Dynamics of stocks is considered for pacific salmons in the North Pacific in 1925-2015 on the data from Russia, Japan, Canada, and the USA. The mean body weight dependence on the stock values and global air and sea surface water temperature is examined and evaluated by means of multi-dimensional regression analysis for the period 1961-2015. For many cases, interannual dynamics of the mean body weight depends strongly on combined effect of the corresponding stocks fluctuations and change of the global temperature anomaly index for the North Hemisphere: the multiple regression coefficient is R > 0.6 for 40 % of the tested time series. The highest correlation is found for chum and chinook salmons from Russia, pink and chinook salmons from Alaska, chum and sockeye salmons from Canada, and pink and chum salmons from Washington, Oregon, and California (Japanese data on body weight aren’t analyzed because of drift nets selectivity). Dominant predictors correlate negatively with the body weight for all species. Contribution of the global temperature index prevails for approximately 70 % of the rows. The stock is more important for pink and sockeye salmons from Russia and Alaska and in the former case the temperature index has positive correlation with the body weight. The relationships do not reflect direct influence of stocks or temperature on the weight but are presumably based on adaptive response of the populations to changes of feeding conditions for optimization of the stocks. This mechanism is confirmed by such temporal pattern as sub-trend dynamics typical for fluctuations of the salmons mean body weight, that means that this parameter demonstrates a tendency to long-term increasing or decreasing, changing periodically. Recent level of the body weight and catch indicates sustainable feeding conditions for pacific salmons in the North Pacific, at least in the last two decades, that unfortunately cannot be confirmed for the whole region by direct observations.

Gametogenesis of rock sole Lepidopsetta polyxystra and its annual cycle of reproduction are described in details. In the reproductive cycle, gonads of its males and females pass a number of stages characterized by certain qualitative and quantitative composition of sexual cells, their sizes, and the size, weight and structure of sexual glands. Detailed description of all these stages is presented on anatomic, microscopic and histological levels. Stage II (immature) - gonads have small size, their anatomic differentiation is completed, sexual accessory is distinct, female gonads have predominantly unyolked oocytes with various degree of development. Stage III (maturing) - gonads are increased in volume and well appreciable, female gonads are basically filled with unyolked oocytes but have a portion of yolked oocytes maturing to forthcoming spawning, spermatogenesis in male gonads becomes more active. Stage IV (prespawning) - active accumulation of yolk in female gonads, spermatogenesis in male gonads is finished. Stage V (spawning) - gonads achieve their maximal sizes, mature oocytes after hydration move into ovarial cavity in female gonads, streams of sperm are clearly allocated on histological cuts of male gonads. Stage VI (postspawning) - gonads are flabby with a number of hematomas, female gonads tissue includes unyolked oocytes of following generation, postovulatory follicles and atretic cells, new generation of sexual cells forms in male gonads. On results of the histological analysis, a separate stage II-III is proposed for mature first-spawning females of rock sole, which will not spawn in the next year. Each set of the histological features of gonads corresponds to their certain external condition, easy diagnosed visually. The described signs can be generalized in the maturity scale for rock sole.

The gonad maturity scale for rock sole Lepidopsetta polyxystra is presented in tabular form. Its reproductive cycle is described on the base of histological studies and analysis of seasonal occurrence of the species individuals with gonads at certain stages of maturity, in comparison with dynamics of the gonad-somatic index. Four phases are determined in the reproductive cycle. The first phase continues until the start of sexual cells maturing in the age 4-5 years (maturity stages I and II) - these juvenile fish live in the coastal shallow waters and are practically absent in trawl catches. Other three phases repeat annually. During the second phase, the rock sole gonads restore after previous spawning (stage VI) and begin the maturing for the next one (stage III, with yolked oocytes appearance in female gonads). This phase continues 8-9 months, usually from March to November-December and associates with active feeding when fish refill their energetic losses. The third phase is the time of fast maturing of gonads (stage IV, with active yolk producing and accumulation in oocytes and mass forming of spermatozoids) during wintering, when accumulated energetic resources are transformed to maintenance of the reproductive system. This phase starts from the moment of divergence between the reserve and reproductive funds of sexual cells in female gonads and continues 2-3 months. The fourth phase is the spawning (maturity stage V). It continues 1.0-1.5 months, usually with the peak of spawning in April.

Abundance and structure of feeding aggregations of chum salmon are analyzed on the results of the otoliths processing sampled in different areas of the Okhotsk Sea in 2011-2014 and scheme of their autumn migrations in dependence on the sea surface temperature (SST) patterns, using the data on catching the fish with the otoliths marked in hatcheries. The migrations were similar for all chum groupings from the Okhotsk Sea and adjacent waters: their juveniles moved to Kamchatka coast until SST decreasing to 11^оС in October, where they formed mixed aggregations, then density of the aggregations increased until SST 9-10^оС, after that the aggregations moved to the central part of the sea and further southward passing the Kuril Straits in November under SST 7-8^оС. The portion of marked fish from hatcheries in mixed catches was 2.1-7.8 % (on average 3.9 %). Taking into account these values and the ratio between marked and non-marked fish for certain hatcheries, the ratio between wild stocks and hatchery release of different origin is determined. The portion of chum salmon from Japanese hatcheries is estimated as 9.6-41.6 % (on average 27.3 %), the portion of chum from Russian hatcheries is considerably lower - 0.5-2.6 % (on average 1.2 %), and chum salmons of natural origin dominate in all years with the portion 55.8-89.9 %. For the fish of artificial origin, the ratio between the number of juveniles feeding in the sea and their release from hatcheries is estimated as 3.0-4.2 % (on average 3.6 %) for Japanese hatcheries and 0.3-0.7 % (on average 0.5 %) for Russian hatcheries. So, survival of chum from Japanese hatcheries is higher in 8 times on average, and total abundance of the feeding artificial chum salmons of Japanese origin is higher than those of Russian origin in more than 20 times. However, the hatcheries in Sakhalin and Kuril Islands has similar efficiency as Japanese ones, in opposite to other areas. The abnormally low estimations of the efficiency for some Russian hatcheries allow us to suppose that the otolith marking program is not realized correctly in some regions of Russian Far East, possibly the marks don’t correspond exactly to the schemes of marking.

Comparative analysis of the greenland turbot otoliths (sagitta) is realized on the materials collected in the western Bering Sea within the Russian EEZ (2005-2015) and in the eastern Bering Sea within the United States EEZ (2013-2014). Software package «Shape V.1.3» is used. The otolith shape and some other biological parameters of turbot are considered. Typical forms of the otoliths are described. The otoliths of turbot from the Anadyr Bay are significantly different (p < 0.001) from those from other areas following to MANOVA and PERMANOVA tests. On the contrary, the otoliths from the Olutorsko-Navarinsky and Navarinsky fishery districts are very similar. Beyond unique oceanographic conditions of the Anadyr Bay, the difference could be caused by partial mixing of the turbots in this area with the fish of American origin. However, following to scientific literature, the turbots in the Olutorsko-Navarinsky and Navarinsky districts are also mixed with the fish of American origin, so additional investigations are necessary to understand the reasons of the otolith shape differentiation. A hypothesis on intraspecific organization of greenland turbot in the Bering Sea is proposed.

Coastal fishery develops in Primorye since 1990s because of negative changes in the resources for Russian fishing industry in the deep-water sea. One of the way to optimize the fish resources usage is introduction of passive fishing gears, as fixed nets. Data of the fixed net control catches in the estuaries and coastal waters in the bays of southern Primorye obtained by Pacific Fish. Res. Center (TINRO) in 2011-2016 are summarized. Quantitative composition and species diversity of fish in certain areas are compared, taking into account their seasonal and interannual variability. The species composition is associated with specific physical and geographical features, so it is similar in the estuaries and bays with similar environments. Fish abundance is evaluated using the methodology adopted for fixed nets.

An overview of published and new estimates of zooplankton density and biomass in the Far-Eastern Seas and North-West Pacific with their daily, seasonal and interannual dynamics is presented on the materials of numerous marine expeditions conducted by Pacific Fish. Res. Centre (TINRO) in the 1980-2010s. The mean annual concentration of zooplankton (10³ ind./m³) in the epipelagic layer is amounted as 4.386 for the Bering Sea, 3.695 for the Okhotsk Sea, 6.842 for the Japan Sea, and 3.399 for the North-West Pacific, whereas its biomass (g/m³) - 1.079, 0.821, 0.626, and 0.800, respectively. Significant differences are shown for spatial distribution and temporal dynamics of the small-, medium- and large-sized zooplankton abundance and its daily vertical migrations in different areas. Zooplankton stocks in all these regions are evaluated as high; their bulks are formed by large-sized fraction. Interannual fluctuations of the zooplankton abundance could be considerable in certain areas, but its total resource within the Far Eastern basin does not change much: the abundance decline in some areas is compensated by its growth in other ones.

Cyclonic activity patterns over the North Pacific in fall-winter have changed prominently in the last two decades (since the middle 1990s) due to a gradual westward shift of the Aleutian Low and Siberian High. The maximum of cyclonic activity was observed in the eastern Bering Sea in the 1990s, but strong winter cyclones moved mostly to the Okhotsk Sea and Kuril Islands in the late 2000s. These changes caused the ice regime change: the ice cover was relatively low in the Bering Sea in opposite to heavy ice conditions in the Okhotsk Sea until the mid-2000s, but the ice cover decreased in the Okhotsk Sea and increased in the Bering Sea when tracks of cyclones had changed. Some changes concern the moderate latitudes, too, because cyclones in the Bering Sea made a cooling effect on the North Pacific area southward from Aleutian Islands but those in the Okhotsk Sea cool the Japan Sea area.

Seasonal dynamics of temperature and salinity at the standard depths is restored for the network of oceanographic stations on southeastern shelf of Sakhalin by the methods of statistical modeling (GIS Sakhalin Shelf) using the data base of ~40 years observations. Spatial fields of temperature and salinity are reconstructed by means of the oceanic model of the University of Bergen. Some new features of the oceanographic regime are revealed. Detailed annual cycles of temperature and salinity are determined for the first time that has allowed to calculate the mean month three-dimensional water circulation for all seasons, including the ice period.

The sea surface temperature (SST) variability in recent conditions of climatic warming is analyzed for coastal areas of the Okhotsk Sea on the data of regular observations on hydrometeorological stations in 1980-2016 and NOAA_OI_SST_V2 reanalysis data, taking into account the climate indices variations. The data series are analyzed using the methods of Empirical Orthogonal Functions (EOF), cluster analysis and correlation analysis. The SST fluctuations with period of 2-5 years prevailed in the year-to-year variability on the background of longer cycles and irregular changes with three periods of different thermal regime: cold (1977-1987), transitional (1988-2003), and warm (2004-2016). These periods were observed for the whole sea area and coincided with similar changes of the air temperature and sea ice. A tendency to warming was the most noticeable in the last 15 years when the average growth rate of mean annual SST was 0.17^oC per 10 years, with 1.5-2.0 times higher values for some stations. The positive SST trend in summer was approximately twice higher than in winter; the trend increased 3-fold from northern to southern areas of the Okhotsk Sea. The trend contributed 46 % of the mean annual SST dispersion. Large-scale process of the SST regime changing is described by the first EOF mode and could be parametrized by PDO, NPI and OKH climatic indices.

Composition and distribution of macroepibionts on scallops Swiftopecten swiftii, Mizuhopecten yessoensis and Azumapecten farreri (Pectinidae, Bivalvia, Mollusca) are investigated in 13 shallow-water areas at southern Primorye. The epibionts were collected from the upper and lower valves of living specimens of scallops in 1979-2016. The scallops (1150 specimens in total) were sampled by divers from natural and cultured dense populations of the mollusks. The depth and the type of bottom substrate were determined at each station. The sample size ranged from 10 to 72 individuals of scallops. All epibionts were removed from scallop shells, then fixed with 4 % formalin and preserved in 70 % alcohol, except algae; the algae were dried on air or frozen. The sampled macroepibionts were identified to species level and counted, except of amorphic encrusting organisms as hydroids, bryozoans and algae. Occurrence of boring polychaetes and sponges were determined by presence of the drilling traces. For common epibionts, the settlement density and biomass were determined for each scallop, mean values of these indices were calculated for entire sample, taking also into account the scallops without epibionts, then the biomass and density were recounted by a square decimetre. The epibionts were categorized into four groups, as the dominant, subdominant, typical, and others, with the biomass > 45 %, 15-30 %, 5-10 %, and < 5 %, respectively. The mean total biomass of epibiosis varied from 0.15 to 35.52 g/dm², and the settlement density - from 1 до 220 ind./dm². Mollusks, polychaetes and algae prevail in the most of areas both by the species number and occurrence. The highest biomass of crustaceans and polychaetes is recorded in suspended culture of M. yessoensis in the Ussuri Bay. High biomass of cirrepedes is recorded in natural populations of M. yessoensis and A. farreri at Vladivostok and in natural settlement of S. swiftii in the Vostok Bay. High biomass of polychaetes in epibiosis of M. yessoensis is recorded in the mixed settlement in the Posyet Bay and in natural polulation in the Nakhodka Bay. Mean total biomass and settlement density are generally higher in polluted and eutrophic areas where the most of epibionts (algae, cirripedes, serpulid polychaetes, oysters, bryozoans, ascidians) evidently suffer from siltation and prefer to attach to barnacle shells, dead or living, which are raised above the surface of scallop shells submerged into silt. Barnacles and serpulid polychetes dominate in these communities. In pure areas, as the southwestern Peter the Great Bay, the mean total biomass and settlement density of epibionts are lower. Macroalgae, bivalve and gastropod mollusks dominate by number and form the bulk of epibiosis biomass there. In on-bottom plantations of M. yessoensis where the scallops lie on the ground usually on the lower valve, the macroepibionts preferably colonize the upper valves of shells. In suspended plantations of this species, the total biomass of epibiosis is on average 10 times higher in comparison with on-bottom plantations; polychaetes, macroalgae (mostly Rhodophyta), crustaceans and ascidians are common epibionts there. In mixed settlements of M. yessoensis , the epibioses are the most diverse and abundant - the main taxa there are Polychaeta, Algae, Porifera and Mollusca; their total biomass is measured in grams per dm². In natural scallop populations of M. yessoensis, the epibiotic communities are formed mainly on the upper valves of shells, but the epibioses have multilayer structure. Barnacles, polychaetes and bivalves are the basic epibionts for native M. yessoensis in polluted areas, but macroalgae, bivalves and gastropods - in pure areas. Infestation of scallop shells by boring polychaetes Polydora spp. and Dipolydora spp. increases with silting of bottom sediments from 27 to 100 %. Biomass of Cirripedia increases in epibiosis of native M. yessoensis to tens of grams per dm². Composition of epibionts on scallops A. farreri and S. swiftii is investigated for the first time in 2 and 1 areas of southern Primorye, respectively. The epiobioses of A. farreri include 6 groups of animals (Porifera and Bryozoa as the basic ones) and S. swiftii - 4 groups (basically Bryozoa and Polychaeta). A. farreri and S. swiftii in their natural settlements often attach themselves to oyster or mussel druses and so they have different orientation in the near-bottom layer. Therefore, epibiotic communities could be formed both on the lower valves and upper valves of their shells. In opposite to M. yessoensis , cirripedes and polychetes never dominate in epibiotic community of A. farreri and S. swiftii . The epibiotic flora of three scallop species has 87 species, including 49 red algae, 16 brown algae, and 22 green algae. The red algae only (9 species) are recorded on the valves of S. swifti . 16 algal species are found on the valves of A. farreri : 13 red, 1 brown, and 2 green algae. Rhodophyta dominate in terms of species number in the epibiosis of M. yessoensis , except of its natural populations in the Nakhodka Bay where 50 % of algal species belong to Chlorophyta and in the Vostok Bay (41 %) and also suspended culture in the Ussuri Bay (41.5 % of Chlorophyta species). Brown algae have the maximum species number in the epibiosis of the natural scallop population at Vladivostok (28.5 %) and on-bottom culture in the Posyet Bay (27.0 %). Besides of the species and habitat differences, composition of epibioses depends on age of scallop and depth.

Rivers are the main source of terrigenous nutrients to the coastal sea which could be responsible for such adverse impacts as red tides or hypoxia in the estuarine areas. To evaluate the rivers influence on chemical environments in the coastal zone, monitoring of water properties in the rivers of southern Primorye was conducted in 2016 (and continues till nowadays). Retrospective data of chemical measurements on the Razdolnaya, Artemovka, Knevichanka and Ryazanovka rivers in different seasons of 1985 were used for comparison with modern data. Prominent seasonal dynamics of chemical parameters is revealed that generally corresponds to seasonal changes of freshwater discharge caused by monsoon cycle of precipitations. The seasonal dynamics of water temperature is conditioned by climate features of the region and geographic location of the rivers: the temperature at the surface is about 0^оC in February, then rises in spring-summer and decreases in autumn, with the maximum values in August as 26-27^оС for the flat rivers and 18-20^оС for the mountain rivers. The pH variations are conditioned by the carbon dioxide saturation in water, so its level is 6.1-7.2 in winter and 7.4-8.2 in summer. Nutrients, except iron, have the maximum concentration in winter (DIN ~2.5 µM/L, DIP ~0.5 µM/L, silicates ~115.0 µM/L) but the iron concentration is the highest in spring (~0.1 mg/L). However, natural seasonal variation of nutrients is distorted by anthropogenic load for some rivers with industrial and agricultural activity in the basins, including the territories of P.R. China (Suifen/Razdolnaya River): their waters are the richest by nitrogen and phosphorus in summer (DIN ~45.0 µM/L, DIP ~0.5 µM/L) and by dissolved iron in autumn-winter (~0.9-1.3 mg/L). Spatial variability is very similar between all nutrients in any season (correlation coefficients between DIN and Fe concentrations are 0.75-0.99, between DIP and Fe - 0.83-0.99) that means that their growth in the polluted rivers has common nature, presumably a decomposition of organic wastes Being transferred. Transferred to the sea, the nutrient elements of terrestrial origin are converted back to organic matter enhancing the coastal waters productivity, but consequences of this impact are principally different for the natural regime with the winter-spring maximum and for the distorted regime with the summer-fall maximum. Huge oxygen demand determines the lowered DO in the Suyfen/Razdolnaya and Knevichanka in winter. Other rivers of southern Primorye (Ryazanovka, Barabashevka, Kievka, Partizanskaya, Sokolovka, Artemovka) could be considered as «clean» ones, following to Russian standards of water quality. Seasonal variability of oxygen content in their waters is driven by changes of water temperature and photosynthesis. Comparison of the long-term changes in water quality for the rivers Razdolnaya, Artemovka, Knevichanka and Ryazanovka over the last 30 years (relative to 1985) has revealed unfavorable changes of dissolved oxygen content for the Razdolnaya and Knevichanka, whereas the changes are not significant for the Artemovka and the oxygen content has increased for the Ryazanovka. The latter indicates the Ryazanovka water quality improvement that is important since a fish farm is located on the river.

Needs for artificial food for salmons considerably increase recently because of foundation of new salmon hatcheries and reconstruction of existing hatcheries in Sakhalin, Kamchatka, Primorye, and Khabarovsk and Magadan regions. In conditions of shortage of Russian-made mixed fodders of high quality and urges toward substitution of imported fodders by domestic ones, highly productive fodders for salmons should be developed using modern scientific knowledge and industrial technologies. Fermented pastas on the base of raw pollock and wastes of other fish processing (chum salmon, saury, herring) are presented as components of mixed fodders for juvenile salmons corresponding by their quality and safety to nutritional requirements of juveniles. Recipes of starting fodders for farming of salmons are proposed with 6 % and 10 % of dry fermentolyzate of these raw materials. These experimental fodders are successfully tested in conditions of salmon hatcheries. The mixed fodder B-1-6 % has lower content of protein (38.5 %) but higher content of lipids (14.5 %) and carbohydrates (37.5 %), as compared with the B-1-10 %, its amino acid composition corresponds to the needs of chum salmon. In the experiments, the feeding coefficients of the experimental fodders (0.64-0.86) were better than those of the fodders Aller Aqua (Denmark) and Dalkorm (Russia) with feeding coefficients 1.00 and 1.44, respectively. The fodders Aller Aqua and Dalkorm caused some pathomorphological changes in digestive system of juvenile chum salmon that reduced quality of juveniles and impeded their growth; the experimental fodder with 6 % of dry fermentolyzate caused mild lipoidal degeneration of liver in reversible form for 15 % of the examined juveniles, but this pathology had no significant effect on quality of the released juveniles. Introduction of high-protein dry fermentolyzate to mixed fodders allows to reduce the portion of fish flour without reducing quality of their protein component, herewith the juveniles vitality increasing.

Lipid fatty acids composition for muscle tissue of pacific saury is determined in dependence on the fish body size. The percentage is 40.97 % of monounsaturated fatty acids and 34.20 % of polyunsaturated fatty acids for small-sized fish and 43.87 % and 31.09 %, respectively, for large-sized fish. The summary content of EPA and DHA is 2.30 g per 100 g of muscle tissue for small-sized fish and 3.77 g/100 g for large-sized fish. Decreasing of the omega-3 fatty acids content in the process of the canned food sterilization does not exceed 5.2 % of the initial amount. The saury of various size could be processed to the canned goods of pate type that excludes the fat losses in the process of broth and fat separation under high temperature. The portion of omega-3 polyunsaturated fatty acids in the canned food from saury is 42.1-46.7%, with average content of EPA and DHA 1.73-2.71 g per 100 g that corresponds to daily requirements of human organism.