Abstract:
The saddled seabream, Oblada melanura (L.), is a common seawater species present in the Mediterranean. Between July and August 2023, during diving activities along the Sicilian coast of Italy, we recorded with a digital camera several specimens of O. melanura showing an abnormal pattern of swimming in the water column. The unusual swimming behaviour was characterized by fast, uncoordinated directional changes and isolation from the remaining fishes in the shoal. Four dead fish were found and collected for necropsy and parasitological evaluation/examination. Upon gross examination, all fish showed an evident coelomic distension; the coelomic cavity of two fish was filled with nematodes that dislocated the coelomic organs, and the other two had degraded nematodes and a conspicuous quantity of fluid in the coelomic cavity. All collected parasites were identified as Philometra obladae (Nematoda: Philometridae) according to morphological criteria. Here, we describe the unusual swimming behaviour of O. melanura naturally infected with Ph. obladae and the results of the examination of dead fish infected with this parasite. Future studies are needed to better evaluate and describe the dynamics and the epidemiology of Ph. obladae infection in wild O. melanura.
摘要:
背负的海底,Obladamelanura(L.),是地中海中常见的海水物种。2023年7月至8月,在意大利西西里海岸的潜水活动期间,我们用数码相机记录了几个O.melanura标本,显示出在水柱中游泳的异常模式。不寻常的游泳行为的特点是快速,不协调的方向变化和与浅滩中剩余鱼类的隔离。发现并收集四只死鱼进行尸检和寄生虫学评估/检查。经过粗略检查,所有的鱼都表现出明显的体腔扩张;两条鱼的体腔充满了线虫,使体腔器官脱臼,另外两个在体腔中有降解的线虫和大量的液体。根据形态学标准,所有收集的寄生虫均被鉴定为费城(Nematoda:Philometridae)。这里,我们描述了自然感染了Ph的O.melanura的异常游泳行为。球藻和感染这种寄生虫的死鱼的检查结果。需要进一步的研究来更好地评估和描述Ph的动态和流行病学。野生O.melanura的球藻感染。