Oncorhynchus masou macrostomus
subspecies of fish
The amago or the red-spotted masu salmon (Oncorhynchus masou macrostomus) is a salmonid fish endemic to western Japan, and a subspecies of the more widespread Northwest Pacific masu salmon or cherry salmon (Oncorhynchus masou).
It is distinguished by the presence of red or vermilion spots on the body along with black ones, while the nominate form O. masou masou, known as the yamame, only has black ones. The amago is distributed in western Japan, on the Pacific side of the Honshu and Shikoku islands, and on the Inland Sea of Japan side of Kyushu. The subspecies is a subject of aquaculture. It can grow up to 50 cm (20 in) length.
There are both anadromous (sea-run) and persistently stream-dwelling populations of the amago. Previously it was considered a subspecies of Oncorhynchus rhodurus, a name that currently only refers to the Biwa trout, which has a restricted distribution within the range of the amago.
O. m. ishikawae and the satsukimasu salmon
Varying scientific nomenclature has been used of the various forms of cherry salmon. The vermilion-spotted amago has been referred to alternatively as O. m.
The public source identifies “Oncorhynchus masou macrostomus” as subspecies of fish. This brief keeps that definition visible, then builds a research path around Oncorhynchus, masou and macrostomus.
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The date and method of observation matter as much as the stated conclusion, especially where classification or consensus has changed. The source revision retrieved here is dated May 19, 2025. The linked authority identifier is Q3767959. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Oncorhynchus masou macrostomus” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.