Utilization of paddy field by Hotoke loach -Case study of Yatsu paddy field in the upper stream of the Okuri River-

Abstract

To evaluate how Lefua echigonia use paddy fields, we studied the so-called "yatsuda" paddy fields in Tokyo from April through November of 2006. The investigation consisted of trapping fish that migrate between the paddy fields and the irrigation channel, followed by a distributional survey at the channel. In the analysis, we compared the results of each item assessed for Lefua echigonia with those for Misgurnus anguillicaudatus and found that while both L. echigonia and M. anguillicaudatus bred in the paddy fields, the main breeding site for L. echigonia was apparently the channel. These results along with the observation that many juvenile L. echigonia enter the paddy fields suggest that the paddy fields function mainly as the growth place for L. echigonia. It was also found that L. echigonia tended to exit the paddy fields at the point of water entry.