2015 Volume 18 Issue 2 Pages 127-137
In an intermittent reach of the Shigenobu River （Ehime Prefecture, southwestern Japan）, two floodplain ponds （Matsubara Spring and Hirose-gasumi wetland） were created in 2006-2007 as a part of a habitat rehabilitation project. Fish assemblages and habitat characteristics of the two created ponds were investigated in 2008, and compared with those of ten pre-existing spring-fed ponds （reference ponds）. Structural characteristics （canopy shade, cover habitat, substrate, and bank condition） of the two created ponds were similar to those of the reference ponds. The created ponds were characterized by lower values of water level fluctuation, indicating that the created ponds can function as stable, permanent habitats in the intermittent reach. The number of fish species in the reference ponds ranged from 4 to 14 species, while that in the two created ponds was 13 and 9. This indicates that most of the major fish species had colonized the newly created ponds, although total fish density in both created ponds was low relative to that in the reference ponds. Overall, our data suggest that the two ponds created by the habitat rehabilitation project provide suitable habitats for freshwater fishes. However, exotic largemouth bass （Micropterus salmoides）, which can have strong negative effects on native biota, was found in a created pond （Hirose-gasumi）. Management of the created ponds should include consideration of this invasive species.
