Migration and Wintering of Fish in Irrigation Channel in Non-irrigation Period

概要

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Irrigation channels commonly have no or little water flowing during the non-irrigation period but should ensure a fish wintering area. Environmental factors for fish wintering were investigated to determine a suitable environment of wintering spots in an irrigation channel of the Kushida River System in Mie Prefecture from 2008 to 2009. A survey leg where the largest numbers of fish were caught had a water depth of about 60 cm on January. The maximum water depth in a survey leg was identified by correlation analysis as the most important factor for wintering when compared to other factors such as bottom sediments and plant cover, but Carassius spp. may needs not only large water depth but also covers such as undercut banks. Fish migration was tracked by a marking-and-recapture method. More than 70 percent of the tracked distances of fishes from points marked in the non-irrigation period to recapture points in the irrigation period were shorter than 200 m. Consequently, water spots greater than 30 cm deep near temporary water areas may be effective for fish wintering in paddy field areas.
公益社団法人農業農村工学会の論文