ПОКАЗАТЕЛИ ФЛУКТУИРУЮЩЕЙ АСИММЕТРИИ СЕЙСМОСЕНСОРНЫХ КАНАЛОВ ГОЛОВЫ У ПЛОТВЫ RUTILUS RUTILUS (L.) ИЗ СРЕДНИХ РЕК УДМУРТИИ С РАЗНЫМ УРОВНЕМ ХИМИЧЕСКОГО ЗАГРЯЗНЕНИЯ

Abstract

In the middle rivers of the Udmurt Republic, fish were caught near the sampling stations for the state environmental monitoring. The fluctuating asymmetry (FA) of the pore number of the seismosensory canals in the dermal head bones of the roach, Rutilus rutilus (L.), which prevailed in the catches, was estimated using osteological analysis. Its indicators in the roach individuals caught in the different river sections have been collated with the values of specific combinatorial water pollution index (SCWPI) of the examined sections and with the average concentrations of some pollutants in water in late spring and early summer for the several years preceding the years of catching. A statistically significant trend for the increase in the FA variance (Sas2), calculated on the basis of the total number of pores in the head seismosensory system of the roach, with the increase in the SCWPI and the content of some anions (chlorides, nitrites, nitrates) in the river water of its habitats has been identified. The highest (Sas2) was observed in the roach individuals caught in the Izh River dowstream from Izhevsk in the environment, severely polluted by municipal wastewater, while the lowest one was recorded in the Kilmez River, the least polluted by wastewaters. No significant relationships between the FA indicators in this fish species and the content of heavy metals or other pollutants in the middle rivers of Udmurtia have been revealed. These results are considered to be attributable to a decrease in stability of morphogenesis in the fish organisms that developed under non-optimal (stressful) hydrochemical conditions.