Oncorhynchus kawamurae Jordan & McGregor, 1925
Kuchiguromasu, Kunimasu, Black kokanee, Black-jaw trout
Taxonomy & Nomenclature
Synonym/s: Oncorhynchus nerka kawamurae Jordan & McGregor, 1925
Conservation Status
Last record: 1940
Rediscovered outside natural range in: 2010
IUCN RedList status: Extinct in the Wild
Distribution & Habitat
Lake Tazawa (native), Akita Prefecture & Lake Saiko (introduced), Yamanashi Prefecture, both Honshu, Japan
Biology & Ecology
Hypodigm
Media
https://www.youtube.com/watch?v=qwZKLBPvM-Q
References
Original scientific description:
Jordan, David S. and McGregor, R. C. in: Jordan, D. S. and Hubbs, C. L. (1925). Record of fishes obtained by David Starr Jordan in Japan, 1922. Zoologicheskii Zhurnal 10(2): 93-346.
Other references:
Aoyagi, T., Okazaki, T., Kaji, N., Oohama, H., Hasegawa, Y., Kanzaka, K., Ichida, K. and Yoshizaki, G. (2014). Studies on the ecology and aquaculture of Kunimasu (Oncorhynchus kawamurae) in Lake Saiko (part 2). Y-CROST Res Rep 9: 49-65. [in Japanese with English abstract]
Dalrymple, S. E., Abeli, T., Ewen, J. G., Gilbert, T. C., Hogg, C. J., Lloyd, N. A., Moehrenschlager, A., Rodríguez, J. P. and Smith, D. (2023). Addressing Threats and Ecosystem Intactness to Enable Action for Extinct in the Wild Species. Diversity 15: 268. https://doi.org/10.3390/d15020268
Fukatani, Mahiro, Oyama, Daichi and Aizawa, Masahiro. (2026). Historical museum specimens reveal the identity of “Kuchiguromasu” in Lake Tazawa, Japan, as immature Kunimasu Oncorhynchus kawamurae. Ichthyological Research. https://doi.org/10.1007/s10228-026-01061-2
Holmes, Branden. (2021). What's Lost and What Remains: The Sixth Extinction in 100 Accounts (eBook). Self published.
Miyazaki, Y., Mukai, T., Nakajima, J., Takaku, K. & Taniguchi, Y. 2019. Oncorhynchus kawamurae. The IUCN Red List of Threatened Species 2019: e.T110463465A110463483. https://dx.doi.org/10.2305/IUCN.UK.2019-2.RLTS.T110463465A110463483.en. Accessed on 04 July 2022.
MOE (Ministry of the Environment). (2014). Fifth National Report of Japan to the Convention on Biological Diversity. Tokyo, Japan: Ministry of the Environment, Government of Japan. 101 pp.
Moreira, A.L. and Taylor, E.B. (2015). The origin and genetic divergence of "black" kokanee, a novel reproductive ecotype of Oncorhynchus nerka. Canadian Journal of Fisheries and Aquatic Sciences 71: 1584-1595.
Morris, A. R. and Caverly, A. (2004). 2004 Seton and Anderson Lakes kokanee assessment. British Columbia Conservation Foundation and Ministry of Water, Land and Air Protection, Kamloops, British Columbia.
Muto, N., Nakayama, K. and Nakabo, T. (2013). Distinct genetic isolation between “Kunimasu” (Oncorhynchus kawamurae) and “Himemasu” (O. nerka) in Lake Saiko, Yamanashi Prefecture, Japan, inferred from microsatellite analysis. Ichthyological Research 60: 188-194.
Nakabo, T. (2021). On “Kunimasu” Oncorhynchus kawamurae, a deepwater trout, from Lakes Tazawa and Saiko, Japan. Sinchosha, Tokyo. [in Japanese]
Nakabo, T., Aizawa, M., Oyama, D., Mochizuki, K., Kobayashi, K., Fukatani, M. and Ueshima, R. (2025). Specimens of Oncorhynchus kawamurae discovered from the University of Tokyo. Ouroboros 30(1): 4-7. [in Japanese]
Nakabo, T., Nakayama, K., Muto, N. and Miyazawa, M. (2011). Oncorhynchus kawamurae ‘‘Kunimasu,’’ a deepwater trout, discovered in Lake Saiko, 70 years after extinction in the original habitat, Lake Tazawa, Japan. Ichthyological Research 58: 180-183.
Nakabo, T., Tohkairin, A., Muto, N., Watanabe, Y., Miura, Y., Miura, H., Aoyagi, T., Kaji, N., Nayakaya, K. and Kai, Y. (2014). Growth-related morphology of “Kunimasu” (Oncorhynchus kawamurae: family Salmonidae) from Lake Saiko, Yamanashi Prefecture, Japan. Ichthyological Research 61: 115-130.
Nakayama, K., Muto, N. and Nakabo, T. (2013). Mitochondrial DNA sequence divergence between “Kunimasu” Oncorhynchus kawamurae and “Himemasu” O. nerka in Lake Saiko, Yamanashi Prefecture, Japan, and their identification using multiplex haplotype-specific PCR. Ichthyological Research 60: 277-281.
Nakayama, Kouji, Tohkairin, Akira, Yoshikawa, Akane and Nakabo, Tetsuji. (2018). Detection and morphological characteristics of “Kunimasu” (Oncorhynchus kawamurae)/”Himemasu” (O. nerka) hybrids in Lake Motosu, Yamanashi Prefecture, Japan. Ichthyological Research 65: 270-275. https://doi.org/10.1007/s10228-018-0613-z
Senboku City Municipal Office. (2017). Lake Tazawa Kunimasu Miraikan Senboku City. Senboku City Municipal Office, Senboku City.
Smith, Donal et al. (2023). Extinct in the wild: The precarious state of Earth’s most threatened group of species. Science 379(6634): eadd2889. https://doi.org/10.1126/science.add2889
Sugiyama, H. and Goto, A. (2012). Impressions of the sumposium "Kunimasu: its biological entity and conservation" held at the lecture open to the public of the Ichthyological Society of Japan in 2012. Japanese Journal of Ichthyology 59: 182-184.
Tokui, T. (1964). Studies on the kokanee salmon (V). Transplantation of the kokanee salmon in Japan. Sci Rep Hokkaido Salmon Hatchery 18: 73-90. [relevant reference?]
Vardakas, Leonidas, Perdikaris, Costas, Freyhof, Jörg, Zimmerman, Brian, Ford, Matthew, Vlachopoulos, Konstantinos, Koutsikos, Nicholas, Karaouzas, Ioannis, Chamoglou, Maria and Kalogianni, Eleni. (2025). Global Patterns and Drivers of Freshwater Fish Extinctions: Can We Learn From Our Losses? Global Change Biology 31(5): e70244. https://doi.org/10.1111/gcb.70244 [Table S1]
Yaguchi, Takao. "Tsurikichi-Sanpei Heisei-Ban (1) Chitei-ko no Kinoshirimasu." Comic strip. In Shonen Magazine. 1-228.
http://www.asahi.com/ajw/articles/AJ201705100037.html
https://www.kingcounty.gov/elected/executive/constantine/news/release/2018/December/18-kokanee-salmon-habitat.aspx
https://extinctanimals.proboards.com/thread/16406/oncorhynchus-nerka-kawamurae