Nikolskii & Soin, 1948.
Classification: Order: Siluriformes; Family; Siluridae
English Name: Northern sheatfish, Soldatov’s catfish.
Environment: Demersal; non-migratory; freshwater.
Climate / Range: Temperate; 5°C-25°C ; 54°N-44°N, 126°E-141°E
Description: D 6; A 83-90, average 86.2; V 11-14, average 12.4; P 12-13; gill rakers 13- 16, average 14.9. In adults, length of the anterior mandibular barbels 5-8%, average 6.1%, of body length (without C); length of the posterior mandibular barbels 2-4%, average 3%. Height of D 7-11%, average 8.5%, of body length. Standard length less than 4 times head length. Body elongate, caudal part compressed, head large and depressed; snout blunt and rounded; eyes small and situated in upper-sides of head; mouth large, upper jaw shorter than lower one and reaching backward over hind margin of eyes; maxillary barbels 1 pair and reaching pectoral fin, numerous papillae at tip of maxillary barbel; chin barbels 2 pairs and anterior one larger than posterior one; skin naked. Dorsal fin rays 6, longer than that of pelvic fin and without spine; adipose fin absent; anal fin rays 83 — 90 and somewhat connected with caudal fin; pectoral fin situated in lower-sides, first pectoral ray feeble, reaching pelvic fin; pelvic fin opposite behind the base of dorsal fin, reaching anal fin, caudal fin truncate. Mouth larger than in the European catfish, head heavier (larger), vomer stronger (vomerine tooth band wider medially than laterally), it has smaller eyes, as well as shorter lower jaw barbels. Body color lightly yellowish gray on back and sides, rather pale on abdomen, lighter than in Silurus asotus. Amur River at Elabuga village 90 km downstream from Khabarovsk. Sungari from Harbin to the mouth (lenght up to 2 m, weight up to 40 kg). Report of the Limnobiological Survey of Kwantung and Manchoukuo, 1940, pp. 26, 70, Figure 85 (Sungari at Harbin; length up to 4 m) (in Japanese). Close to S. glanis (a good example of the interrupted amphiboreal distribution).
Distribution: In Asia; Amur and found in the lower reaches Liao He drainages (North Korea). In Russia, this species inhabits the Amur River: from about Blagoveshchensk downriver to Sungari (or Songhua), Ussuri, Khanka Lake and Amurskiy Liman. In China mainly distributed in the Heilongjiang River (Amur in Russian) below Aihun (Heihe River) down to Boli, Songhuajiang River (Songhua in Russian), Nunjiang River and Wusulijiang River (Ussuri in Russian). They are also found in in Buyr Lake (Mongolia).
Biology: This is a phytophilic species, which prefer living in the bottom. Like to live in the main streams and tributaries and does not like to go to areas of lakes and zones of flood. Unlike Amur catfish, this species spends most of its life in the main channel of the Amur and goes to the floodplain only for spawning. Females mature at the age of 4-6 years and length 90-100 cm, males mature at the age of 4-5 years and length 85-90 cm, weight 6-7 kg. They lay eggs on water plants. Fecundity is 87-350 thousand eggs. They are carnivorous and live on other fishes and other aquatic animals. This is an active predator feeding on large prey. The prey of one year old Soldatov catfish may constitute 25-43 % of predator length, for adults usually 15-35 %. Sometimes they swallow waterfowl. They grow quickly and their body length can reach 559 — 583 mm in 2 years plus and 675 — 685 mm in 3 years. Males of S. soldatovi are larger than the females and reach 20-40 kg in weight. Life span is 18-20 years. It grows very fast and may reach 4 meters length (larger than Silurus asotus). According to A.N. Voronets, he personally measured a catfish weighing over 260 kg.
Catch and Abundance: As for many other Amur fish, exact abundance is unknown. In commercial fishing statistics it was recorded together with Amur catfish. We estimate it to be five times less abundant than Amur catfish. In 1960s-1970s catches of Soldatov catfish in Amur were one ton per year, and three to four tons in Khanka Lake. In the Lower Amur, this species is most abundant from the mouth of Songhua (or Sungari) to Bolon Lake. It is quite rare elsewhere in the Lower Amur and Khanka. In 1970s-1980s this species was “steadily decreasing”. Because of that, it was liste in the Red Book. Today, the species has recovered, and fishermen generally encounter as much Soldatov catfish as a smaller-sized Amur catfish in Amur harvests.