The material was the data of trawl-acoustic surveys and fishing nets in the reservoirs of the Tver region during resource research in 2007–2022, as well as archival data. As a result of the closure of the fishery by the State Committee of the Russian Federation for Fisheries in 2007, in order to preserve and more efficiently use the ichthyofauna of rivers, lakes, reservoirs, there was a decrease in commercial fish stocks in the reservoirs of the Tver region. Also, due to an increase in the concentration of some fish species (bream, bream), infection with ligulosis has increased. Periodic outbreaks of this disease have already been noted in reservoirs after the closure of the fishery, which will lead to a decrease in the efficiency of natural reproduction and further to a decrease in the number of fish. Due to the lack of fishing in the reservoirs of the Tver region, the possibility of catching almost 32,3 thousand tons of fish was lost for 15 years, which in monetary terms amounts to 5,15 billion rubles.