No abstract

Information on the state of commercial stocks of the fish population of the Ivankovo reservoir from 1980 to the present is presented. According to our data, the total commercial fish stocks in the Ivankovo reservoir in comparison with the 1980s and 1990s decreased by almost 1,000 tons. Over the past 5 years, they have been in the range of 2245–2808 tons. The closure of industrial fishing in 2007 led not to an increase, but to a decrease in fish stocks, due to a decrease in the rate of their linear and weight growth, deterioration of exterior and commercial qualities. The material damage caused by the closure of industrial fishing at the Ivankovsky reservoir since 2007 has been determined. To determine the material damage caused by the closure of industrial fishing at the Ivankovsky reservoir, retail prices for 21 types of fish were determined. The resulting value for each type of fish was correlated with the volume of fish that was not caught due to the absence of fishing in the period from July 2007 to 2022. Data on catch volumes in the Ivankovo reservoir are taken from the Orders on approval of the total allowable catches and recommended catch of aquatic biological resources in 2007–2022. Over the past 15 years, the possibility of catching almost 7.4 thousand tons of fish has been lost, which in monetary terms is 1,103 million rubles.

No abstract

The study presents materials on the status of aquatic biological resources and their habitat in the Dnieper River within the territory of the Russian and the Belarus. In the recent period, there has been hardly any complex fishery research in the upper reach of the river within the boundaries of the Smolensk Region due to the lack of commercial fishing; the same can be applied to the reach of the river within the Vitebsk Region in Belarus. The collection of materials and scientific and research accounting network surveys for monitoring the state of aquatic bioresources were carried out on the Dnieper River as part of the research in 2019 according to a preplanned grid of stations. When fishing for scientific research purposes, 20 net-stops of smooth frame nets were made in the Russian section, and 9 net-stops were made in the Belarusian section. In the Russian section of the Dnieper River, the species composition was 16 species of fish, and in the Belarusian section — 22 species. The main catch in the Russian section is roach 29% and chub 20%, in the Belarusian section bream — from 3 to 46%, roach — from 19 to 63% and gustera — from 1.8 to 33%, in a slightly smaller number of river perch (on average up to 10%). The share value of roach and guster tends to decrease from the upper to the lower areas, bream-on the contrary to increase, the value of perch is approximately equal in all areas. In the size structure of the caught fish species, there is a dynamic with a good reproductive potential.