Masu salmon
Pacific salmonid native to East Asian coasts and rivers.
The masu salmon is a Pacific species found from Russia to Taiwan. It lives in both fresh and salt water, migrating between rivers and the sea. Anglers prize it for sport, while fisheries harvest it for food. Several distinct subspecies exist, including landlocked forms in Japan and Taiwan.
- Adults commonly weigh 2.0 to 2.5 kg
- Maximum recorded length is 71 cm
- Critically endangered form exists in Taiwan
- Spawning run starts earlier than other salmon
- Known as cherry trout due to red stripes
What it is
This fish belongs to the Pacific salmon genus. Adults typically weigh between two and two and a half kilograms. They measure about fifty centimetres in length. The largest recorded specimen reached seventy-one centimetres and nine kilograms. Mature individuals develop a dark back. Bright red stripes appear on their sides, merging into a lighter band on the belly. This colouration gives rise to the name cherry trout.
Where it lives
Its distribution spans the North Pacific along East Asian coasts. Populations exist from the Russian Far East, including Kamchatka and Sakhalin, down through Korea and Japan to Taiwan. It prefers temperate climates near specific northern latitudes. In marine environments, it stays within depths of zero to two hundred metres. Some subspecies remain entirely in freshwater lakes or mountain streams.
How it lives
The life cycle includes both freshwater and marine phases. Young fish stay in river upper reaches for one to three years. They feed on insect larvae and airborne bugs in slow currents. Older juveniles move to the ocean for two to three and a half years. There, they eat crustaceans and small fish. Most adults die after spawning, though some dwarf males may survive to breed again.
Breeding and life cycle
Spawning occurs when the fish are three to seven years old. This run begins earlier than for other Pacific salmon species. Adults enter rivers to lay eggs in nests. After hatching, the young do not migrate to sea immediately. They remain in shallow spawning areas with weak currents. Migration to the ocean usually happens in the second or third year of life.
Fish and people
Fisheries catch this species for commercial sale. It is also raised in aquaculture programmes. Markets offer it fresh or frozen, often prepared by broiling or baking. Anglers seek it as a game fish due to its fighting ability. In Japan, it holds cultural significance as a common freshwater salmonid. Various local names reflect its importance in regional traditions and cuisine.
Status and threats
However, the Formosan salmon in Taiwan is critically endangered. This landlocked form survives only in specific mountainous waters. Other subspecies like the Biwa trout are endemic to single lakes. Conservation efforts likely focus on these restricted populations rather than the main anadromous groups.
Questions people ask about Masu salmon
Why is it called cherry trout?
Mature fish develop bright red stripes on their sides. These markings merge into a lighter band on the abdomen. The crimson tinge resembles cherry blossoms, leading to the name cherry salmon or cherry trout in Japan.
Do all masu salmon go to the sea?
No. While the main form is anadromous and migrates to the ocean, several subspecies are landlocked. The yamame, Biwa trout, and Formosan salmon live entirely in freshwater rivers or lakes.
What do masu salmon eat?
In the ocean, they feed intensely on crustaceans and occasionally young fish. Freshwater juveniles eat chironomids, stone fly larvae, mayfly larvae, and airborne insects found in river pools and shallows.
How large do they grow?
Most adults measure roughly 50 cm and weigh between 2.0 and 2.5 kg. The maximum size recorded is 71 cm in length and 9 kg in weight, typically found in the Primorsky Krai region.
Good reading and sources
- Oncorhynchus masou on WikipediaEncyclopedia
- More photos on Wikimedia CommonsPhotos
- Wikidata recordOpen data
The facts on this page come from the Wikipedia article "Oncorhynchus masou", written by its contributors and used under the CC BY-SA 4.0 licence, and from its Wikidata record (CC0). EveryFish rewrote the text in its own words, with AI assistance, and compares every page with the article to make sure no passage is copied. It may be reused under the same CC BY-SA 4.0 licence with a link back.
It may contain mistakes, and figures change over time. Nothing here is investment or buying advice. If something is wrong, tell us. Last refreshed 2026-11-15.
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