The article presents an overview of the current state of fisheries in Belarus in the light of global trends in the development of freshwater aquaculture. The article provides data on the volumes and ratio of aquaculture objects grown over the past 10 years. It is shown that pond cultivation of carp fish remains and will be decisive in the near future, while industrial cultivation of more valuable fish species expands the range, but does not determine the main economic indicators of fish farming. The article analyzes the main problematic issues of the fisheries industry in Belarus, which are primarily economic in nature and depend less on the applied fish farming technologies. The article presents data on modern scientific support for fish farming in the main areas of freshwater aquaculture and considers the prospects for scientific research in the fish industry in order to achieve its sustainable development.

An overview of the development of fishing on the territory of Belarus from the beginning of the 20th century is presented. Until now. Data are provided on the organizational structure, dynamics of commercial fish catch, fishing intensity and the structure of the resulting catches at different stages of fisheries development. It is shown that the development of fishing went from individual occupation to satisfy priority needs and generate additional income to commercial production based on the organization of state fish procurement structures and regulation of fishing. At the present stage, the functions of fisheries have changed somewhat in accordance with changes in general approaches to fishing, economic feasibility and ideas about the exploitation of natural resources. Additionally, available data on the dynamics and structure of amateur fishing at the present stage, as well as stocking of lands with various species of fish, are presented.

This study focused on mirror carp of the Sarboyan breed, which are part of the collection breeding stock of SPU “Izobelino.” During the research, biological material samples were collected from the senior breeding stock and producers of Sarboyan carp for subsequent molecular-genetic studies. The formation of a selection group of producers was conducted with consideration of the genetic diversity of the individuals, and their assessment was made based on a set of phenotypic characteristics.
It was noted that the fifth and sixth generations of Sarboyan carp from the collection stock retain the characteristic features of the breed standard. The producers are characterized by high condition coefficients (2.96 and 3.34, respectively) and possess a high-backed body shape with a shortened tail stem.
A high degree of heterogeneity was established while studying the senior breeding stock and producers of Sarboyan carp at the transferrin locus. Five alleles were identified: A, A’, B, C, and Y, which form 10 genotypes. In the process of forming the breeding stock of Sarboyan carp, it was decided to mark it with alleles A, A’, B, and C.
To analyze the genetic structure of a sample of the breeding stock of 60 Sarboyan carp, GenAIEx v.6.5 software was used, yielding characteristics such as the mean number of alleles per locus (Na), effective number of alleles (Ne), levels of expected (He) and observed (Ho) heterozygosity, the Shannon information index (I), and fixation index (FIS).
The diversity of alleles was studied across 14 microsatellite loci (MFW1, MFW2, MFW6, MFW9, MFW10, MFW11, MFW13, MFW16, MFW20, MFW24, MFW26, MFW28, MFW29, and Cid0909) in the studied sample. Each locus was represented by either two alleles (heterozygous state) or one allele (homozygous state). It was found that the researched sample of Sarboyan carp identified 187 alleles across the 14 STR loci. The number of alleles in these loci varied from 7 to 20, with a mean of 13.429±0.912.
According to the principal component analysis (PCA) graph, the sample of Sarboyan carp shows significant genetic diversity. Based on the DNA profiling results of the Sarboyan carp samples, it was established that the most genetically diverse were 10 individuals (K ≥ 8), which demonstrated a high level of diversity. At the same time, 8 individuals showed average levels of diversity. No genetically impoverished individuals (K ≤ 4), with low genetic diversity, were found in the sample.
The analysis of molecular variance (AMOVA) revealed individuals with different frequencies of allelic variants across the studied loci, which could become potential pairs for breeding:
Thus, the calculation of genetic indicators for each individual allows for the identification of promising producers for participation in breeding programs based on their high heterozygosity levels, as well as optimizing the maintenance processes of the breeding stock and selection (pairing for breeding).

The physiological state of junior replacement groups of collection breeds of carp and two-breed crosses was assessed using a biochemical study of blood serum for the main indicators: the content of total protein, glucose, cholesterol. Pure lines and crosses were established, in yearlings of which an increased content of total protein, glucose and cholesterol was noted. A comparison of the content of total protein, glucose, cholesterol in reciprocal crosses was carried out and crossbreeding combinations with advantages were established. The cross Yugoslav carp × Izobelin carp offshoot, scaly mixture, was characterized by increased physiological and biochemical parameters for the sum of the three considered indicators. In general, the group of reciprocal combinations of Yugoslav carp with the scaly mixture layer had advantages in the considered characteristics compared to the groups of crosses formed by German carp with the layers of Tri Prim and the scaly mixture and the group of crosses formed by the layer of the scaly mixture with German carp.

The article presents the results of a study of the working and relative working fertility of carp females during the formation of a selection gene pool and the first generation obtained from the original material. During the formation of a carp gene pool characterized by increased fertility, females with well-defined sexual characteristics of older age groups (8—10 yearlings) were selected. Selection by fertility level was carried out with an intensity of about 40.0 %. The females selected to obtain selection offspring gave up eggs completely, without blood clots. A comparative assessment of the selection groups of the original gene pool and the first generation of carp with potentially increased fertility was carried out with the average indicators of collection breeds and lines of Belarusian and foreign selection, the spawning of which was carried out simultaneously under the same conditions with the selection material. Despite the fact that the fertility of females selected during the formation of the initial selection material was higher than in the first generation, the advantage of the selection group compared to purebred collection material, the spawning of which took place simultaneously and under the same conditions, remains.

The article presents the results of wintering of each age group of the broodstock of two lines of mirror carp and scaly carp bred in Belarus, the selection of which is aimed at improving reproductive qualities. The results of wintering of the bred carp were compared with collection lines of Belarusian and foreign selection, the wintering of which took place together with the selection material, that is, in the same conditions. In general, the broodstock and producers of the bred carp were characterized by wintering indicators close in value to the regulatory requirements. Some decrease in the survival rate of yearlings of the bred mirror carp was noted compared to purebred groups from the collection stock. In older bred groups and producers, an increase in the exit from wintering was observed compared to carp lines that wintered in the same conditions (together). In terms of the level of body weight loss during the wintering period, all age groups of selective carp were characterized by significant advantages compared to regulatory requirements.

The article is an analytical review of global trends and the promising areas of activity in freshwater aquaculture justified by this are applicable to the conditions of Belarus. It is devoted to finding a practical opportunity to significantly increase production performance through the use of a promising ichthyocomplex and the use of modern energyefficient technical means with pronounced economic feasibility. Conceptually, the possibility of the actual implementation of the principles of a “smart farm” in the conditions of any pond aquaculture enterprise in Belarus is revealed (reducing labor costs, feed per unit of production, simplifying infrastructure and, accordingly, reducing the cost of fish), while the effect of import substitution will be observed (by excluding a significant amount of animal protein from feed, increasing the share of its own fish products in the sales network and its assortment). t is concluded that due to the implementation of the concept, the fish productivity of ponds can be increased at least 1.5 times, while reducing the cost of production by 10—15 %.

The article discusses the results of using a new premix for carp fish. The developed economical premix for carp allows to increase the efficiency of feeding carp of different ages. It was found that the body of yearlings of experimental groups of carp that received compound feed with the introduction of 1 % of the new premix contains more fat, which contributes to an increase in the survival of carp in the winter. The use of the economical premix for carp fish PK-100-E in the composition of compound feed increases fish productivity by 3.3 times higher and reduces feed costs by 2.7-13.8 times depending on the method of compound feed production. Economic indicators revealed that the introduction of the economical premix slightly increases the cost of compound feed, but reduces the specific costs of fish growth and production profitability.

Recently, biotechnology has been developing the use of living organisms and their metabolic products to solve technological problems in feeding. The object of study is the black soldier fly (Hermetia illucens). The black soldier fly (BFS) utilizes organic matter and converts it into protein-rich food. The insect regulates the number of pathogens and parasites in the substrate and reduces their number. BFS is also used in fish and poultry feed, agriculture and aquaculture. The article shows the experience of industrial cultivation of this BFS in industrially created conditions of the Tashkent region.

In the paper is presented the result of one experimental study on the growing of the black soldier fly Hermetia Illucens (Diptera: Stratiomyidae) on wheat and rice brans (from 7 days old to the prepupal stage of larvae). Feeding ration was given for larvae every four days in the following amounts: 45, 90 and 120 mg/larvae/day. For each experimental group (100 larvae, n=3) was calculated the indices related to its growth, mortality and feeding efficiency of wheat and rice brans. In general, the results of study showed a trend, in which larger ration of wheat and rice brans contributed to higher biomass and faster growth of the H. Illucens larvae. However, for wheat bran feed the diet 90 mg/l/d was the optimal and met both conditions: the nutrient requirement to gain of a big larvae biomass and provide a high degree of fed substrate degradation. The protein content of the prepupals in this experimental study was consisted from 36—43 % and confirmed the opportunity to usage of dry prepupa meal in the aquaculture feed industry.

The current state of fisheries and fish stocks in six fishing lakes of the Narochansky National Park is considered. The fishing load for each of the lakes, the dynamics of commercial and amateur catch at the current stage of operation are studied, the degree of use of fish resources in the conditions of the functioning of the national park is determined, and the growth of the importance of amateur catch is shown. Against the background of changes in the ecosystems of water bodies and in the fishing load, the main trends in the change of commercial stocks as a resource base for fisheries are determined.

Biomonitoring of the state of the ecosystem of the Zelvyansky reservoir was carried out. The hydrochemical regime, composition and degree of development of aquatic communities. The degree of overgrowth of the reservoir, the species structure and quantitative development of phyto-, zooplankton and zoobenthos were determined, and the eutrophic type of the reservoir was confirmed. It was established that over a thirty-year period, zooplankton production decreased almost twice under the influence of planktivorous fish, the number and biomass of zoobenthos increased more than three times due to mollusks, and the hydrochemical regime of the reservoir did not undergo significant changes.

This article presents the results of all-season studies of the bacterial flora of introduced fish of different species bred in fish farms of Belarus and inhabiting natural water bodies of the republic. The species composition of rod and coccal microflora of fish has been determined. Potentially dangerous representatives of bacterial flora for fish have been noted. It has been established that the bacterial flora of fish in Belarus during the study period was represented by 39 species of bacteria, for some of which the seasonal dynamics of occurrence has been traced. The most common etiologic agents of bacterial diseases of fish include representatives of the genera Aeromonas and Pseudomonas.

In the article show the results of studies of the parasitofauna of fish bred in fish farms in Belarus and Uzbekistan. Was studied the species composition of the parasitofauna of fish in this countries, were determined the range of host fish and the indexes of invasion, were noted and the similarities and differences in the parasite fauna of fish in this countries. It was found that the parasitofauna of fish in Belarus during the study period was represented by 10 species of parasites, and the parasitofauna of fish in Uzbekistan was represented by 8 species. Common representatives of the parasitofauna of fish in both countries are trematodes of the genus Diplostomum, ciliates of the species Ichthyophthirius multifiliis and cestodes of the species Khawia sinensis.

This article reflects the results of a dissertation research on the topic: “Assessment of the influence of environmental factors on the safety of fish products (live fish) produced in fish farms in the Tashkent region,” conducted in the period from 2021 to 2023. The influence of environmental factors on the life activity of pond fish was studied. Fish of the carp family. The species composition of zoobenthos organisms was determined, the level of organic pollution was determined using the bioindication method. Potentially dangerous species of zoobenthos organisms for commercial fish species grown in the fish farm under study were also identified.

This article presents the morphology of cestode Schyzocotyle acheilognathi found in fish from large fisheries of the Fergana, Syrdarya and Tashkent regions of our Republic. The research has shown that 22 out of 225 fish samples of three studied species (Cyprinus carpio, Hypophthalmichthys molitrix, Ctenopharyngodo nidella) were infected with S. acheilognathi, with the highest infection rate recorded in the Tashkent region (12 %). The average length of parasitic cestodes was 15.30±0.42 mm, body width 0.204±0.006 mm, scolex length 1.2±0.02 mm. The egg length was found to be 0.55±0.04 mm and width 0.045±0.006 mm.