Karelia is often called the land of lakes and rivers. The abundance of freshwater bodies, it is much superior to other areas of the Soviet Union and such foreign countries as Finland, Sweden and Canada, also famous for its abundance of lakes. On the territory of Karelia over 60 thousand big and small lakes with a total area of over 42 thousand square km, including the largest lake in Europe — Ladoga and Onega.
Only one third of the Karelian lakes — waste, the other ows have. Closed to include numerous forest ponds, usually with peat marshy shores, called Lambada. Large, medium and small lakes are part of the flow and often form lake-river systems, connected by rivers and canals. The flowage lakes is a positive one for living in them fish, because it reduces the likelihood of a fish kill caused by lack of oxygen in water in the winter.
The depth of the lakes that are important in fish life is quite varied. The greatest depths are typical for large lakes: Ladoga (260 m), Onega (120 m), Segozero (97 m). On small lakes depths usually do not exceed 3-5 m Deep places often alternate with underwater rocky bottom or shoals, called Lud.
Annual fluctuations of levels that are essential for spawning and juvenile Continue reading