Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria.
Dis Aquat Organ. 2023 Feb 16;153:31-43. doi: 10.3354/dao03718.
The thick-shelled river mussel Unio crassus Philipsson, 1788 is a species native to many European habitats, with declining populations. The impact of parasite communities on health status of this species is poorly understood. In this study, parasites of 30 U. crassus specimens from the Our and Sauer Rivers in Luxembourg were identified morphologically and, in some cases, using molecular genetic methods. The findings were correlated to selected parameters (total length, visceral weight, shell lesions, gonadal stage). The 2 populations did not differ in shell length, visceral weight, number of males and females, gonadal scoring, shell lesions, and the occurrence of glochidia. The prevalence and infestation intensities of detected Trichodina sp., Conchophthirus sp., and freshwater mite larvae did not differ between the 2 populations, whereas the prevalence and infestation intensities of mite eggs, nymphs, and adults were significantly higher in the Sauer River. Rhipidocotyle campanula and European bitterling Rhodeus amarus larvae were only present in the Sauer. Histopathology revealed the destruction of the gonads by R. campanula and tissue damage by the mites. The only significant correlation of the selected parameters was a positive correlation between R. amarus occurrence and total length as well as a negative correlation between R. amarus occurrence and gonadal stage. In the Sauer River, 2 mussels were found to be hermaphrodites.
厚壳河蚬 Unio crassus Philipsson, 1788 是一种原产于许多欧洲生境的物种，其种群数量正在减少。寄生虫群落对该物种健康状况的影响还知之甚少。在这项研究中，对来自卢森堡的乌尔河（Our River）和绍尔河（Sauer River）的 30 个厚壳河蚬样本的寄生虫进行了形态学鉴定，在某些情况下还使用了分子遗传方法。研究结果与选定的参数（全长、内脏重量、壳损伤、性腺阶段）进行了相关性分析。这两个种群在壳长、内脏重量、雌雄个体数量、性腺评分、壳损伤以及豆娘幼虫的发生方面没有差异。两种群中检测到的 Trichodina sp.、Conchophthirus sp. 和淡水螨幼虫的流行率和感染强度没有差异，而螨卵、若虫和成虫的流行率和感染强度在绍尔河显著更高。Rhipidocotyle campanula 和欧洲拟鲤 Rhodeus amarus 幼虫仅存在于绍尔河。组织病理学显示，R. campanula 破坏了性腺，螨类造成了组织损伤。所选参数的唯一显著相关性是 R. amarus 的出现与全长呈正相关，与性腺阶段呈负相关。在绍尔河，有 2 只河蚬被发现为雌雄同体。
