The masu salmon (Oncorhynchus masou), also known as masu (Japanese: マス, lit. 'salmon trout') or cherry trout (桜鱒, サクラマス, sakura masu) in Japan, is a species of salmonid belonging to the genus Oncorhynchus, found in the North Pacific along Northeast/East Asian coasts from the Russian Far East (Primorsky, Kamchatka Peninsula, Sakhalin and Kuril Islands) to south through Korea, Japan and Taiwan. Although generally accepted as a salmon in the West, the fish is actually regarded as a trout in Japan (its most famous native range) as it is the most commonly seen freshwater salmonid in the Japanese archipelago.

A number of subspecies are known, including the widespread nominate subspecies yamame (O. m. masou), the critically endangered Formosan salmon (O. m. formosanus) in landlocked waters of Taiwan, the Biwa trout (O. m. rhodurus) endemic of Lake Biwa, and the anadromous amago (O. m. macrostomus) restricted to western Japan.

...