄生甲壳动物区系及其寄生-宿主互作关系展开调查。本次受检鱼类中，50.9%的个体的口部、鳃部与体被均被奇鲺（Argulus chicomendesi）、图鲁库颚虱（Ergasilus turucuyus）以及贝氏外棒钩虾（Excorallana berbicensis）寄生，总计采集到118只寄生虫。研究发现贝氏外棒钩虾为优势类群，其在宿主体表的感染强度最高；而图鲁库颚虱在宿主鳃部的感染率最高。聚类分析结果显示，相较于寄生位点，贝氏外棒钩虾与奇鲺的感染模式具有更高相似性。宿主性别与相对条件因子（Kn）未受中度寄生感染的影响，但寄生虫丰度与宿主体重及相对条件因子呈显著负相关。本研究为首次针对尖吻脂鲤寄生虫类群开展的调查，结果显示该宿主的寄生虫物种多样性较低，感染率处于中等水平，且寄生虫丰度偏低。