Recreational Effects in Vostok Bay, Sea of Japan

The paper presents the results of three hydrochemical surveys performed in October 2000 and May and July 2001 and microbiological monitoring performed in June, July, and August 2001 in Vostok Bay (Sea of Japan), which is a favorite recreation area for the inhabitants of Primorye and the Russian Far East. It is shown that at the height of recreation occurs during late summer, as determined by the concentration of water-dissolved oxygen, the biochemical oxygen demand (BOD₅), the concentration of detergents, and the number of colony-forming enterobacteria in 1 ml of water. However, in autumn, especially by October, the anthropogenic pressure decreases and the quality of the water environment in the bay improves.     

Species composition and distribution of free-living marine nematodes in Vostok Bay, Sea of Japan

The qualitative and quantitative composition of free-living marine nematodes have been studied in Vostok Bay (Peter the Great Bay, Sea of Japan). It is found that the population density of nematodes in the bottom sediments of Vostok Bay shows an uneven distribution. The mean population density equaled 56800 ± 23400 specimens/m². A correlation has been revealed between the population density of nematodes and the substrate type. Altogether, 85 species of nematodes have been found; they were dominated by Sabatieria palmaris, Rhabdodemania orientalis, Araeolaimus parvibulbosus, Oncholaimium paraolium, Doryolaimopsis peculiaris, and Metachromadora itoi. Six taxocenoses of nematodes were distinguished, taking into account the species dominating in the population density and using cluster analysis of the obtained data. The dominating trophic assemblage of nematodes was “scrapers.” In general, the species composition of nematodes in Vostok Bay is characterized by the relatively great similarity with that in other areas of Peter the Great Bay (Sea of Japan).     

Trophic Assemblages of the Rocky Intertidal Zone in Vostok Bay,Sea of Japan

The ratios between the indices of relative abundance for different trophic life forms have been used to characterize bionomical types of a rocky intertidal zone. It has been shown that the distribution of life forms is determined by the geomorphological peculiarities of the surveyed intertidal areas. A brief critical historical review has been provided of the terms bionomy and bionomical type.     

Fauna of Sipunculans (Sipuncula) of Vostok Bay, Sea of Japan

Fauna and systematics of sipunculans inhabiting Vostok Bay, Sea of Japan, are discussed. A revision of the local species of sipunculans is performed for the first time. On the basis of study of outer and inner morphology, some species are reduced to synonyms. Extended diagnoses are proposed for all registered species. An identification key is presented for the sipunculans of Vostok Bay.     

Growth and Longevity of the Gastropod Nucella heyseana in Vostok Bay,Sea of Japan

Features of the morphology, longevity, and growth of the gastropod mollusk Nucella heyseana collected in different seasons in 2000–2001 in Vostok Bay (Sea of Japan) were investigated. Shell surface features such as grooves and spurs of the axial sculpture have proven to be unhelpful in the estimation of individual age and growth rate of this species. Concentric rings on the outside of the operculum formed yearly in the cold season are useful for these purposes. The longevity of N. heyseana in southern Primorye is 10 years; this value is similar to the life span of mollusks from the southern Kuril Islands. Local differences in longevity, growth allometry, and age changes in the body size and mass of N. heyseana in relation to habitat conditions are discussed.     

Vertical Distribution of the Far East Trepang Apostichopus japonicusin Vostok Bay,Sea of Japan

The abundance, weight, and age structure of aggregations of the Far East trepang Apostichopus japonicuswere studied in Vostok Bay, Sea of Japan, during the first part of September 2000. The highest density of aggregations (8.3 ± 0.5 ind/m²) and biomass (131.88 ± 10.50 g/m²) of animals was characteristic for coastal sites at the depth 0.5–1.5 m. With anincrease in depth the biomass and density of A. japonicusreduced 1.5 and 3 (depth 5–6 m), 220 and 830 times (depth 8–15 m) respectively. The ratio of large animals concurrently increased in the aggregation structure. The specifics of the distribution and spatial variability of the aggregation structure are discussed in relation to uncontrolled fishing of holothurians of large sizes.     

Reproduction and larval development of the gastropodAlaba vladivostokensis in Vostok Bay, the Sea of Japan

The reproduction and development of the prosobranch gastropodAlaba vladivostokensis Bartsch were studied. In Vostok Bay,A. vladivostokensis reproduces in the warmest season at water temperatures of 19–23°C. The females lay egg masses in the shape of flat, coiled bands on eelgrass leaves and on sargosso thalluses. The total period of development from egg laying to larval settling takes 25–27 days. The reproduction and development patterns and larval morphology ofA. vladivostokensis are similar to that ofAustralaba picta (A. Adams), which inhabits the coast of Japan. It is suggested that the population ofA. vladivostokensis in Peter the Great Bay should considered as part of the wide geographical range ofA. picta.     

Arenicolous mycelial fungi from the littoral of the Vostok Bay (Peter the Great Bay,the Sea of Japan)

The taxonomic composition of marine mycelial fungi was determined in the interstitial habitats of the Vostok Bay littoral (Peter the Great Bay, the Sea of Japan). A total of 39 species of ascomycetes and anamorphic fungi were detected and identified. The predominant species of the intertidal zone were Corollospora maritima, C. lacera, Carbosphaerella leptosphaerioides, Arenariomyces trifurcatus (Ascomycota), Alternaria alternata, Scolecobasidium arenarium, and Zalerion maritimum (anamorphic fungi). The complete list of species of obligately marine ascomycetes and anamorphic fungi from the interstitial habitats of the Vostok Bay littoral is presented for the first time     

Seasonal Changes in Hemolymph Parameters of the Bivalve Modiolus kurilensis Bernard, 1983 from Vostok Bay,Sea of Japan

Russian Journal of Marine Biology - Hemolymph is one of the main tissues providing invertebrates’ immunity and homeostasis. Earlier, we showed that some of the hemolymph immune parameters of...     

Larval settlement of the bivalvesMya arenaria andM. uzenensis on scallop collectors in Vostok Bay, Sea of Japan

This paper discusses data on the horizontal and vertical distribution of the spat ofMya arenaria andM. uzenensis on collectors for the cultivation of the scallopMizuhopecten yessoensis in Vostok Bay. The maximum settlement of the mollusks on scallop collectors occurred in the innermost part of the bay. The spat density ofM. arenaria on collectors was 2.6 times that ofM. uzenensis. M. arenaria larvae preferred settling on the upper portions of collectors, while the distribution ofM. uzenensis was random. The time of collector placement in the sea influenced spat numbers.     

Some Data on the Composition and Distribution of the Meiofauna in Vostok Bay (Sea of Japan)

The effect of some environmental factors on the composition and spatial distribution of the meiobenthos were studied in Vostok Bay. The spatial density of the meiobenthos significantly positively correlated with ground type and was maximum in fine- grained sands. The eumeiobenthos was dominated by harpacticoids in coarse-grained ground and by nematodes in ground with a high silt content. The pseudomeiobenthos was dominated by polychaetes and bivalve mollusks in all ground types. The depth distribution of the meiobenthos was highly heterogenous, harpacticoids being the only group whose distribution correlated significantly with depth.     

Subtidal macrobenthos communities of Vostok Bay (Sea of Japan) under conditions of anthropogenic impact

Quantitative samples of the macrobenthos were collected in May, July, and October–November from 2000 to 2002 in Vostok Bay, Sea of Japan. The main characteristics of the subtidal macrobenthos communities are described. The present study shows that the rocky bottom communities of Vostok Bay have changed little over the past 30 years. Changes have occurred in the structure of soft bottom communities and phytocenoses. Analysis of the macrophytes species composition and the value of the floristic coefficient suggest a currently moderate anthropogenic load on Vostok Bay.Original Russian Text Copyright © 2004 by Biologiya Morya, Galysheva.     

Monitoring of phytoplankton in the area of a sea farm in Vostok Bay (Sea of Japan)

The qualitative and quantitative composition of phytoplankton in the area of a sea farm in Vostok Bay (Sea of Japan) was investigated from July 2001 to May 2002. The overall numbers of phytoplankton were 0.008 to 5.3 million cells/liter, and the biomass was 0.02 to 20.5 g/m³. The maximum density and biomass of phytoplankton were observed in summer, fall, and winter. Ten species known to be toxic were recorded. Of these, Pseudo-nitzschia multiseries (Hasle) Hasle, Alexandrium acatenella (Whedon et Kofoid) Balech, and Chattonella marina (Subrahmanyan) Hara et Chihara were found in Vostok Bay for the first time. For the diatom Skeletonema costatum (Greville) Cleve, which is an indicator of extremely eutrophic waters, the cell density was positively correlated with the area of the culture site.Original Russian Text Copyright © 2005 by Biologiya Morya, Morozova, Orlova.     

The Parasitic Fauna of Common Species of Hermit Crabs of Vostok Bay (Sea of Japan)

The parasitic fauna of common species of hermit crabs was investigated in Vostok Bay (the northwestern Sea of Japan). Pagurus proximus and Areopaguristes hirsutimanus had no parasites. The average prevalence of rhizocephalan infestation in other five species of hermit crabs ranged from 5.67 to 20.83%. The prevalence of the isopod Parapseudione lata on hermit crabs did not exceed 1%, the prevalence of infestation with the isopod Athelges takanoshimensis was significantly higher, reaching 14.58% in Pagurus middendorffii. Parasitism by the isopod P. lata on the hermit crabs Pagurus minutus and P. ochotensis, as well as parasitism by the rhizocephalan Peltogaster reticulata on P. minutus were recorded for the first time. Several variants of simultaneous infestation with two parasitic species were found. The decline in the abundance of P. middendorffii accompanied by the high prevalence of parasites, primarily the colonial rhizocephalan Peltogasterella gracilis, suggests that parasite invasion may play a more significant role in regulating the abundance of hermit crabs than was previously assumed.     

Pelagic larvae of benthic invertebrates of the Vostok Bay,peter the great bay,Sea of Japan: Composition,phenology, and population dynamics

For the first time, year round and long-term seasonal research on the composition, phenology, and population dynamics of pelagic larvae of bottom invertebrates were conducted in the Vostok Bay of the Sea of Japan. Larvae of 98 taxa of various ranks were found. The larvae of bivalves and polychaetes were the most diverse. The larvae of bottom invertebrates occurred in plankton year-round. Their density was at its minimum in January (less than 100 ind./m³), and its maximum from June to November (more than 1000 ind./m³). The larvae of polychaetes dominated in the autumn and winter seasons, whereas bivalve and gastropod larvae dominated in the spring and summer seasons. It was shown that the proportion of pollution tolerant meroplankton larvae of the Polydora and Pseudopolydora genera was high in the Vostok Bay, and could indirectly indicate increasing anthropogenic pressure in the area.     

The species composition and pattern of distribution of hermit crabs (Decapoda: Paguroidea) in Vostok Bay,Sea of Japan

The species composition, abundance, and vertical distribution of hermit crabs (Decapoda: Paguroidea) were investigated in Vostok Bay, Sea of Japan, from September 2014 to September 2015. A total of seven species from two families were found in the monitoring area of approximately 5000 m² located on the bottom within a depth range of 0–11 m: Pagurus minutus, P. proximus, P. brachiomastus, P. pectinatus, P. ochotensis, P. middendorffii (Paguridae), and Areopaguristes hirsutimanus (Diogenidae). Their population density varied from 22 ± 13 to 26 ± 2 ind./m²; the biomass varied from 55.76 ± 26.10 to 93.38 ± 27.00 g/m². The species composition remained invariable throughout the study period. The proportions of species abundance changed between seasons, as this parameter is largely determined by seasonal migrations of hermit crabs. Pagurus minutus predominated in number in winter and spring (up to 71%); P. proximus, in summer and autumn (up to 47%). In autumn and spring, P. ochotensis and P. pectinatus constituted a major part of biomass (18–25% and 19–20%, respectively). The proportion of a previously abundant species, P. middendorffii, was very small (no larger than 1.3%) during the study period. Another four species of hermit crabs occurred in other parts of Vostok Bay; thus, the fauna of the bay currently includes 11 species of this group.     

Some aspects of the embryonic and postembryonic development of the Japanese anchovy Engraulis japonicus Temminck et Schlegel, 1846 in Vostok Bay, Sea of Japan

This study revealed additional data concerning the spawning period of the Japanese anchovy Engraulis japonicus Temminck et Schlegel, 1846 in Vostok Bay (Peter the Great Bay, Sea of Japan). The spawning of E. japonicus in this area ends in September at a water temperature of 17.5 ± 3°C. Some important peculiarities of the embryonic and postembryonic development of E. japonicus in the natural environment are described. The anchovy larvae have characteristic upper and lower rows of melanophores and subcaudal paired rows of melanophores on the trunk. Regular alternating rows of long and short cones were found in the retina of the early larval stages (TL 5.5 ± 0.1 mm). The planes of the photoreceptive lamellae in the outer segments of the short cones are oriented parallel to the long cell axis, which evidently provides sensitivity to polarized light.     

Resting stages of microalgae in recent marine sediments of Peter the Great Bay,Sea of Japan

Data on the qualitative and quantitative composition of resting stages of planktonic microalgae in recent marine sediments of Peter the Great Bay (Sea of Japan) over the period 2000–2007 are presented. A total of sixty one morphological forms of resting stages represented by dinoflagellate and raphidophyte cysts and diatom spores and resting cells were recorded in the sediment samples. This study revealed cysts of the potentially toxic species Alexandrium tamarense, A. cf. minutum, Alexandrium sp., Gymnodinium catenatum (PSP toxin producers), and Protoceratium reticulatum (yessotoxin producer); resting cells of Pseudo-nitzschia sp. (potential producer of domoic acid); and cysts of bloom-forming species Cochlodinium cf. polykrikoides and Heterosigma cf. akashiwo.     

The Karyotype of the flathead sculpin Megalocottus platycephalus taeniopterus (Kner, 1868) (Pisces: Cottidae) from Vostok Bay,Sea of Japan

For the first time, we studied the karyotype of the flathead sculpin Megalocottus platycephalus taeniopterus (Kner, 1868) from Vostok Bay of the Sea of Japan. The karyotype is stable: 2n = 42 (2 metacentric, 2 submeta-subtelocentric, 30 subtelocentric, and 8 acrocentric chromosomes), NF = 44 + 2. The nucleolar organizers (NOs) were identified using Ag banding in two pairs of chromosomes: in the telomeric parts of the short arm of the medium-size subtelocentric chromosome and the long arm of the large acrocentric chromosome. Variations in the number of nucleolar organizer chromosomes and in the number of NO staining blocks were found. Comparison of the karyotypes of M. p. taeniopterus and previously studied M. p. platycephalus (Pallas, 1814) from the northern Sea of Okhotsk revealed their similarity in the number and morphology of chromosomes and the number of chromosome arms and difference between the subspecies in the number and location of NO, which allows their discrimination.