- 著者
-
中島 淳
鬼倉 徳雄
- 出版者
- 一般社団法人 日本魚類学会
- 雑誌
- 魚類学雑誌 (ISSN:00215090)
- 巻号頁・発行日
- vol.56, no.2, pp.135-143, 2009 (Released:2014-03-05)
- 参考文献数
- 39
- 被引用文献数
-
2
The natural growth and habitat selection of the green chub, Aphyocypris chinensis, an endangered species in Japan, was investigated in an agricultural waterway located in northern Kyushu Island, Japan. From April 2007 to March 2008, green chub were captured by hand net and 5 physical environmental variables measured (water temperature, water depth, water current velocity, connection to paddy field, and presence or absence of tunnel-like cover) at 10 survey sites every month. After obtaining an image of the captured fish with a digital camera, all individuals were released alive at their capture location. The standard lengths of 823 individuals were later determined from the images. Monthly changes in the standard length distribution showed that green chub had a life-span of 1 year, the spawning season occurring from mid-June to August. Multiple linear regression analysis applied to the 5 environmental variables separately in the irrigation (from June to September) and non-irrigation seasons (from October to May), showed water depth to be most significant in the former and absence of water movement in the latter. Fish occurrence patterns indicated that temporary waters were utilized as spawning sites and permanent waters for overwintering. Accordingly, continued ease of movement between temporary and permanent waters is essential for future conservation of the species.