Abstract
In this report, we clarify the habitat of freshwater fish during winter and describe the environmental factors of section of an irrigation channel where freshwater fish spend their winter. The investigation was carried out between September 2006 and January 2009 in Fuchu-channel, Kunitachi Tokyo. From the results, we think that the upper sections of the channel, which many fish inhabited, were an important habitat for the fish during the winter. Further we found that the number of fish fewer in the non-irrigation period than in the irrigation period. The density was higher locally than the period. The deep and slow sections (depth >35cm, water velocity <10cm/s) where silts, sands and litters accumulated under the bridge were constantly inhabited during the winter.
