The Kaluga (Huso dauricus) has undergone a sharp decline in both stock and recruitment. The dramatic stock decline began in the late 19th century and continues to the present day. From the late 19th century to 1992 the population experienced a decline of more than 90%. During the last ten to fifteen years a very large decrease in the abundance of this species has occurred. The average age of fishes is consequently decreasing as a result of poaching for caviar and meat. This has resulted in females reproducing only once in their lifetime. This species has therefore been assessed as Critically Endangered.

The Kaluga Sturgeon inhabits the Amur River basin from the estuary to the river’s upper reaches. It occurs in the following tributaries: the Shilka River, Onon River, Argun River, Nerch River, Sungari River, Nonni River and the Ussuri and Neijiang Rivers (Krykhtin and Svirskii 1997). It is rarely found in Lake Khanka. Young specimens also appear in the coastal waters of the Sea of Okhotsk, near the northeastern part of the Tatar Strait, and in the Sea of Japan near the islands of Hokkaido and Honshu (Krykhtin and Svirskii 1997, Shmigirilov et al. 2007).

Most data on population trends are based on diverging catch efforts and methods. A decline of catches has been observed since the end of the 19th century (Vaisman and Fomenko 2007). In China, a decrease by 80% in mature fish based on catch per unit effort between 2008 and 2018 (annual surveys) has been observed (Wei pers. comm. 2019). Towards the end of the 19th century, annual catch was approximately 500 tons mostly in the lower river section. Before 1992 the annual catch was 92 tons. The stock size of the species in the lower river was estimated to be 7,100 tons in 2012. Currently, there are no commercial fisheries, but this species is affected heavily by illegal fisheries in Russia. Many poachers have moved from the overexploited Caspian Sea to the Amur River. A decline of more than 90% over 90 years (three generations) is estimated for this species.

There are four subpopulations of Kaluga sturgeon. The first lives in the estuary and coastal brackish waters of the Sea of Okhotsk and Sea of Japan, the second lives in the lower Amur, the third in the middle Amur, and the fourth in the lower reaches of the Zeya and Bureya rivers (Krykhtin and Svirskii 1997). Kaluga consume mostly invertebrates in the first year of life, later switching to juveniles of pelagic fishes. Males from the estuary population spawn for the first time at age of 14–21 years, and females, at age of 17–23. In autumn and early winter, most of these future spawning fish migrate from the estuary into the Amur River, where they spend the winter in preparation for spawning during the next spring. Adult Kaluga Sturgeons travel in small groups of three to 20 individuals to the shallow gravel beds to spawn, eggs hatch in shallow gravel beds. In the early life of a Kaluga the offspring prefer to live in a clear habitat setting (Krykhtin and Svirskii 1997).

Using the calculation Age of first reproduction + [z * (length of the reproductive period)] (IUCN Standards and Petitions Committee 2019), with z=0.6, average generation length is 61.6 years; three generations is therefore estimated as approximately 185 years for this species.

The cause of the population decline is still overfishing, both legal (past) and illegal (now). Furthermore, environmental pollution in the Amur River basin threatens the habitat and reproduction of this species (Shmigirilov et al. 2007, Chen 2007). Hybrids between Amur Sturgeon (Acipenser schrenckii) and Kaluga (Huso dauricus) have been produced in aquaculture and have found their way into the wild, where they are now frequently found and pose a threat to the native parental species.

This species is removed from the wild for human consumption.

Historically, the majority of  'conservation' measures were directed to control local and national fisheries. Commercial sturgeon fishing was prohibited in the Soviet Union during the periods 1923-1930, 1958-1976 and from 1984 to the present (Vaisman and Fomenko 2007). The Kaluga Sturgeon was listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 1998. The species is maintained in two large governmental hatcheries in Russia and it is also kept in four farms in China. From these farms, about 800,000 juveniles have been released totally between the years 2008 and 2019 in China, and 286,000 in Russia in 2019.