Morphofunctional transformations in fishes of the middle and lower Ob’ basin under increasing anthropogenic influence

Abstract

The results of a long-term (1981–2009) study on the gametogenesis and sexual cycles are given, and the state of gills and liver is characterized in Coregonidae, Cyprinidae, and Percidae fishes in waterbodies of the Ob’-Irtysh Basin considered intact and in those affected by anthropogenic influence to various degrees. The resistance to pollution of the branchial epithelium, liver, and gonads in fishes is shown to decrease in the following sequence: cyprinids → percids → coregonids → juvenile coregonids. Specific features of the composition and quantitative dynamics of primary sexual cells during the embryonic and early postembryonic periods are described in different coregonid species. The influence of weak pulsed electromagnetic fields on coregonid embryos and larvae has been analyzed with the purpose of developing methods for increasing the ecological plasticity under extreme natural and technogenic conditions.