Abstract
We surveyed fish fauna from 2001 to 2006, and crab and insect fauna in 2006 in an artificial wando-pool in the Kitagawa River, Gokasegawa River System, Miyazaki Prefecture, Japan. The artificial pool is located 4 km upstream of the river mouth, and it is 50 m in width, 400 m in length, and average of 1.5 m in depth. This pool was constructed in 2001 to replace the natural wando-pool lost that was due to river improvement. In this survey, we recorded 72 fishes, 12 crabs, and 7 insects. The number of fish species captured in the artificial pool was almost identical to that in the earlier natural pool. In addition, various species of fishes, crabs, and insects were captured in the tidal flat and the Zostera japonica vegetation zone present along the waterfront of the pool. These results indicate that the species diversity in the artificial pool is identical to that in the natural pool, and this species diversity was maintained despite the diversified environments at the waterfront. In addition, this artificial pool also varied in other aspects and exhibited roughness of the bottom, substantial differences in water depth and salinity, and formation of a halocline. We assume that the diversified environment of not only the waterfront but also other places contributed to maintenance of the species diversity in this artificial pool.
