Seasonal changes in upstream movements of fishes were examined in an irrigation ditch flowing into an inland-sea lake, Kitaura, Ibaraki Prefecture, eastern Japan, from April 2020 to March 2021. A total of 1,762 individuals representing 6 families and 12 species were collected using small fyke nets throughout the study period. The most abundant species were the gobiid Rhinogobius sp. OR（70.8% of the total number of individuals collected）, the gobiid Gymnogo- bius urotaenia（22. 5%）, the cobitid Misgurnus anguillicaudatus（2. 7%）, the gobiid Tridentiger brevispinis（1.7%）and the cyprinid Gnathopogon elongatus elongatus（1.1%）. Based on the body sizes, developmental stages and seasonal occurrence patterns of fishes sampled, it is highly likely that the irrigation ditch would be used as a place of temporary growth and spawning by several fishes including amphidromous gobiids.

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