Amur sturgeon

Sinosturio schrenckii, the Amur sturgeon, sometimes known as the Japanese sturgeon, is a freshwater species of fish in the sturgeon family. Being able to grow up to a length of 3 meters and weight of 190 kg, this species can be primarily found in its two distinct morphs of grey and brown in the Amur River and Amur Estuary. This sturgeon is a potamodromous migrator, performing their migrations through the Amur river. Due to over-fishing and caviar production, this species is currently listed as critically endangered on the IUCN red list.

Description

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. 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. However, the Amur sturgeon lacks a lateroventral band and a fontanel in between the frontal bones that can be found in many species within Sinusturio. This species has very large pectoral fins and a long caudal peduncle that lacks oblique scale rows.