ATLANTIC SALMON (Salmo salar L.), a fish of the family of anadromous and freshwater salmonids, belongs to the genus of noble salmons.
Spread in Karelia are anadromous and freshwater, or landlocked, salmon representing the largest part of the landlocked salmon population in the European continent. Individuals are up to 1-1.5 m in length, with the weight 2 to 7 kg, very rarely exceeding 30 kg. It inhabits 18 relatively small (46-194 km) rivers of the Karelian or western coasts of the White Sea, as well as lakes Ladoga, Onego, Janisjarvi, Sandal, Kuito, Niuk, Kamennoje, Segozero. In the Ladoga lake basin reproduction of Atlantic salmon continues in 13-15 rivers. In the Onego lake basin 10-13 rivers are considered salmon rivers, but reproduction is unstable in some of them. The basin of the rest of the lakes have preserved the total of about 10-13 rivers where landlocked salmon spawns.
Atlantic salmon propagates in rivers only, where it migrates upon feeding in marine and freshwater bodies. Salmon rivers in Karelia are noted for mountain-type gradients, lengthy shallow rapids with violent flow and gravelly boulder-strewn bed. A characteristic feature of Karelian rivers is the high number of lakes in their course which turns them into typical lake-river systems. In autumn, during the spawning period, male salmon dress in breeding livery, acquire darker colouring, their jaws bend into a hook. Salmon lay eggs into the ground of the rapid stretches and bury them into gravel forming redds. In spring as the temperature rises eggs develop into alevins which grow into fry by the end of June, independently spread across rapids and live there for 2-3 years. The next spring fry (parr) lose their protective spotted colouring, turn into silvery smolts and migrate to the sea or lake to feed. Having completed the feeding period in 1-2 or even 4 years adult individuals return to spawn to their native rivers in several waves: immediately after the ice breaks
down there come early spring fish "zaledka" - large fish which had spent the winter in the estuary, in 2-3 weeks late spring fish "zakraika" follow, which are also quite large, midsummer is the time for the low-water period fish "mezhen", comprised of the fish of varied size, and August - for late summer fish "tinda" or small males. Spawned-out fish (kelts) are carried to the sea (lake) most them to die. The survivors recover the ability to spawn in 1-2 years.
The reproductive part (mature fish) of salmon populations in most rivers is made up of a small number of individuals - less than 500 or even 100.
For centuries Atlantic salmon fisheries in the coastal zones and rivers of the White Sea, lakes Ladoga, Onego and Kuito was one of the major occupations of the local people in Karelia. The greatest salmon catches in Karelian rivers of the White Sea fell on the 1930's (100-160 t.). The main salmon populations at the time lived in the rivers Kem, Vyg and Keret where large-scale fisheries were a long-standing practice. In the 1950-60s the rivers became regulated by hydropower plant dams, and natural reproduction almost ceased. One of the best salmon rivers up to 1990's was the river Keret. In the period from 1991 to 1998 however total catch on the marine coast dropped to 4-6 ton. In 1930-36 the catch in lake Onego reached 25-27 t. whereas in the 1950's it exhibited considerable fluctuations and subsequent reduction. The river Svir was the reproduction site for over a half of the Ladoga basin salmon. After the
hydropower plant had been built on the river the population went extinct. Most of the salmon caught in the Onego lake basin in the 1990's was contributed by the rivers Shuja, Vodla and Pjalma. Average annual catch in Shuja was 8, sometimes 10-14 ton. In the 1960's this population yielded as little as 2-3 t, and in 1968 the figure fell to 0.7. Annual catches in Pjalma reduced from 2.4-3.0 (1950's) to 0.5 t (1960's), in Vodla - from 4-6 t to 0.7-0.4 t during 1963-65. Early in the 1960's official salmon fisheries were halted in lakes Onego and Ladoga.
In the 1950-60's overfishing and illegal fisheries, dam construction, drift floating, pollution (particularly of river biotopes) with industrial and domestic discharges caused a marked decrease in the stock abundance and total extinction of individual populations. By the beginning of the 1990's the rivers of the Karelian White Sea coast, lakes Ladoga and Onego lost their significance for fisheries. Salmon catches here are low sufficing just to meet the demand of fish hatcheries and private fishers.
First data on Atlantic salmon in the White Sea rivers and lakes of Karelia are related in works by the Russian academicians P.S. Pallas (1811) and L.S. Berg (1916, 1923, 1932 etc.), as well as by R.P. Jacobson (1913), V.R. Aleev (1914, 1928), V.K. Soldatov (1920, 1928, 1938). Systematic studies of salmon began with the organization of the Karelian Fisheries Research Station in 1931. In this period papers by N.V. Gorsky (1932, 1935) M.P. Virolainen (1935, 1936), P.I. Novikov (1936, 1947, 1957), I.F. Pravdin (1931, 1937, 1939, 1946, 1954), T.I. Privolnev (1933), V.G. Meljantsev (1952), and others are published. Later surveys include monographs by Yu.A. Smirnov (1971, 1979), Yu.A. Schustov (1983, 1995) and the fundamental volume "Atlantic salmon" (1998). At present the research continues in the Institute of Biology, Karelian Research Centre, RAS; Northern Lake and River Fisheries Research Institute, Petrozavodsk State University and Karelrybvod (Republic of Karelia Committee for Fish Farming).