2007 Volume 1 Pages 47-51
Dwarf topmouth gudgeon Pseudorasbora pumila pumila is listed as an endangered species in the Red List of Ministry of the Environment, Japan. It is endangered because of hybridization with Topmouth gudgeon Pseudorasbora parva, and the influence of alien fish such as Largemouth bass Micropterus salmoides. The Society for Shinaimotsugo Conservation study group is engaged in increasing and reestablishing Dwarf topmouth gudgeon populations in ecosystems by developing successful artificial breeding, and determining the proper timing for transplanting spawns. As a spawning substrate, we used plastic pots instead of conventional chloroethylene pipes, and obtained excellent results (spawning rate = 100%). Experiments examining the timing to transplant the spawns found that transplanting at the eyed-egg stage had the highest hatch success. These results brought marked improvement in artificial breeding success of Dwarf topmouth gudgeon, and consequently in methods for restoration of ecological systems.
