Huso dauricus, also known as the Kaluga sturgeon, is a large, freshwater fish native to the Amur River basin in Russia and China. It is known for its immense size, reaching lengths of up to 5.6 meters and weights over 1,000 kg. The species is carnivorous, preying on fish and small mammals, and features a long lifespan, sometimes exceeding 50 years. Kaluga sturgeons are critically endangered due to overfishing and habitat loss.

Huso dauricus, commonly known as the Kaluga sturgeon, is native to the Amur River basin, which runs along the border between the Russian Far East and Northeastern China. This region includes the main channel of the Amur River, as well as its tributaries and associated water bodies.

The Kaluga sturgeon inhabits large river systems and requires freshwater environments with deep, slow-moving waters. The Amur River basin experiences a temperate climate with significant seasonal variations, including cold winters with ice cover and warmer summers.

Huso dauricus occupies the ecological niche of a top predator in its freshwater ecosystem. It primarily feeds on fish and invertebrates and plays a critical role in maintaining the balance of the aquatic food web. The species is adapted to migratory patterns, moving between different parts of the river system for spawning and feeding.