抄録
SAKUTA ditch is the oldest irrigation channel in Japan. The first description is described in the Japanese Chronicle of Japan that is the Japanese oldest history book. SAKUTA ditch is located in FUKUOKA Prefecture. In other words it is the very precious irrigation channel which continues being used for more than 1500 years. According to the field observation results performed in SAKUTA ditch, it becomes clear that 24 species of fishes are existed. In recent years, however, there have been increasing demands from local residents for the creation of the convenient irrigation channel.
The objective of this study is to evaluate the fish habitat and to discuss the relationship between vegetation covered ration and physical environmental condition in SAKUTA ditch. The study results indicate that the density of fishes in channel is related to the vegetation covered ratio and the velocity distribution in the ditch. These results suggested that the water's edge structure and the vegetation covered ratio in channel are greatly influenced to fish habitat evaluation.
