Complex method of quick quantitative evaluation of the spawners escapement to the Kamchatka River is developed for pacific salmons on the base of analysis of their passing dynamics through certain parts of the river (main stream, tributaries, spawning grounds). The runs of different temporal forms of anadromous salmons were separated taking into account their biological parameters using the data of biological analysis of commercial catches in Ust-Kamchatsky district. The spawners abundance was evaluated from CPUE value for the main stream where control catches of spawners were made in the periods predetermined for escapement, and directly using two duplicate hydroacoustic complexes for the tributary important for salmons reproduction or visually from ashore, boats, or flying vehicles for other tributaries. These data were coupled with general assessments of the escapement values in the river basin from helicopters. Numeral model was developed to evaluate the salmons escapement to the spawning grounds. The escapement dynamics was simulated retrospectively for sockeye, chum and coho salmon in 2016 and 2017. The method was successfully used for fishery management in the fishery campaign of 2018. Efficiency of the fishery regime was estimated using this approach. The value of sockeye salmon escapement was determined as enough for medium reproduction, and the values of chum and coho salmons escapement — as enough for medium or high reproduction. For chinook salmon, the model was not tested, but the method of control catches was developed and applied as a part of integrated methodology for quantitative operational assessment of escapement.

Chum salmon in the Amur River basin are represented by two races: summer and fall ones. For the summer race, one population with specific type of spawning grounds is known, but the fall race includes three populations with different types of spawning grounds. In total, four eco-geographical groupings of the species are separated in their reproduction by geographical boundaries of geomorphological zones, as well as temporally and ecologically. Chum salmon do not spawn in the Chinese part of the Amur basin in more than 50 years. In the Russian part, the summer chum salmon spawn completely in the hyporheic waters in late July — August, the major grouping of fall chum (77.1 %) spawns in the spring waters in September-November, other two groupings spawn in the hyporheic waters of the lower Amur in September (20.4 %) and in the spring waters of the lakes near the Amur mouth in October-November (2.5 %).

Recent changes of the main oceanographic, chemical, and biological parameters of the Okhotsk Sea ecosystem are considered briefly for the last decades (2000–2010s), mostly on the data obtained in marine expeditions conducted by Pacific Fish. Res. Center (TINRO) annually. Since the mid-2000s, anomalous oceanographic conditions were formed there with prevailing heightened temperature in all layers of the sea and lowered ice cover caused by changes in the atmosphere circulation with northward shift of cyclones tracks in winter and weakening of winter monsoon. The ice cover was below the normal value every year since 2004. In the warmer winter conditions, producing of the high-density water on the northern shelf decreased from 3.2–7.8 . 103 km3 in 1998–2002 to 1.2 . 103 km3 on average in 2004–2015, and the water with density sq > 26.8 was not formed at all in 2007–2009, 2011, and 2014–2015. As the result, winter convection, including the slope convection, became weaker and shallower and ventilated worse the water column, so dissolved oxygen content decreased in the lower portion of the intermediate layer, usually ventilated by slope convection. For the core of the intermediate layer (isopycnal surface 27.0 σθ), positive trend of temperature is estimated as +0.04…+0.16 o/decade, by areas, while the trend of dissolved oxygen content is negative: –0.07…–0.14 mL/L.decade, by areas. From the other hand, spring phytoplankton bloom became less intensive, presumably because of poorer upward flux of nutrients in conditions of weaker vertical mixing, and zooplankton biomass decreased, particularly for phytophages. However, these changes did not cause significant response in fluctuations of stocks for the main commercial fish and crab species. The largest stock of walleye pollock had cyclic fluctuations driven mostly by intra-population regulations, the stocks of pacific herring were rather stable, and the stocks of deep-water fish species, as flounders and halibuts had a slight tendency to growth, possibly because of better conditions for reproduction. Indeed, the densest aggregations of greenland halibut shifted from the depth of 600–700 m to 500–600 m that may be caused by de-oxygenizing of the lower portion of the intermediate layer. Crabs abundance also had positive dynamics obviously because of the effect of protective measures for red king crab in the 2009–2012, though its biomass continued to grow even after restoring the commercial landings. There is concluded that recent changes in the macroecosystem of the Okhotsk Sea correspond to the conception of the sub-polar ecosystems transformation under climate warming toward decreasing of their productivity and increasing of their functioning efficiency that was proposed earlier for the Japan Sea. Thus, from position of commercial exploitation of marine biological resources, the modern reconstruction of the Okhotsk Sea ecosystem under the climate change impact could be considered as a positive process.

Critical analysis is done of the main conclusions in the article published by Yury Zuenko and co-authors in this issue of «Izvestia TINRO» journal about changes in the Okhotsk Sea biota in 2008–2018. In that paper, a continuing warming in all layers of the sea is shown quite convincingly, but weight explanations of the observed changes in marine communities and commercial stocks are not offered. Moreover, the authors ignore results of long-term studies of the Okhotsk Sea bioresources conducted from ecosystem positions. From this alternative point of view, some integrated quantitative data on dynamics of zooplankton, zoobenthos, fish, and other biota in the Okhotsk Sea are presented, as well as the schemes of organic matter and energy flows through trophic networks that show a normal functioning of the Okhotsk Sea ecosystem at the present time. On the base of these data, doubts are claimed in correctness of Zuenko’s concept of the ecosystem restructuring in direction to lower productivity and higher efficiency of its functioning.

Discussion about limiting influence of climate conditions on dynamics of the pacific salmon populations and generally on biological resources of the Far-Eastern Seas is continuing. Multifactor impacts of climate and oceanographic conditions on populations and communities are concluded that cannot be described only by climatic indices and anomalies of the surface water temperature in the ocean in winter. Dynamics of the fish and invertebrates populations in various regions of the Far-Eastern Seas show a positive effect of climate warming on state and sustainability of the resource base for fisheries.

Landings of manila clam Ruditapes philippinarum were steady high in 2010–2016 and exceeded the recommended volume that caused deterioration of its resources in the areas of large aggregations. Any significant growth of the clam colonies in the surveyed area could not be expected in the nearest future because of continuing press of fishery. Total stock of Ruditapes philippinarum in the Aniva Bay is estimated as 240 t, including 203 t of clams with commercial size.

Some biological parameters of the local group of rеd king сrаb in the Dalnezelenetskaya Bay (Barents Sea) are determined in summer 2013. The large-sized mature сrаbs with the carapace width > 100 mm prevailed in scuba diving catches, with equal proportion of females and males. The females with violet eggs dominated among the egg-bearing females. Barren females were not caught. Percentage of the limbs injuries was 62 % that was lower than in the previous year. Total stock of red king crab in the bay was assessed as 4750 individuals. Significant increasing of the large-sized males abundance is noted that corresponds with general growth of their stock in the Barents Sea after the ban on the species fishery within the 12-mile coastal zone in 2011.

Tanner crab Chionoecetes bairdi is the highly valuable object of commercial fishery dwelling in the seas surrounding Kamchatka Peninsula. Its landings started at the southeastern coast of Kamchatka in early 1980s and continued till 2009, when the fishery was stopped by reasons independent on the stock state. It was launched again in 2017. Now the species is landed mostly in the Petropavlovskaya fishery subzone (62 % of the total allowable catch of tanner crab in Russia in 2019), whereas its stocks at southwestern Kamchatka and in the northwestern Bering Sea are rather low. Modern condition of the tanner crab population and its distribution at southeastern Kamchatka are considered on the data of the trap surveys conducted in spring and summer of 2012 and 2018. Between these years, commercial males of these species spread wider at southeastern Kamchatka and formed commercial aggregations in the northern Avachinsky Bay and in the southern and central parts of the Kronotsky Bay, but were rare southward from Cape Povorotny. They became larger: while size of the males varied in the range 50–170 mm in both years, the males with the carapace width < 120 mm prevailed in 2012, but the large-sized males with commercial size were more numerous in 2018. Percentage of the females in the catches was low both in 2012 and 2018 that is typical for the trap catches. The crabs at the 3rd stage of molting dominated both in May and August of 2012 and 2018. Injury level of the commercial males was rather high and increased from 2012 to 2018 in 8 %. Good current condition of the tanner crab population at southeastern Kamchatka is concluded.

Powered paraglider using for local aerial surveys and observations on real seals is described in combination with routine watch from the coastal observation point and motor boat. The results of conventional and combined observations are compared.

New finding of rare fish species mirror dory Zenopsis nebulosa in Peter the Great Bay (Japan Sea) is described.

The main bioenergetic parameters of pacific salmons are presented on the data obtained in marine expeditions in 2003–2015. Among the examined species, the minimum energy content is registered in the muscle tissue of chum salmon and pink salmon, and the maximum energy content — in the muscles of king salmon. Total amount of the energy accumulated by juvenile pink salmon during its life within the Okhotsk Sea is estimated as 532 kcal or 27 % of the total energy accumulated in the whole marine period of its life, for juvenile chum salmon this amount is 492 kcal (11 %). The rest is accumulated by adults during their feeding in the ocean: pink salmon, without ranking by age and sex, gains in the North Pacific on average 1 442 kcal or 73 % of the total energy accumulated in the marine period of life, chum salmon — 4 071 kcal (89 %).

 Climatic indices reflecting the environmental conditions and patterns of their variability in the entire northern Pacific and in its local regions are overviewed. Their physical nature and mechanisms of the processes, their geography and methods of calculation are presented, with citing of the first descriptions. Among a variety of global and regional climatic indices concern ing the North Pacific, the following ones are described: the indices of Arctic Oscillation (AO), El Niño — Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Aleutian Low Pressure Index (ALPI), Siberian High Index (SHI), North Pacific Index (NPI), Pacific/North American (PNA) Index, and West Pacific Index (WP). AO is a large-scale index of atmospheric circulation reflecting the processes both in the troposphere and stratosphere, where «pumping» of air masses between the high and moderate latitudes occurs continuously. ENSO is also a large-scale index that reflects large-scale interactions in the fields of temperature, atmospheric pressure, wind, and cloudiness over the whole Pacific. Other indices are rather regional, since their influence does not extend far beyond the limits of the domains of their definition. Nevertheless, their role in environmental fluctuations in certain areas could be significant and their influence could be traced throughout the Northern Hemisphere.

Combined effect of cadmium (10, 30, and 50 mg/L) and salinity (32, 24, and 16 ‰) on marine unicellular alga Plagioselmis prolonga (Cryptophyta) is investigated. Such parameters as the cells number dynamics, their size, side scattering (as a characteristic of internal structure of cells), photosynthetic pigments fluorescence (chlorophyll a, phycoerythrin, allophycocyanin, as a measure of the photosynthetic apparatus function), and reactive oxygen species (ROS) content (as an index of the cellular membranes destruction) were registered in experiments using the flow cytometer CytoFLEX (Beckman Coulter). Addition of cadmium in concentration of 10 mg/L to the water with salinity 32 ‰ did not influence on alga growth and its physiological parameters. The higher concentrations of cadmium, as 30 and 50 mg/L, stimulated the cells growth and ROS increased under the concentration of 50 mg/L, but other parameters did not altered. The same contamination with cadmium under salinity 24 ‰ caused the cells size rising and their intensive growth, ROS increasing on 3rd day and decreasing on 7th day of exposition, and phycoerythrin and allophycocyanin fluorescence diminishing, but the side scattering and chlorophyll a fluorescence still did not differ from the control. Any concentration of cadmium in the water with salinity 16 ‰ caused the population growth inhibition, decreasing of side scattering and all photosynthetic pigments fluorescence, and increasing of ROS and cells size. There is concluded that cadmium contamination in conditions of normal (32 ‰) salinity has a stimulation effect on Plagioselmis prolonga growth and no effect on its photosynthetic apparatus, but the same contamination in conditions of lowered salinity has a negative effect on both its growth and photosynthetic functions, whereas the reactive oxygen species content increases and the cells become larger under the cadmium contamination regardless the salinity factor.

Morphology of phylonems infesting whitespotted char Salvelinus leucomaenis and sockeye salmon Oncorhynchus nerka in Lake Kisi at the northern coast of the Okhotsk Sea is described for the first time. Sockeye was infected with adults of Philonema oncorhynchi Kuitunen-Ekbaum, 1933 and larvae of other nematode species (Philonema sp. II), and char — with adult dracunculoid nematode designated as Philonema sp. I. This Philonema sp. I differs considerably from Ph. oncorhynchi by number of reproductive papillae, their distribution, and structure of cuticular appendices on the caudal end of males. Larvae of Philonema sp. I (1st stage) and Philonema sp. II (3rd stage) are described, as well. These new data allow to reconsider the species belonging of nematodes infesting chars (Salvelinus) in North-East of Russia, which are identified now mostly as Ph. oncorhynchi.

Yesso scallop Mizuhopecten yessoensis is the main object of aquaculture in Primorye with annual yield measured in hundreds ton. However, further development of its farming could be restricted by lack of the spat. Availability of the spat imported from China using for the scallop cultivation at the coast of Primorye is explored. The spat from Chinese hatchery located in Shandong province was supplied for one aquaculture company in Primorye in the volume of 660 . 106 ind. in 2018 and settled to hanging collectors (1000 ind. per bag), then to cages in the marine farm located north-eastward from the Moryak-Rybolov Bay. Survival and growth rate of the scallop juveniles were examined in early November 2018, when the water temperature was from 10.3–10.4 оС at the sea surface to 9.7–9.9 оС at the bottom, salinity was about 33.60 psu in the whole water column, chlorophyll a concentration varied in the range 0.4–0.8 mg/L with the maximum in the layer 8–24 m. The spat mortality during transportation was estimated as 15 %, but it increased to 56–90 % during its growing up in cages. This level of mortality is much higher than mortality of the spat collected from the coastal waters at southern Primorye. The highest mortality of artificial spat was observed for large-sized mollusks, whereas it was satisfactory for the small-sized ones. Possible reason of high mortality is too high density of juveniles and damaging of their soft tissues by other shells. The spat shells height did not exceed 5–10 mm in the collectors but increased during their growing in cages to 20–25 mm. This size is similar to the size of scallop growing from natural spat in southern Primorye. However, growth rate of the scallop growing at the Moryak-Rybolov Bay (2.0–2.7 mm/month) is lower than in Peter the Great Bay (3.0–3.5 mm/month) though higher than in the Vladimir Bay and Aniva Bay. Mean body weight of the cultivated scallop in November was 1.5 ± 0.1 g.

Seabirds interaction with trawl fishing gear was observed aboard the large freezing-processing trawler «Moskovskaya Olimpiada» during the pollock fishery in the Okhotsk Sea in January-April, 2015. In total, 579 observation rounds were realized including 105 ones during the trawl setting, 116 ones during hauling, and 358 ones during trawling, with total duration of 280.7 hours. In the observations, 1443 contacts of birds with the fishing gear were recorded. Light contact of a flying gull with the trawl net was observed in one case only; all other contacts were collisions with the wires. The warps and the depth sounder cable were the greatest hazard for birds. Collisions with the sounder cable during the trawling were the most frequent, with approximately 5 times higher frequency than with the same cable during the trawl setting or hauling. Almost all strikes with the wires were registered for northern fulmars (97.5 %) and the rest of the strikes — for large gulls. Gulls had only light contacts with the depth sounder cable (2 contacts afloat and 34 contacts in flight). Fulmars had contacts both with the depth sounder cable and warps. Flying birds of this species contacted with the depth sounder cable more frequently (75.5 %) than those sitting on the water. On the contrary, majority of fulmars (61.6 %) contacted with the warps being afloat in the process of their feeding. Several cases only (0.6 %) of direct interactions with the fishing gear caused the bird’s death. All these cases occurred with the fulmars drowned when they fell under the depth sounder cable (7 ind.) or under the warp (1 ind.). Frequency of the bird collisions with the wires differed prominently by the fishery districts, with the maximum in the Kamchatka-Kuril subzone (8.35 contacts/hour for fulmars and 0.22 contacts/hour for gulls). These spatial differences are related to the birds abundance near the ship that depends on distribution patterns of certain bird species in the Okhotsk Sea in winter. General frequency of the contacts depends credibly on intensity of the waste discharges after fish processing and on wind direction relative to the ship course.

Method of building of optimal Hamiltonian cycle is proposed for study of cyclic changes in species composition of macrophytobenthos in the Vostok Bay. Compiled lists of macroalgae and higher plants are composed for each month. Requirements for the species lists comparing are established. The optimal Hamiltonian cycles for the lists without permanent species are different from those for the complete lists because of higher values of the measures of difference, particularly in winter. The Sørensen–Dice coefficient, Jaccard similarity index, or equivalent measures are recommended to use for assessment of the differences between the species lists.