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.     

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).     

Genus Alexandrium Halim, 1960 (Dinophyta) from the Pacific coast of Russia: Species composition, distribution, and dynamics

At present 8 species of Alexandrium genus have been found in seas and adjacent waters of Russia: A. acatenella, A. catenella, A. insuetum, A. margalefii, A. ostenfeldii, A. pseudogonyaulax, A. tamarense, and A. tamutum. The distribution and population density of Alexandrium species varied within the surveyed area of the Pacific: in the Sea of Japan and Sea of Okhotsk, 7 species were recorded; 3 species were recorded along the Pacific coast of Kamchatka; and 2 species were found in the Bering Sea. A. tamarense was the most widespread and abundant species over the area. A. insuetum was recorded only in the Sea of Japan, and A. catenella, in the Sea of Okhotsk (Terpeniya Bay). The highest concentration of Alexandrium spp. (2–7 million cells/l) was recorded along the Pacific coast of Kamchatka and in the Bering Sea; in the Sea of Okhotsk, a rather high concentration (51000 cells/l) was registered in Aniva Bay; in the Sea of Japan, the highest concentration was recorded in Peter the Great Bay (6000 cells/l). The distribution of cysts (spores) in surface sediments of the Pacific coast of Russia as a whole reflected the pattern of distribution of vegetative cells of Alexandrium. Cysts of Alexandrium cf. tamarense prevailed all over the area, with the maximum concentration along the Pacific coast of Kamchatka. Beyond that type of cysts, insignificant numbers of cysts of Alexandrium cf. minutum were recorded in Peter the Great Bay and Aniva Bay. Analysis of seasonal dynamics revealed that cells of Alexandrium spp. occurred in Peter the Great Bay from June up to September, and along the Pacific coast of Kamchatka from April to October. In the first region, the maximum density was recorded in August; it was provided by A. pseudogonyaulax (59% of the total density of Alexandrium), A. tamarense (35%), and A. insuetum (6%). In the second region, it was recorded in July, thanks only to development of A. tamarense.     

An autumn bloom of diatoms of the genus Pseudo-nitzschia H. Peragallo, 1900 in Amursky Bay, the Sea of Japan

A bloom of potentially toxic diatoms of the genus Pseudo-nitzschia was observed in October?CNovember 2005 in the northeastern part of Amursky Bay in the vicinity of Vladivostok (northeastern Sea of Japan) at a salinity of 31?C33.5?? and a water temperature of 6?C12°C. The most intense peak of Pseudo-nitzschia spp. cell density (with a mean value of 1428.9 thousand cells/liter), which was recorded in the second half of October after heavy rains, was mainly caused by the massive development of P. multistriata (67% of the total density) and P. calliantha (9%). A negative correlation was found between Pseudo-nitzschia spp. cell density and water salinity and NH4 concentration; a positive correlation was observed between diatom population density and water temperature.     

The morphology and seasonal dynamics of the potentially toxic microalga <Emphasis Type="Italic">Prorocentrum foraminosum</Emphasis> Faust 1993 (Dinophyta) in Peter the Great Bay,the Sea of Japan

The morphology of the potentially toxic dinoflagellate Prorocentrum foraminosum was examined in detail using light and scanning electron microscopy for the first time for the seas of Russia. New morphological features of this species were found and documented. Long-term observations showed that P. foraminosum occurred regularly from April to November in the epiphytic assemblages of Peter the Great Bay. The highest cell abundance was recorded in June (1.5 × 10³ cells/g macrophyte dry weight). This dinoflagellate was also found rarely at a low cell densities in coastal sands.     

Seasonal dynamics and spatial distribution of epiphytic dinoflagellates in Peter the Great Bay (Sea of Japan) with special emphasis on Ostreopsis species

Studies of epiphytic dinoflagellates in Peter the Great Bay, Sea of Japan in 2008–2011 revealed the presence of 13 species. Five of the species are known as potentially toxic: Amphidinium carterae, A. operculatum, Ostreopsis cf. ovata, O. cf. siamensis and Prorocentrum lima. The maximum species richness and abundance of epiphytic dinoflagellates were observed in autumn (from September to October). Ostreopsis spp. were most widely distributed and predominated, amounting to 99% of the total density of dinoflagellates. Multi-year seasonal dynamics of Ostreopsis spp. in Peter the Great Bay showed that these cells appear as epiphyton in August after maximum warming of surface waters (22–24 °С) and disappear in early November, when the water temperature decreases below 7 °С. Ostreopsis spp. proliferation occurred in September, when the water temperature was 17.2–21.0 °C. The highest densities of Ostreopsis spp. were recorded on September 9, 2010 on the rhodophyte Neorhodomela aculeata – 230 × 10³ cells g⁻¹ DW or 52 × 10³ cells g⁻¹ FW. The spatial distribution of epiphytic dinoflagellates was investigated in the near-shore areas of Peter the Great Bay during the second half of September 2010 to evaluate the role of hydrodynamic conditions. Epiphytic dinoflagellates were not found in sheltered sites having weak mixing hydrodynamics. However, the abundances of Ostreopsis spp. were significantly higher at sites having moderate turbulence compared to biotopes experiencing strong wave action. Densities of Ostreopsis spp. were not significantly different on macrophytes with branched thallus of all taxonomic divisions. However, the average cell densities of Ostreopsis spp. on green algae with branched thallus were significantly higher than on green algae having laminar thallus.     

Seasonal and long-term dynamics of sand-dwelling dinoflagellates (Dinoflagellata) in Peter the Great Bay,Sea of Japan

The seasonal and long-term dynamics of the species composition and abundance of dinoflagellates that live in subtidal sands in Russian waters of the Sea of Japan was studied for the first time. The overall species composition of sand-dwelling dinoflagellates in Peter the Great Bay was represented by 67 taxa that belong to 25 genera. Among them, 17 species were recorded for the first time from the seas of Russia, and 8 species were found from the Pacific coast of Russia for the first time. The greatest number of species belonged to the genera Amphidinium, Amphidiniopsis, and Thecadinium. A list of the species composition, including the distribution of taxa throughout the localities and seasons, is presented. Most species of the microalgae are illustrated by light and scanning electron micrographs. The species richness varied from 18 to 44 during the year. In the winter, at a water temperature less than 0°C, the species richness of sand-dwelling dinoflagellates (24–26 taxa) roughly coincided with that found in summer (20–44 taxa). The average density of dinoflagellates ranged from 16 to 1121 cells/cm³ across localities and throughout the year. During the annual cycle, the highest cell density (595 and 2576 cells/cm³) were recorded in the winter–spring period and a slight increase in abundance was observed in fall. This was due to the high cell densities of the dominant species Amphidiniopsis uroensis Toriumi, Yoshimatsu et Dodge, and Thecadinium kofoidii (E.C. Herdman) Larsen. Sand-dwelling dinoflagellates contributed 58 to 80% to the total annual density of the subtidal microphytobenthos in different localities of Peter the Great Bay.     

Finding of the Hydromedusa Hydractinia minima (Trinci, 1903) (Cnidaria: Hydrozoa: Hydractiniidae) in Peter the Great Bay, Sea of Japan

The first finding of the hydromedusa Hydractinia minima (Trinci, 1903) in plankton of Peter the Great Bay (Sea of Japan) is reported. The hydromedusae are 0.24–0.51 mm in bell diameter and 0.25–0.53 mm in height. The size characteristics of the nematocysts of this species (desmonemes and microbasic euryteles) are given. H. minima is present in the plankton of Peter the Great Bay from June through October at water temperatures of 16.4 to 22°C with the highest mean monthly density of 151 ind./m³. The finding of H. minima in Peter the Great Bay extends the area of this species in the North Pacific to the low-boreal subzone.Original Russian Text Copyright © 2005 by Biologiya Morya, Chaplygina, Dautova.     

The formation of the Lycodinae fauna (Perciformes: Zoarcidae) of the Sea of Japan

The subfamily Lycodinae is represented in the Sea of Japan by two genera (Lycodes and Petroschmidtia) and seven species (Lycodes japonicus, L. nakamurae, L. raridens, L. tanakae, L. teraoi, L. yamatoi, and Petroschmidtia toyamensis), which are widely distributed on the shelf and upper continental slope. Based on the geographic and bathymetric distribution of eelpouts of the Sea of Japan and adjacent waters, two groups of closely related species with different types of distribution ranges were distinguished. The first group includes pairs of species that live primarily on the continental slope and are completely isolated in the Sea of Japan or in the Sea of Okhotsk. The second group is comprised of upper interzonal species of the Sea of Japan that are found on the continental slope and shelf, as well as in the southern Sea of Okhotsk from Terpeniya Bay to the southern Kuril Islands. Their related species in the Sea of Okhotsk are mostly found to the north of the Terpeniya Bay. The study of the eelpout distribution and the data on the geological history and paleoclimate of the Far East show that the Lycodinae fauna of the Sea of Japan was formed from North Pacific eelpout-like fishes during the isolation of the sea in the late Pliocene-early Pleistocene, which was concomitant with the general cooling of the Earth’s climate. During the Pleistocene interglacials, the eelpout migrations were unidirectional, from the Sea of Japan to the southern Sea of Okhotsk. The reconstruction of the formation of the Sea of Japan Lycodinae fauna suggests that the related taxa from the Sea of Japan and the Sea of Okhotsk are separate species, while the northern and southern forms of species from the Sea of Japan (Lycodes yamatoi and L. teraoi) are no more than subspecies.     

Ecology and taxonomy of potentially toxic Pseudo-nitzschia species in Lim Bay (north-eastern Adriatic Sea)

The population dynamics of Pseudo-nitzschia in relation to environmental factors was investigated from March 2002 to July 2008 in Lim Bay, in the north-eastern Adriatic Sea. Domoic acid was monitored in the breeding population of Mytilus galloprovincialis from 2005 to 2008. The principal-component analysis of environmental parameters showed that the system is mostly temperature driven. The phytoplankton community was mainly composed of diatoms. Pseudo-nitzschia was the dominant diatom, present in 60% of samples, with a maximum (1.6 × 10⁶ cells L⁻¹) contribution up to 97% of the total diatom abundance. Morphological analysis revealed Pseudo-nitzschia manii and potentially toxic Pseudo-nitzschia pseudodelicatissima, Pseudo-nitzschia pungens, Pseudo-nitzschia fraudulenta and Pseudo-nitzschia calliantha as the dominant species in blooms. Pseudo-nitzschia abundance positively correlated to temperature, phosphate and ammonia in accordance with its maximal abundance in the summer/autumn period when fish farms had a maximum impact on the environment. Domoic acid was detected in M. galloprovincialis in concentrations below regulatory limits, ranging from 0.097 to 0.8721 μg g⁻¹ in five cases from April to October 2005 in Lim Bay, but so far it is not clear which of the species was responsible for DA production. This study is also the first record of P. manii, P pungens and P. fraudulenta species in the Adriatic Sea.     

Distribution of ichthyoplankton in the eastern Peter the Great Bay,Sea of Japan,in June and July of 2007

Comparison of the results of ichthyoplankton surveys conducted at 97 stations in the eastern part of the Peter the Great Bay of the Sea of Japan, in June–July 2007 with the similar research data of the 1950s shows that at present, as was the case 50 years ago, flatfish eggs belonging mainly to the yellowfin sole Limanda aspera and brown sole Pleuronectes herzensteini prevail in the local ichthyoplankton (up to 86%). The highest concentrations of these species’ eggs were recorded in the Vostok Bay and Strelok Bay. The spawning activity of flatfish in 2007 is found to be lower than in the mid 1900s, but the significance of the eastern part of the Peter the Great Bay for flatfish reproduction remains large. The importance of long-term monitoring in this area, which is being subjected to steadily growing anthropogenic impacts, is also proven.     

The distribution,morphology, and taxonomic position of Psychrolutes pustulosus (Schmidt, 1937) (Scorpaeniformes: Psychrolutidae)

The external morphology, osteology, and distribution of a rare fish species Psychrolutes pustulosus (Scorpaeniformes: Psychrolutidae) is examined based on an extensive material for the first time. P. pustulosus shows an extreme degree of reduction of the skeleton among the Psychrolutidae. The comparative morphological analysis confirms the placement of this species in the genus Psychrolutes rather than in Gilbertidia. The new data show that P. pustulosus is widespread in the Sea of Okhotsk. The occurrence of this species in the Sea of Japan (Tatar Strait, Peter the Great Bay) is recorded for the first time. Reports on the findings of P. pustulosus in the Bering Sea are erroneous.     

Foraging conditions of planktotrophic larvae of echinoderms in the southwestern part of Peter the Great Bay of the Sea of Japan

Foraging of planktotrophic larvae of echinoderm common species in the Peter the Great Bay (Sea of Japan) was estimated on the basis of distribution of phyto- and meroplankton. The diversity and abundance of phytoplankton in the studied area in summer months were shown (141 algae species; abundance—up to 743000 cells/m³; biomass—more than 2.7 g/m³ of fresh weight). It was found that in Peter the Great Bay the diet of echinoderm larvae depended on their feeding behavior, duration of their pelagic stage, and abundance and size composition of phytoplankton, included up to several micrograms of fresh algae per larva.     

Hermit crabs Pagurus parvispina Komai, 1997 and Discorsopagurus maclaughlinae Komai, 1995 (Decapoda: Paguridae): New records for Russian waters of the Sea of Japan

The hermit crab Pagurus parvispina Komai, 1997 (Decapoda: Paguridae) was found in Vostok Bay (Peter the Great Bay, Sea of Japan) at a depth of 50?C65 m. Earlier, this species was recorded from the type locality in northern Japan at a depth of 150?C200 m. The finding of P. parvispina in Vostok Bay is its first record in Russian waters and substantially expands the distribution area of this species in the Sea of Japan. Discorsopagurus maclaughlinae Komai, 1995 inhabits Russian waters and was earlier identified as Orthopagurus schmitti (Stevens, 1925); its taxonomical position is discussed.     

Composition of the genus Leptosagitta of the family Sagittidae (Chaetognatha) with descriptions of four new species from coastal waters of the Northwestern Sea of Japan

Keys for the identification of the presently known species of the genus Leptosagitta (fam. Sagittidae) are presented. Four new species of this genus found in shallow waters of Vostok Bay, Amursky Bay (Peter the Great Bay), and Kievka Bay (all of the Sea of Japan) are described in detail: L. kiyashkoi sp. n., L. latyshevi sp. n., L. magna sp. n., and L. pauca sp. n.     

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.     

Microelement composition of the green alga Ulva fenestrata from Peter the Great Bay, Sea of Japan

Concentrations of heavy metals Fe, Mn, Cu, Zn, Pb, Cd, and Ni were determined in the thalluses of the green alga Ulva fenestrata sampled from different locations in Peter the Great Bay (Sea of Japan). According to the metal concentrations in Ulva, the degree of pollution of the surveyed areas in Peter the Great Bay decreases in the following series: Amur Bay > Ussuri Bay > Nakhodka Bay > Vostok Bay > the water area of Far Eastern State Marine Nature Biosphere Reserve. The microelement composition of Ulva from open-shore stations reflects the heavy metal pollution level of water areas as a whole. The concentrations of trace elements in U. fenestrata from closed coastal areas are indicative of marine coastal water pollution from local sources. Generally, metal concentrations in U. fenestrata from Peter the Great Bay are similar to heavy metal levels in non-polluted or weakly polluted coastal areas of the world.     

A population genetic study of the hybrid zone of Mytilus trossulus Gould, 1850 and an introduced species,M. galloprovincialis Lamarck, 1819, (Bivalvia: Mytilidae) in peter the great bay in the Sea of Japan

This paper examines the genetic variability of the Pacific mussel Mytilus trossulus and an introduced Atlantic species, M. galloprovincialis, in the northwestern Sea of Japan (Peter the Great Bay and Kievka Bay). The genotyping of individuals from eight populations was carried out using eight polymorphic enzyme loci and two nuclear DNA markers (Me-5 and ITS-1,2); the occurrence frequency of parent species and their hybrids was determined. The enzyme and nuclear markers demonstrated concordant genetic variation. The genotypes of the native species M. trossulus were predominant in the samples studied. The frequency of the introduced species M. galloprovincialis in the total material was relatively low; however, it reached 42 ± 2% in samples that were collected in Possjet Bay near the town of Zarubino in a zone of active international navigation. In this area the greatest number of hybrids was found as well. It is concluded that the invasion of M. galloprovincialis in the northwestern Sea of Japan is continuing; permanent populations of this mussel appeared in Possjet Bay that were not recorded here previously.     

On the growth of the blue king crab (<Emphasis Type="Italic">Paralithodes platypus</Emphasis>) population in the Peter the Great Bay of the sea of Japan

The causes of the appearance of large blue king crabs (Paralithodes platypus) in Peter the Great Bay for the last decade are discussed. This species is an important commercial resource in the waters of Russian Far Eastern seas, and its general concentrations are related mainly to the sublittoral and upper bathyal zones of the northwestern Bering Sea and the northern Sea of Okhotsk. Until recently, this species has been observed in areas along the continental coast of the northwestern Sea of Japan up to the Peter the Great Bay, where it incidentally showed up in red king crab (P. camtschaticus) and snow crab (Chionoecetes opilio) catches but was also commercially used. This area was considered as the southern periphery of the species range. Since the late 1990s, both male and female blue king crabs have been recorded in trawl and trap catches during research works conducted within the Peter the Great Bay. Since 2002, any commercial catches of shelf crab species are prohibited in the waters south of 47°20′ N because of a dramatic decline in their populations. Since then all the illegally caught crabs, including blue king crabs that are seized live from poachers, are released back into the water in certain places of the bay. In total, at least 29 503 blue king crabs, including egg-bearing females, were released within the period from 2002 to November 2009. At present, the overall blue king crab abundance in Peter the Great Bay, estimated based on the trap catches over an area of 7048 km², is 50500, the abundance of commercial-size males (with a carapace width over 130 mm) is 7500, and the male to female ratio is 1.00: 1.35. The increase in the blue king crab population observed in the bay is the result of the immigration of mature and viable individuals from other areas of its range. After this “uncontrolled introduction” blue king crabs adapted to new conditions, and then began breeding and spreading over the entire area of the bay.