Two different views on factors limiting the abundance of pacific salmons in the marine period of their life are compared. According to traditional point of view, food resources are limited in the marine and oceanic epipelagic biotopes, so a strong competition for food exists between different species of genus Oncorhynchus or between pink salmon O. gorbuscha and other species that makes theIr abundance lower and biological conditions worse. Negative anomaly of the sea surface temperature is considered traditionally as a factor controlling the salmons distribution in the ocean because of the food supply worsening. The other point of view is proposed by authors in the 1980s and is based on comprehensive ecosystem studies of the Far Eastern Seas and the North Pacific. Following to this view, the food resources do not limit the abundance of salmons, which play secondary roles in trophic networks within the subarctic epipelagic layer. Besides, these data do not confirm stenotherm habits of salmons, particularly in conditions of low temperature (salmons could be found in the northern Bering and Okhotsk Seas even in winter). In favor of the latter view, new data are presented for 2018, when the highest biomass of the Russian salmons was observed, primarily due to pink salmon abundance, and the absolutely record Russian catch of pacific salmons in 677,200 t was landed.

The major aspects of density regulation of the pacific salmons spawning are analyzed. Uncertainty of the ecological parameters considered traditionally as indicators of the salmons reproduction efficiency is discussed. If the method of the efficient spawning density is applied to the whole area of spawning grounds, without examination of conditions for spawning, false conclusions on optimum abundance of the spawners could be made. Clear criteria of the spawning grounds environments suitable for spawning are necessary for correct evaluation of the density factor for regulation the population abundance. Efficient escapement to the spawning grounds could be determined adequately by analysis of the reproduction curve. Critical analysis of tools for short- and long-term management of the salmon fishery is presented. Variants of compromise decisions for the multispecies fishery are discussed. The optimal escapement to the spawning grounds in not an absolute norm, but is a statistical parameter used for reaching the maximum production. Conflict between the strategies of saving the reproduction basis of salmon populations and the landing increase by fishing companies is demonstrated. Criteria and algorithm of short-term corrections of the salmon catches during the fishery campaign are provided. Major local units of the pacific salmon stocks in the Far East of Russia are outlined; biological parameters necessary for management of their exploitation are defined. Numbers of the spawners necessary for local and general support of spawning stocks for 5 commercial species of pacific salmons are evaluated to provide the most effective and sustainable natural reproduction of the stocks in the Russian part of the North Pacific.

The effects of different water salinities on the number and area of chloride (mitochondriarich) cells and on plasma glucose level in Sparidentex hasta were studied. Fish were exposed to a salinity of 5, 20, 40, and 60 ppt for 14 days. The group kept at 40 ppt was considered as the control. Samples were collected at 6 and 12 h and on days 1, 2, 7, and 14 of exposure. The results of this study revealed changes in the plasma glucose level and in the number and area of chloride cells in S. hasta associated with water salinity variations. It can be concluded that S. hasta has a wide tolerance towards salinity changes in the environment, which is provided by the mechanisms of osmoregulation and the involved organs, mostly by gills.

Results of ichthyoplankton surveys conducted in the Avachinsky Bay in the springs of 2003–2018 are presented. The larvae of 3 species of genus Sebastes occurred in the bay, starting in March, as shortraker rockfish Sebastes borealis, pacific ocean perch Sebastes alutus, and rougheye rockfish Sebastes aleutianus. The maximal catches of the larvae were obtained at the depth ≤ 500 m, mostly over the deep-water canyons. Problems of the rockfish larvae identifying to species are discussed, as absence of the detailed identifier for these species. Photo-images of the larvae are presented for Sebastes alutus and Sebastes aleutianus collected in spring of 2018, their typical differences are considered. Size composition is presented for the larvae of Sebastes.

Size composition and growth rate of blue king crab males are analyzed on the data of 8 bottom trawl surveys conducted in the western Bering Sea in summer-fall seasons within the period from 2005 to 2017. Significant changes in size structure of this population are revealed. Portion of commercial males was the lowest (18.7 %) in 2010 because of the strong yearclass appeared in the catches in 2005, when its males carapace had the width 20–40 mm, that provided in 2008–2010 the percentage of juveniles with the size < 100 mm about 59–60 %. Then this strong year-class reached the commercial size, so the portion of commercial males increased to 66 % in 2014 and to 85 % in 2015–2016. The portion of juveniles was extremely small (3.1–6.5 %) in these years. The portion of commercial males had reduced again to 67 % in 2017 because of a new strong year-class appearance that provided the juveniles percentage increasing to 24.6 %. The mean size of commercial males has increased since 2012 in 18 mm and reached the value of 160.4 mm in 2017. Age of the crab males entry into the commercial cohort is estimated as 8 years. The observed cyclic changes in size composition of blue king crab and estimated value of its growth rate indicate indirectly a good and stable state of its population in the western Bering Sea.

Within Peter the Great Bay, common icefish Salangichthys microdon forms commercially valuable aggregations in two areas of the Amur Bay and in one area of the Ussuri Bay. It spawns in the internal estuaries of the rivers entered to the bays and in the external estuarine zones in the tops of the bays, mostly on small pebble grounds from late April to late May and feeds in the bays waters. Data on its size and weight composition were obtained in 2017–2018 both from the Amur Bay (for spawning period) and from the Ussuri Bay (for feeding period). During the spawning (on May 6 and May 18), the body length was 59–90 mm, on average 74.9 mm, and the weight was about 750 mg; sex ratio males : females was 1.0 : 0.8. During the feeding, the average body length was 66.8 mm.

Modeling the dynamics of the relative number of diatoms in epiphytic diatom communities of the macrophyte Ulva lactuca Linnaeus from three different coastal areas of Peter the Great Bay, Sea of Japan (Amur Bay, Ussuri Bay, and the Stark Strait), based on a tool of recurrent equations, makes it possible to identify the communities’ own natural dynamics in the water areas studied [Parensky, Levchenko, 2018]. It has been found that the reproductive capacity of the epiphytic diatom communities decreases in the following sequence: Amur Bay — Ussuri Bay — Stark Strait. As reported in literature, the nitrogen and phosphorus enrichment of the above-mentioned water areas decreases in the same sequence [Zvalinsky et al., 2013]. A relationship existing between the relative number of epiphytic diatoms and the level of trophicity of their habitat is assumed. Possible variants of relationships of the model coefficients with the trophicity level, including the necessary point (X = 0, Z = 0), are considered. Trophicity has proven to regulate all parameters of the multistep recurrent models describing the relative number of epiphytic diatoms. A generalized recurrent model for regulation of the relative number of epiphytic diatoms has been built; in this model, a regulating (trophic) factor is added to two limiting factors (photosynthetically active radiation and oxygen). A study of the model has shown that the trophicity level influences the interannual dynamics of the relative diatoms’ number and the duration of communities’ existence.

Interannual variations of the ice cover in the Tatar Strait are analyzed for the period from 1882 to 2018 and compared with the ice cover dynamics in the Okhotsk Sea. Synchronicity of the ice cover long-term oscillations in these regions is noted for the periods of 1894–1920 and 1985–2009, but it is not statistically significant for the whole time series. Current trend to the ice cover decreasing began in the Tatar Strait 5 years later than in the Okhotsk Sea. Besides, the cases of extremely low ice cover were observed in the Tatar Strait along the whole period of observations, whereas were happened in the Okhotsk Sea only in the period of warming since 1990s. Possible influence of the Amur River runoff on the sea ice forming in the Tatar Strait is discussed.

Environmental conditions in the Razdolnaya/Suifen Estuary and adjacent marine area were monitored from 2008 to 2018, by seasons, including winter observations in January 2014 and January 2018. The river discharge in winter was low: 6 m3 /s (mean annual discharge is 73 m3 /s). The estuary was covered by ice. The cline of salt water at the bottom was traced upstream up to 28 km from the river mouth. The currents in the estuary changed in tidal cycle. Increasing of salinity and temperature (> 2о ) at the bottom was observed in the distance 20–24 km from the river bar (this area was distinguished by relatively thin ice, 20 cm, against 40–70 cm in the rest of estuary). Modeling of the water balance in the estuary showed an additional source of salt water in the internal estuary, beyond the direct exchange with the sea over the river bar, that was presumably the water flow through the aquifer. This groundwater discharge was responsible for supporting of the salted bottom layer and for temperature and salinity increasing in the internal estuary during the ebb phase in conditions of limited water exchange by two-layered estuarine circulation because of ice cover at the river mouth.

Structure and quantitative indices of macrobenthos, features of its distribution along the river bed, and basic communities of macrobenthos are described for the crenal and rithral zones of the Dagi River (northeastern Sakhalin) on the data collected in the expedition of Sakhalin State University in September 2017. Five river landscapes are described: 1) plain riverbed with significant alluvial forms; 2) mountain riverbed with significant alluvial forms; 3) plain riverbed with weak alluvial forms; 4) wellhead zone of a plain riverbed with significant alluvial forms; 5) estuary. The main elements of the river bed are partially mixed in the middle stream: the mountainous landscapes with significant alluvial forms are overlapped with the plain landscapes with weak alluvial forms. Distribution of macrobenthos along the river bed and the types of bottom communities are clearly corresponded with the river landscapes. So, the macrobenthos distribution in the Dagi River is physically controlled: the species diversity and abundance of macrozoobenthos increases downstream from the crenal to the rithral zone and further to the combined rithral-potamal zone. A significant increasing of the biomass is noted in the middle and lower rithral zone due to aggregations of freshwater pearl mollusc Margaritifera dahurica which confine with the spawning grounds of pacific salmons. The most common are the bottom communities of Hexatoma and Gammarus lacustris, which are noted almost in all surveyed areas. Other bottom communities are landscape-specific. In the rithral zone, composition and structure of macrobenthos are determined by distance to the riverbank, type of bottom sediments, flow velocity, and lithodynamic regime, so the communities form a consequence determined mainly by lithodynamic regime — the Hexatoma community in the lithodynamic zone of transportation could be followed either by the communities of Trichoptera, Plecoptera, and Diptera in the lithodynamic zone of erosion or by the communities of amphipods G. lacustris and larvae of day-flies Ephemera sachalinenesis in the lithodynamic zone of accumulation.

Contamination of bottom sediments in Peter the Great Bay is spatially variable, but for majority of stations it exceeds the natural geochemical background and «safe» level with at least one pollutant, mainly with hydrocarbons, pesticides, cadmium and mercury. The main sources of contaminants are the waste discharge of Vladivostok and other cities (oil products, pesticides, phenols, heavy metals: Cd, Cu, Hg, Pb, Zn) and rivers fall into the northern parts of Amur and Ussuri Bays (Co, Mn, Ni, Fe). The Golden Horn Bay and the Bosphorus East Strait are the most polluted areas, where concentrations of both heavy metals and hydrocarbons exceed the natural background and «safe» level considerably. The Amur Bay has moderate contamination, and the Ussuri Bay is contaminated slightly. Recently the chemical contamination and eutrophication are the main factors that determine the ecological status of bottom populations, though the former one is valid locally, in the most contaminated areas only.

Results of cherry salmon juveniles rearing at Reidovo fish farm on Iturup Island during two annual cycles of cultivation are analyzed. Different variants of the breeders selection, feeding, preventive treatment, and release were tested. The breeders were caught in the river mouth and near the fish farm. Mass mortality of young fish in the first and second years was avoided by decreasing of their density and other preventive measures. Minced fish was used as a food for them that is less expensive in compare with a combined fodder. The best diet for the second year of rearing was the minced pink salmon with the daily ration of 2 % of the juveniles body weight; it provided a significant decrease of mortality and enhanced their growth. After 2-year rearing, percentage of females, anadromous males, and dwarf males was 42.1, 36.3, and 21.6 %, respectively. Their weights were similar, though a group of fast-growing males was found among the dwarfs. The mass of ovaries varied from 13 to 46 mg in close dependence on females’ body weight (r = 0.81). Before the release, the ovaries of all females contained oocytes of similar size (varied in 2–4 times) at the final stage of previtellogenesis. Number of the oocytes per transverse section varied from 4.7 to 32.3, on average for 5 cuts and their diameter varied from 164.3 to 279.2 mm and did not correlate with the females body weight. The mass of dwarf males’ testes varied from 14 to 488 mg in dependence on their body weight (r = 0.78). The elder oocytes of females would mature in a year, and majority of dwarf males would reach the maturity in autumn of the current year.

Composition of fatty acids of lipids in muscle tissue of chub mackerel is determined, in dependence on its body size. For the small-sized mackerel (< 20 cm), the lipids content is evaluated as 8.5 ± 0.5 % of the body weight, whereas for the large-sized fish (> 20 cm) it is 23.2 ± 1.2 %. The lipids of mackerel are distinguished by high portion of phospholipids that reaches 14.9 % for the small-sized fish and 8.4 % for the large-sized fish. The portion of unsaturated fatty acids is 74.5 % for the small-sized fish and 77.5 % for the large-sized fish. The portions of monounsaturated and polyunsatuarted fatty acids are 34.5 % and 36.2 % for the small-sized fish and 37.9 % and 36.6 % for the large-sized fish, respectively. The main part of the polyunsaturated fatty acids (85.0–86.2 %) is represented by the fatty acids of family n-3, among which docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids dominate; stiоridovoic fatty acid of this family (18:4 n-3) is presented, as well, that is essential for a human organism functioning. High biological value is determined for the lipids of chub mackerel, taking into account their chemical composition. Daily demands of an adult human body for these valuable unsatuarated fatty acids could be satisfied with 100 g of meat of chub mackerel, irrespectively on its size.

The main trends in fisheries are considered by the fishery basins, including dynamics of annual catches and changes in their structure, both for inland and marine areas, on the data of fishery statistics for 2005–2017. The landing in the inland waters of Russian Federation is estimated as 8.4–10.0 % of the total national annual catch. Its mean annual volume for this period was 375.103 t; it grew on average in 2.2 % annually. This volume was landed mainly (85 %) in four inland basins: Volga-Caspian, Far Eastern, Azov-Black Sea, and West Siberian ones. About ⅓ of the volume was provided by cultivated fish, in particular in the Azov-Black Sea basin (87 % of the total freshwater catch) and Northern basin (69 %). Marine fishery produced 2990–4644 . 103 t, or 90.0–91.6 % of the total Russian catch. Its annual landing has increased by more than a half since 2005, with the average growth in 3.7 % annually. This volume was landed mainly within the exclusive economic zone (EEZ) of Russia — 74.7 %, the rest was landed in the neutral areas of the World Ocean (5.9 %) or in EEZ of foreign states (19.4 %). The main region of marine fishery is the Far-Eastern basin, which portion in the national catch increased in 13 years from 62.6 % to 68.7 %, whereas the portion of the Northern and Western basins decreased in 3.7 % (to 21.5 %) and 3.0 % (to 7.9 %), respectively. In the Far-Eastern basin almost whole catch was landed within EEZ of Russia (3149 . 103 t), though in the Northern and Western basins the catch was obtained mainly in EEZ of foreign states (on average 557 . 103 t and . 103 t, respectively) and beyond EEZ (116 . 103 t and 94 . 103 t, respectively). Influence of the export supplies on the fish supply to the domestic market of Russia is analyzed. The landings increase contributes to the export increasing, but other factors are likely to be the main drivers of the export growth. This information on quantitative structure of the national annual catch could be used in economical forecasts and for developing of programs and strategies for the fishery industry of Russia. Examples of its practical using for solving of some applied problems in the economics are presented.

The review started in 195 volume of «Izvestiya TINRO» is continued. The most important aspects of a new concept of adaptive zone are illustrated on cited data and results of trawl and plankton surveys collected by Pacific Fish. Res. Center (TINRO) in the FarEastern Seas and North Pacific for several decades. Practical benefits of this concept are shown and prospects of its further application are outlined, as managing of fishery and aquaculture and some issues of agriculture, forestry, hunting, natural nidality, fighting against alien species, weeds, pests and parasites, environmental protection and preservation, and artificial ecosystems creation.

Lukyanova Olga Nikolaevna (18.01.1957 — 16.01.2019).