The article presents an overview of publications by the staff of the Khabarovsk branch of the State Scientific Center of the Russian Federation FGBNU VNIRO (KhabarovskNIRO) over the entire period of its existence (1945–2023) devoted to the study of Pacific salmon. Of the 1,5 thousand scientific papers, 450 (29,1%) were published on this group of fish. In the 1950–1980s and 2000–2010s, the works were dominated by studies on the population dynamics (27,1%) and biology of salmon (24,5%), their artificial reproduction (17,6%), biology, trophic links and food supply of their young (9,2%) (a total of 78,4% of works). In 2020–2023, against the backdrop of a sharp decline in the number of Pacific salmon in the Amur River basin, within the framework of the Second Amur Ichthyological Expedition, the main efforts to study them were focused on studying fisheries and developing measures to regulate it (24,4%), methodological developments (24,4%), biology research (17,8%), modeling population dynamics (15,6%) and surveying spawning grounds, assessing the number of spawned producers (11,1%). It is concluded that further progress in developing a deeper understanding of the biology of Pacific salmon and the mechanisms of their abundance, as well as developing effective measures to regulate the fishery, will be facilitated by creating a database based on GIS technologies using both archival data and large-scale materials on salmon obtained in recent years as part of innovative scientific research using AI, GIS, UAVs, and the NetCor-3 hydroacoustic complex. In addition, it is necessary to involve in the analysis the extensive data of the Second Amur Ichthyological Expedition on zooplankton, benthos, other fish, the overall productivity of the Amur basin ecosystem, and the dynamics of its hydrological regime. Such an integrated approach will increase the number of analytical works and, in particular, prepare a summary of the Amur salmon based on the results of the expedition.

We analyzed the reasons for deviations in the number of summer Amur chum salmon offspring from the theoretical «parent-offspring» relationship described by the Ricker equation. It is shown that the strongest deviations are caused by precipitation in the year of spawning and in the year of downstream migration of juvenile fish. The second most influential factor is the pre-winter air temperature in the year of spawning. These both factors are positively correlated with the magnitude of deviations. It is proposed an equation describing the relationship between the number of offspring and the number of parents, precipitation and air temperature, which satisfactorily simulates the dynamics of the number of offspring. The results are discussed in connection with similar results from studies of other salmon populations and species.

We analyzed the relationship of the number of descendants of fall Amur chum salmon with the number of parents and the variability of weather factors in the reproduction area. Chum salmon offspring abundance was shown to be more strongly dependent on weather variability than on parental abundance during the period under consideration. It was possible to identify a relatively weak relationship between the number of generations and the number of parents only after eliminating the calculated influence of weather factors on the dependent variable. Three weather factor variables have been identified that are statistically related to the number of descendants, but the close correlation between them does not allow us to unambiguously identify the most likely explanatory variable. The number of descendants of the autumn Amur chum salmon, as well as other populations and species of Pacific salmon in adjacent reproduction areas, is most closely related to the amount of precipitation falling during the river period of life. The similarity of explanatory variables is probably related to the common conditions of formation of the water regime of spawning rivers, determined by the monsoon character of climate. The variability of precipitation in the breeding areas of the Amur autumn chum salmon explains 80% of the variance in the number of descendants, therefore, their number is formed mainly at the early stages of the life cycle.

The paper presents the results of studying the masu salmon (Oncorhynchus masou) in the water bodies of the Tatar Strait (hereinafter – the rivers of the specified region within the Khabarovsk Territory). After a significant period of low numbers, an increase in masu salmon stocks was noted in the rivers of the coast of the Tatar Strait (the Botchi, Koppi, Tumnin Rivers, etc.). The number of masu salmon here in the last 10 years has been 100–350 thousand specimens with a biomass of 300–1000 tons. Analysis of masu salmon stocks allows us to recommend opening the production (catch) of this species in the Khabarovsk Territory in the mode of amateur fishing in areas, with fishing gear and in order to ensure the traditional way of life and the implementation of traditional economic activities of the indigenous peoples of the North, Siberia and the Far East of the Russian Federation.

The problems of choosing a model type when studying the causes of generation size variability, as well as the consequences of attempts to approximate multifactor processes with single-factor models, are considered using the example of sockeye salmon from the Okhotsk region. It is shown that single-factor models in a multifactor space give a distorted idea of cause-and-effect relationships. A model of generation size formation for sockeye salmon has been developed, including the number of parents, variability in precipitation, and air temperature in the freshwater phase of juvenile life as explanatory variables. The combined effect of parental size and weather factors explains more than 90% of the variance in generation size for sockeye salmon.

The paper presents the results of using microchemical analysis of otoliths to identify the return of autumn chum salmon, the juveniles of which are released from salmon hatcheries in the Amur basin. It was previously found that juvenile autumn chum salmon of hatchery origin were characterized by higher values of the ⁸⁸Sr/⁴³Ca ratio in the marginal zone of otoliths compared to juveniles of natural origin, which may be due to the high strontium content in the feed used to grow juveniles at hatcheries. Using the ⁸⁸Sr/⁴³Ca value to determine fish of artificial and natural origin among spawners of autumn chum salmon collected in the Amur River, at salmon hatcheries and base rivers of hatcheries, fish with a high level of the analyzed isotope ratio in the juvenile zone of otoliths were identified, which indicates their artificial origin. Among the fish from the Anyui and Udinsky hatcheries, the majority of fish (56,0 and 56,4%) are characterized by marker values above the threshold, which also indicates their artificial origin. In addition, a high proportion of such fish was found among the individuals of autumn chum salmon collected in the Amur mouth (40,2%). We obtained similar results using another method for assessing the return – the method of otolith marking of juveniles at the hatcheries (in 2015–2021) and the subsequent search for «factory» fish in a mixed sample of spawners from the lower reaches of the Amur River in 2019–2023. It should be noted that in the base rivers of the hatcheries, on the spawning grounds of autumn chum salmon located upstream from the hatcheries, the proportion of fish of hatchery origin was also identified (Anyui River – 37,9%, Gur River – 11,1%). The obtained results may indicate the effectiveness of using microchemical analysis of otoliths to identify the return of autumn chum salmon, the young of which are released from the hatchery, and also determine the need for continuing research in this direction.

The paper is devoted to assessing the contribution of artificial reproduction to replenishment of commercial resources of autumn chum salmon and assessing the economic efficiency of its reproduction in the Amur River basin. The research results show that, according to otolith marking data, the share of artificially produced fish in 2019–2023 was 31,0–33,2%, which indicates a significant impact of artificial reproduction on the formation of commercial stocks of autumn chum salmon in the Amur River basin. The economic efficiency of the salmon fish hatcheries (SRH) of the Amur branch of Glavrybvod was assessed; the costs of maintaining the fish hatchery system are many times (6,2–8,2 times) lower than the possible gross revenue from the sale of returnable fish. It is recommended to maintain the level of artificial reproduction of autumn chum salmon at least in the volumes of the capacities of existing state SRH.

The paper presents data proving the importance of factory farming of autumn chum salmon in the formation of its commercial stocks in the Amur River basin. It has been established that an increase in the release of chum salmon juveniles by 1 million specimens gives an average increase in the catch after 3 years of 0,18 thousand tons. A set of measures aimed at developing the resource base of autumn chum salmon is proposed. In the Amur basin, it is proposed to increase the release volumes of autumn chum salmon juveniles from state hatcheries and to create a network of private hatcheries. The total release volume of juveniles is supposed to be set at 200 million specimens of autumn chum salmon juveniles per year, which can potentially bring an additional approximately 13,6 thousand tons of autumn chum salmon return. To achieve this indicator, it is necessary to build 10–15 hatcheries. It is proposed to allocate 3 areas with specific features of fish farming activities: small rivers of the Amur estuary; the lower reaches of the river. Amur from Komsomolsk-on-Amur to Nikolaevsk-on-Amur and the mouth of the Amur River from Nikolaevsk-on-Amur to the mouth of the Amur.

Currently Russian-Chinese scientific cooperation in the field of fisheries in the Amur River basin is carried out exclusively within the framework of intergovernmental commissions. Within the framework of the work of the commissions, an annual exchange of data on the volumes of catch of chum salmon Oncorhynchus keta and sturgeon (Acipenseridae) fish species in the boundary waters of the Amur River, information on the number of released juveniles and materials on the state of sturgeon fish stocks is carried out. A new format of Russian-Chinese scientific coop­eration in the field of fisheries in the Amur River basin is proposed within the framework of the agreements concluded between the State Science Center of the Russian Federation Russian Federal Research Institute of Fisheries and Oceanography with the Northeast Agricultural University and the Heilongjiang River Fishery Research Institute of Chinese Academy of Fishery Sciences. The main areas of cooperation are defined as work on studying the ichthyofauna in the boundary waters of the Amur, developing unified approaches to the artificial reproduction of aquatic bioresources, exchanging experience and conducting joint research in the field of com­mercial aquaculture, feed production technology and processing of aquatic bioresources. The creation of a Russian-Chinese fisheries institute within the framework of the Weilai Technopark (Harbin) is proposed as a platform for cooperation.

Pacific salmon enumeration by means of unmanned aerial vehicles is promising, but its imple­mentation is associated with the difficulties of manually processing large volumes of aerial imagery in order to count the number of spawners, post-spawn individuals (i.e. spawned out salmon). Automation of counting individuals in unmanned photographic materials by means of artificial intelligence (AI) methods, in particular, using neural networks from deep learning technologies domain, is one of the most promising ways to optimize salmon enumeration by means of unmanned aerial vehicles by increasing its productivity and efficiency. At present, the use of AI to identify individuals in unmanned survey materials has been implemented only for large cartilaginous fish (sharks, rays). This work demonstrates for the first time this possibility for teleosts, namely for post-spawn chum salmon. The proposed approach demonstrates the fundamental possibility of counting relatively small and highly variable in appearance aquatic species, such as Pacific salmon, even in poor visibility in rivers utilized for spawning. The example of the rivers of the Khabarovsk Territory shows that the use of correctly configured (trained) neural networks allows automating the detection and counting of post-spawn chum salmon using unmanned aerial photography materials. A description of the completed creation of a model based on a neural network for solving this problem, implementing the detection and counting of post-spawn salmon using AI methods on a desktop GIS platform is given. The importance of developing the Pacific salmon enumeration using AI methods specifically on a desktop GIS platform is substantiated due to a number of objective advantages of this approach. The proposed automation of post-spawn chum salmon enumeration in the Khabarovsk Territory using neural networks is the beginning of the automation of unmanned enumeration of Pacific salmon using AI methods, taking into account species and regional specifics. The importance of inter-branch interaction of VNIRO divisions for maintaining a common repository of models based on neural networks and their supporting datasets is shown.

The article presents an overview of scientifically based measures to regulate Pacific salmon fishing during the period of decline in their numbers in the Amur River basin in 2018–2024, implemented in the form of amendments to the Fishing Rules for the Far Eastern Fishery Basin, annual regional Pacific Salmon and Char Fishing Strategies (Salvelinus species) and orders of the Russian Ministry of Agriculture establishing individual restrictions for the calendar year. All the developed measures were aimed at prohibiting the use of certain fishing gear, reducing their dimensions and increasing the intervals between their locations, and updating the prohibited areas in the mouths of spawning rivers. As a result, the fishing load was minimized and the expansion of the spawning part of the range was noted. The positive effect of the introduced measures is reflected in the opening of industrial fishing in the Amur Estuary in 2024.

An analysis of the indicators of the fishery complex of the Khabarovsk Territory was conducted. The effectiveness of the Fisheries Committee of the Government of the Khabarovsk Territory for state regulation of fisheries has been assessed. The projects of new mechanisms of interdepartmental interaction for the formation of fish farming areas and the allocation of users with production (catch) volumes of Pacific salmon were substantiated. During the implementation of the projects, it is proposed to introduce amendments to the State Program of the Khabarovsk Territory «Development of the Fisheries Complex of the Khabarovsk Territory»; creation of an information analytical platform «Аquaculture of the Khabarovsk Territory» and development of a list of criteria and coefficients used by the Commission for regulating the production (catch) of anadromous fish species to allocate users with production (catch) volumes. The set of proposed measures will create favorable conditions for the construction of new salmon hatcheries with a total capacity of 200,0 million specimens of juveniles. It is predicted that fishing enterprises will be involved in the artificial reproduction of chum salmon in the river basin. Amur in the amount of 50,0 million specimens of juveniles. The end result of the projects will be an increased resource base of the fisheries of the Khabarovsk Karya by 2035 by about 19,0 thousand tons of Pacific salmon.

As part of the monitoring of infection of Pacific salmon (Oncorhynchus) of the Amur basin with pathogens of human parasitic diseases, the invasiveness of the autumn and summer forms of chum salmon O. keta and pink salmon O. gorbuscha caught during the spawning anadromous migration in 2022–2024 was assessed. As a result of the conducted studies, Nanophyetus schikhobalowi metacercariae were found in chum salmon with an invasion intensity of 61,5%. Larvae of Anisakis simplex were observed in 32,0% of the studied individuals, Dibothriocephalus nihonkaiensis plerocercoids were detected in 14,8% of cases. The studied pink salmon individuals contained A. simplex larvae in 11,4% of cases. The results of the study confirm the need for annual measures to assess the parasitological state of fishery reservoirs in the Khabarovsk Territory to reduce the risk of infection of the population.

This report presents individual considerations on the issues of implementing fishing in order to ensure the traditional way of life and implementation of traditional economic activities of the indigenous peoples of the North, Siberia and the Far East of the Russian Federation (traditional fishing of the indigenous peoples of the North) in the Amur basin. The procedure for establishing the volumes of production (catch) of freshwater fish and Pacific salmon for traditional fishing in the Amur River basin is considered. Some problems associated with the implementation of this type of fishing are discussed. An opinion is expressed on the need for additional regulation of this type of fishing, in particular, establishing liability for failure to submit reports on the catch. A proposal is made to develop a procedure for providing simplified access for fishing to persons who are not related to the indigenous peoples of the North, but traditionally living along the banks of the Amur.