Results of salmon fishery in 2025 are briefly presented for the North Pacific and adjacent areas of the Arctic Ocean.

Results of pacific salmon fishery in Sakhalin-Kuril Region in 2025 are summarized. The fishing sea- son of 2025 was one of the worst for the Sakhalin Region for a long time. With the forecasted volume of 62194 t, the total actual catch of pacific salmon was no more than 21244 t (34.2 % of the forecast), including 5377 t of pink salmon On- corhynchus gorbuscha, 14423 t of chum salmon O. keta, 1118 t of sockeye salmon O. nerka, 311 t of coho salmon O. kisutch, and 15 t of masu salmon O. masou. It was the third amount among the Far Eastern regions, after Kamchatka (258916 t) and Khabarovsk Region (32926 t). According to fisheries statistics, the landing in commercial aquaculture reached 12751 t, including 759 t of pink salmon and 11992 t of chum salmon. The most significant decline was observed in key fishing areas, as the East Sakhalin fishing subzone (16.8 % of the forecast) and the South Kuril fishing subzone (20.8 % of the forecast). The most erroneous was the catch forecast for pink salmon (25900 t, whereas the actual catch was in 5 times lower). The run abundance for pink salmon was estimated in 12.1·106 ind., among them 9.4·106 ind. escaped to the rivers (77.7 % of the run, or about a half of the optimum number), and the rest of 2.7·106 were caught. The spawning grounds in southwestern Sakhalin and the southern Kuril Islands were filled by the spawners with the lowest levels for all years of observation (36.6·103 and 75.1·103 ind., respectively). The errors were caused by extremely unfa- vorable environmental conditions during the spawning migration. The catch of chum salmon (14423 t) was closer to the forecast (34400 t), but this accuracy in 41.9 % cannot be considered as appropriate, too. Almost total loss of hatchery- reared chum salmon of all age groups was observed in the southern Kuril Islands where the catch of 10700 t was predicted and only 420 t (3.9 %) was caught. Synchronous decline in chum salmon abundance is noted for all sites in the southern part of their range (Iturup, Kunashir, Hokkaido), in opposite to relatively stable situation in the northern regions (Kamchatka, East Sakhalin and the Okhotsk Sea coasts of Khabarovsk and Magadan Regions). The problems of operational regulation of chum salmon fishery in southeastern Sakhalin Island are analyzed, and solutions are proposed, partially within the framework of the «Strategy for the Pacific Salmon Fishery in Sakhalin Region in 2026».

The pacific salmon run and catch in the main fishing areas of Khabarovsk Region in 2025 are analyzed. The data on fishery statistics are presented, the forecasted and actual volumes of the pacific salmon catch are compared. The catch dynamics are described, estimates of the spawners approach and escapement to rivers are provided.

Results of salmon harvesting in the Magadan Region in 2025 are summarized. The salmon fishery organization and its scientific support are described, the data are presented on the forecasted and actual catch of pacific salmon and char (gen. Salvelinus) and on the forecasts realization. Current state of the salmon stocks is evaluated, the expected and actual run of pacific salmon and their escapement to the spawning grounds are discussed.

Results of the pink salmon (Oncorhynchus gorbuscha) fishery season in the Russian Far East in 2025 (odd-year brood line) are analyzed on data of fishery statistics and marine trawl surveys conducted in 2024 – 2025. The salmon run abundance and catches are considered by regions, their deviations from the for ecasted values are examined, and factors able to influence on the fishery are discussed. The total annual catch of pink salmon is evaluated in 222.6 · 103 t that is below the long-term value for odd years (on average 294.0 · 103 t for 2003–2023). Strong regional contrasts were detected: a record-high harvest in the Primorye fishing subzone (8.8.103 t in Primorye Region and 10.8 · 103 t in Khabarovsk Region) against the lowest catch since early 2000s in East Sakhalin (3.5 · 103 t that was 17.6 · 103 t below the forecast). Results of the marine trawl surveys in fall 2024 (offshore migration of juveniles) and summer 2025 (pre-spawning migration of adults) allowed to develop rather accurate basin-scale forecasts of the pink salmon run, but their differentiation from mixed aggregations within the Okhotsk Sea was forecasted with overestimation of the southern Okhotsk Sea stocks contribution (run to East Sakhalin and southern Kuril Islands). Possible reasons for these discrepancies are analyzed. The pink salmon annual catches decline steadily in East Sakhalin (since 2009), West Kamchatka (since 2018), and East Kamchatka (since 2019) on the background of de- clining reproductive potential and hierarchical shifts between brood lines in major spawning areas that presumabl y occurs within long-term climate-induced cycle.

Surveys of juvenile pink salmon during their feeding in the sea in fall season provide information on possible returns of pink salmon in the next year used for the catch forecasting. Recently, these surveys are conducted by two research vessels that ensures the study area covering in a short time and excludes repeated counts of fish on adjacent transects. In 2025, the trawl surveys for pink salmon in the Russian parts of Bering and Okhotsk Seas provided abundant and representative data for assessing the species returns and catches in the Karaginskaya fishing subzone of Bering Sea and in the Okhotsk Sea, respectively. In the western Bering Sea, the juvenile pink salmon number was estimated as 179 · 106 ind. that was close to the average value in the past cycle of odd years since 2017 to 2023, when the number ranged from 100 · 106 to 300 · 106 ind. The expected return of pink salmon to the Karaginskaya subzone is evaluated in 51 ± 15 · 106 ind. that provides the catch of 32 ± 9 · 103 t with the expected spawner weight of 1.25 kg and 50 % escapement of the spawners to the spawning grounds. In the Okhotsk Sea, the abundance of juvenile pink salmon was estimated as 500–550 · 106 ind. This was one of the lowest value observed in the recent cycle, but perhaps the survey did not cover the whole spatial range of the juveniles distribution because of unfavorable weather. Based on this value, the pink salmon return to the Okhotsk Sea is forecasted within the range of 66–94 · 106 ind. that provides the catch between 65–92 · 103 ind. with the expected spawner weight of 1.30 kg and the escapement of 25 %. The cluster analysis (EM-clustering) of juvenile pink salmon in the Okhotsk Sea allowed to identify the northern and southern complexes of pink salmon herds and estimate their abundance in the ratio of 80 : 20 % in favor of the northern group.

The data on abundance and biological indices of downstream-migrated juveniles of pacific salmon and their returns for the spawning in 2025 are presented. The total number of returned pink salmon adults (8.801 · 106 ind.) exceeded in 3 times the initial forecast (2.820 · 106 ind.). The total catch of pink salmon in the Primorye Region reached the amount of 8837.8 t that was the highest harvest in the region history and provided the 6th high annual catch of salmon in the Far East of Russia. Oceanographic and meteorological conditions of the pink salmon run are considered, including the Tsushima Warm Current intensity in spring and summer and patterns of its water advection to the coast of Primorye in May and June, which contributed to the salmon run. This current was extremely active in 2025 due to spreading of the western spur of Hawaiian High over the Japan Sea that forced southern winds and strengthened northward water flows. Early warming of the sea surface along the routes of anadromous migration promoted the massive approach of pink salmon to the coast in 15 days earlier than in 2023. General state of stocks, fishery, and reproduction of pacific salmon spawned in the Primorye Region is discussed.

Biological and morphophysiological parameters of juvenile pacific salmon (pink, chum and coho) grown at salmon hatcheries in the Magadan Region in 2024–2025 are considered. The data on salinity tolerance of the chum salmon juveniles are presented, as well, which reflect their viability.

The first documented cases of the ulcerative dermal necrosis (UDN) lesions are described for pacific salmon (pink salmon Oncorhynchus gorbuscha and chum salmon O. keta) in the waters of Kamchatka. The fish with lesions were sampled in the rivers of Kamchatka in 2019 (5 specimens of pink salmon) and 2021 (11 sp.) and from the catches of marine trawl survey off Kamchatka in 2023 (9 specimens of chum salmon and 1 sp. of pink salmon). After visual examination, the samples of tissue for histological analysis were fixed on-site and the samples for microbiological