Abstract
ln order to clarify the distribution of Lefua echigonia Jordan and Richardson, 1907 (Cypriniformes: Cobitidae: Nemacheilinae) in Atsugi City，Kanagawa Prefecture, Japan, a field survey was carried out at a total of 122 stations on 8 river systems from June 2009 to October 2011. As a result, the species was found from the following 36 stations: 10 in Oginogawa River System; 4 in Mayumigawa River System; 1 in Koayugawa River System; 8 in Onzogawa River System; 10 in Tamagawa River System; 3 in Hinatagawa River System. Among these stations, the species occurred in high density at the source of river in secondary nature called as "yato." On the other hand, the density was low in an upper reach and a main stream in a river. The environment of "yato" was characterized by having spring water, slow flow, rich water plants and/or dead leaves on sandy-muddy bottom, and low density of Procambarus clarkii, where located at altitudes of 40 to 90 m. The density was much higher than that of "yato" in a biotope reconstructed artificially. Therefore, it is essential to manage their habitat for conservation of this species. Coloration of 163 live specimens were analyzed by a digital image taken in a field. The pattem of coloration was divided into 4 types on the basis of distribution of black spots on body. The ratio of occurrence of each type was different every river system. This suggests thatitis necessary to make a plan for conservation every river system.
