Abstract：
The construction of dams and hydroelectric plants affects biodiversity in aquatic environments and can facilitate the invasion of species. Few studies assess the long-term response of parasite fauna under these events. The aim of this study was to investigate possible changes in the endoparasite composition of the invasive catfish Trachelyopterus galeatus (Linnaeus, 1766) in the floodplain of the upper Paraná River over a 27-year study period. A total of 79 fish were collected in period 1 (1993) and 31 in period 2 (2019/2020) at the same sampling points, and the endoparasites were located in the gastrointestinal system using a stereomicroscope. It was found that the development of the fish and the composition of their endoparasitic fauna changed over time. In the second period, the fish presented smaller values for mass (g) and standard length (cm) when compared to period 1. It was found that three species of endoparasites were found per period, but although the richness was the same, the composition differed, and only one digenean (Microrchis oligovitellum Lunaschi, 1987 (Trematoda: Paramphistomidae)) was shared. The Porto Primavera Dam was built upstream of the site between the sampling periods (1999) and caused a number of environmental changes, possibly being the main factor responsible for changes in components of the parasite community. Anthropic modification to an environment can cause loss of diversity and loss of ecological interactions. Through our results, we emphasize the importance of including parasite fauna in studies that assess environmental impacts.
摘要：
水坝和水力发电厂的建设会影响水生环境中的生物多样性，并可能促进物种入侵。很少有研究评估寄生虫动物在这些事件下的长期反应。这项研究的目的是调查入侵的of鱼Trachelyopterusgaleatus（Linnaeus，1766年）在巴拉那河上游的洪泛区进行了27年的研究。在相同的采样点，在第1期（1993年）共收集了79条鱼，在第2期（2019/2020年）共收集了31条鱼，使用立体显微镜将体内寄生虫定位在胃肠系统中。发现鱼类的发育及其内寄生物动物区系的组成随时间而变化。在第二阶段，与第1期相比，鱼的质量（g）和标准长度（cm）值较小。发现每个时期发现了三种体内寄生虫，但是尽管财富是一样的，组成不同，只有一个双生动物(小毛卵黄Lunaschi，1987年（Trematoda：Paramistoidae）被共享。PortoPrimavera大坝在采样期间（1999年）之间的站点上游建造，并引起了许多环境变化，可能是导致寄生虫群落成分变化的主要因素。人为改变环境会导致多样性的丧失和生态相互作用的丧失。通过我们的结果,我们强调将寄生虫动物纳入评估环境影响的研究的重要性。
