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

50 150 250 350 100 200 300 90 49% 70 80 111 ou 42% 60 70 35% 50 60 > 03І 50 § 28% 40 40 1 21% 30 30 14% / 20 20 10 7% \ 10 о о ... r~1 .... _ 0 8 10 12 14 16 18 20 22 24 26 28 30 > f о Fig. 79. Size and weight distribution ofperch in Lake Suovaselkajarvi. Weight, g Length, cm Fish p a th o lo g y The most frequently occurring pathologies of whitefish are liver disorders, primarily changes in colour, shape (oblong) and fatty degenerations (pale liver) (up to 83%). The development of connective tissue expansions in the kidneys occur in 59% of specimens. Changes in the gills and reproductive system are characteristic of 15% and 8% of the fish, respectively. H eavy m eta ls in fish Heavy metal accumulation (Cu, Ni, Pb, Cd and Hg) in fish muscle of fish does not exceed the standard values (Table 49). The highest concnetrations of Cu (pg/g of dry weight) occur in fish liver (up to 38 pg/g in whitefish and up to 31 pg/g in perch). The Ni concentrations in fish kidneys (3.9 pg/g in perch) and skeleton (4.8 pg/g in white- fish, 4.2 pg/g in perch and 6.3 pg/g in pike) are very high. The Cd concentrations in fish kidneys are much higher than those in muscle. Analysis ofheavy metal accumulation in different fish species showed that the high­ est Cu concentrations occur in the liver, and of Pb, in the muscles of whitefish. Perch has maximum Ni concentrations in the kidneys, and pike has higher Hg concentra­ tions in the muscle than the other fish species (Fig. 80). 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 Hq 0.5 0.23 1.02 Ni 0.5 0.11 0.48 Cu 20 0.17 0.74 Cd 0.1 0.003 0.01 Pb 1 0.03 0.11 Perch Hq 0.5 0.15 0.74 Ni 0.5 0.10 0.51 Cu 20 0.12 0.56 Cd 0.1 0.002 0.01 Pb 1 0.02 0.07 Pike Hq 0.5 0.27 1.32 Ni 0.5 0.10 0.50 Cu 20 0.16 0.77 Cd 0.1 0.002 0.01 Pb 1 0.01 - * Source: Sanitary..., 1986. Table 49. Standard values for heavy metal concen­ trations in foodstuffs and in fish muscle in Lake Suovaselkajarvi (in рд/д wet and dry weight). Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea 133