Anadyr whitefish (Coregonus anaulorum)
The Anadyr whitefish lives in the rivers and are closely connected with chum salmon spawning grounds; it is eating not only salmon eggs lost from the redds, but even the bodies of spent, dead salmon.
The maximum sizes of this whitefish in the Anadyr River are 51 cm and 1750 g, and in the Penzhina River – 45 cm and 1150 g. The age of this fish in the Anadyr can be up to 19+ years. In the lower reaches of the river, and especially in the Anadyr estuary, the juveniles predominated, and in the middle part of the river the mature fish aged 9+ to 12+ years were the most common.
The maturation occurs not earlier than at the age of 7-8 years. The majority of the males mature at the length of 33 cm (310 g), and the females – 35 cm (450 g). The fecundity at the end of the 20th century ranged from 7.2 to 63.3 thousand eggs. The spawning takes place later than that of the common whitefish – from the end of October to the end of November, under the ice at a water temperature close to zero. The main spawning grounds are located in the upper reaches of the river, on swift current, and on the pebble bottom and the depth from 1 to 2.5 m.
As a regional endemic, the Anadyr whitefish is included in the Red Book of the North-East of Russia.