Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

Fish p a th o lo g y Despite the considerable remoteness of the lake from anthropogenic emission, the fish have pathological changes in their organs and tissues. The most frequently oc­ curring pathologies of whitefish are pathologies of the liver (54 - 68 %), kidneys (54 - 75%) and reproductive organs (26 - 30%). The pathologies of whitefish organs are currently in the initial stage, and are mainly associated with changes of the colour of organs and fatty degenerations (pale liver); connective tissue expansions (kidneys and gonads); segmentation and asynchronous maturation of gonads. Gonad patholo­ gies are the most typical for male specimens ofperch; their gonads resemble in appear­ ance a brain structure. Pathological changes in the fish may indicate airborne pollution of the water body. H eavy m eta ls in £sh The heavy metal (Cu, Ni, Pb) concentrations in fish muscle do not exceed the standard values (Table 17). However, the Hg concentrations in the muscles of perch are higher than the standards, and in trout they are very close to the standard values (Table 2). Copper concentrations (pg/g ofwet weight) in the other organs ofwhitefish are higher than in the muscles: liver (up to 7.4 pg/g), kidneys (up to 4.3 pg/g), and gills (up to 0.5 pg/g). The same applies to Ni in liver (up to 0.2), kidneys (up to 0.4) and gills (up to 0.3). Comparative analysis of metal accumulation in different fish species shows that Cu is more strongly accumulated in the liver of whitefish. The Ni concentrations in liver and Hg concentrations in muscles are higher than those in perch. Pike has the highest concentrations of Pb in muscles (Rg. 18). An upward trend in heavy metal concentra­ tions in fish organs was observed throughout the study period, and this is related to airborne pollution of the water body. Standard value (|ig/g wet weight)* Concentration in muscle ( ц д / д wet weight) Concentration in muscle ( ц д / д dry weight) Whitefish Hg 0.5 0.12 0.55 Ni 0.5 0.23 1.10 Cu 20 0.17 0.79 Pb 1.0 0.01 0.07 Perch Hg 0.5 0.56 2.86 Ni 0.5 0.18 0.90 Cu 20.0 0.18 0.91 Pb 1.0 0.02 0.08 Pike Hg 0.5 0.29 1.41 Ni 0.5 0.15 0.73 Cu 20.0 0.32 1.56 Pb 1.0 0.04 0.20 Trout Hg 0.5 0.4 1.57 Ni 0.5 0.2 0.96 Cu 20.0 0.3 1.15 Pb 1.0 - <0,05 * Source: Sanitary..., 1986. Т а Ы е 17. Standard values for heavy metal concentra­ tions in foodstuffs and in fish muscle in Lake Kochejaur (in цд/д wet and dry weight). Catalogue o f Lakes in the Russian, Finnish and Norwegian Border Area 53