Common whitefish (Coregonus lavaretus)
Often this fish has a well-defined flat area at the snout, the height of which is less than its width. The spawnig dress of the species (epithelial tubercles) is more pronounced by the males. Often, the common whitefish in the same water body is represented by two or more forms that differ in the number of gill rakers, food spectra, and spawning sites. In the large lakes, the number of such forms can reach 4–5 and even 9.
The common whitefish range is circumpolar. In Russia, it lives in most of the rivers flowing into the Arctic Ocean; it is also found in the Baltic Sea basin. In addition, in Chukotka, the whitefish is found in the Pacific basin – in the Erguveyem and Anadyr rivers, and in the water bodies of the Beringovski Rayon of Chukotka south of the Anadyr River.
In the Eastern Siberia and the Far East, the common whitefish has a short head with a hard snout and a small subterminal mouth, large silver scales and a humpbacked, laterally flattened body. This fish reaches the weight of several kilograms and can live both in rivers and in non-winterkill lakes. The local names for this species are «sig» in Siberia, and «gorbun» (humpy) in the Anadyr basin. Whitefish spawning takes place mainly in the fall, but some spring-spawning populations are known: such is the Baunt whitefish from Transbaikalia, described as a separate subspecies. Individual populations (the Volkhov and Baunt whitefishes) are placed on the pages of the Red Book of the Russian Federation.