Classification and distribution of Sturgeons

Acipenseridae・・・They inhabit the sea in the northern hemisphere, and some migrate up rivers during spawning, while others live their entire lives in freshwater.

Polyodontidae・・・They inhabit freshwater areas, as well as brackish water in rare cases, in China and the United States.

Many sturgeons inhabit the Russian coast. The Amur River, which flows into the Sea of Okhotsk, has Acipenser ruthenus. The Ob River, which flows into the Arctic Ocean, has Siberian sturgeon, and the Caspian Sea has Huso huso. Some Arctic sturgeon are landlocked and inhabit Mongolia. In China, there are sturgeon from the Yangtze River, Changjiang River, and Yellow River. Although sturgeon were widely distributed in Europe, all are on the verge of extinction. The main reason for the decrease in their populations is thought to be the decrease in the spawning grounds due to overfishing and river improvement works.

In Japan, there used to be upstream-migrating groups of stuegeons in the Niigata Prefecture, north of Fukushima Prefecture, the coastal areas of Hokkaido, Teshio River, and Ishikari River. However, they are now extinct as river improvement works have eliminated suitable pools for spawning.

Huso dauricus was discovered in the Ishikari River in 2004, and Acipenser mikadoi was discovered in Rausu in 2013. It is likely that the individuals inhabiting Russia have migrated to these rivers.