Lake Maslozero Ecosystem and the Results of the Release of the Smelt Osmerus eperlanus into the Lake

The results of the study of the Lake Maslozero ecosystem (the White Sea basin) are reported. The lake is small, deep, and poorly lotic. Its hydrochemical and hydrobiological parameters were studied. The quantitative and structural characteristics of the state of zooplankton and macrozoobenthos in the lake are presented for the first time. The lake is an oligo-mesotrophic water body, as indicated by the nutrient content scale. The lake is inhabited by 14 fish species of 11 families. The perch Perca fluviatilis, the whitefish Coregonus lavaretus, the pike Esox lucius, the roach Rutilus rutilus, and the introduced smelt Osmerus eperlanus are the most abundant. The work on the introduction of smelt into Lake Maslozero is evaluated. The smelt in the lake has naturalized, is successfully reproducing, and has become abundant. Its growth rate is identical to that of the smelt from its parental water body, Lake Ladoga. The food ration of predatory fish (pike, burbot, perch, and char) is dominated by smelt as the most abundant and accessible food item available all year round. The lake is used by the local population for economic purposes, recreation, amateur fishing, and fish culture.