The efficiency of Yesso scallop (<Emphasis Type="Italic">Mizuhopecten yessoensis</Emphasis>) aquaculture in Ussuri Bay (Sea of Japan)

Data on cultivation of the Yesso scallop, Mizuhopecten yessoensis, in Ussuri Bay are summarized. The sea-based farms that are established in the shallow waters at depths of 2–18 m differ in the area occupied by their facilities and the hydrodynamic characteristics. A farm with a complex structure (collectors, cages, and bottom cultures) operates in the semi-enclosed Sukhodol Bay. In the other two bays, mostly bottom facilities for ranching scallop and sea cucumber are used. The local scallop broodstocks were formed by introducing juveniles from Posyet Bay. As a result, at least 20 million scallop spat were collected in these three bays from 2000 to 2014. The total yield of market-size scallops was approximately 216 tons, of which over 111 t were obtained in Sukhodol Bay, 70 t in Ilmovaya Bay, and 35 t in Malye Kushi Bay. Analysis showed that the potential for the development of this type of aquaculture in the region was limited. The mean long-term value of the spat density was not higher than 200 spat per collector and did not increase throughout the period of operation of the farms. Thus, farmers had to increase the number of collectors to obtain the required quantity of scallop seed. Some years were unfavorable for harvesting juvenile scallop at all of the farms along the eastern coast of Ussuri Bay. The environmental conditions in these waters are not optimal for Yesso scallop cultivation by the extensive method.     

An analysis of the quality of the marine environment based on determination of the genotoxicity of DNA in the gill cells of the Yesso Scallop,Mizuhopecten yessoensis (Jay, 1856)

This study showed that chronic pollution of the aquatic environment causes destructive changes to DNA in the gill cells of the Yesso Scallop, Mizuhopecten yessoensis.     

The Current Status of Populations of the Sea Cucumber <Emphasis Type="Italic">Apostichopus japonicus</Emphasis> (Selenka, 1867) in the Far Eastern Marine Reserve

The spatial distribution of the sea cucumber Apostichopus japonicus (Selenka, 1867) in the Far Eastern Marine Reserve was studied using scuba. The abundance, size composition, population density, and distribution of A. japonicus were determined. The population density of this species at the mainland coast was higher than in waters around islands in the reserve. Seasonal movements of sea cucumber were observed: in autumn large individuals migrate to greater depths, but at the beginning of summer they move to shallow water. The average sizes of individuals and population density of sea cucumber in the reserve do not differ from those in unprotected areas of Peter the Great Bay. A comparative analysis of our own and literature data showed that the current estimates of sea cucumber population density in the reserve are 5?7 times lower than estimates for the period before the illegal fishing of sea cucumber began in Primorye.     

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.     

The effect of environmental conditions on distribution,growth and life span of <Emphasis Type="Italic">Protothaca euglypta</Emphasis> (Mollusca: Bivalvia)

The distribution and growth of the bivalve mollusk Protothaca euglypta in Peter the Great Bay and at the northern boundary of its area were investigated. It is shown that in some biotopes P. euglypta biomass reaches 1–2 kg/m², which exceeds the estimated values of abundance obtained for most associated species of mollusks. It has been established that local variability of P. euglypta growth rates can be compared with latitudinal variability, and the life span increases from the southern part of the area towards its northern boundary. It has been concluded that P. euglypta occupies a more prominent position in the malacofauna of shallow waters in its abundance, than it was considered earlier.     

The Meiobenthos in the Area of Japanese Scallop Cultivation in Minonosok Bay (Peter the Great Bay,Sea of Japan)

In Minonosok Bay, in a region of long-term industrial mariculture of mollusks, a steady biohydrochemical complex with increased organic matter content has been formed, in which the meiobenthos community was represented by a rather complete set of taxonomic groups of low population density. There were 16 groups (order, class) of the meiobenthos revealed, and the greatest population density was recorded in the central part of the bay under installations with suspended mollusks, (333000 ind./m²). Nematodes dominated in the eumeiobenthos; however, crustaceans prevailed in the bottom water layer and sediments at stations with increased oxygen content. Bivalves and gastropods dominated in the pseudomeiobenthos. Correlation analysis has revealed the dependence of the population density of the total meiobenthos and eumeiobenthos on the type of ground. There were 42 nematode species revealed; Axonolaimus seticaudatus, Enoplolaimus medius, Daptonema sp., Paracomesoma sp., and Oncholaimium paraolium dominated. Three nematode taxocens were discriminated by dominating species in the population density and results of cluster analysis of the data. Detritivorous nematodes prevailed in all types of ground. A correlation was found between the index of species diversity of nematodes and the content of organic carbon in the ground.     

Discovery of larvae of the hermit crab <Emphasis Type="Italic">Diogenes nitidimanus</Emphasis> Terao, 1913 (Decapoda: Diogenidae) in ship ballast waters: Evidence in support of its introduction into Peter the Great Bay

The larva of the hermit crab Diogenes nitidimanus Terao, 1913 was found in the ballast waters of the tanker Minotaur that arrived from the Chinese port of Laizhou (Bohai Bay, Yellow Sea). Earlier, an abundant population of mature adults of D. nitidimanus was found in Vostok Bay (Peter the Great Bay), this suggested the introduction and naturalization of this species in the Peter the Great Bay. The finding of its larva in ballast waters of a ship on the Russia-China route confirms the introduction of this species into Peter the Great Bay.     

The seasonal dynamics and distribution of burrowing shrimp larvae of the infraorders Gebiidea and Axiidea in Amursky and Ussuriysky Bays,the Sea of Japan

The species composition, period of occurrence, density, and distribution of the larvae of burrowing shrimp of the infraorders Gebiidea and Axiidea in Amursky and Ussuriysky bays (Sea of Japan) were studied in May–October 2008. Larvae of eight species of this group were found in plankton samples. The period of occurrence of larvae in the bays was longest in Upogebia major and Nihonotrypaea petalura (4 and 3 months, respectively). Zoeae of the rest of the species occurred in the plankton for no more than 2 months, indicating a single larval hatching during the reproductive season. The average density of gebiidean and axiidean larvae was low and reached the highest values (4 ind./m³) in June in Amursky Bay and in July in Ussuriysky Bay; their contribution to the total density of decapod larvae was not above 18%. In general, larvae of the family Upogebiidae dominated in Amursky Bay and larvae of the Callianassidae were predominant in Ussuriysky Bay. The zoeae of U. major (up to 37 ind./m³) and Nihonotrypaea makarovi (up to 46 ind./m³) were most numerous. Larvae of the family Axiidae were recorded only in very low numbers in both bays.     

Zooplankton of Lake Kandrykul (Republic of Bashkortostan,Russia) under Conditions of Anthropogenic Eutrophication

The species diversity, abundance, and biomass of zooplankton in the pelagic and coastal zones of Lake Kandrykul were studied in 2007–2012. The community was dominated by large Cladocera. The maximum abundance of zooplankton was observed in the anomalously warm 2010. In July, the highest abundance of zooplankton (1300 thousand ind./m³) was recorded near the southern coast in stands of mare′s-tail Hippurus vulgaris; that of biomass (9 g/m³) was found near the northern shore in stands of narrow-leaved cattail Typha angustifolia. The lowest values of the number and biomass of aquatic invertebrates were observed in the pelagial (32 thousand ind./m³ and 0.1 g/m³) and along the M5 motorway stretching aside the northeastern coast (188 thousand ind./m³ and 0.5 g/m³). The Shannon index value (1.3–2.1) corresponded to the meso-eutrophic type of water bodies. In 2007, according to the Mjaemets trophicity index (E), the lake ecosystem was oligotrophic (E 0.11); in 2010–2012 it was mesotrophic (in the pelagial, E value was 0.54; in the open littoral it was 0.76) or weakly eutrophic (E values of protected littoral were 1.52). The estimates of water trophy as assessed by zooplankton are close to those assessed by the number and biomass of phytoplankton (meso-eutrophic type). The rapid eutrophication of the lake ecosystem was revealed. In 6 years the trophic status of the lake changed from oligo-mesotrophic to meso-eutrophic.     

Population Structure of Pacific Cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> in the Southern Part of the Range Based on the Microsatellite Analyses

The population structure of Pacific cod Gadus macrocephalus in the southern part of the range and adjacent regions is studied on the basis of the results of microsatellite analyses. Collected data indicate heterogeneity of this species population within the studied area. According to the obtained F_ST values, Pacific cod from the waters of the Republic of Korea (Yellow Sea side) and northwestern part of the Sea of Okhotsk significantly differ from all other studied regions (Table 4). Significant differentiation was also revealed between samples from the waters of the Tatar Strait and all other regions except for South Kurils Pacific cod (both Sea of Okhotsk and Pacific Ocean sides). These two latter sample collections were similar to each other as well. A low level of differentiation was also shown for the Peter the Great Bay and the East Sea/Sea of Japan waters of the Republic of Korea.     

The effect of bloom of filamentous green algae on the reproduction of yellowfin sculpin <Emphasis Type="Italic">Cottocomephorus grewingkii</Emphasis> (Dybowski, 1874) (Cottoidae) during ecological crisis in Lake Baikal

In shallow water areas of open Lake Baikal, filamentous green alga of the genus Spirogyra grows abundantly. Together with alga of the genus Ulothrix, it forms algal mats. According to our observations from 2010 to 2013, the spawning habitat conditions for the yellowfin sculpin Cottocomephorus grewingkii (Dybowski, 1874) (Cottidae) proved to be significantly disturbed in the littoral zone of Listvennichnyi Bay (southern Baikal), which, in turn, reduced the number of egg layings. With a 100% projective cover of the floor and a high density of green filamentous algae, the shallow-water stony substrate becomes completely inaccessible for spawning of the August population.     

A Genome-Wide Association Study Identifies the Genomic Region Associated with Shell Color in Yesso Scallop, <Emphasis Type="Italic">Patinopecten yessoensis</Emphasis>

The shell color polymorphism widely exists in economic shellfish, which not only results in a better visual perception but also shows great value as an economic trait for breeding. Small numbers of reddish-orange shell Yesso scallops, Patinopecten yessoensis, were found in cultured populations compared to the brown majority. In this study, a genome-wide association study was conducted to understand the genetic basis of shell color. Sixty-six 2b-RAD libraries with equal numbers of reddish-orange and brown shell individuals were constructed and sequenced using the Illumina HiSeq 2000 platform. A total of 322,332,684 high-quality reads were obtained, and the average sequencing depth was 18.4×. One genomic region on chromosome 11 that included 239 single-nucleotide polymorphisms (SNPs) was identified as significantly associated with shell color. After verification by high-resolution melting in another population, two SNPs were selected as specific loci for reddish-orange shell color. These two SNPs could be used to improve the selective breeding progress of true-breeding strains with complete reddish-orange scallops. In addition, within the significantly associated genomic region, candidate genes were identified using marker sequences to search the draft genome of Yesso scallop. Three genes (LDLR, FRIS, and FRIY) with known functions in carotenoid metabolism were identified. Further study using high-performance liquid chromatography proved that the relative level of carotenoids in the reddish-orange shells was 40 times higher than that in the brown shells. These results suggested that the accumulation of carotenoids contributes to the formation of reddish-orange shells.     

The Mediterranean Copepod <Emphasis Type="Italic">Calanipeda aquaedulcis</Emphasis> Kritschagin, 1873 (Crustacea,Calanoida) in the Volga River Reservoirs

The Mediterranean copepod Calanipeda aquaedulcis Kritschagin, 1873 was first recorded in the Kuibyshev Reservoir in August 2015. It has been detected at all surveyed stations from the Volga-Kama reach to the dam of the Zhiguli hydroelectric power plant; the most northern finding of the copepod has been recorded in the mouth of the Kama River (55°24′ N). C. aquaedulcis (0.3–7.3 thous. ind./m³) is in the group of dominant species and forms, on average, 13% of the total abundance and biomass of zooplankton. Comparatively large (1.0–1.4 mm) copepods reproduce intensively; females carry up to 18 eggs (on average 10 ± 0.6). The main part of the population (>90%) are represented by nauplii. The species has been found in smaller quantities (0.04–1.1 thous. ind./m³) throughout the Saratov Reservoir, which is located downstream the cascade. The ecology of the species and its potential importance in the zooplankton of the Volga reservoirs is discussed.     

The size and age structure of <Emphasis Type="Italic">Tridacna crocea</Emphasis> Lamarck, 1819 (Bivalvia: Tridacnidae) in the coastal area of islands of the Cön Dao Archipelago in the South China Sea

In May 2010, an expedition on the research vessel Akademik Oparin explored the populations of the clam Tridacna crocea on reefs of the Bay Canh and Cau islands of the Cön Dao Archipelago in the South China Sea. A retrospective approach using phototechniques revealed a great similarity of the vertical distribution, growth, size, and age composition of the tridacna at these islands. The maximum density of tridacna (25 ind/m²) was characteristic of a depth of about 3 m in the area of reef flat transition to reef slope. The growth of clams can be approximated by a Bertalanffy-type equation: L _t = 133.8[1 ? e ^{?0.1181(t ? 0.2596)}]. The lack of discreteness in the size and age compositions of populations of T. crocea indicated that population recruitment was quite stable over the years. This tends to maintain the population in a relatively stable condition, which enabled us to consider it as a possible reserve for the artificial restoration of populations of the species in impoverished coastal areas of Vietnam.     

Density dynamics of <Emphasis Type="Italic">Notholca squamula salina</Emphasis> Focke (Rotifera) in Lake Wujka,a freshwater Antarctic lake

The Antarctic Lake Wujka (62°09′28.3″S, 58°27′56.3″W), a shallow water body (Z _m  = 1.38 m), situated at c.15 m from the seashore was sampled at two points (Sp 1 and Sp 2) at 3-day intervals from December 2003 to June 2004. The two sampling points differing in location and depth: Sp 1 (Z _m  = 0.50 m) was the shallowest site, located near the lake outlet, while Sp 2 (Z _m  = 1.38 m) was the deepest spot of the lake. The population density of Notholca squamula salina peaked in June (at 114 ind. l^?1) at Sp 1, while at Sp 2 peaked in January (80 ind. l^?1) and May (150 ind. l^?1). Spearman non-parametric correlations with temperature, salinity, total dissolved solids, conductivity and pH revealed effects that characterize N. squamula salina as a species capable of surviving in a range of aquatic environments, but with a preference for high salinity, food and low temperature. It occurred in highest numbers when the diatom Achnanthes lanceolata var. rostrata (Øestrup) Hust., normally a benthic species, was stirred up into the water during storms that also raised the lake’s salinity to above 20 psu.     

The Structure and Density of Aggregations of the Hermit Crab <Emphasis Type="Italic">Pagurus proximus</Emphasis> Komai, 2000 in Epibiosis of the Brown Alga <Emphasis Type="Italic">Costaria costata</Emphasis> (C. Agardh) De A. Saunders, 1895 in the Sublittoral Zone of Vostok Bay,Sea of Japan

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.     

Variations in the Carbon and Nitrogen Isotope Composition of the Crabs <Emphasis Type="Italic">Chionoecetes opilio</Emphasis> (Fabricius, 1788) and <Emphasis Type="Italic">Hyas coarctatus</Emphasis> Leach, 1816 (Crustacea: Decapoda) from the Chukchi Sea

Some regions of the Chukchi Sea shelf are characterized by an unusually high abundance of the benthos. The carbon and nitrogen isotope composition (δ¹³C and δ¹⁵N) of two crab species, Chionoecetes opilio and Hyas coarctatus, which occupy the upper trophic levels in bottom communities in the southern regions influenced by the Anadyr Water (AW) and in the regions exposed to the influence of the Siberian Coastal Current (SCC), was analyzed in order to compare between the trophic characteristics of their benthic communities. It has been found that these two species have similar spatial trends of stable isotope signature variations. As the effect of the productive AW on bottom communities decreases, a substantial depletion of δ¹³C with a simultaneous growth of δ¹⁵N values are observed in crab tissues. The trophic niches of C. opilio and H. coarctatus, which are represented by “isotope” niches as standard ellipse areas in the δ¹³C/δ¹⁵N biplot, significantly overlap in communities of the southern part of the shelf and become completely separated in those of the regions influenced by the SCC. The separation of the isotope niches of C. opilio and H. coarctatus and the simultaneous increase in δ¹⁵N values in both species by more than 3‰ indicate partitioning of the trophic resources between them and elongation of the food chains of both these carnivorous generalists by almost one trophic level in the communities that exist under the influence of less productive waters.     

The distribution of zooplankton and bowhead whales, <Emphasis Type="Italic">Balaena mysticetus</Emphasis> Linnaeus, 1758, in Akademiya Bay,Sea of Okhotsk

The modern pattern of distribution and feeding habits of the bowhead whale, Balaena mysticetus, in the Sea of Okhotsk are studied. The existence of a feeding aggregation of this whale species in the southwesternmost portion (apex) of Ulban Bay has been confirmed. There, the animals feed in shallow waters with depths of 3–5 m, which are only slightly larger than their body height. The quantitative composition and species structure of zooplankton at the stations that were set near feeding whales have been analyzed. In the samples taken in the immediate proximity to the feeding whales, the abundance of zooplankton reached 31409 ind./m³, with the average value of 17565 ind./m³. The lowest abundance, from 56 to 1879 ind./m³ (mean 927 ind./m³), was in the samples from western Konstantin Bay, where bowhead whales were not observed. In 16 samples collected in the immediate proximity to the feeding whales in the shallow waters of Ulban Bay, the average zooplankton biomass was 547.9 mg/m³, which is 3.9 times higher than that in the samples from waters where the whales were absent. Copepods dominated quantitatively at all the stations in Akademiya Bay. The proportion of euphausiids in the zooplankton biomass was lower than 1%, both near the feeding whales and in the absence of whales.     

Larvae and Juveniles of Temperate Bass, <Emphasis Type="Italic">Lateolabrax latus</Emphasis>, Occurring in the Surf Zones of Tosa Bay,Japan

A total of 343 larval and juvenile Lateolabrax latus (9.2–27.0 mm TL) was collected with a small seine in surf zones of Tosa Bay. They are very similar in general morphology to those of the closely related L. japonicus, but can be distinguished from them by the distribution pattern of melanophores on the tail, head spination, proportion of head length to standard length and the 15 or 16 dorsal fin soft-rays. They occurred in surf zones of Tosa Bay from early January to middle May, being most abundant in middle April. Temperatures and salinities of waters where any number of them were collected ranged from 12.2 to 24.0°C and from 23.7 to 34.5%, respectively. Larval and juvenile L. latus have not been reported so far in coastal and shallow waters, and eelgrass beds of southern Japan. It may be possible that they have been confounded with those of L. japonicus. Their occurrence seems to be limited in extremely shallow waters such as surf zones.     

Soil microarthropods and macrofauna in monsoon tropical forests of Cat Tien and Bi Dup-Nui Ba National Parks,southern Vietnam

The abundance, biomass, vertical distribution, and taxonomic composition of soil invertebrates (springtails, macrofauna, and termites) were studied in forest formations differing in edaphic and climatic conditions: lowland forests dominated by Lagerstroemia spp. or Dipterocarpus spp. in the Cat Tien National Park and in a mountain pine (Pinus kesiya) forest on the Da Lat Plateau, southern Vietnam. In the lowland forests, springtails had a relatively low density (10000–12000 ind./m²), but their diversity was high (41–43 species in each forest). The density of large soil invertebrates (without ants and termites) reached 500–700 ind./m² at a biomass of approximately 30 g/m² (with earthworms accounting for up to 230 ind./m² and 19–28 g/m²). Among termites, species of the genera Macrotermes and Odontotermes were dominant. Their total biomass in some areas exceeded 15–20 g/m². In the mountain pine forest, the total biomass of soil macrofauna was approximately 11 g/m², the abundance and diversity of springtails were low (7500 ind./m², 28 species), and wood-destroying species of the genera Schedorhinotermes sp. and Coptotermes sp. dominated among termites.