The comparative study of RNA/DNA ratio, enzymes activity of energy and carbohydrate metabolism, enzymes gene expression in muscles, liver, kidney and gills of whitefish inhabiting the tailing dump of the Kostomuksha iron mining and ore dressing mill (lake Kostomukshskoe) and non affected lake Kamennoe were examined. The RNA/DNA ratio in white muscles of whitefish from the tailing dump was lower in comparison with whitefish from lake Kamennoe, that indicates the lower growth rate of fish from the tailing dump. Energy metabolism of muscles and liver of whitefish from affected lake is characterized by the low level of aerobic ATP synthesis and the high level of anaerobic metabolism. The aerobic metabolism in gills of whitefish from the tailing dump was intensified. The using of carbohydrates in energy metabolism and in pentose_phosphate pathway were intensified in liver of affected lake fish. The difference in expression level of genes of lactate dehydrogenase and cytochrome c oxidase in muscles of different ages whitefish from clean and antropogenically affected water bodies were established. It reflected the age_dependent alterations in transcriptional regulation of cytochrome c oxidase and lactate dehydrogenase during adaptation to unfavorable environmental conditions.