The Channel Catfish Ictalurus punctatus, an invasive species introduced from North America in the 1970s, has since become established in several rivers and lakes in Japan, impacting negatively on aquatic communities and commercial fisheries. In Lake Biwa, the Channel Catfish was first captured in the north basin in 2001, a total of 820 individuals being captured subsequently until 2020, mostly in the lower reach from the Setagawa weir of the outflowing Seta River. In the latter, variously-sized individuals, including juveniles, have been captured every year since 2008, suggesting that the species can now be considered to have become established. It is unknown, however, whether or not the species is established in the north or south basins of Lake Biwa, due to the relatively low numbers of Channel Catfish caught in the lake. Efforts to eradicate the species from both the lake and river must be made to avoid future impacts on the local ecosystems and associated fisheries.
