Year-round infections and complicated demography of a food-transmitted parasite Heliconema anguillae implying the feeding activity of Japanese eels in saline habitats

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• 作者：Hirotaka Katahira ; Kouki Mizuno ; Kazuya Nagasawa
• 关键词：Parasite ; Nematoda ; Biological indicator ; Anguilla japonica ; Feeding habits
• 刊名：Fisheries Science
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：82
• 期：6
• 页码：863-871
• 全文大小：737 KB
• 刊物主题：Fish & Wildlife Biology & Management; Freshwater & Marine Ecology; Food Science;
• 出版者：Springer Japan
• ISSN：1444-2906
• 卷排序：82

文摘

Seasonal changes in population structure of a trophically transmitted parasite Heliconema anguillae (Nematoda: Physalopteridae) were examined in Japanese eels Anguilla japonica caught from a small cove in Ehime Prefecture, western Japan. Demographic classification of the samples from May 2008 to March 2009 showed that the nematode infrapopulations in host individuals continuously involved newly recruited worms besides adults. Considering the complex life cycle of H. anguillae infecting the eel definitive hosts via their feeding on littoral crabs as the source of infection, this finding suggests that the eels in the cove constantly consume those intermediate hosts regardless of season. However, temperate eel species, including Japanese eels, are generally thought to lose their feeding activities during winter, and indeed, the winter water temperature at low tide in the sampling locality falls below the optimal thermal range for feeding. We thus suggest that the estuarine Japanese eels have a specific overwintering response to keep their feeding activity, unlike freshwater individuals, and require further studies to compare winter activities between various habitats within a river-estuarine system in different climatic zones along with the eel’s geographical distribution.