PDF(Pubmed)
Abstract：
The silver perch, Bidyanus bidyanus (Mitchell) (Terapontidae) is a freshwater fish, endemic to the Murray-Darling river system in south-eastern Australia. Population declines have led to the fish being listed as critically endangered by the Australian Government. Knowledge about parasites and diseases of wild populations of freshwater fish are limited in Australia. During an examination of wild-caught silver perch, digenean mesocercaria were observed in the head tissues. A total of five of the 11 silver perch collected from the Wakool River, New South Wales, were infected with mesocercaria. All mesocercaria were found in the head tissues; no mesocercaria were found encysted in the eye lens. The mesocercaria were found to belong to the family Strigeidae based on the sequences of their internal transcribed spacer (ITS) region. The lack of comparable sequences of strigeid digeneans from Australian hosts precludes being able to determine if the mesocercaria found in this study are a new species or representatives of an already described species. However, genetic results confirm that this is a different species to other digeneans previously described from silver perch, thus increasing the number of digeneans reported from B. bidyanus to three species. The presence of digenean mesocercaria in the head tissues of a wild population of silver perch, as found in the present study, is of potential conservation significance. Given the critically endangered conservation status of B. bidyanus, and previous evidence of strigeid infection altering fish behaviour, ecology, and predation mortality, further research on the potential impacts of infection on wild populations is warranted.
摘要：
银色的鲈鱼，Bidyanusbidyanus（Mitchell）（Terapontidae）是一种淡水鱼，澳大利亚东南部的Murray-Darling河系统特有。种群减少导致该鱼类被澳大利亚政府列为极度濒危物种。在澳大利亚，有关淡水鱼野生种群的寄生虫和疾病的知识有限。在检查野生捕获的银鲈鱼时，在头部组织中观察到了Digenean中耳c虫。从瓦库尔河收集的11只银鲈鱼中总共有5只，新南威尔士州,都感染了中胚粒虫.在头部组织中发现了所有中耳ceria；在眼睛晶状体中未发现中耳ceria。根据其内部转录间隔区（ITS）区域的序列，发现中胚囊car属属于Strigeidae家族。缺乏来自澳大利亚寄主的条纹双基因的可比较序列，无法确定本研究中发现的中耳ceria是否是新物种或已经描述的物种的代表。然而,遗传结果证实，这是一个不同的物种，从银鲈鱼，因此，从B.bidyanus报告的双基因数量增加到三个物种。在野生银鲈鱼种群的头部组织中存在二连体中丝虫，正如在本研究中发现的那样，具有潜在的保护意义。鉴于B.bidyanus的极度濒危保护状况，和先前的证据显示，纹状体感染改变了鱼类的行为，生态学,和捕食死亡率，有必要进一步研究感染对野生种群的潜在影响。
