ニホンウナギの生息状況からみた中小河川水際域の評価－福岡市樋井川流域を対象に－

抄録

This study is focused on Japanese eel (Augullia Japonica) which is designated as an endangered species and conservation is urgently required. We conducted surveys for evaluate river shoreline of Jpanese eel habitats in the Hii River flowing through Fukuoka city. The density of Japanese eel was largest in sections of articulated concrete mattress + boulders section, in order of natural vegetation river section, large tension block section, concrete block section. It was confirmed that many individuals of various sizes with the standards length of 10 to 70 cm were inhabited in the articulated concrete mattress + boulders section and natural riparian section. In addition, it was shown that the proportion of boulders, oversized blocks, underwater roots, and vegetation covers positively correlated to the population density of Japanese eel. In particular, it was revealed that monotonous watershed area was improved when boulders were installed, and the population density of Japanese eel was increased. However, setting up boulders is merely a coping improvement method, so it is more important to essentially restore the health of rivers.