Results of long-term studies of the zoobenthos of the Megra river (White Sea basin)

The results of long-term studies of the zoobenthos for the downstream of the Megra salmon spawning river (White Sea Basin) have been presented. The benthic fauna of the rapids and riffles for the lower reaches of the river is represented by 25 taxa of invertebrates. The abundance and biomass of zoobenthos in June-July vary within a wide range. Based on the results of the analysis of the abundance and biomass of invertebrates for all the years of observation the highest rates were found to be at the upper stations in June - early July. By the end of July, the situation changed: the maximum abundance and biomass were noted at the lowest station, while the abundance and biomass of invertebrates decreased sharply at the uppermost section. A more gradual decrease was noted at the intermediate station.