The aim of the work was to develop an algorithm for analysis and to elucidate the trends in the dynamics of the age composition of red king crab males in different areas of the Barents Sea.

Materials were the data of research surveys and fisheries monitoring obtained in 2001–2022, as well as published results of long-term observations on juveniles and tagging.

As results, an original algorithm which makes it possible to determine the age composition of the catches of red king crab males is suggested. The mean carapace widths of individuals of age 4+ — 11+ are 78, 99, 121, 142, 164, 185, 207, 228 mm respectively. The combination of the Hiat linear growth model with assumption of the normal distribution of size frequencies in the age class made it possible to give an adequate description of the dynamics of the age composition of king crab males in the Barents Sea. In each area to the west and east of 36 ° E. the number of noticeable generations exceeds that obtained from the size composition data. Noticeable generations appear with different annual frequency, and one can find different generations in different areas in the same years. It is suggested that 3 spatially isolated local populations inhabit in the (1) Varanger-Fjord, (2) in the area between the Motovsky and the Teribersky bays, (3) off the coastal area to the east of 36°E. If the generation of the age 5+ consider as recruitment, it seems that noticeable recruitment in the Varanger Fjord is formed in the closed bays of its southwestern part. The recruitment in the second region, is also formed in closed bays. In the third local population, recruitment is currently formed in the open areas of the shelf, while the coastal areas are gradually turning into eviction zone of the large males.

Practical value. The obtained results can improve the efficiency of management of the red king crab stock in the Barents Sea and adjacent waters.

The aim of the paper is a qualitative assessment of the stock of long - clawed crayfish on the basis of the indicator approach.

Methods used: indicator approach of qualitative stock assessment, methods of descriptive statistics, regression analysis.

Novelty: a qualitative assessment of the stocks of long - clawed crayfish in the Astrakhan region by the indicator approach has not been previously carried out.

Result: Qualitative assessments of the state of the stock of long- clawed crayfish in the Astrakhan region in 2016-2020 were obtained. The results of the assessments showed that in 2016, 2019 and 2020 its stock in the Astrakhan region was in an uncertain state (an integral assessment showed no dynamics in the state of the stock for the worse or better), and in 2017 and 2018 - in the alarming state (the integral assessment showed a negative trend in the state of the stock). The final integral assessment made it possible to formulate recommendations for the further exploitation of the stock of this species of hydrobiont.

Practical significance: this study represents the application of the indicator approach in the biological sub -stantiation of the assessment of the total allowable catch of long - clawed crayfish in the Astrakhan region.

Objective: to characterize age-length composition of fish population in the lake Ozeryavki at National Park «Sebezhsky» and to estimate the density and biomass of main species using A method for estimating fish density through the catches of gillnets Methods: a method for estimating density by catches of gill nets applied to the catches of different mesh size.

Methods: a method for estimating density by catches of gill nets applied to the current data.

Novelty: estimates of mortality of 3 main species, roach, white bream and perch, in one of the lakes of the national park were obtained for the first time; the density and biomass of 3 species are calculated and the proportion of mortality from predation is estimated.

Results: instantaneous natural mortality coefficients for roach, white bream and perch corresponds to Z = 0.59 year-1, Z = 0.51 year^-1 and Z = 0.71 year^-1, respectively; the general density of all age groups is: for roach 2.7 ind./m³, for white bream 0.9 ind./m³ and for perch 2.0 ind./m³; average biomass: for roach 14.3 g/m³, for white bream 4.5 g/m³, for perch 3.0 g/m³; mortality rate from pike predation accounts for 0.34 of biomass of three species.

Conclusion. The study of fish population of lake Ozeryavki as a typical medium-sized reservoir in the Sebezhsky National Park gives an idea of local ichthyocenoses parameters and aquatic ecosystem condition as a whole.

Purpose: To find out the main parameters of the life cycle and the reproductive contribution of females depending on the age of their puberty.

Method: Analysis of metal tagging in fur seal pups and tag return obtained by reading tags on live fur seals using optical instruments. Reading marks was carried out in 1982-2014 during the harem period on the Central site of the Northern rookery (Bering Island).

Novelty: For the first time, data have been obtained on the reproductive contribution of female fur seals during the life cycle in relation to their age of puberty.

Results: The birth of puppies in early maturing (at 2-3 years old) females is shifted to an earlier age, their life cycle is shorter, natural loss after the first fertilization is higher, they miss more breeding seasons during the life cycle. During the life cycle, early maturing females give birth to about 40% of the total number of puppies born by tagged females, and most of them (31%) are under the age of 8 years. Medium maturing (at 4-5 years old) females give birth to almost the same number of puppies (39.7%), however, the proportion of puppies born in these females is distributed more evenly over the life cycle. In late-maturing (at 6-7 years old) females and females entering the rookery at the age of 8+ years, the reproductive contribution is lower - they give birth to 13.4% and 6.3% of puppies, respectively, and the age at which puppies are born is higher - mostly 11 years and older.

Purpose of the work: revealing the relationship between the emergence of high-yielding generations of mass commercial fish and the temperature regime of surface waters and the ice cover of the Far Eastern seas and adjacent areas of the open part of the Pacific Ocean.

Methods used: to achieve the set goal from 1921 to 2020, data on the yield of generations of 27 groups of marine fish were analyzed. As part of the discovery of the initial factors that have a potential impact on the biomass of aquatic organisms, long-term data on water temperature and ice cover are involved.

Novelty: elements of novelty are the relationship of fish productivity with certain environmental factors, which can be used for forecasting purposes. The results of the study showed that the largest number of productive generations in fish as a whole falls on temperate years, followed by warm types of years, and to a lesser extent such generations are born in cold years. This is true for most of the analyzed species, with the exception of Pacific cod, which was dominated by generations that appeared in years warm in terms of water temperature, and flounders, with their maximum occurrence of overproductive generations (after moderate years) in years with cold ice cover.

Practical significance: the results of this study in the form of regularities found in the impact of abiotic environmental factors on the productivity of fish will improve the efficiency of the use of their raw material base.

The purpose of this article is analysis of the relevance of whitefish commercial fisheries regulation in Kubenskoye Lake and development of measures to preserve the endemic whitefish population, increase its commercial stocks and catches.

The material for the study is the statistics of whitefish-nelmushka catches in Kubenskoye Lake and the longterm dynamics of the size and age characteristics, terms of puberty.

The research methods: field ichthyological materials were collected and processed according to standard methods; the fishing stocks were estimated based on the results of the analysis of non-water fishing catches, as well as taking into account the volume of water filtered by fixed fishing nets per unit of time.

Results: the long-term dynamics of whitefish-nelmushka catches are described in the article. The effectiveness of its fisheries regulation has been studied. Fishing does not have a significant impact on the whitefish abundance dynamics. The exclusion of whitefish from the category of aquatic biological resources, in respect of which the total allowable catch is established, is justified in the article. The size and age population characteristics of the whitefish, age of puberty last years have been summarized in the article.

Practical significance: artificial reproduction of the Kubenskoye Lake whitefish is recommended to be carried out to restore the population abundance, which is significant for the preservation of the gene pool of the polymorphic species Coregonus lavaretus. Recommendations on changing the Fishing Rules for the Northern Fishery Basin to reduce the legal size for whitefish-nelmushka were developed for the implementation of commercial and recreation fisheries.

The goal of the research was to study the viability of the offspring of the Coregonus muksun obtained from eggs inseminated at different time (-from 0 to 220 min) after collection.

Classical fish breeding methods were used in the work: eggs was inseminated by dry method, incubation was carried out in sieves and modified Weiss devices with a volume of 1 l, juveniles were grown in 60 liter pools with a stocking density of 150 ind./pool, artificial diet and artemia nauplii served as food.

Such studies in fish breeding practice are carried out for the first time, which determines their novelty.

As a result of the research, an almost linear dependence of the survival rate of the offspring of muksun on the time of insemination of ovulated eggs was established with a very high degree of approximation reliability (R²) for embryos 0,906, larvae 0,846. The best survival rate of embryos and larvae was obtained in experimental variants in which eggs were inseminated in the first hour after collection. The proportion of live eggs at the end of incubation and larvae after 38 days of rearing was 57,5-58,9% and 78-84%, respectively. The survival rate of embryos and larvae in the experimental variants in which eggs were inseminated 80-100 minutes from the moment of collection were in the range of 40,1-42,2% and 49,4-50,1%, respectively; for 120-160 minutes 9,4-15,3% and 45,3-47,6%; for 180-220 min the survival rate of caviar did not exceed 5,0%, larvae- 45,6%.

The practical significance of the work lies in determining the optimal period between the collection and insemination of eggs with the least risk to the viability of the offspring, which is of great importance in works on the artificial reproduction and cultivation of valuable fish species.

The aim: to study the amount of mercury found in muscle tissue and liver of the main commercial fish species of the Barents Sea.

Research material was comprised of fish samples collected during the expeditions of “PINRO” named after Knipovich in the Barents Sea in 2009-2020. The study was based on muscle and liver samples taken from cod, haddock, long rough dab, Greenland halibut, plaice and spotted catfish. Over 1500 samples were analyzed. Novelty: for the first time a comparative analysis of Hg concentration in six commercial fish species of the Barents Sea was run and background readings were provided using such a big amount of data.

Methods used: the total content of Hg in fish samples was measured using Shimadzu (Japan) Cold Vapor Atomic Absorption Spectrophotometer (CVAAS). Statistical data processing and charting were done using MS Excel and application software package of Statistica 13.

Results: it was shown that the mean amount of Hg in muscle and liver of the studied fish was below the maximum concentration of 0.5 pg/g of wet weight acceptable by sanitary standards. Content of Hg in liver was two times higher than in muscle. No evidence of anthropogenic contamination of the studied species by mercury was found. The total content of Hg in muscle and especially in liver demonstrated a considerable variability, which is probably linked to seasonal changes in the diet. There might be other factors influencing the mercury concentration, such as taxonomic affiliation, regional peculiarities, physiological state, and fattiness.

Practical significance: the acquired results were used to determine whether the commercial fishes meet the sanitary standards used in Russia.

The purpose of the work: to propose express methodological approaches for establishing the quality and ensuring the safety of fish food products based on the use of sensory analysis, based on the results of a scientific review.

The methods that were used: a descriptive-analytical research method was used, a theoretical analysis of scientific, reference and methodological literature, as well as international and national regulatory documents in the field of organoleptics (sensorics) of food products was carried out.

The element of novelty is the systematization of information on methodological approaches to assessing the quality of fish food products using sensory analysis, followed by the development of a methodological manual for use in the fisheries industry.

Research results: determination of methodological system techniques for organoleptic (sensory) assessment of the quality of raw materials of aquatic origin and food products from it.

Practical significance: the possibility of using operational approaches to assessing the quality and safety of fish food products as express methods. The research materials will be used in the preparation of a methodological manual on quality control and safety of fish food products using sensory analysis for use in the fish processing industry and trade, for the implementation of control and supervisory measures, as well as for use for educational purposes.

The purpose of the work: systematization of trends in the development of scientific research on the creation of effective cryoresistant systems for the refrigeration technology of food, including from aquatic biological resources.

Results: analytical studies have shown the widespread use of cryoprotectors in cryobiology, aquaculture, the production of various food products and other industries. In the food industry, it is advisable to use natural materials that do not have toxicity and are components of food products as cryoprotectors.

Novelty of the work: a promising direction is the use of products from hydrobionts of dry seafood concentrates obtained by cryotechnology as cryoprotectors in refrigeration technologies. They have high functional properties and can be used both as separate preparations and as part of composite systems.

Practical significance: the results obtained are used by specialists in the development of new technologies for frozen minced fish products, which, due to the use of cryoprotectors, have higher quality indicators compared to control samples.

Methods used: Analytical evaluation of modern domestic and foreign scientific works in the field of cryotechnology using cryoprotectors, systematization of scientific data and justification of directions for the creation of cryoprotective compositions for food refrigeration technology.

The purpose of the work is to study the institutional environment that ensures the sustainable development of the Russian fisheries complex and the changes that contribute to the intensification of fish and seafood trade between the EAEU countries

The methods used: monographic, statistical, scientific abstraction, logical analysis allowed us to explore the theoretical foundations of the creation of institutions and changes in the institutional environment under the influence of external factors.

Novelty: the methodological aspects of the formation of the institutional environment have been clarified and the systematization of institutional changes aimed at ensuring the sustainable development of the Russian fisheries complex and increasing the volume of fish and seafood trade with the EAEU countries has been carried out on the basis of the Technical Regulation “On the Safety of Fish and Fish Products No. (EAEU TR 040/2016), which provides for appropriate requirements for the safety and quality of products.

Practical significance: High-level use of the potential of the Russian fisheries complex and increasing the efficiency of control of trade operations with the EAEU countries in the digital environment, minimizing risks and transaction costs caused by changes in the institutional environment to ensure mutually beneficial trade in fish and seafood.

The purpose of the paper is to improve the methodology of fisheries management by expanding the set of factors for investment decisions.

Materials and methods. Our work is a further development of the bioeconomic approach, which is based on the interdependence of natural and produced capital in fisheries. Author's solutions are based on methods of analysis and synthesis, and use the modeling of economic processes in fisheries.

Results. The paper describes a theoretical model for making investment decisions. This model is used to analyze the investment policy of the firm. The key modeling parameters used are: stock of fish resources, catch size, capital and investment. Our study showed that for this fishery, the main factor in deciding on the optimal level of investment is the ratio of the unit values of existing assets and investments.

Practical significance. Although the proposed modified model is preliminary and has a number of limitations, empirical testing allows us to draw conclusions about the possibility of using it to develop optimal production and investment decisions for a fishing company and about the advisability of continuing work in this direction.

The purpose of the research is to form scientific basis of effective management of salmon fisheries in the Russian Far East.

Applied methods: research work was carried out in accordance with standard methods used in fisheries research.

Scientific novelty: data on qualitative and quantitative composition of juvenile Pacific salmon migrating from the Savushkina River for rearing in marine waters in May-July 2022. Based on qualitative heterogeneity of juveniles, presence of eco-temporal groups within chum salmon and coho salmon was supposed.

Result: data on timing and dynamics of seaward migration of Pacific salmon juveniles, as well as their qualitative and quantitative patterns.

Practical relevance: Results of the research would be used in forecasting of commercial catch of Pacific salmon in the Northern Kurils.

The purpose of the work: to collect materials for assessing the state and dynamics of scallop stocks in the North Kuril zone, to study the spatial structure of settlements, to monitor the dynamics, distribution and composition of commercial catches in 2022.

Materials and Methods: The work was carried out on a specialized rowing vessel “Vladimir Nikora” performed 210 dredging in the area limited by coordinates 49°20'N 49°30'N. and 154°57'E154°53'E at depths of 79-170 meters. The data collection tool is an industrial scallop dredge with a working width of 3.7 m (scallop dredge 1.04 / 3.74 m). The material type of the scallop dredge bag is kapron. The length of the dredging was 0.4-0.5 miles. The research covered the water area of 23 square meters. miles. Biological analysis was carried out for 5 thousand specimens of chlamy scallops. The biological state of hydrobionts was studied according to the methods generally accepted in fisheries research. For comparability of data on the distribution of hydrobionts, the catchability coefficient of the scallop dredge was used equal to 1. The linear dimensions of the scallops were measured with an accuracy of 1 mm.

The practical significance of the research: to provide commercial and biological information materials on the total allowable catches of scallops in the North Kuril.