吸蟲與飛魚之寄生關係

Abstract

飛魚棲息於熱帶溫暖水域，具有一對特化的寬大胸鰭，具有滑翔的能力在海洋食物鏈中為其他大型魚類之重要食物來源。吸蟲隸屬扁形動物門，為海水魚中常見的寄生蟲，主要分為單殖吸蟲與複殖吸蟲。本研究將探討飛魚之寄生蟲相，以及鑑定採集之吸蟲種類。 飛魚樣本於2017至2018年4月至6月在臺東長濱漁港向漁民購買，共包含三種飛魚：白鰭飛魚(Cheilopogon unicolor)、黑鰭飛魚(Cheilopogon cyanopterus)及斑鰭飛魚(Cypselurus poecilopterus)，經調查發現有三種吸蟲寄生於鰓部。白鰭飛魚受到匙狀連腸吸蟲以及本研究發表之新品種多睪似歪尾蟲感染，白鰭飛魚為以上兩種吸蟲之宿主新紀錄。斑鰭飛魚則受到斑紋斧形蟲感染，為斑紋斧形蟲之寄主新紀錄。另外，斑紋斧形蟲與新種多睪似歪尾蟲皆為台灣首例，屬於地理新紀錄。黑鰭飛魚則沒有發現任何吸蟲及其他寄生蟲感染。 統計結果顯示，白鰭飛魚之吸蟲盛行率顯著大於斑鰭飛魚與黑鰭飛魚，同時白鰭飛魚之感染強度顯著大於斑鰭飛魚，可以認定為寄生白鰭飛魚之多睪似歪尾蟲的感染能力，大於感染斑鰭飛魚之斑紋斧形蟲；性別分組中僅雄性飛魚平均感染強度顯著高於雌性；飛魚體長與吸蟲感染參數比較中，僅斑鰭飛魚之體長分組與吸蟲之盛行率顯示中度負相關。感染白鰭飛魚之匙狀連腸吸蟲的樣本數量過少，統計上無明顯的意義。

Flying fishes live in warm tropical waters with enlarged wing-like pectoral fins that enable them to jump and glide above water to evade predators. They are also important food sources for other large fishes in marine food chain. Flukes belong to Phylum Platyhelminthes which are common parasites in marine fishes. The aim of this study is to investigate and identify the parasitical flukes of flying fishes. Flying fishes were purchased from Taitung Chang-bin fish harbor in eastern Taiwan from April to June in 2017 and 2018, respectively. There were three species of flying fishes: Cheilopogon unicolor, Cheilopogon cyanopterus and Cypselurus poecilopterus. C. unicolor was infected by Syncoelium spathulatum and a new species of monogenean which was classified and named Loxuroides pleorchia n.sp. in this study. Therefore, C. unicolor is a new host record of L. pleorchia n. sp. and S. spathulatum. Besides, C. poecilopterus was infected by Axine cypseluri and is a new host record of A. cypseluri. In addition, both L. pleorchia n. sp. and A. cypseluri are new locality record. C. cyanopterus was not found infected by any fluke and parasite. The prevalence of trematode in C. unicolor is significantly greater than C. poecilopterus and C. cyanopterus. The mean intensity of C. unicolor is significantly greater than C. poecilopterus. These results indicate the infectivity of L. pleorchia stronger than A. cypseluri. In the gender group, the mean intensity of male flying fishes was significantly higher than females. In the comparison of body length between infection parameters of flukes, only the prevalence of flukes has moderate negative correlation with C. poecilopterus. The numbers of S. spathulatum is small, and there is no statistically significant result.