Basic information | ||
Scientific name | Oncorhynchus nerka | (No picture) |
Common names | Sockeye salmon, Kokanee | |
Higher taxon | Salmonidae, Salmoniformes, Actinopterygii | |
Natural range | Freshwater in California, Canada, far eastern Russia, Chishima (Kuril) Islands, to Hokkaido, Japan, and N Pacific Ocean. | |
Habitat | Lakes, rivers, and ocean. |
Invasion information | ||
Range in Japan | Landlocked form (kokanee): Hokkaido (Shikotsuko and Toyako Lakes), Aomori (Towadako Lake), Tochigi (Chuzenjiko Lake), Kanagawa (Ashinoko Lake), Yamanashi (Saiko and Motosuko Lakes), and Nagano (Aokiko Lake) Prefs. Anadromous form (sockeye): Hokkaido (Nishibetsu and Abira Rivers). |
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Origin | Within Japan. Shikotsuko Lake population was from Akanko Lake, Hokkaido. The almost other introduced populations were from Shikotsuko Lake or Etorofu Is., southern Chishima (Kuril) Islands. | |
Date | Introduction from Akanko Lake to Shikotsuko Lake was in 1894. | |
Route | Deliberate: As fishery resource | |
Impact | Potentially: Predation on zooplankton. Competition with native fishes. Native organism(s) affected: Native fishes and zooplankton. | |
Regulation in Japan | Fishing of this species is prohibited by Hokkaido local government. In other lakes, fishing is prohibited in some season. | |
Introduced range in other countries | New Zealand (from Canada). |
Reference | Notes |
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In Saiko Lake of Yamanashi Pref., another introduced salmon O. kawamurae was found in 2010. Oncorhynchus kawamurae, endemic to Tazawako Lake, Akita Pref., was assumed to be extinct in 1940s, and current living population is in Saiko Lake only. This species has sometimes been regarded as a subspecies of O. nerka. |