Stepwise multidimensional regressive analysis was carried out based on the long-term data (1971–2018), including biological statistics and series of observations on 10 climate indices, allowing to identify the most meaningful climatic factors affecting the numbers of some fish species at different stages of the ontogenesis in the Eastern part of the Sea of Okhotsk. All the results obtained indicate of existing true correlations with the number of the two-years-old individuals and the number of the fish reached the age of the mass (>50%) maturation. Threedimension regression models, describing the dynamics of the initial number of some fish satisfactorily. Were made, based on the obtained equations of multiple regression of the relationship between the number of the fish and the most effective climatic indices selected. The major indices affecting the abundance of different fish species are: SST, NPGO, SanSpot – Pacific herring; NPA – saffron cod; PDO – Pacific cod; NPA, SanSpot – great sculpin; SanSpot, PNA, AO – yellowfin sole; PDO, SSTa – Pacific halibut; Ice SanSpot, NPGO – Greenland turbot. Pelagic, demersal and bottom species are under the complex influence of the oceanographic, meteorological and planetary-space indices.

The Nachikinskoe Lake and its tributaries were first examined in detail with the help of a quadrocopter during running and spawning of early and late sockeye salmon. Quantitative estimates of adult salmon filling in different areas of lake tributaries and its coasts were obtained. The number of spring sockeye salmon was estimated at ~30 thous. specs, and late — at ~145 thous. specs (summation of adults counted every ~2 weeks) and 140 thous. specs (127–153 thous. specs), by means of imitation model. According to the photos from the quadrocopter, the boundaries of the spawning grounds of the late sockeye salmon in 2018 are marked on the space picture. The area of spawning grounds is calculated — 307 thous. m². The maximum density of distribution of adult salmon exceeded 0.64 specs/m², the density of spawning was 4.5 specs/m².

Results of in situ testing of BioSonics DT-X and Didson hydroacustic systems set on migrating path to spawning grounds of adult sockeye salmon in the Ozernaya River are presented. Two million 374 thousand fishes was recognized and counted for the whole working period of the systems, including one million 276 thousand individuals registered by BioSonics DT-X echo-sounder and 1 million 98 thousand – by Didson imaging sonar. The data on the assessment of Pacific salmon escapement in the Ozernaya River allow to make recommendations on the use of the BioSonics DT-X and Didson hydroacustic systems as a tool for assessment of Pacific salmon escapement in rivers of Kamchatka.

The information about of the features of the biological structure of coho salmon is provided, the issues of the dynamics of spawning runs, commercial use and adult escapement for spawning grounds are considered. The importance of coho salmon as commercial or recreational fishery object is demonstrated.

Counting pink salmon Oncorhynchus gorbuscha fry, migrating seaward in the Malaya Khuzi River (NorthEastern Sakhalin), revealed the total half-million stock of the migrants in 2018. Forming such generation from extremely poor parental stock, entered the river in 2017 had been possible due to a high survival rate in the course of incubation. Seaward migration was about 1.5 month long and finished 7–10 days earlier than in previous years. Major part of the fry stock emigrated during the I decade of June. Dense aggregations of ice on the seashores during the mass seaward migration could bring negative effects on survival of the fry. Migration occurred at night. Day time migration was observed in case of decreasing water transparency on flooding. The migrants in most cases did not have yolk sack residuals. Mean values of the body length and weight of the migrants did not exhibit extensive changes for the period of migration.

In 2005 in sublittoral zone of Koryak coast 79 species of amphipods belonged to 43 genera, 20 families and two suborders are revealed. The main part of the fauna was endemics of Pacific boreal area. The biomass varied from the several 100-th shares of gram to 15.6 g/m². The maximum biomass of amphipods at population density 230 ind./m² was registered at Cape Hajtyrka. The average biomass was 2.0 ± 0.6 g/m² or 0.4% from the total biomass of a benthos. In places of amphipods accumulations their part in the total biomass of a benthos could reach 56.9%. Quantity indicators of amphipods on a shelf of Koryak coast above, than in Anadyr Bay. In different places of the investigated water area dominating species was different (Atylus bruggeni, Pontogeneia rostrata, Anisogammarus pugettensis, Caprella paulina). Rigid soil are extended on main parts of water area of narrow geosynclinal shelf of Koryak coast, mobile filter feeder, building small houses-tubes in thickness of a soil (Byblis erythrops, Ampelisca macrocephala and some other) had here no such wide development as in of Anadyr Bay. The shelf of Koryak coast distinguishes from the other areas of the Far East seas by small species wealth of amphipods at the stations – basically no more than five species.

Structure, quantitative indicators and specifics of distribution of principal macrozoobenthos communities of krenal, ritral and estuarine zones in the body of nameless stream (Shikotan Is.) are described. General patterns of the distribution are explained.

Data about new conservant “Aldofix” to fix ichthyoplankton are demonstrated. Series of experiments on the conservation of ichthyoplankton and eggs of walleye pollock were carried out with the use of “Aldofix” and its modernized solutions. External view, including color of the eggs, as a result of fixing in different solutions was described, and difference in the egg diameter was noted in case of fixing in formalin and “Aldofix”. It is concluded, that “Aldofix” (example № 1) was the most convinient fixing solution to preserve ichthyoplankton.

Results of the research indicate that the eggs of Atka mackerel are a part of forage for this speciesis from May to December. Captures of the Atka mackerel individuals spawning and feeding on the own eggs far from the coast indicate that a certain part of the stock spawns at the depths considerably lower than normal spawning grounds. Spawning individuals of Atka mackerel is were observed in research from June to December. Emergence of larvae from the eggs laid in November–December is expected in spring.