INFLUENCE OF SUSPENDED FLUVIAL SEDIMENTS ON THE RIVER ICHTHYOCENE

Abstract

Published data on direct and indirect impacts of suspended matter on freshwater fish are overviewed, both for short-term (hours) experiments and long-term (weeks and months) monitoring in natural conditions. Lethal or paralethal concentrations of the suspended matter are determined for 18 species from 8 families. Accumulation effect of the permanent concentration is observed for charr Salvelinus malma in the laboratory experiment. The most common fish families of the freshwater ichthyofauna in Russia are ranked by threshold of their sensitivity to suspended matter in the order: sturgeon and catfish (1000 mg/L) — carp (250 mg/L) — perch (100 mg/L) — salmon (10 mg/L, with paralethal concentration 25–35 mg/L). Fish mortality is estimated in dependence on the suspended matter concentration and time of exposure, by species. Environmental consequences of the suspended sediments impact are assessed for fish communities of the rivers of Kamchatka, the Lena River, and the Selenga River.