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 The whitefish in this water body have similar changes in their organs and tissues as the fish in Lake Kochejaur.The most frequently occurring pathologies ofwhitefish are pathologies of the kidneys (60-88 %), liver (27-67%) and gills (34%). The pathologies of whitefish organs are currently at the initial stage, and are mainly associated with changes in the colour of organs and fatty degenerations (pale liver); connective tis­ sue expansions (kidneys and gonads); segmentation and asynchronous maturation of gonads. H eavy m etals in fish The heavy metal (Cu, Ni, Pb and Hg) concentrations in the muscles of fish do not exceed the standard values (Table 19). However, the Cu concentrations (pg/g of dry weight) in the other organs ofwhitefish are higher than those in the muscles: liver (up to 41.5 pg/g), kidneys (up to 48.9 pg/g), gills (up to 2.0 pg/g). The same applies to Ni in liver (up to 1.4), kidneys (up to 6.6), gills (up to 2.0), skeleton (up to 5.6 pg/g). The Cd concentrations in the kidneys ofwhitefish reach 5.3 pg/g dry weight. The analysis of metal accumulation in different fish species shows that Cu is more strongly accumulated in the liver of whitefish, and Ni in the kidneys. The Hg concen­ trations in the muscles of pike are considerably larger than the concentrations in perch and whitefish. Perch has the highest concentrations of Cd in the muscles (Fig. 24). ТаЫе 19. Standard values for heavy metal concen­ trations in foodstuffs and in fish muscle in Lake Virtuovoshjaur Lake (in цд/д wet and dry weight). Standard value ( ц д / д wet weight)* Concentration in muscle ( ц д / д wet weight) Concentration in muscle ( ц д / д of dry weight) Whitefish ня 0.5 0.08 0.38 Ni 0.5 0.20 0.93 Cu 20 0.25 1.14 Cd 0.1 0.002 0.01 Pb 1 0.02 0.10 Perch H9 0.5 0.16 0.79 Ni 0.5 0.13 0.64 Cu 20 0.14 0.69 Cd 0.1 0.002 0.01 Pb 1 - <0.05 Pike Hq 0.5 0.31 1.55 Ni 0.5 0.19 0.92 Cu 20 0.15 0.72 Cd 0.1 0.002 0.01 Pb 1 - <0.05 * Source: Sanitary..., 1986. Catalogue o fLakes in the Russian, Finnish and Norwegian BorderArea 59