Abstract
Host fish species that contributed to recruitment and reproduction of Unio douglasiae nipponensis in the newly-built biotope pond were examined by artificial parasitic experiment. Juveniles of U. d. nipponensis were obtained from 6 of 12 fish species and transformation ratio was higher in Zacco platypus and Rhinogobius sp. (95.3 and 88.1%, respectively) than the other host fish species (less than 5%). Additionally, in the survey of field, intensity and prevalence of glochidia on fish was the highest in Z. platypus, and the relative abundance of Z. platypus was relatively high among fish species inhabiting the biotope pond. For these reasons, it became clear that Z. platypus played a significant role in the recruitment and reproduction of U. d. nipponensis in the biotope pond.
