The marine leech, Zeylanicobdella arugamensis, is a major threat to aquaculture in grouper‐producing countries including Indonesia. This study aimed at investigating prevalence, intensity and histopathology of the ectoparasite in humpback and hybrid groupers cultured in different rearing systems. A total of 260 groupers (60 humpback groupers and 200 hybrid groupers) were used for samples. The marine leech was observed on skin, fins, gills and mouth, followed by histopathological assay on the skin tissue. The results showed that prevalence of the leech in both groupers was higher when they were cultured in the floating net cages compared with the hatchery, p < .05. Furthermore, humpback grouper had a higher prevalence than hybrid grouper when they were cultured in a similar system, p < .05. Meanwhile, there was no significant difference in intensity between the two groupers, p > .05. Within the hybrid groupers, the highest prevalence was obtained from hybrid groupers reared in the earthen ponds. Histopathological studies showed that the infected groupers exhibited inflammation, congestion and erosion of the epidermis layer. Hybrid grouper had more severe histopathological lesions in the skin tissues. These results suggested that species and type of aquaculture system had significantly determined the prevalence, intensity and severity of lesion in Z. arugamensis infestation.

中文翻译：

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在不同水产养殖系统上饲养的石斑鱼中Zylanicobdella arugamensis感染的发生率，强度和组织病理学。

在包括印度尼西亚在内的石斑鱼生产国，海洋水ech（Zeylanicobdella arugamensis）是对水产养殖的主要威胁。这项研究旨在调查在不同饲养系统中培养的座头鲸和杂种石斑鱼的体外寄生虫的发生率，强度和组织病理学。总共使用了260个石斑鱼（60个座头鲸和200个杂种石斑鱼）作为样本。在皮肤，鳍，g和嘴上观察到海洋水ech，然后在皮肤组织上进行组织病理学测定。结果表明，与孵化场相比，两个石斑鱼在浮网笼中养殖时水ech的患病率均较高，p  <.05。此外，在相似的系统中培养时，座头石斑鱼的患病率比杂交石斑鱼高，p  ＜.05。同时，两个石斑鱼的强度没有显着差异，p  > .05。在杂种石斑鱼中，从土池中饲养的杂种石斑鱼中患病率最高。组织病理学研究表明，被感染的石斑鱼表现出表皮层发炎，充血和糜烂。混合石斑鱼在皮肤组织中具有更严重的组织病理学损害。这些结果表明，水产养殖系统的种类和类型已显着确定了A.rugamensis侵染的病变的发生率，强度和严重性。