Nuclear Anomalies and Micronuclei in Peripheral Blood Erythrocytes of Cyprinid Fish in Rivers With Natural and Altered Thermal Regimes (Beryozovka and Teplaya Rivers, Yenisei River Basin)

The paper presents data on the occurrence of micronuclei and nuclear anomalies in peripheral blood erythrocytes of three carp species: the gudgeon Gobio gobio (Linnaeus, 1759), the Eurasian minnow Phoxinus phoxinus (Linnaeus, 1758), and the sunbleak Leucaspius delineatus (Heckel, 1843)). These species inhabit rivers with both natural (Beryozovka River) and altered thermal regimes (Teplaya River). During the study, an extensive list of nuclear anomalies – 20 and 22 types, respectively – was found in the erythrocytes of fish from both the Teplaya and Beryozovka Rivers. The occurrence of abnormal nuclei in erythrocytes of the three studied fish species from the Teplaya River averaged 1.52±0.25–2.61±0.91 %, while in fish from the Beryozovka River, it ranged from 2.27±0,63–3.53±0.97 %. The assessment of the significance of differences between the occurrences of anomalies revealed no statistically significant differences among individuals of each of the fish species from the two studied watercourses. The values of the Mann-Whitney test (U) for the gudgeon samples were 74.0 (p=0.45), for the Eurasian minnow were 39.0 (p=0.43), and for the sunbleak were 29.0 (p= 0.96). Despite the absence of statistically significant differences, variations in the occurrence of specific types of anomalies were observed among the erythrocyte samples. Based on the obtained data, an assumption was made that the intensity of anomalies in the erythrocyte nuclei of carp fish living in the Teplaya River was influenced more by hydrochemical factors than by the altered thermal regime.