Abstract The worldwide extinction of species especially affects freshwater ecosystems. Even widespread species like the European freshwater duck mussel Anodonta anatina face population declines in many countries and regions. Due to an obligate parasitic phase in its life cycle, knowledge on host fish use is essential for effective conservation of A. anatina. Therefore, in this study host suitability of ten different fish species (native and invasive to Europe) from four different fish families was tested by simultaneously infesting them with the glochidia of A. anatina. Nine out of ten fish species were identified as suitable hosts, but infestation rates, duration of metamorphosis phase as well as duration and rate of juvenile mussel excystment differed significantly between all host species. The bitterling (Rhodeus amarus) was the only fish species with no juvenile mussel excystment. Surprisingly, one of the tested invasive fish (Ctenopharyngodon idella) turned out to be the second best host for the larvae of A. anatina, suggesting that the general assumption that non-native fishes would be a threat to native mussel populations no longer holds true. Compared to the second native Anodonta species in Europe (Anodonta cygnea), this study revealed that A. anatina had higher infestation rates and rates of juvenile mussels excystment as well as a different host compatibility than A. cygnea. These findings illustrate that species-specific assessments of host suitability form an urgent basis for evidence-based conservation and restoration of freshwater mussel populations and the ecosystem services they provide.

中文翻译：

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淡水贻贝 Anodonta anatina 的本地和入侵物种的寄主鱼类状况 (Linnaeus, 1758)

摘要 世界范围内的物种灭绝尤其影响淡水生态系统。在许多国家和地区，即使是像欧洲淡水鸭贻贝 Anodonta anatina 这样分布广泛的物种也面临着数量下降的问题。由于其生命周期中的一个专性寄生阶段，宿主鱼类使用的知识对于有效保护 A. anatina 至关重要。因此，在这项研究中，来自四个不同鱼类科的十种不同鱼类（欧洲本土和入侵）的宿主适用性通过同时用 A. anatina 的 glochidia 感染它们来测试。十分之九的鱼类被确定为合适的寄主，但所有寄主物种之间的侵染率、变态阶段的持续时间以及幼年贻贝脱囊的持续时间和速度存在显着差异。苦口鱼 (Rhodeus amarus) 是唯一没有幼年贻贝脱囊的鱼类。令人惊讶的是，经过测试的入侵鱼类之一（Ctenopharyngodon idella）竟然是 A. anatina 幼虫的第二大宿主，这表明非本地鱼类将对本地贻贝种群构成威胁的一般假设不再成立. 与欧洲的第二个本地 Anodonta 物种 (Anodonta cygnea) 相比，这项研究表明，Anodonta cygnea 与 Anodonta cygnea 相比，Anodonta 具有更高的侵染率和幼年贻贝脱囊率以及不同的宿主相容性。这些发现表明，对寄主适宜性的特定物种评估构成了淡水贻贝种群及其提供的生态系统服务的循证保护和恢复的紧迫基础。