Invasion information | ||
Range in Japan | Kanto District to western Japan. | |
Origin | Unknown. | |
Date | Imported as an experimental material for physiology in 1920s-1930s. Feral population was recorded in 1961 at Biwako Lake, Shiga Pref. | |
Route | Deliberate: As an experimental material for physiology. | |
Impact | Competition with native species. Prevention of water current. Native organism(s) affected: Native submerged plants (e.g., Hydrilla verticillata) | |
Regulation in Japan | Keeping of this species in Saga Pref. are controled by a prefectural ordinance. Import to Australia is prohibited. | |
Introduced range in other countries | Europe, East Asia. |
Reference | Notes |
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100 of the Japan’s Worst Invasive Alien Species. For eradication of this species, grass carp Ctenopharyngodon idella was introduced in 1980s in Kizaki Lake of Nagano Pref. As a result, ecosystem of this lake was seriously changed. |