Results of the salmon fishing campaigns in the Kamchatka Region in 2024 and 2025 are reviewed. Detailed data of fishery statistics concerned pacific salmon, estimations of their runs abundance and spawning stocks are presented for all salmon species and compared between these years and with long-term indices of the regional stocks dynamics (annual catch, spawning escapement and run abundance) for 2001–2025. Accuracy of the run and catch forecasts is analyzed for the major stock units in 2024–2025 and possible reasons for discrepancies of the forecasted expectations with real situation are discussed.

Relationships of year-to-year dynamics are analyzed between the body size of pink salmon and their regional and total abundance and between the size of juveniles and the size of returned adults. The dependencies are estimated for odd and even year-classes, separately, and for different periods of years. The body size variations relate closer with changes of regional abundance than with changes of total abundance for pink salmon from almost all  regional herds except those reproduced in East Sakhalin and southern Kuril Islands. Variations of the body size correlate well between the juveniles and adults returning for spawning for the herds from East and West Kamchatka (both for odd and even year-classes) and East Sakhalin (for high abundance odd years-classes). Sustainability of some size-weight features formed in the early period of life during the further stages of feeding and spawning migration is assumed for pink salmon.

Landlocked masu salmon Oncorhynchus masou were found in the Dachinskoye Reservoir in the Ussuri River basin (the right tributary of the Amur) in 2012. Results of laboratory analysis of the samples fixed in formaldehyde solution are presented, including the data on fish size, age, sex, and stage of gonad maturity. Concepts of landlocked and migratory forms of masu salmon are overviewed briefly, all known cases of masu salmon habitation in the reservoirs of Primorye are considered.

In the first decade of 21st century, aggregations of japanese anchovy were regularly observed off the western and eastern coasts of Sakhalin in summer and autumn seasons, where reached 52о00′ N in the Tatar Strait and 53о20′ N in the Okhotsk Sea. In total, they migrated to the eastern coast during 23 years and to the western coast during 35 years (since 1989 till 2023). The anchovy approaches to the Sakhalin coasts corresponded with dynamics of this species populations in the Tsushima Current and Kuroshio waters and coincided well with the period of japanese sardine depression both in the Japan Sea and North-West Pacific. In the years of high abundance, about 100–300 thousand tons of japanese anchovy could be landed at Sakhalin annually, if the fishery would be organized properly.

New data on distribution, ecology, and size composition of rex sole Glyptocephalus zachirus in the northwestern Bering Sea in summer are presented. Fish of this species were recorded at the depths of 120–718 m, mainly within the warm Intermediate water mass, under water temperature of 2.6–4.9 ^оC at the bottom, with the maximum of distribution density in the bathymetric range of 200–400 m. The fish of 11–49 cm in length prevailed in the trawl catches. The juveniles avoided shelf areas and dwelled in the upper bathyal layer only. The main habitat of rex sole is supposedly subjected to influence of the warm Navarin Current.

Reliability of the fish stock assessments is affected by many factors, including seasonal patterns of fish distribution and inhomogeneity of distribution density. Results of two bottom trawl surveys are compared, which were conducted in the same area of Peter the Great Bay (Japan Sea) and in the same year 2013 but in different seasons, as spring and summer. The fish species stock assessments were mostly higher in summer, with exclusion of sculpins with insignificant difference between the seasons (except actively migrated graypurple sculpin). The observed difference was reasoned by seasonal bathymetric migrations. Therefore, an optimal for trawl surveys season can be determined taking into account the bathymetric migration of bottom species. In spring, the fish concentrated mainly at the depths more than 300 m, with the maximum density of 24.86 t/km² in the range of 400–500 m, where walleye pollock and blackfin flounder prevailed. In summer, the highest concentration was found in the range of 20–50 m but its value was much lower, 14.5 t/km². No more than 10 % of fish biomass remained in the deep-water areas with the depth from 200 to 700 m. The fish concentration in dense but small-sized aggregations increases inhomogeneity of the biomass mosaic distribution and reduces accuracy of their stock assessments. That’s why the summer season with relatively even distribution of bottom fish is the optimal time for bottom trawl surveys.

The horsehair crab Erimacrus isenbeckii fishery develops actively in the eastern Okhotsk Sea since 2017. The main commercial aggregations of this species are located around the 40 m isobath in the Kamchatka-Kuril fishing subzone. Significant fluctuations in its abundance and distribution density are noted. The maximum density of the crab aggregations up to 4,300 ind./km² was observed in 2024, when the stock was assessed in 3.8 . 106 ind. The fishery is regulated taking into account seasonal dynamics of molting and distribution of functional groups. The results of the study allow to optimize the resource management strategy and to provide sustainable exploitation of the horsehair crab population at southeastern Kamchatka.

Species composition, functional structure and production of plankton communities is considered on the long-term data collected in 1986–2022 together with diet and ration for two species of pacific salmon (Oncorhynchus gorbuscha and Oncorhynchus keta) during their feeding in the deep waters of Bering Sea and Okhotsk Sea. Significant regional differences are found for the macroplankton. The functioning of plankton communities in the Okhotsk Sea is more efficient for maintenance of the salmon feeding. Both salmon species consume mainly amphipods, copepods and arrowworms. Bathymetric distribution of plankton and seasonal succession of the plankton communities are different between the seas, so the feeding intensity, daily ration and species composition of diet vary considerably between them, as well. However, high production of large-sized planktonic predators and active transport of zooplankton from outside areas are noted for both regions that provides a stable food base for salmon even in cases when the total production of zooplankton community is low there. The results obtained are important for understanding the feeding abilities for salmon species and the mechanisms of their year-classes yield formation as a basis for the stocks management.

Climatic trend of the entropy flux across the water-air boundary is determined for the oceanographic section along 180o meridian in the Pacific Ocean. The flux is calculated on the average annual data for SST and components of heat balance with 4-degree spatial resolution for 1979–2024. The flux is negative with the value ~3 ^. 10^–2 W/m²K and has a tendency toward zero. Mean rate of the turbulent energy dissipation per unit mass is evaluated as ~2.10^–7 m²/s³. Different trends in thermal conditions for the «closed» and «open» polar areas in the Southern and Northern Hemispheres, respectively, are discussed. Possible feedback of the parameters toward climate stability is noted: the lower the entropy flux, the weaker water dynamics, and the higher SST difference between tropical and polar zones, that leads to reverse process of increasing the entropy flux and returns the ocean back to its previous stationary state.

Data on size and sex composition are presented for broodstock of amur catfish, their spawning and the progeny rearing in a full-system warm-water farm are described. The juveniles were reared successively in the water tank, pond, and cages, and fed with alive and artificial granulated feeds. Two females weighing 1.95 and 3.10 kg and one male weighing 1.20 kg were selected for the spawning, their maturation was stimulated with extract of pituitary gland of carp. The females yielded 300 g of eggs with an unswollen egg weight of 3.3–3.5 mg. The eggs were dry inseminated and distributed throughout the artificial spawning grounds. The larvae hatched 69 hours after the onset of egg cleavage. Within 13 days after the larvae began active feeding, the weight of juveniles increased to 0.3 g, then they continued to grow in the pond where reached the mean weight of 112 g in two months, and further after 1.5 month of growing in the cages the weight of fingerlings increased on average to 220 g, with a wide range from 30 to 590 g. Cannibalism and aggressive behavior of juveniles were observed when they were reared in the tank and cages.

Low molecular weight peptides in the fish feed can enhance growth of fish fry. The protein-containing components of such feeds as raw and hydrolyzed fish, fly larvae, haprin, hydrolyzed yeast, and experimental extruded starter feeds are examined. The extruded feeds (KRLS-1, KRLS-2, KRLS-3, and EF) were produced by another branch of VNIRO (VNIPRH) on the Amandus Kahl pilot production line (Germany). The contents of moisture, mineral fraction, water-soluble proteins and lipids were assessed using standard analytical procedures and the nitrogen content was measured by Kjeldahl method. Protein fractionation was performed using high-performance chromatography. On these data, daily rations of fry were calculated. Mortality of fry was determined by direct counting. Absolute weight gain was calculated as the difference between final and initial weights of fry. The feed coefficient was calculated as the total amount of feed consumed during the 60-day rearing divided by the weight gain, corrected for mortality. Fish farming tests were conducted according to the standard protocol. The examined starter feeds contained 3.5–6.0 % moisture, approximately 50 % protein, 10–11 % lipids, up to 9 % minerals, and 20–30 % carbohydrates. The hydrolysate from raw fish had the highest portion of low molecular weight peptides (1–10 kDa) – 98 % of the water-soluble protein fraction. Hydrolyzed yeast, fly larvae, and haprin contained 96, 51, and approximately 30 % of low molecular weight peptides, respectively. The extruded feeds were well-balanced and contained substantial amounts of low molecular weight peptides, with the highest content for KRLS-3 (55 %) due to its heightened hydrolysate fraction, whereas KRLS-1, KRLS-2, and EF contained 49, 18, and 35 % low molecular weight peptides, respectively (relative to the water-soluble protein fraction). The fish farming tests demonstrated that the fry fed with KRLS-3 starter feed had the biggest final weight (0.830 g) and the highest mean daily weight gain (1.45 %), with the lowest feed conversion ratio (0.88). The feeds KRLS-1 and KRLS-2 showed comparable results. The feed EF was less effective by growth parameters but provided the best survival of fry (98.9 %, compared to 97.0 % for KRLS-3). All tested starter feeds are quite suitable for industrial rearing of chum salmon fry.

The population of european eel Anguilla anguilla is in critical condition, having reached a historic low. In the framework of the Eel Management Plans, juvenile eels have been stocked in the Kaliningrad and Curonian Lagoons since 2022. The key indicator for effectiveness of these measures is the commercial return, but its calculation is complicated by lack of systematic monitoring. To justify the volume of stocking and effect of measures for restoring the population, the expected commercial return is estimated by three methods of calculation: i) direct calculation based on expected catch and planned escapement of spawners to the spawning grounds; ii) interpolation of data from scientific literature; and iii) modified formula proposed by S.V. Shibaev. As the result, the expected value of commercial return for juvenile eels weighing 1–5 g is estimated as 12–14 % for these two vast lagoons in the Kaliningrad Region. This value can be used as a basis for planning resource activities, but require further clarification within the long-term monitoring program that conducts annual assessments of the eel stock taking into account the species features, as separate counting the yellow and silver stages of eel in catches.

Cultivation of whiteleg shrimp Litopenaeus vannamei is overviewed, data on this species yield in the world aquaculture are presented, and information from world-wide literature sources on using the larvae of black soldier fly Hermetia illucens in feed rations for this shrimp species are summarized. Morphology and life cycle of H. illucens are considered briefly. Protein and fatty acid contents of the native and defatted larvae are investigated in details and effectiveness of insect larvae usage for feeding fish and invertebrates in aquaculture is concluded. In diets for growing and adult whiteleg shrimp, the fish meal can be replaced by the feeds produced from fatty and defatted H. illucens larvae in amounts from 5 to 100 % with positive effect on growth and physiological and morphological parameters of cultivated shrimps. The replacement of fish meal in 30 % is optimal for their growth and physiological development. The larval fat, three by-products of the larvae (exuviae, cocoons, imago), and compost of the wastes can be used for the shrimp feeding, as well.

Methodology for the aerial photogrammetric counting of pacific salmon spawners with serial unmanned aerial vehicles (UAVs) is developed and tested for the rivers of southeastern Sakhalin on example of pink salmon Oncorhynchus gorbuscha. In total, 22 water streams with the total length of about 230 km were surveyed during the spawning migrations in July-August of 2022–2024. Traditional methods of the counting are labor-intensive and ineffective in this area because of hard relief and high afforestation of the river shores, but operational monitoring with consumer-class UAVs (DJI Phantom 4 Pro V2.0, DJI Mini 2, DJI Matrice 300 RTK) is available. The optimal parameters for aerial survey have been established: the flight altitude 20–100 m, UAV speed up to 6 m/s, longitudinal overlap of the images ≥ 80 % and the transverse overlap ≥ 40 %. The materials of 88 flight missions are processed in Agisoft Metashape Professional software package and orthophotoplans with resolution of 1.0–1.5 cm/pixel are obtained, suitable for visual identification and counting of fish using the geoinformation system NextGIS QGIS. Effectiveness of different UAV models is compared. The main limitations of the method concerned to weather conditions and the riverbed cover are defined. The developed methodology is an effective and economically feasible tool for operational control of spawning that can be used for the fishery regulation and evaluation of reproduction efficiency for pacific salmon in the Sakhalin Region.