Based on data from the industry system of monitoring of aquatic biological resources, observation and control over the activities of fishing vessels for 2008–2022, the article provides information on the total catch of walleye pollock in the northeastern part of the Sea of Okhotsk, including by season and during the specialized trawl fishery. According to the data collected by scientific observers on fishing vessels in October–December 2009–2011, 2019, 2021–2022, data from the industry monitoring system for the same years, the distribution of catches, the intensity of specialized trawl fishing, size-age composition of walleye pollock are studied.

Specifics of coastal fishery and species composition of marine fish communities in the sublittoral zone during spring-summer period is considered based on the results of studies of the composition of commercial catches by fixed nets and Danish seines in the coastal zone and on the shelf of Kunashir Island in 2021–2023, analysis of seasonal and annual catch statistics in 2014–2023 and archival materials. It is shown that the species composition of catches in the coastal zone includes up to 30 species of fish from 13 families. The most diverse were Flounders – 8 species (26.7%), Sculpins – 5 species (16.7%) and Greenlings – 4 species. Saffron cod, whitespotted char, Pacific herring, starry flounder, cresthead flounder, toothed smelt and arabesque greenling were the most widespread. These species contributed between 67.2 and 99.9% into the total catch weight. The Saffron cod formed the basis of the fixed net catches on the Pacific coast. Its contribution ranged from 84.7 to 86.5%. The contribution of cresthead flounder varied in the range of 4.1–7.9%, of starry flounder – 1.1–3.9%, of whitespotted char – 1.2–2.3%, of toothed smelt – 4.1–0.7%. Cresthead flounder dominated (28.7%) on the coast of the Sea of Okhotsk in terms of biomass. The contribution of saffron cod and whitespotted char – both were about 19.7%, of Pacific herring – 18%. According to the fishery statistics obtained from processing plant, the composition of the catch in 2014–2023 corresponds well to the results of the analysis of species composition of the catches according to scientific observations. The main commercial object was saffron cod with average contribution into the annual catch of 75.1%. Flounders contributed 15%, herring – about 4.5%, the other species can be considered as by-catch. About 83.2% of the annual catches by fixed nets in 2014–2023 were obtained on the Pacific coast of Kunashir Island and only 16.8% – on the coast of the Sea of Okhotsk. Obtained results can be used for stock abundance assessment, evaluation of the allow- able catches of marine fish in the South Kuril zone and planning expeditionary researches. 

Results of studies of microalgae representing harmful bloom complex in the coastal aquatic zone of the Avachinsky Gulf in 2023 and data on hydrology and biogenic background in mentioned area are demonstrated.

Efficiency of using camera trap to monitor spawning sockeye salmon on small spring-type spawning grounds is evaluated and optimal criteria for installation are determined in the paper. The time of sock- eye salmon migration in different sections of spawning route from Kamchatka Gulf to the spawning grounds in the Azabachye Lake is clarified, and recommendations on the timing of aerial surveys in the lake basin were given.

Method of thermal induction was tested for the first time in the practice of Far Eastern aquaculture to obtain polyploid Pacific oyster Crassostrea gigas. Experimental blocking of meiosis was performed 25 min after fertilisation by brief (3 min) exposure to the temperature of 32 ^oC. Efficiency of the method was evaluated with assessment of survival, growth and development of control and experimental larvae (groups 2N and 3N, respectively) in conditions of plant. Growth rate of juvenile Crassostrea gigas in Voyevoda Bay, Russky Island (Peter the Great Bay, the Sea of Japan) during two years was studied also. The content of DNA in haemocytes evaluated using flow cytometry revealed 35% triploids, 22.5% tetraploids and 40% heteroploids in the group 3N. The maximum weight increment in this group (0.34 g/day) was observed in summer at the second year of life, and the maximum linear growth rate (1.55 mm/day) – in September at the second year. The values for the group 2N were 0.31 g/day and 1.47 mm/day respectively. After 22 months, 57.9% of diploid and 80.9% of polyploid oysters reached their commercial size. The total weight of oysters in the group 3N was 124.6 ± 2.7 g, what was 43% more compared to the group 2N.

The article updates information on the northern shrimp fishery since 2017. Averaged daily reports from vessels from the industry monitoring system of Rosrybolovstvo were analyzed. Results obtained from vessels in the course of fishery monitoring in 2018–2019, 2022 were added. It is found out that, similarly to previous years, the main fishing period falls on the winter-spring period with maximum catches in March– April. The proportion of the catch at this time reached 70% of the TAC. The fishery was mainly conducted at depths of 300–400 m, where, according to data obtained during the fishery monitoring, the highest abundance rates were observed. In autumn, the catch did not exceed 0.1–13% of the TAC, depending on the year of fishing. According to the ship’s daily reports, there has been an increase in average daily catch in recent years from 2.8 in 2018 to 4.5 tons in 2022. The quantitative and qualitative composition of the catches in recent years has been at the same level as in previous years, with all averages remaining at the same level.