Amur sturgeon

Appearance

Being this size, these fish have 32-47 lateral scutes, 7-9 ventral scutes, and 11-17 dorsal scutes that can be found in two distinct color morphs of grey and brown, with brown morphs being the more rare of the two. Each of their scutes can be found with spines in the center, and of the 11-17 dorsal scutes present the first dorsal scute is the largest. Sinosturio schrenckii shares many traits with other Western Pacific species within its genus, most notably being a large compressed snout, small barbels, multiple dermal skin ossifications covering the body, and a laterodorsal row of scutes.

Amur sturgeon are massive fish that can grow to a length of 3 meters, and achieve a weight of up to 190 kilograms, though known hybrids between the Amur sturgeon and the kaluga, a much larger species also of genus Sinosturio present in the Amur, can be found with a maximum length of 1.9 meters and a weight of 70 kilograms.

Range and habitat

The Amur sturgeon is a freshwater fish that has a distribution almost entirely limited to the range of the Amur river, otherwise known as Heilongjang River, and Amur estuary, although a documented catch in Hokkaido, Japan has suggested that this species may make rare anadromous migrations. In the Amur river Sinosturio schrenckii are most concentrated near the mouth of the river, with the most concentrated region being 100 - 200 kilometers from the mouth. In the Amur estuary, Amur sturgeon can be primarily found in the Western and Northwestern sections, decreasing in abundance as estuary salinity increases.

In an effort to preserve this species, while also allowing for the industry for this fish to continue, the provincial government put efforts to limit the fishing of the Amur sturgeon by lowering the number of issued fishing licenses every year.

Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.

Diet

The Amur sturgeon's diet consists of over 90% mollusks, small fish, and crustaceans and the remaining 10% content being insect larvae, oligochaetes, and polychaetes. Even so, the contents and primary prey changes as Amur sturgeon grow in age and size.

Amur sturgeons that are less than 100 centimeters in length will typically eat small fish, most commonly the pond smelt Hypomesus olidus, as their primary source of food. As Amur sturgeon grow so does the importance of mollusks in their diet, as mollusks have shown an average of 87.6% of food mass in Amur sturgeons. Sinosturio schrenckii are potamodromous migrators, with their spawning migrations being contained in the Amur River system.

In crisis

Due to over-fishing and caviar production, this species is currently listed as critically endangered on the IUCN red list. As of 2022 the Amur sturgeon is currently listed as a critically endangered species on the IUCN Red List and their numbers only continue to lower. This species has been threatened for multiple decades now, primarily as a result of over-fishing and population depletion.

Even though despite these efforts, the Amur sturgeon population has shown to consistently decline in numbers, and reported ages of caught sturgeon have shown to become younger annually.

CITES lists this taxon on Appendix II. Confirm the current appendix on the CITES checklist.

Amur sturgeon is Critically Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.

Sources

Written for this catalog from the English Wikipedia article on Amur sturgeon, Wikidata item Q481710. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.