Oncorhynchus masou, known as the masu salmon, masu, or the cherry hybrid salmon, is a species of salmon found in the northern part of the Pacific Ocean along East Asia, ranging from the Kamchatka, Kuril Islands, Sakhalin, and Primorsky Krai south through Korea, Taiwan, and Japan. A number of subspecies are known, including the anadromous, widespread masu Oncorhynchus masou masou, the critically endangered, landlocked Taiwanese or Formosan salmon Oncorhynchus masou formosanus found in certain freshwater systems of Taiwan, the Biwa trout endemic of Lake Biwa, and the anadromous or stream-dwelling amago Oncorhynchus masou macrostomus restricted to western Japan.
