During the 50-year period of pollock fishery from 1970 to 2020, the historical maximum catch of 2,1 million tons was recorded in 1981 and is based on numerous generations born in 1973–1977. The rapid decline in stocks between 1982 and 2000 was due to the emergence of a series of weak generations caused by a climate change, known as the «climate shift», which was observed in the North Pacific Ocean in 1977–1978 and in the end of 80s. The results showed that favorable climatic conditions have developed in recent years for pollock living off the coast of western Sakhalin, Primorye and Hokkaido, which have allowed a positive impact on the emergence of high abundance generations. There is no reliable information on the dynamics of pollock stocks in the economic zone of the DPRK, but probably conditions for reproduction were favorable in this area, too. The assessment of the fishing potential of pollock in the Sea of Japan, based on the values of maximum sustainable yield for all units of stocks, amounted to a significant value – more than 1 million tons. However, this value has an average long-term meaning and is theoretically possible if favorable conditions for the emergence of productive generations of pollock occur with the same frequency as in retrospective, along with maintaining rational level of fishing.

The purpose of this review article is to describe changes in the ichthyofauna of the Aral Sea in the 20th and 21st centuries and comparison of the structure of fish catches in the Aral Sea of the 20th century with those in the Small Aral of the 21st century, as well as a generalization of data on the biology of fish species anew introduced into the Small Aral. In the first half of the 20th century, 20 species lived in the sea, of which cyprinids predominated. After a series of acclimatization measures were carried out in order to enrich the ichthyofauna, 17 new species of fish appeared in the Aral Sea, but the composition of commercial species changed a little. Until 1960, the Aral Sea was in a quasi-stable state. The regression of the Aral Sea began in 1961 and led to the extinction of most species in the ichthyofauna. At the time of the division of the Aral Sea into two reservoirs, only seven species of fish remained in both of them, of which only one species was native. The Small Aral, after dividing the former reservoir into two parts, stabilized its borders. The stabilization of the level of the Small Aral and its freshening led to the return of freshwater fish to the sea. This process had a favorable effect on the size of catches. Currently, the catch volume is about 8000 tons. The future of the ichthyofauna and fish catches depends on what project for the reconstruction of the Small Aral will be chosen. If the option of a singlelevel reservoir will be chosen, the prospects for the fishing industry in the Aral Sea will be more favorable than if the option of a two-level reservoir will be chosen.

Based on material collected in 2012–2022, some features of the biology of the white-eye in the Nizhnekamsk reservoir are presented. An analysis of the structure of its population, population dynamics and the state of the fishery was carried out. The size-age structure of catches, sex composition, fertility indicators and growth characteristics were analyzed. Due to its small numbers, low commercial value and problems with the organization of fishing, its reserves are underutilized.

Based on literature data and the results of our own research, three types of formation of redfish aggregations in the pelagic zone of the deep-water part of the Norwegian Sea have been identified, based on different ideas about its migrations to this area. It is shown that each of them should to have its own fishing strategy, aimed at achieving maximum, long-term, sustainable catch. The correspondence of the identified types of migrations to fisheries data and stock assessments of the Norwegian-Barents Sea beaked redfish is considered. Uncertainty regarding the background concept that can combine and explain available actual data and theoretical ideas about the distribution, migrations and recruitment of the Norwegian-Barents Sea beaked redfish can be a reason of inadequate management decisions. Therefore, under such conditions, the recommended catch should be based more on an analysis of actual fishing data and identified trends in stock dynamics, rather than on TAC estimates obtained using model fishing mortality rates and biological reference points.

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.

A comparison was made of the fatty acid composition of whitefish lipids from water bodies of varying degrees of pollution and those grown on artificial feed in aquaculture. The increase in oil pollution led to an increase in lipid oxidation products and the depletion of antioxidants in the body of fish, which caused a structural rearrangement of fatty acids in a negative direction. In aquaculture, similar changes occurred in fish that consumed food with an extended shelf life. The introduction of vitamin C and a sorbent with antioxidant properties into the composition of diets improved the antioxidant system and the composition of fatty acids. The greatest changes during oxidation occurred in polyunsaturated fatty acids. In fish from a clean reservoir, their content was significantly higher (55,8%) than in fish fed fresh food (36,0–38%) and diets with the addition of antioxidants (40,0–43,4%). In polluted waters, their number decreased to 37,9 and 33,4%, and on expired feed to 24,4 – 32,6%, and in individuals that did not receive antioxidants, to 28,8–42,7%. Changes occurred mainly due to decosahexaenoic acid. A feature of the fatty acid composition of wild fish is the high content of arachidonic acid – 7,9% from a clean reservoir and 5,1 and 2,5% from polluted areas. In cultivated fish, its content did not exceed one.

The paper deals with reproduction potential features (including seasonal occurrence and frequency of female maturation during the year) of rainbow trout under fish farming. Several hypotheses explaining biannual spawning phenomenon are discussed; farming conditions (i.e. photoperiod duration and temperature) and long-term selection for early maturation are among of them. On the basis of fish sexual cycle evolution analysis, the authors suggest that the significant potential of genetic variability of rainbow trout reproductive features and genetic determination of some individuals to its appearance can be viewed as the reason of biannual spawning. Uncovering of theoretical backgrounds of multiple maturation of rainbow trout during the year can serve as a basis for practical use of biannual spawning phenomenon in fish farming.

The results of the spawning campaign using producers of beluga and Russian sturgeon, whose offspring were grown in industrial conditions and released into a water body of fishery importance, are considered. A genetic and fish-breeding-biological assessment of producers of sturgeon species for the purposes of artificial reproduction is given. Indicators of genetic characteristics of fish producers have been revealed. It has been determined that beluga producers have a reason for If the homozygosity of the species is high, it is necessary to carefully select parent groups taking into account the genetic characteristics of individuals to avoid closely related crosses and to use parental pairs rather than groups. Due to the high number of breeders, Russian sturgeon producers have a choice that allows them to take pairs of individuals with the least number of common alleles to obtain genetically diverse offspring. Fishbreeding and biological studies of beluga producers showed a tendency to reduce reproductive indicators depending on the number of generations in factory conditions, in Russian sturgeon producers the indicators of females with the second and third generations of offspring were almost identical, with slight deviations from each other. The practical significance is determined in the rational and effective use of the fish-breeding and genetic potential of producers in order to obtain the most genetically diverse juveniles, which will ultimately have a positive impact both on the preservation of the gene pool of sturgeon populations and on the survival of offspring at the rearing stage.

The methodological features of assessing the economic efficiency of commercial fish farming are considered, taking into account such specific industry characteristics as the specific profitability of brood, wintering, feeding ponds, production of fish planting material, yearlings, «growth temperature», the use of which will improve the quality and reliability of the economic assessment of the state and development of the industry. The analysis of the main production and economic indicators of the development of the commercial fish farming industry in Russia, including the dynamics of the areas of natural and artificial reservoirs, including industrial type, production volumes, fish productivity and profitability of product sales. 

The indicators of production and use of the cost of resources of goods and services in the prices of buyers of the Fishing and fish farming industry for 2012–2020 are analyzed. The dynamics of intermediate consumption, wages, profits, value added and the cost of output of the industry are considered. Econometric models of the dynamics of the value of the product of fishing and fish farming, the dynamics of the profit margin and the organic structure of the cost of production of RHC, the ratios of individual indicators of the value of the RHC product, the ratio of labor productivity indicators in the system of reproduction of the value of the RHC product for 2012–2020 are constructed. Conclusions are drawn about the numerical interaction of the studied cost indicators. The correlation coefficients of the cost of the product and its components in the prices of buyers of the Fishing and Fish farming industry for 2012–2020 are calculated and analyzed. The generally positive results of reflecting the requirements of economic laws in the processes of value reproduction in the agricultural sector have been revealed. The fundamental provisions of the hypothesis put forward are confirmed – the need for further development of the theory and practice of optimizing the proportions of cost reproduction in the agricultural sector. Based on the developed linear econometric statistical models, the necessity of accelerating the growth rate of the cost of means of production in comparison with the increase in the cost of living labor in the industry is proved.

The article analyzes the quality, completeness and accessibility of data sources for the study of the state and development of aquaculture, including by territorial location, volumes and types of products and production capacity

The efficiency of using fish resources in the Kamchatka Territory has been studied. The efficiency indicators of the fishing industry are listed. Attention is paid to the performance indicators of the Kamchatka Territory RHC at the meso- and microlevels. An analysis of the main indicators affecting the use of fishery resources in the region, such as the volume of catches, profitability of goods sold, the share of exports and the level of production of the main types of fishery products, was carried out. Factors influencing the efficiency of use of fish resources in the Kamchatka Territory were also considered.