Catalogue of Lakes in the Russian, Finnish and Norwegian Border Area = [Каталог озер в приграничном районе России, Финляндии и Норвегии] / Nikolay A. Kashulin, Vladimir A. Dauvalter, Sergey S. Sandimirov etc. - Apatity : Institute of the North Industrial Ecology Problems KSC RAS etc., 2008. - 141 с. : ил., табл.
Trout is occasionally caught. Some 5-year-old individuals have a length of 39.7 cm and weight of 694 g.The only grayling was a 2-year-old female specimen with a weight of 77 g and length of 21.0 cm. The vendace inhabiting the pelagic zone are of small size (9.3 - 13.6 cm, 6-19 g).The mean values are 10 g and 11.0 cm. Female fish predominate (1.4: 1). Fish p a th o lo g y The most serious and irreversible fish pathologies were recorded in this lake. The fre quency of occurrence of pathologies of the liver and kidneys in whitefish varied from 54 to 90% throughout the whole study period. Kidney stones of whitefish, which are typical only of this region, occurred in 21% of the fish. 20% of the fish had serious al ternations of their reproductive system (gelatiniforme, asynchronous and asymmetric maturation of the gonads). All the fish had reduced muscle turgor and colour changes of the skin. The muscles of pike had a green hue, and the colour of the liver in 92% of the fish was sandy-grey to dark-green. H eavy m etals in fish Heavy metal concentrations (Cu, Ni, Pb) in fish muscle does not exceed the standard values. The Ni concentrations in fish muscle are very close to the maximum permissi ble concentration (Table 23). The accumulation of metals in other fish organs is much higher. For example, the Hg and Pb concentrations in liver, kidneys and gills can be from 2 to 14 times higher than in the muscles. The difference for Cu (liver) and Ni (kidneys) can be even higher (up to 47 and 17 times). Comparative analysis of metal accumulation in different fish species showed that the concentrations of Cu (liver), Ni (kidneys) and Pb (muscles) are higher in both forms of whitefish than in the other species. Perch had the highest mean Hg concen trations in muscles (Fig. 38). Standard value ( ц д / д wet weight)* Concentration in muscle ( ц д / д wet weight) Concentration in muscle (pg/g of dry weight) Sparely rakered whitefish Hq 0.5 0.01 0.03 Ni 0.5 0.31 1.55 Cu 20 0.21 1.05 Cd 0.1 0.01 0.03 Pb 1 0.02 0.09 Densely rakered whitefish Hq 0.5 0.01 0.02 Ni 0.5 0.44 2.06 Cu 20 0.24 1.13 Cd 0.1 0.01 0.03 Pb 1 0.02 0.09 Perch Hq 0.5 0.03 0.13 Ni 0.5 0.23 1.04 Cu 20 0.13 0.60 Cd 0.1 - < 0.01 Pb 1 0.01 0.06 Pike Table 23. The standard values for heavy metal concentrations in foodstuffs and in fish muscle in Lake Kuetsjarvi (in цд/д wet and dry weight). Hq 0.5 0.01 0.07 Ni 0.5 0.22 1.05 Cu 20 0.19 0.91 Cd 0.1 0.06 0.01 Pb 1 0.30 0.07 * Source: Sanitary..., 1986. 72 Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea
Made with FlippingBook
RkJQdWJsaXNoZXIy MTUzNzYz