Multiparasitism in gills of Metynnis lippincottianus from the environmental protection area of Curiaú river, Eastern Amazon

ABSTRACT: The high fish diversity of the Amazon has been the subject of study for several research projects because of the importance of its ecosystems. The Environmental Protection Area of the Curiaú River is composed of permanent and temporary lakes within the floodplain forests, favoring a rich diversity of fish species. Pratinha. (Metynnis lippincottianus) is an ornamental fish, widely distributed throughout Brazil and French Guiana. Fish parasites may reflect the environmental quality, as well as the habits of their host. Considering the importance of understanding and contributing to the expansion of studies on fish parasites, the present study aimed to investigate the gills of Metynnis lippincottianus from the Curiaú River basin in the municipality of Macapá (Eastern Amazon). A total of 200 specimens of Metynnis lippincottianus from the Curiaú River were examined and 89% of the analyzed fish were parasitized by metacercariae, Dactylogyridae gen. sp., Piscinoodinium pillulare, Trichodina sp., Henneguya sp., and Myxobolus sp. Despite this high parasitic load, body conditions were not affected. This is the first documented incidence of a species belonging to the Phylum Cnidaria: Myxozoa in Metynnis lippincottianus.

摘要：亚马逊流域极高的鱼类多样性因其生态系统的重要价值，一直是多项研究课题的关注对象。库里亚乌河（Curiaú River）环境保护区由洪泛林内的永久性与临时性湖泊构成，孕育了丰富的鱼类物种多样性。普拉廷哈鲳（Metynnis lippincottianus，俗称Pratinha）是一种观赏鱼类，广泛分布于巴西及法属圭亚那境内。鱼类寄生虫可反映环境质量与宿主的生活习性。鉴于深入探究并推动鱼类寄生虫相关研究的重要意义，本研究以亚马逊东部马卡帕市库里亚乌河流域的普拉廷哈鲳（Metynnis lippincottianus）的鳃部为对象开展寄生虫调查。本次研究共检测了200尾采自库里亚乌河的普拉廷哈鲳样本，其中89%的受检个体被后囊蚴、指环虫科（Dactylogyridae gen. sp.）未定属物种、多子小瓜虫（Piscinoodinium pillulare）、车轮虫（Trichodina sp.）、半尾粘孢子虫属（Henneguya sp.）以及碘泡虫属（Myxobolus sp.）寄生。尽管寄生负荷较高，但受检鱼的身体状况并未受到影响。本研究为首次在普拉廷哈鲳（Metynnis lippincottianus）中记录到隶属于刺胞动物门（Cnidaria）粘孢子虫类（Myxozoa）的物种感染案例。