Characteristics of habitat, fishing regime and state of burbot Lota lota L. population in lakes-reservoirs of White Sea basin (Republic of Karelia)

The fishery water fund of the North and North-West of the European part of Russia is characterized by a high specific gravity of water bodies with a regulated flow regime. Recently, some reservoir lakes in the region have been decreasing their fishery importance. The Vygozero (Vygozersko-Ondskoe) and the Topo-Pyaozero (Kumskoe) reservoirs located in the Republic of Karelia and belonging to the White Sea basin which differ in some limnological parameters have been chosen as model lakes-reservoirs. The results of the research works carried out as part of forecasting themes and economic and contractual tasks (SevNIORKh, NFRI PetrSU, NWPI KarRC RAS, KarelNIRO) are presented. The actual industrial facilities and types of economic activities in the Vygozero and the Topo-Pyaozero reservoirs have already affected and continue to exert their negative impact on fish stocks. The greatest damage to fish resources including burbot is done in terms of reproduction due to the anomalous level regime, water discharge, erosion of shallows, irrational fishing, hydro-construction, hydropower, pollution of the aquatic environment and soils with industrial wastes, etc. The main biological and structural-population indicators of burbot in the reservoirs have been studied. The analysis of its abundance and biomass at the present stage that are necessary for the rational regulation of the fishery have been carried out. Calculating the burbot stock abundance based on materials of 2000-2020 will allow to recommend the volume of the total allowable catch for the Topo-Pyaozero (Kumskoe) Reservoir - 37 tons (21% of the commercial reserve) and for the Vygozero (Vygozersko-Ondskoe) Reservoir - 20 tons (25% of the commercial reserves), which is within the seizure rate (20-27%). The intensity of fishing and increasing catches of burbot in these reservoirs should be considered as mandatory measures in terms of biological reclamation in the reservoirs.