REGIONAL APPROACH TO FISHERY NORMALIZATION OF SUSPENDED MATTER CONTENT

The article discusses regional approach to fishery suspended sediment guidelines. The authors have proposed a system of regional normalizing with taking into account the ichthyofauna structure and background conditions to be realized at the basin level. We used the fish ranking against the sensitivity threshold by the tolerance decrease from sturgeon and catfish species (1000 mg/l) to carp (250 mg/l), perch (100 mg/l_ and salmon 910 mg/l, obvious changes with 25-35 mg/l). We have tested the system for three major territories of the Russian Federation (the Selenga River and Lena River basins and the Kamchatka Peninsula). For the Kamchatka rivers we have substantiated a critical value of the suspended matter content stable exceeding of which should lead to negative consequences for salmon species, within the concentration (S) range from 25 to 35 mg/lл; the norm's action does not cover the rivers of the current volcanism territories. We recommend the differentiated following norm for the Selenga River basin: 25 mg/l for rivers that are habitats of salmon and grayling and 50 mg/l for rivers where whitefish species predominate. The norm for the Lena River basin is in the range from 25 to 35 mg/l for the whole river network but some downstream ranges with higher values of suspended matter content (50–100 mg/l).