Morphological anomalies in the reproduction system of fish under pollution

The study area is situated near the Nikel city, where some lakes and reservoirs of the Pasvik River Basin have been investigated. The Pechenga-nikel factories are the main sources of pollutants in the area. Оur observations and conclusions about the influence of pollution on the fish community in the Nikel region are as follow: 1) The detoxication system of an organism is affected at firstly (blood, gills, liver, kidney); 2) Changes in a colouration of body, in external morhology (fins, jaws) and in internal organs are recognised; 3) The reproduction system is heavily affected; 4) Decreasing of biological diversity on the all levels of community. All anomalies are well correlated with concentracion of heavy metals in the fish. The reproduction system is heavily affected. At firstly damages of the reproduction system are recognised as the following characters: twisted gonad and "brain-form" of perch male, the female gonads are asymmetric and have wrinkles. The asymmetry of gonads and deterioration of the quality of sexual products have been noted, as well as the decrease in egg fertilization and high egg mortality during incubation. More serious abnormalities of oogenesis may appear up to full degradation. As a result of pollution an early maturation have occurred among all fish species (at the early age and at the smaller size). At last hermaphroditic forms (in perch, burbot and whitefish) and appearance of a dwarf form among whitefish are observed (for example, whitefish of Kuetsjarvi has spawned after 1 year-age, 8 cm in length and 10 g in weight).