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A comparative morphological analysis has been conducted for antlered sculpins of the genus Enophrys from three remote regions: the Sea of Japan, the Sea of Okhotsk, and the Bering Sea. Variations in their body color pattern and also meristic and measurable characters have been analyzed. As the analysis has shown, antlered sculpins from the Sea of Japan differ significantly from the two other samples in their body color, some head proportions, and the size and location of the fins D1, D2, A, V, and P. Differences on the subspecies level (CD > 1.28) have been found for five of the studied characters and a hiatus (differences on the species level) for one character (depth of D1). The data we obtained confirm the previously published assumption that the fish from the Sea of Japan possibly belong to the species E. namiyei. [ABSTRACT FROM AUTHOR]

A comparative assessment of the contents of Fe, Zn, Cu, Cd, Mn, Pb, and Ni in the soft tissues of bivalve mollusks Mytilus trossulus, Mytilus galloprovincialis, and their hybrid forms from Minonosok Bay of Peter the Great Bay (Sea of Japan) has been made. No significant differences in the accumulation of Fe and Cd in the tissues of all studied groups of mollusks were found. It has been shown that the hybrid forms of these species had more intensive growth, and against this background they accumulated significantly lower concentrations of such metals as Cu, Mn, Pb, and Ni in their soft tissues compared to the parental species. A significant negative correlation has been found between the accumulation of these metals in the tissues of mollusks and the length and weight of their shells and whole soft tissues M. trossulus, which had a significantly lower weight of valves and soft tissues, differed from M. galloprovincialis in the accumulation of significantly higher concentrations of Zn, for which no relationship has been found between its content and all the studied size and weight characteristics. The conducted testing did not reveal any significant dependence of the accumulation of all studied metals, with the exception of Pb, in the tissues of mollusks on their condition index. The results we obtained indicate the need to take the above features of the trace metal composition of the soft tissues of the studied species into account when using them in monitoring environmental pollution with heavy metals. [ABSTRACT FROM AUTHOR]

The current status of Chlamys swiftii beds and resources of this species in the coastal waters of Primorsky krai, Sea of Japan, are assessed on the basis of data collected in 2007–2021. It has been found that scallops do not form dense aggregations sufficient for commercial harvesting. Scallop beds with the highest average biomass (22.5 ± 5.0 g/m2) are concentrated in the waters from Cape Povorotny to Cape Yuzhny; beds with the lowest biomass are in Peter the Great Bay (3.7 ± 2.1 g/m2). All beds have a mosaic pattern of distribution. The total stock of this scallop species is estimated at 1400 t; the commercial stock, at 1300 t. About 99% of the total stock in the coastal waters of Primorsky krai is concentrated in the area from Cape Povorotny to Cape Zolotoy. In these waters, the recruitment of juveniles to the stock has been found to be more regular and active than in Peter the Great Bay. The percentage of scallops of noncommercial size varies from 1.9 to 19.0%. The Ch. swiftii beds in Peter the Great Bay are dominated by individuals at age of 3–6 years with a shell height of 80–115 mm; in the area from Cape Povorotny to Cape Zolotoy, by individuals at ages of 3–7 years with a shell height of 70–110 mm. The modal age of scallops is 4 years, and the maximum age ranges from 7 to 12 years. [ABSTRACT FROM AUTHOR]

Rhizocephalan barnacle Parasacculina pilosella Van Kampen & Boschma, 1925, being a common parasite of the spider crab Pugettia aff. ferox Ohtsuchi & Kawamura, 2019, was founded for the first time on the crab Scyra bidentata (A. Milne-Edwards, 1873) (Brachyura: Epialtidae) in Peter the Great Bay (Russian waters of the Sea of Japan). Taxonomical identification of the parasite was made using morphological and molecular methods. [ABSTRACT FROM AUTHOR]

The taxonomic and quantitative composition of the meiobenthos, with an emphasis on foraminifera and gromiids were studied on the coast of Primorsky krai, northwestern part of the Sea of Japan, at water depths of 0.3–86.0 m. The Protozoa were evaluated for the first time in this region as a component of the meiobenthic communities. The protozoa are represented by four morpho-ecological groups: Ciliophora (free-moving and epibionts), both hard-shelled and soft-walled Foraminifera, and Cercozoa (class Gromiidea). The total abundance of the meiobenthos varied from 32 500 to 2 107 500 ind./m2. The presence of Protozoa was extremely variable. They were completely absent (station 62) and reached a maximum 155 000 ind./m2 (station 42). Among the protozoans, soft-walled foraminifers (SWF) and gromiids (GR) dominated. GRs accounted for up to 51–85% of the abundance of the total protozoa at some stations in Peter the Great Bay. At other stations, SWFs prevailed and reached 93–100% of the total protozoa. The most numerous hard-shelled foraminifers (HSF) and ciliates (CL) were obtained in the Vladimir Bay and at individual stations off the eastern coast of Primorsky krai. Brief descriptions with illustrations are given for 45 representatives of the SWF belonging to the families Allogromiidae and Saccamminidae, of which 22 of them are identified to the species or genus level, and 23 morphotypes are identified to the family level. The gromiid fauna is represented by six morphotypes. [ABSTRACT FROM AUTHOR]

In July–August 2022, the spatial distribution and the composition of local settlements of the bivalve mollusc Mya japonica Jay, 1857 in the Vostok Bay (Peter the Great Bay of the Sea of Japan) were studied. M. japonica occurred almost throughout the entire bay in a wide range of depths from 0 to 22 m at water temperatures from –1.9 to 25°С and salinity from 0 to 34‰. M. japonica was the most abundant in the shallow areas of the bays, closed from the direct wave impact, where, at a depth of up to 4–5 m, the density of the mollusc reached 27 ind./m2, and the biomass was almost 4 kg/m2, which averaged 56% of the total macrozoobenthos biomass. With increasing depth and moving from the dead-end of the bay to the open sea, the abundance of M. japonica decreased by one or two orders of magnitude. Local settlements differed significantly in size and age composition, size-frequency distribution of molluscs, indicating the nature of the replenishment of the benthic population with juveniles, as well as the proportion of commercial size individuals, which ranged from 37 to 98%. The reasons for the revealed features of the distribution and structure of the population of M. japonica are discussed. [ABSTRACT FROM AUTHOR]

This paper presents the recent data on the distribution and breeding abundance and distribution of the Mongolian Gull, Slaty-backed Gull, Black-tailed Gull and the Common Tern nesting within Peter the Great Bay of the Sea of Japan. Over the past 30 years, all species of gulls increased their abundance, while the Common Tern has almost ceased to nest on the islands of the bay. [ABSTRACT FROM AUTHOR]

We identified Gymnocanthus detrisus as the absolute dominant species in the taxocene of sculpins (family Cottidae) caught below the 20-m depth in the aquatic area between Cape Povorotny and Cape Mapatsa. Myoxocephalus polyacanthocephalus, Gymnocanthus herzensteini, Enophrys diceraus, and Triglops pingelii are dominant as well. Subdominant species are Triglops septicus, Icelus cataphractus, Hemilepidotus gilberti, Myoxocephalus brandtii, Myoxocephalus jaok, Taurocottus bergii, and Gymnocanthus pistilliger. Other types of fish identified in this area are insignificant in abundance. Sculpins aggregate at greater depths in the southern aquatic areas, from Cape Povorotny to Olga Bay, and from Olga Bay to Cape Belkin, than in the northern areas, between Cape Belkin and Cape Zolotoy, particularly between Cape Zolotoi and Cape Mapatsa. We attribute this phenomenon to the differences in water regimes. The highest densities of sculpins are generally typical for the southern area. Conversely, the lowest densities are typical in the northern area. However, some species prefer northern areas. The minimum depths of the habitat for different species vary from less than 20 m to 82 m; the maximum depths range from 80 m to 530 m. Due to the high species diversity, aggregations of sculpins are observed in a wide bathymetric range from 20 to 300 m, with peak values at depths of 150–200 m. Sculpins live in summer at water temperatures above 0.4ºC. The shallow water species of sculpins tolerate much greater temperature ranges then deep water species. Hence, the stenotherm increases in deep water species. [ABSTRACT FROM AUTHOR]

In September 2021, the contents of the Pb, Cu, Cd, Zn, Ni, Fe, and Mn heavy metals were estimated in the tissues of the oyster Magallana gigas (= Crassostrea gigas) (Thunberg, 1793) and in the silty fraction of bottom sediments from mollusk habitats in coastal waters around the Muravyov-Amursky Peninsula, including the most polluted area off the western coast of Ussuri Bay of the Sea of Japan. It has been shown that, despite the reclamation of the landfill located here in 2010, which is the main source of metal pollution, copper is present in high concentrations in bottom sediments and tissues of oysters, giving them a green color. The mollusks living in this area also retain a high concentration of zinc. The concentrations of Pb, Cd, and Ni in oyster tissues over the past 20 years have decreased by 2–5 times in accordance with the decrease in the number of mobile forms of these metals in bottom sediments; however, they are still 3–6 times higher than regional estimates for polluted water areas. With the abnormal accumulation of copper, manganese demonstrates a decrease in the concentration in the tissues of oysters from the most polluted stations, reflecting the deterioration of the physiological state of mollusks. The results we obtained indicate the need to continue the remediation of the western coast of Ussuri Bay and monitor the pollution of coastal waters with metals. [ABSTRACT FROM AUTHOR]

This pioneering project was conducted to study the sea ice microalgae community collected along the coast of Russky Island, which is located in the Peter the Great Bay, Sea of Japan. We examined the sea ice microalgae species composition and its quantitative characteristics. Eighty-eight microalga taxa assigned to 50 genera and 7 divisions have been identified. The greatest species diversity was noted for algae of the Bacillariophyta where it reached 57 to 99% of the total assemblage. The most abundant taxa were planktonic, marine, mainly ice-neritic diatoms: Chaetoceros socialis f. radians, Detonula confervacea, Entomoneis gigantea var. decussata, Navicula granii, N. septentrionalis, Nitzschia frigida, Thalassiosira gravida and T. nordenskioeldii. The total number of microalgae collected in 2020 from ice horizons in Novik Bay varied from 23.8 to 68.6 cells/mL, while in Voevoda Bay it ranged from 21.1 to 1296.2 cells/mL. In samples collected in 2021, the number of microalgae in Novik Bay changed from 1160.9 to 3296.9 cells/mL, and in Voevoda Bay it varied from 32.3 to 1607.5 cells/mL. The quantitative characteristics of the ice algal flora in the two areas of our study, Novik Bay and Voevoda Bay, were found to differ depending on the year of study, water area, and ice core layer. [ABSTRACT FROM AUTHOR]

Larvae of eight burrowing shrimp species from Vostok Bay, Sea of Japan, were analyzed for their carbon (δ13C) and nitrogen (δ15N) isotope composition. In zoeae I of these species, the δ13C values varied in a range characteristic of planktotrophic organisms, with the average values for larvae of gebiids being lower than for larvae of axiids. The highest δ15N values, comparable to those reported for omnivorous zooplankton, were recorded from larvae of Leonardsaxius amurensis and Boasaxius princeps. The dominance of phytoplankton in the diet of zoeae I of Nihonotrypaea makarovi was indicated by the low δ15N values close to the nitrogen isotope ratio of particulate organic matter. According to the nitrogen isotope composition, the larvae of three Upogebia species and two Nihonotrypaea species held an intermediate position (with δ15N values ranging from 6.2 to 6.4‰). It was found that the diet of the studied burrowing shrimp larvae does not depend on the taxonomic position, and food preferences differ markedly even in zoeae of congener species, which should be taken into account when cultivating decapod larvae under laboratory conditions. [ABSTRACT FROM AUTHOR]

Under laboratory conditions, the effect of temperature on the reversible arrest in embryo development, which occurs as a result of winter spawning, was studied in the hermit crab Pagurus proximus, Komai, 2000 from Amurskiy Bay (Peter the Great Bay, Sea of Japan). In clutches of females that spawned under natural conditions at a water temperature of 5°C and below, an increase in water temperature to 14–16°C led to the termination of embryonic diapause and the synchronous resumption of egg development, regardless of whether the temperature conditions changed at the beginning or at the end of the winter breeding season. No embryonic diapause was observed in clutches of females of P. proximus that were captured in December–April and spawned in the laboratory at a water temperature of 14–16°С. From this it follows that the primary signal for diapause initiation and termination in P. proximus is temperature, which directly affects the embryo. The data we obtained confirm that embryonic diapause of the hermit crab P. proximus is not obligate but is induced by habitat conditions, primarily by ambient temperature. The possibility of using P. proximus as a model object for studying the mechanisms of embryonic diapause in decapods is considered. [ABSTRACT FROM AUTHOR]

For the first time, we report the finding of egg masses and an egg-guarding male of the whip sculpin Gymnocanthus intermedius (Temminck et Schlegel, 1843) in Peter the Great Bay (Sea of Japan). Bottom eggs were found in the post-wintering period during a scuba dive at a depth of 12 m. Exact data on the depth of occurrence and structure of the egg masses, the number of eggs per mass, and the sex of the guarding parent fish are provided. The characteristics of the eggs and the substrate on which the egg masses were laid are described. The diagnostic features of the male that allowed it to be assigned to G. intermedius are given. [ABSTRACT FROM AUTHOR]

The vertical distribution of the bivalve Tetrarca boucardi is studied at several sites in Vostok Bay, which largely characterize the diversity of biotopes of the upper subtidal zone of Peter the Great Bay (the Sea of Japan). In this part of the species range, at a depth of 0.5–10 m, T. boucardi forms stable perennial populations, in which there is the regular replenishment by juveniles; the population lifetime apparently many times exceeds the bivalve's individual lifespan. The maximum shell length of T. boucardi is 74 mm; the maximum individual age is 19 years. The most abundant accumulations of T. boucardi with a biomass of 530 g/m2 (36.7% of the total biomass of macrozoobenthos) are found in shallow water at a depth of about 3 m in semi-protected inner parts of the bay, which are well warmed in summer. For the first time, it is found that relatively sheltered habitats on wave-exposed rock reefs mainly at a depth of 0.5–1.5 m are also favorable for the species (average biomass, 72.7 g/m2; 11.2%). T. boucardi also occurred on soft bottoms at a depth of 1–10 m (average biomass, 22.2 g/m2; about 2%) in druses of large bivalves Modiolus kurilensis and Crenomytilus grayanus. Local differences in the abundance and composition of T. boucardi populations are discussed in relation to the habitat conditions. [ABSTRACT FROM AUTHOR]

This paper presents the results of the study of the species composition and seasonal dynamics of the qualitative characteristics of phytoplankton in Paris and Zhitkov bays of Russky Island in relation to the hydrochemical structure of waters. The composition of dominant species differed between the bays. The occurrence of Bacillariophyceae was recorded; Cyclotella atomus var. gracilis was for the first time identified in marine waters. Thalassiosira lundiana is the first record for the northwestern Sea of Japan. Minidiscus comicus occurred as the dominant species of phytoplankton in the seas of Russia for the first time. The use of electron microscopy for identification of dominant species showed that the mass development of members of Thalassiosira was more often caused by a complex of species. The general trend of the seasonal variations of environmental parameters and nutrients in the studied bays mostly coincided with the features of the dynamics of quantitative parameters of microalgae. [ABSTRACT FROM AUTHOR]

The contents of heavy metals (HM) Fe, Cu, Mn, Zn, Cd, and Ni were determined in common species of long-lived mussels Crenomytilus grayanus (Dunker, 1853) and Modiolus kurilensis F.R. Bernard, 1983 from Ussuriisky Bay. Fe and Mn are indicators of the influence of terrigenous runoff; Cu and Zn, industrial and municipal waste pollution; and Cd and Ni, technogenic impacts. C. grayanus was sampled at eight stations, M. kurilensis was collected at one station (Cape Basargin); therefore, the HM content in organisms and the environment was mainly assessed from analysis of Gray's mussel samples. The current distribution of HM levels in mollusks of Ussuriisky Bay was generally more or less uniform. The concentration of Cu was only increased in Gray's mussel from Сape Telyakovsky, and increased Cd and Ni levels were found in mollusks collected from the pier of the port of Vera. In comparison with 2006, the upper values of the concentration ranges increased 1.5 times for Zn, more than 2 times for Cu, and almost 1.5 times for Cd. In mollusks from Lazurnaya Bay (a popular recreation site), the concentrations of Zn and Cu, tracers of anthropogenic impacts, increased by 10 and 20%, respectively. Since the mollusks studied are commercially valuable their HM content was compared with the maximum permissible concentration levels (MPCL). The content of Cd exceeded the MPCL in two specimens of Gray's mussels from the pier of the port of Vera and in a single specimen from Cape Sedlovidny. [ABSTRACT FROM AUTHOR]

Studies conducted in April−October showed that the Japanese sandfish Arctoscopus japonicus occurred in Peter the Great Bay in the near-bottom water layers at a depth of 1.5 to 550 m at a temperature of –0.2 to 16.5°C; however, distribution of the species varied during this period significantly. After a period of pelagic development, young fish with a length (FL) from 3.5 cm pass to the benthic mode of life and leave in July the coastal area. In summer, juveniles live at a depth of approximately 25–55 m; in the autumn, they spread over the shelf. Maturation of some individuals in the first year of life was not observed in the bay; it is typical only for the southern areas of the range. In the warm season, the majority of older fish adhere to the bathymetric range of 40–60 m and adjacent depths. In the autumn, before spawners approach the coast for spawning they descend into deeper waters and penetrate into the lower part of the shelf and onto the continental slope. [ABSTRACT FROM AUTHOR]

Data on the first records of Pholis nea Peden et Hughes, 1984 from Russian waters of the Sea of Japan (Tatar Strait) and a description of the species morphology are presented. The genetic identification is based on an analysis of the COI gene region of mitochondrial DNA (mtDNA). A new common English name is here proposed for Pholis nea, the Lesser Gunnel. [ABSTRACT FROM AUTHOR]

This article presents data on the contents of Fe, Mn, Cu, Zn, Ni, Pb, and Cd in the tissues of the tunic, muscular sac, stomach, digestive gland, and gonads of the ascidian Halocynthia aurantium Pallas, 1787 from Peter the Great Bay and Kievka Bay (Sea of Japan). The physiologically important elements Fe, Mn, and Zn prevailed in almost all organs of ascidians in terms of their concentration levels. Patterns of metal distribution in the organs and tissues of H. aurantium were determined depending on their age. The levels of content of Zn, Mn, and Cu were similar in the organs of 2- and 3-year-old individuals. The element concentrations were highest in the digestive gland (Zn), stomach (Zn, Cu), tunic (Mn), and gonads (Cu). The content of Mn in the tunic of H. aurantium from different biotopes was higher compared to other organs. The content of Pb in the tissues of H. aurantium from Kievka Bay was higher than that of the tissues of ascidians from the other studied localities. [ABSTRACT FROM AUTHOR]

The concentrations of Fe, Mn, Cu, Zn, Pb, Cd, and Ni were studied in the brown algae Sargassum miyabei Yendo and S. pallidum (Turner) C. Agardh collected in Ussuri Bay, Sea of Japan, from 2001 to 2018. The degree of heavy metal pollution in different parts of the bay was assessed by comparing the actually measured concentrations of the metals in algae with the upper threshold values of their background ranges of concentrations (CUT). The coefficient of metal contamination risk for algae (KR) was calculated as the ratio of the metal concentration in algae to CUT. In 2016–2018, the KR values for Cd and Ni reached 1.7; for Zn, 2.0; for Fe, 3.1; for Mn, 7.2; for Pb, 12.3; and for Cu, 15.0. The maximum concentrations of most elements were recorded from the Sargassum algae collected off the Vladivostok municipal solid waste landfill operated in 1967–2010. In this part of the bay, the major pollutants in 2016–2018 were Pb and Cu; the accompanying pollutants were Zn, Mn, Fe, and Ni. [ABSTRACT FROM AUTHOR]

Hemolymph is one of the main tissues providing invertebrates' immunity and homeostasis. Earlier, we showed that some of the hemolymph immune parameters of the common Far Eastern mollusk Modiolus kurilensis are sensitive to bacterial and anthropogenic challenges. In this work, a number of cellular parameters such as total hemocyte count (THC), hemocyte phagocytic activity (PA), and reactive oxygen species (ROS) and humoral parameters such as hemagglutination (HA) and hemolytic (HL) activity of plasma, as well as its protein concentration (CP) and profiling in M. kurilensis were studied depending on the season and environmental indicators (temperature, salinity, and oxygen concentration). The total hemocyte count was weakly correlated with water oxygen concentration (R = –0.25) and temperature (R = 0.27), and the 36 kDa plasma protein was weakly correlated with temperature (R = –0.33). Also, there was a correlation (R = 0.38) between hemagglutination activity and the 19 kDa protein fraction. The minimum values for a number of parameters were noted in January (THC, PA, ROS, HA, HL), while the maximum values were observed in late spring (THC, PA, ROS, HA, HL). At the same time, in other months, these and most other parameters had metastable values. Thus, the indicators that were identified in previous studies (THC, PA, ROS, HA, HL, CP, protein fractions 55 and 124 kDa) are suitable for assessing the physiological state of M. kurilensis during most of the year. [ABSTRACT FROM AUTHOR]

A total of 137 strains of mesophilic and psychrotolerant hydrocarbon-oxidizing bacteria have been isolated from three regions of the Sea of Japan exposed to different levels of anthropogenic pollution. The taxonomic affiliations of the culturable bacteria from surface waters and bottom sediments that are involved in the biodegradation of petroleum hydrocarbons in these regions have been identified. The isolated microorganisms belong to the phyla Actinobacteria, Firmicutes, and Proteobacteria. The hydrocarbon-oxidizing ability of the bacteria Okibacterium sp., Lechevalieria flava, Patulibacter sp., P. minatonensis, Gracilibacillus massiliensis, Thalassobacillus sp., Virgibacillus dokdonensis, Chryseomicrobium amylolyticum, Jeotgalibacillus marinus, Moraxella osloensis, Idiomarina maritima, and I. piscisalsi has been recorded for the first time. The results we obtained extend our knowledge about the potential of biodegradation of pollutants by members of certain taxa in the marine environment. [ABSTRACT FROM AUTHOR]

The limpet Lottia cf. borealis, a gastropod species widely distributed in the Far Eastern Seas of Russia, has been subjected to genetic analysis. Three genetic markers (COI, 16S, and 12S) showed no evidence of a distinct genetic structure of this species within the studied part of its range (the southern coast of Primorsky Krai and the coasts of Sakhalin Island and the southern Kuril Islands). A phylogenetic analysis revealed that Lottia cf. borealis is a sister taxon to L. paradigitalis (Fritchman, 1960). [ABSTRACT FROM AUTHOR]

The reproduction, growth, and variability of the shape of the shell in the gastropod Boreotrophon candelabrum (Reeve, 1848) from Peter the Great Bay (Sea of Japan) were investigated. In aquarium conditions, the mollusks started to lay transparent hemispherical egg capsules in late April at a water temperature of 5.6°C. The females with a shell height of 38–51 mm laid 13–46 egg capsules. The diameter of the base of the egg capsules ranged from 6.0 to 10.1 mm. Each capsule contained from 411 to 1710 eggs with a diameter of 0.204 ± 0.024 mm. In nature, egg capsules appeared in the first half of May and were commonly found from May to the first half of June; a few may be encountered until September. The release of the larvae from the egg capsules into the sea occurred from the second half of May. Mollusks grew most intensively in the first 2 years of life and reached a shell height of approximately 35 mm. The annual shell growth then decreased and at the age of 6 years the mollusks almost attained the maximum size observed in nature. This was calculated by the von Bertalanffy equation: Lt = 61.2 [1 – e–0.5572 (t – 0.4672). The shape of the shell of B. candelabrum significantly varied depending on habitat conditions. The habitat given in the species description 3 was only observed for 17% of the population in the bay. [ABSTRACT FROM AUTHOR]

The species composition of macrophytic algae in Troitsa Bay (Peter the Great Bay, Sea of Japan) was studied from June to September in 2004–2018. A total of 111 macrophytes were found, of which 28 were epiphytes. The phylum Rhodophyta was the most diverse group represented by 58 species (or 54% of the total number of identified species); the phylum Ochrophyta (class Phaeophyceae) was represented by 35 species (32%); the phylum Chlorophyta, by 15 species (14%); 3 species of sea grasses (3%) were also recorded. The species diversity increased from the intertidal to subtidal zones. There were 23 plant communities identified in the intertidal and upper subtidal zones of Troitsa Bay. [ABSTRACT FROM AUTHOR]

In this study, otolith shape analysis has been used to perform identification of two smelt species specimens (genus Hypomesus),H. japonicus and H. nipponensis, as well as differentiation of local gatherings in the first species, in the north-western Sea of Japan (SJ). Based on the otolith shape and using several multidimension statistical approaches obvious differences were defined for both inter- and intraspecies levels of otolith variation. Species discrimination by otolith shape indices and other variables extends well to within the species H. japonicus gatherings, the individuals sampled from the northern sample in Olga Bay (OB) are most similar morphologically to those from the coastal waters off the village of Terney to the north of OB. In contrast, the individuals of this species from the coastal waters off Russky Island (RI), including another southern sample and those from northern samples, manifest the greatest differences, thus providing evidence on the existence of at least two local stocks of the species in the waters of the north-western Sea of Japan. [ABSTRACT FROM AUTHOR]

This study reports recent data on the distribution and breeding abundance of seven species of colonial birds on the coast of Peter the Great Bay, Sea of Japan. Over the past 30 years, three species of cormorants (great, Japanese, and pelagic cormorants), as well as the black-faced spoonbill, have significantly increased their numbers. The number of breeding pairs of gray heron and Chinese egret decreased, while the numbers of the little egret did not change. [ABSTRACT FROM AUTHOR]

The effect of water temperature on the timing of spawning and spat settlement of the Yesso scallop (Mizuhopecten (=Patinopecten) yessoensis Jay, 1857) in Minonosok Cove (Posyet Bay, Peter the Great Bay) has been studied based on the most complete dataset of observations for 1970–2011. The date of onset of spawning varied from May 1 to June 9 (within 40 days) and the onset of spat settlement varied from June 4 to July 5 (within 32 days). It has been found that the timing of spawning shifts to later dates due to the longer preceding cold periods with a greater accumulated sum and lower average values of below-zero temperatures, due to the short pre-spawning periods (from the date when the sea surface temperature (SST) reaches 0°C to May 1) with decreased sums and low average temperatures over these periods, as well as due to the decreased sums of temperatures in April. Later settlement dates were also recorded in the years with severe winter conditions. The onset of settlement shifts to a later date also in case of low average above-zero temperature in the pre-spawning period (correlation coefficient (R) = –0.46). Early settlement on collectors was observed in the years when SST reached 0°C on earlier dates in spring (at the Posyet Hydrometeorological Station). The higher the sum of above-zero temperatures was accumulated by May 1 and June 1, as well as in April and May, the earlier the scallop spat settled on collectors (R = –0.58, –0.60, –0.55, and –0.42, respectively). Prognostic equations are proposed to predict the dates of the onset of spawning and spat settlement with a lead time of 10 and 15 days, respectively; the equations are tested on the results of a correlation analysis. The accuracy of these predictions based on 10-year independent samples constitutes 70% for the spawning onset date and 60% for the spat settlement onset date. [ABSTRACT FROM AUTHOR]

Strains of Vibrio spp. isolated from samples of water and aquatic organisms of the temperate (173 strains) and tropical (124 strains) climatic zones were phenotypically characterized. Identification, carried out on the basis of an extended analysis of phenotypic properties, made it possible to identify previously undiagnosed species. V. alginolyticus, V. parahaemolyticus, and V. splendidus prevailed in Peter the Great Bay. This is the first report on isolation of V. harveyi from a hydrobiont of the temperate waters of Peter the Great Bay. Сompared to the temperate zone, the tropical zone has a higher species diversity of vibrios. Vibrios from Peter the Great Bay were less resistant to the studied spectrum of antibiotics in comparison to the resistance of vibrios from the tropical zone. A V. vulnificus isolate from the Vietnamese waters was resistant to the maximum number of antibiotics (12 out of 15). [ABSTRACT FROM AUTHOR]

A mycological examination of the saffron cod Eleginus gracilis (Tilesius, 1810) and the Asiatic smelt Osmerus mordaxdentex Steindachner & Kner, 1870, caught in the Amursky Bay (Peter the Great Bay of the Sea of Japan) revealed several species of filamentous fungi. In total, 105 isolates of filamentous fungi were obtained from the skin integument and internal organs (31 isolates from the saffron cod and 74 isolates from the Asiatic smelt). Three species of filamentous fungi were found in the saffron cod: Aspergillus flavus Link, Penicillium brevicompactum Dierckx, and Phialophorophoma sp. Six species of filamentous fungi were found in the Asiatic smelt: Aspergillus wentii Wehmer, Aspergillus sp., Cladosporium cladosporioides (Fresen.) de Vries, Penicillium albidum Sopp., Penicillium nigricans (Bain.) Thom, and Humicola grisea Traaen. All the identified species are anamorphic stages of ascomycetes. In the saffron cod, the organs most frequently invaded by fungi were the gills (three fungal species were found); two species of fungi were found in the muscles and liver and one species each were identified in the skin integument and in gonads. The distribution of fungi in the Asiatic smelt was different: four fungal species were revealed in the skin integument, three species in the gills, two species in muscles, one species in the liver, one species in the gonads, and two species on the fins. [ABSTRACT FROM AUTHOR]

This review analyzes the current state of knowledge of the microphytobenthos in the Russian waters of the Sea of Japan and adjacent sea areas. A retrospective analysis of the literature shows that microphytobenthos, with its primary production that often exceeds the production of phytoplankton, plays an important role in coastal marine ecosystems. Benthic diatoms in the coastal waters of Peter the Great Bay (Sea of Japan), which are the primary food object for many marine invertebrates and mammals, are also used as important indicators of the state of the aquatic environment. Despite the great number of publications on the region, knowledge of the microphytobenthos in taxonomic and ecological-floristic aspects is still insufficient. [ABSTRACT FROM AUTHOR]

This article provides an overview of the species composition of the phylum Nemertea in the Far Eastern seas of Russia. The list of nemerteans includes at least 200 species from the classes Palaeonemertea, Pilidiophora, and Hoplonemertea. Many of the species proved to be new to science; most of them remain undescribed. Currently, the use of gene markers is often the only approach to discriminating between closely related species and identifying them accurately. The well-studied nemertean fauna of Peter the Great Bay (73 species), Sea of Japan, has become a basis for comprehensive studies of these invertebrates at the Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences. [ABSTRACT FROM AUTHOR]

The karyotype of the brightbelly sculpin Microcottus sellaris (Gilbert, 1896) (family Cottidae) from the Sea of Japan and Sea of Okhotsk has been studied for the first time. The karyotype is stable; it includes 42 chromosomes (2 metacentric, 2 submetacentric, 32 subtelocentric, and 6 acrocentric chromosomes); the number of chromosome arms is 46. A comparative analysis of the basic karyotype traits was carried out for M. sellaris and for the Far Eastern species of the genus Myoxocephalus (M. stelleri from the Sea of Japan and Sea of Okhotsk, M. brandtii, M. jaok, M. ochotensis, and M.polyacanthocephalus). The traits that allow differentiation of M. sellaris from species of the genus Myoxocephalus, as well as the common traits indicating their relationship, are identified. [ABSTRACT FROM AUTHOR]

The characteristics of the farming of hatchery-reared juvenile Yesso scallop, Mizuhopecten yessoensis, in suspended net cages off the eastern coast of Primorsky Krai are studied. The work was conducted at a farm located northeast of Moryak-Rybolov Bay during the first 10 days of November 2018. The values of survival and growth rates of scallops on collectors and grow-out cages were determined. The survival rate of the Yesso scallop spat after being transported from Shandong Province, China and seeded in suspended cages was 85%, which is consistent with the regional standard. A high mortality rate of juvenile scallops (56–90%) was recorded in September–November. The mean size (shell height) of hatchery-reared spat in the cages in November did not differ from that of spat on collectors in southern Primorsky Krai. In the waters near Moryak-Rybolov Bay, the growth rate of scallops was somewhat lower than in southern Primorsky Krai but, nevertheless, higher than in Vladimir Bay and Aniva Bay. The mean body weight of scallop spat in November was 1.5 ± 0.1 g. The possible causes of the increased mortality rate of the bivalves and the solutions of the problem are discussed. [ABSTRACT FROM AUTHOR]

The peculiarities of infection with the parasitic bopyrid isopods Gyge ovalis and Progebiophilus sp. and the rhizocephalan Sacculina upogebiae among the mud shrimp Upogebia major population in Vostok Bay (Peter the Great Bay, Sea of Japan) were investigated in April–November 2017. Parasites were found from spring to late autumn. The prevalence of isopod infection in U. major was 5.42%, females and males were equally infected. The prevalence of Sacculina upogebiae was 1.26%; this parasite was more common on the female hosts. Isopods were found on mud shrimp larger than 42 mm; rhizocephalan externae occurred in individuals larger than 57 mm. The highest prevalence of parasites was observed in the summer (7.44%). No cases of simultaneous infection with different species of parasites were noted in U. major. [ABSTRACT FROM AUTHOR]

The population and reproductive characteristics of the hermit crab Pagurus brachiomastus (Thallwitz, 1892) have been examined in Vostok Bay (Peter the Great Bay, Sea of Japan). The average population density of P. brachiomastus was lowest in the spring (2.4 ± 0.6 ind./m2) and highest (3.1 ± 0.4 ind./m2) in the summer; the biomass was 18.24 ± 3.75 and 22.83 ± 2.80 g/m2, respectively. Hermit crabs were found throughout the depth range from 0 to 12 m, but were most numerous at a depth of approximately 5–6 m, with an average population density of 8.3 ± 3.7 ind./m2 and a biomass of 39.09 ± 8.51 g/m2 in the summer. The shield length of males varied from 1.3 to 10.3 mm (on average, 5.3 ± 2.2 mm), that of females varied from 1.3 to 10.6 mm (on average, 4.3 ± 1.5 mm), and that of ovigerous females varied from 1.5 to 8.4 mm (on average, 4.4 ± 1.5 mm). The male to female ratio varied from 0.8 to 3.3 during the observation period, with an average of 1.7. Spawning continued from March through August. The proportion of ovigerous females increased from 8.5% in March to 82.8% in May; embryos in clutches remained in the early stage of development until the second 10-day period of May. Egg development was resumed when the water temperature reached 10°C. Breeding was asynchronous: in June–August, females with late-stage embryos and females with recently laid eggs were observed, indicating the possibility of repeated spawning. The data we obtained showed that the favorable coexistence of P. brachiomastus with other sympatric species in the study area is provided by the spatial dissociation of their clusters and differences in size characteristics, as well as the presence of an embryonic diapause in egg development in part of the females and the possibility of repeated spawning. [ABSTRACT FROM AUTHOR]

The levels of Zn, Cu, Fe, Cd, and Pb were measured in thalli of the common brown algae species Scytosiphon lomentaria, Fucus evanescens, Stephanocystis crassipes, Silvetia babingtonii, and Saccharina japonica from Rudnaya Bay and adjacent waters. These data allowed assessment of the current spatial distribution of these elements over the waters of the study region and the species-specificity of algae as indicators of heavy metal pollution of the environment. It has been established that the main source of heavy metals entering the bay waters is the small harbor in its southern part, where lead and zinc concentrates from the Dalnegorsk Mining and Processing Plant are loaded on vessels for further transportation. The estimated trace-element composition of algae was compared to that of the samples collected in 2009, which is the year of the last increase and, simultaneously, completion of the production activity of the local lead smelting plant. The results show that by 2016 the concentration of Pb in S. lomentaria collected near Cape Briner at the entrance to the bay decreased 7.4 times. The reduction in the Zn content of S. lomentaria was not as impressive: from 2009 to 2016, it decreased 1.7 times. In algae from Lidovka Bay, which is located north of Rudnaya Bay, the Zn concentration in 2016 increased 1.67 times compared to that in 2010, which is obviously explained by the growing recreational pressure on the coast of this bay. [ABSTRACT FROM AUTHOR]

Karyological and molecular genetic research on fringed sculpins of the genus Porocottus has been conducted for the first time. Karyotypes of P. japonicus (2n = 42, NF = 42), P. allisi, and P. minutus (2n = 40, NF = 42) have been studied. An analysis of mitochondrial DNA shows high levels of species differentiation, as well as significant distinctions of P. camtschaticus from P. minutus and P. japonicus. On the basis of a comprehensive study, the characters that allow reliable identification of P. japonicus, P. allisi, P. minutus, and P. camtschaticus have been found. [ABSTRACT FROM AUTHOR]

This paper investigates the depth distribution patterns of bottom vegetation dominants in the western Tatar Strait (within Khabarovsk Krai). Materials were collected during SCUBA diving surveys performed by the Khabarovsk Branch of the Pacific Research Fisheries Center. The vegetation cover, in the presence of suitable bottom substrates, is formed to depths of 18–22 m and is replaced below by sparse settlements. The abundance indices of most of the dominant species remain relatively stable within depths of 2–20 m. Their ecological optima, as a rule, occur at depths of 2–6 m with increased hydrodynamics. A scheme of the vertical division of vegetation in the area is proposed that corresponds to the results of previous studies on phytal zoning. The location of vegetation horizons and strata is not different from those previously identified, while their boundaries are blurred and correspond to the continuous live cover distribution. [ABSTRACT FROM AUTHOR]

Abstract: In October 2015, the strength of attachment to the substrate was studied in the bivalve Modiolus kurilensis in druses on silty sand at a depth of 6-11 m. The byssal attachment strength of M. kurilensis was found to increase substantially during ontogeny. It was dependent on the spatial position of mussels within the druse and differed by a factor of 2-2.5 for individuals of the same size. [ABSTRACT FROM AUTHOR]

The seasonal accumulation of the amnesic toxin domoic acid (DA) in the tissues of two commercial species of bivalves from Vostok Bay (the Sea of Japan) was assessed for the first time. The concentration of domoic acid in the tissues of the Pacific mussel Mytilus trossulus varied from 0.003 to 0.1 mg/kg during the period between October and February, and in the scallop Mizuhopecten yessoensis it varied from 0.003 to 0.09 mg/kg during the period between January and March. The maximum concentration of domoic acid in both species of mollusks was recorded in January. The results indicate the need for year-round monitoring of amnesic toxin concentrations in bivalves from Vostok Bay. [ABSTRACT FROM AUTHOR]

Abstract: The modification of the structure of the subtidal phytocoenosis was investigated along the gradient of the concentration of nutrients brought with sewage effluents into the Sukhoputnaya Bay (Ussuriisky Bay, the Sea of Japan). It was shown that an increase in the concentration of dissolved inorganic nitrogen (DIN) from 4.2 to 16.6 μM was followed by a decrease of 1.7 times in species richness, while the relative biomass of opportunistic species increased simultaneously by more than 1.5 times and by more than 5 times for Ulva lactuca. A decrease in the number of dominant species and in the number of layers in the structure simplified the algal phytocoenoses. The complex polydominant multi-layered phytocoenosis of Stephanocystis crassipes-Laurencia nipponica + Ulva lactuca-Ahnfeltiopsis flabelliformis was first substituted for a bidominant two-layered phytocoenosis of Stephanocystis crassipes-Tichocarpus crinitus, and further by a one-layer monodominant phytocoenosis of Ulva lactuca. A comparison of our own and published data allows us to conclude that complex phytocoenoses of perennial macrophytes can develop in water areas with DIN concentrations that do not exceed 15 μM. [ABSTRACT FROM AUTHOR]

Abstract: The composition and structure of a mixed population of Gray’s Crenomytilus grayanus and horse mussels Modiolus kurilensis were examined in November−December 2015 in Vostok Bay (Peter the Great Bay, the Sea of Japan). In the investigated area of the bottom, in the depth range from the water’s edge to 11 m, boulders were gradually replaced by strongly silted sand and the hydrodynamic activity was reduced. The pattern of spatial organization of the Gray’s and horse mussel population varied from solitary living individuals to large aggregations of 93-100 sexually mature mollusks. The population density of Gray’s and horse mussels increased with increasing depth; at a depth of 10-11 m it was an average of 101 ± 78 and 51 ± 41 ind./m2, respectively (without taking young-of-the-year into account). At different depths, Gray’s mussel spat made up 13.3 to 42.4% of the population while horse mussel spat were 1.9 to 5.2%; the proportion of mollusks of pre-reproductive size (age) varied from 56.5 to 85.6% and from 13.2 to 31.5%, respectively. The greatest multi-age composition was found in C. grayanus aggregations on boulders at 0-1 m; the age range narrowed with depth. For M. kurilensis, the opposite trend was found. The oldest individuals of Gray’s mussel (29 years) were found on boulders at 0-1 m; while the oldest individuals of horse mussel (46 years) occurred on silty sand at 10-11 m. The differences are discussed from the standpoint of the morpho-physiological adaptations of mollusks of the genera Mytilus and Modiolus to living in different biotopes. [ABSTRACT FROM AUTHOR]

We conducted a comparative analysis of the fatty acid (FA) composition and the ratios of stable isotopes of carbon (δ13C) and nitrogen (δ15N) in soft tissues of ten species of bivalve mollusks collected simultaneously on adjacent biotopes in shallow Vostok Bay (the Sea of Japan). Comparison of the FA composition of the lipids of digestive gland and all soft tissues showed that the percentages of C16 and C18 marker FAs were greater in the digestive gland and the levels of marker C20 and C22 FAs were, in most cases, higher in soft tissues. According to the results of cluster analysis and principal component analysis, four groups of samples were identified with a similarity of the FA composition of more than 80% within groups. The carbon stableisotope ratios varied within very wide limits in the studied species of bivalves; the range of δ13C variations was 8.1‰. The range of δ15N variations was much smaller, 2.5‰. Two pairs of species of mollusks (Saxidomus purpurata-Protothaca euglypta and P. jedoensis-Diplodonta semiasperoides) did not differ in the values of both δ15N and δ13C, the remaining species differed in at least one of these parameters. The greatest similarity of the FA composition and stable-isotope ratios was found in species that inhabit similar substrates, except Macoma irus and D. semiasperoides. Particularly marked differences in the FA composition and stable-isotope ratios were found between a filter-/surface deposit-feeder M. irus and filter-feeders Arca boucardi and Mytilus coruscus that live next to this species. [ABSTRACT FROM AUTHOR]

A previous molecular-genetic analysis of clonal cultures and single cells of Ostreopsis spp. that were isolated from Peter the Great Bay (the Sea of Japan) revealed three different genotypes according to the nucleotide sequences of ribosomal DNA (rDNA). Of these, Ostreopsis sp. 1 was earlier found only off the coast of Japan and described as being the most common and highly toxic. We have obtained further molecular evidence and have studied the morphological features of cells from one of the Ostreopsis strains with this genotype and some aspects of its growth at salinities of 24, 28, and 32‰. The results showed that in cells from the Russian coast of the Sea of Japan, the third apical (3') and the third precingular (3") plates do not adjoin one another, being separated by the elongated second apical (2') plate. Cells of Ostreopsis sp. 1 from the Russian coast are significantly larger than Ostreopsis sp. 1 cells with the same genotype from the coast of Japan. Salinity did not have a substantial effect on the growth of Ostreopsis sp. 1. The growth rate varied from 0.24 to 0.35 divisions per day, with maximum values at a salinity of 24‰. When salinity decreased to 24‰, the exponential growth phase was significantly extended and the maximum cell concentration doubled. [ABSTRACT FROM AUTHOR]

The state of the macrophyte community of Zostera marina + Stephanocystis crassipes in the cove off Cape Tokarevsky (Eastern Bosphorus Strait, Sea of Japan) was evaluated, using the method of sample plots, in June 2014. The taxonomical and morpho-functional composition, as well as the structure of the community, has been studied. A total of 39 species of marine macrophytes have been found in this area, including 6 species of Chlorophyta, 22 species of Rhodophyta, 10 species of Phaeophyceae, and 1 species of Tracheophyta (Zostera marina), which constitute 15, 56, 26, and 3% of the total number of species in the community, respectively. The studied phytocenosis is characterized by a poor taxonomic composition, a high biomass of opportunistic species (auxiliary species on the dominance scale), and the proportions of higher algal taxa typical of the clean waters of Peter the Great Bay. Thus, based on a combination of these characteristics, the Zostera marina + Stephanocystis crassipes phytocenosis can be regarded as being in an early stage of anthropogenic transformation and the waters are classified as moderately polluted. [ABSTRACT FROM AUTHOR]

The spatial and bathymetric distribution of the Greenland smooth cockle, Serripes groenlandicus, in Peter the Great Bay, Sea of Japan has been studied based on the data of three dredge surveys conducted in 2010-2012. The bathymetric range of the species habitat is 20-75 m; the densest aggregations are associated with sandy silt sediments in the central part of the bay at depths of 55-60 m. The surveyed area of S. groenlandicus aggregation is 2255 km²; the total area is believed to be 3430 km². The estimated total species biomass averages 8731 t, ranging within 8538-9831 t. [ABSTRACT FROM AUTHOR]

A study of epibiosis of the brown alga Costaria costata in the sublittoral zone of Vostok Bay, Sea of Japan during the spring and summer of 2016 showed that hermit crabs of the following four species accounted for approximately 85% of the total biomass: Pagurus proximus, P. minutus, P. brachiomastus, and P. middendorffii. Of these, the most abundant one (96.5% of the total number of hermit crabs) was P. proximus, the mean aggregation density of which on C. costata (429 _ 221 ind./m²) was higher by an order of magnitude than that in the adjacent area of the bouldery bottom. The size ranges of males and females of this species in aggregations on boulders and those on C. costata were similar, with a predominance of larger individuals on algae. In the size-frequency distribution, three groups of individuals corresponding to three size-age cohorts were differentiated. The male-to-female ratio was 1 : 1.7. Hermit crab aggregations on C. costata are ephemeral; their existence is determined by the duration of the period of algae development, that is, from late spring to the middle of the summer. [ABSTRACT FROM AUTHOR]

The biomass of the walleye pollock ( Theragra chalcogramma) stock in waters of Primorskii krai, Sea of Japan, during the 1976-2015 observation period ranged from 48000 to 373000 tons; their number ranged from 99 to 1115 million fish. Four very strong year-classes born in 1975, 1981, 1997, and 2006 have been identified. It has been shown that the duration of the sexual-maturity period is determined by the periodicity of the dynamics of the year-class strength close to the 9-year cycle. According to the results of numerical modeling, an increase in the walleye pollock stock in Primorye is expected from 2017 to 2020. [ABSTRACT FROM AUTHOR]