Abstract
The Yodo River system supports some of the richest freshwater fish fauna in Japan, and the conservation value of this river is enhanced by the presence of a symbolic fish species, the Itasenpara bitterling, Acheilognathus longipinnis, which is a nationally designated natural monument. The abundance of A. longipinnis has decreased throughout its native range due to the colonization and establishment of invasive fish species such as largemouth bass and bluegill sunfish. Similarly, the Yodo River population of A. longipinnis has recently vanished, albeit temporarily, because of invasive fish species, such that conservation practices including the eradication of invasive fish are required to rescue and to restore the habitat of native freshwater fish populations. The Aquatic Life Conservation Center of Osaka Prefecture, which has developed and demonstrated various practical measures to control and eradicate invasive alien fish species, organized various citizen groups, companies, universities, and administrative agencies to establish a “Citizen Network of the Conservation of the Itasenpara bitterling in the Yodo River watershed” in 2011. This report summarizes how implementation of various control measures by this organization has led to the control of largemouth bass and bluegill sunfish and to the restoration of habitats for native fish species including A. longipinnis in the Shirokita embayments of the Yodo River.
