Least cisco (Coregonus albula)
The least cisco range covers the basins of the North, Baltic, Barents and White Seas. This fish inhabits the rivers and lakes from Denmark in the west to Pechora River and to Vashutkiny Lakes in the east. It dwells in the lakes or forms a lake-river form; this species does not have the typical anadromous form. In Russia, the least cisco is especially numerous in the lakes of Karelia and the Kola Peninsula. The southern border of the range passes through the Pskovsko-Chudsky water body and the lakes of the Upper Volga. In recent years, the least cisco has migrated down the Volga River to the Saratovskoe reservoir.
The length of the small form of the least cisco is 10-12 cm with a mass of 50-70 grams; the large form reaches 20-28 cm and a mass of 200 grams. In the Lakes Ladoga and Onega there are special forms of the least cisco up to 46 cm long and weighing up to 1 kg.
The life cycle goes in the lakes, although there are lake-river forms. The lifestyle of the species is pelagic; its main diet is zooplankton. The spawning occurs mainly in the autumn, but there are some populations spawning in winter-spring. The reproduction occurs on sandy-pebble or rocky areas at the depth of 3 to 20 meters.