Distribution of the larvae of capelin <Emphasis Type="Italic">Mallotus villosus</Emphasis> and lesser sandeel <Emphasis Type="Italic">Ammodytes marinus</Emphasis> in the White Sea

The early developmental stages of capelin Mallotus villosus and lesser sandeel Ammodytes marinus were the major representatives of the fish larvae in the ichthyoplankton of the open waters of the White Sea in June 2007 and 2010 and in July 2010 and 2011. The larvae of these two species were widely distributed in the White Sea and have been registered in the large bays and in the other parts of the sea. The larvae of capelin and lesser sandeel were the most abundant in Onega Bay and in Dvina Bay and in Gorlo Strait of the White Sea; the larvae of lesser sandeel have also been found in the coastal waters of Kandalaksha Bay. The schooling of the larvae of these two species were characterized by a relatively permanent localization that referred to the spawning grounds; the shape and the location of the schoolings usually depend on the presence and configuration of the areas of the pronounced gradients of the hydrophysical parameters in these areas.     

Phototrophic picoeukaryotes of Onega Bay,the White Sea: Abundance and species composition

The abundance, biomass, and composition of phototrophic picoeukaryotes (PPE, cell size less than 3 μm) were studied in Onega Bay of the White Sea in June 2015. The highest PPE abundance and biomass were registered in the 0–5-m water layer. In the bay, in the 0–5-m water layer, the average abundance and biomass varied from 0 to 36.8 × 10⁴ cell/L and from 0 to 117 μg С/m³, respectively. The Illumina sequencing of V4 region of 18S rRNA gene revealed eight classes of PPE. Mamiellophyceae dominated both by number of reads and by operational taxonomic units. The green algae Bathycoccus prasinos, Ostreococcus tauri, and Micromonas pusila, as well as diatoms Skeletonema marinoi and Minidiscus trioculatus, were identified to the species level.     

Diversity of the microscopic fungi in the littoral sands of the White Sea

For the first time, the study of the mycobiota of littoral sands of the cold-water White Sea was conducted. Twenty-four samples were collected in July–August 2015 in the Onega Bay, the Kandalaksha Bay, and on the Terskii coast. Culture methods were used to detect the number of colony forming units (CFU) and the fungi diversity. The number of CFUs is small; it ranges from 0 to 57 per 1 cm³. A total of 54 morphotypes were detected, of which 22 were identified to the species, seven to the genus level, and 25 were not identified, because they did not form sporulation. Only two species, Cladosorium sphaerospermum and Paradendryphiella salina, were characterized by the relative abundance of more than 10% and the frequency of occurrence of more than 50%. Another five species were found in more than one sample: Penicillium chrysogenum, Cadophora fastigiata, Acremonium fuci, anamorph of Pseudogymnoascus pannorum, and teleomorph of Pseudeurotium hygrophilum. All other morphotypes were found in a small number in single samples. In general, darkcolored forms predominated in the mycobiota both in diversity and in number.     

Summer-autumn ichthyoplankton of the Sea of Okhotsk and the Sea of Japan and special traits of feeding of fish larvae and fry in 2003–2004

In summer-autumn of 2003–2004, the ichthyoplankton of the Sea of Okhotsk comprised 35 species. In this period the most widely distributed and numerous were larvae of the lord Hemilepidotus gilberti, the Pacific stout sand lance Ammodytes hexapterus, and the Sakhalin dab Limanda sakhalinensis. The maximum catches of fish larvae were attributed to coastal waters off eastern Sakhalin and to the shelf of the northern part of the Sea of Okhotsk. In November of 2003, the ichthyoplankton of the Sea of Japan was represented by fish larvae belonging mainly to the boreal ichthyocomplex. The catches consisted predominantly of larvae of the arabesque greenling Pleurogrammus azonus, the ronquil Bathymaster derjugini, and the rockfish Sebastes owstoni. Fish larvae and fry in the northwestern part of the Sea of Japan were caught principally within 43°–45° N and 137°–139° E above the depth 1500–2000 m. The food spectrum of fish larvae in the Sea of Okhotsk and the Sea of Japan comprised over 20 plankters of various size belonging to seven taxa. Irrespective of fish species, the food items common of all fish were copepods Pseudocalanus minutus and Oithona similis. The daily rations were calculated for mass species (Hemilepidotus gilberti, Ammodytes hexapterus, Hexagrammos stelleri, Pleurogrammus azonus, Bathymaster derjugini, and Sebastes owstoni). The larvae of all considered species in the Sea of Japan and in the Sea of Okhotsk fed predominantly in the light period of the day.     

Seasonal and interannual variation of ichthyoplankton off Mauritania

Changes of the quantitative and qualitative composition of ichthyoplankton off Mauritania (21–16° N) in different seasons of 1997–2008 are analyzed. In this area, pelagic eggs and larvae of over 120 fish species belonging to 71 families are recorded. In warm periods, the fish of the tropical fauna intensively spawn off Mauritania; round sardinella Sardinella aurita, West-African horse mackerel Trachurus trecae, and jack mackerel Caranx rhonchus are dominant. In cold periods, active spawning of fish belonging to the tropical fauna is recorded, the most abundant are European pilchard Sardina pilchardus, European horse mackerel Trachurus trachurus, and Atlantic mackerel Scomber japonicus. The spawning biomass of principal commercial fish species is calculated on the basis of the quantity of eggs laid by females. Environmental factors control fluctuations of abundance and distribution of ichthyoplankton in the considered region.     

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.     

Findings of new and rare fish species in the coastal zone of the Crimea (the Black Sea)

Characteristics of seven Atlantic-Mediterranean fish species are provided. Of them, four (gobies—yellow-headed Gobius xanthocephalus and red-mouthed G. cruentatus, incognito blenny Parablennius incognitus, and greater pipefish Syngnathus acus) were either first found in the Black Sea coastal zone of the Crimea, or their findings were doubted, and three species (thin-lipped grey mullet Liza ramada, European barracuda Sphyraena sphyraena, and Black Sea salmon Salmo trutta labrax) are very rare. Over the last decade, the authors recorded 15 fish species; of them, seven Atlantic-Mediterranean species have dispersed along the Crimean coasts by now, one endemic of the far eastern seas (chameleon goby Tridentiger trigonocephalus) has naturalized in Sevastopol Bay, four invading species, freshwater by origin, permanently occur in the estuary zones of the peninsula; the remaining three species are known from single findings and apparently belong to the category of accidental fish. An increase in the species composition of ichthyofauna off the Black Sea coasts of the Crimea results from the on-going process of mediterranization—the invasion in the estuary of freshwater tolerant species at the expense of accidental species that penetrated here either independently or with ballast waters.     

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.     

Species composition and distribution of summer ichthyoplankton in Chupa Estuary (Kandalaksha Bay of the White Sea)

On the basis of ichthyoplankton surveys performed in July 2002 and June 2004–2005 in Chupa Estuary and adjacent waters of Kandalaksha Bay, species composition and distribution of eggs and larvae of fish were studied. Early stages of development of seven fish species were found in the composition of ichthyoplankton. The bulk of abundance of ichthyoplankton was formed of Clupea pallasii marisalbi larvae. It was shown that the sites of aggregation of larval C. pallasii marisalbi from June to July are constant and located in the central and preestuarine areas of Chupa Estuary. Possible routes of their passive migrations within Chupa Estuary and the adjacent water area of Kandalaksha Bay are considered. It is suggested that the drift of larvae beyond the estuary proceeds slowly, and after hatching they can long stay in the estuary concentrating in its central and preestuarine areas.     

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 and interannual variation of ichthyoplankton off the coast of the Moroccan Sahara

Changes in the qualitative and quantitative composition of ichthyoplankton off the coast of the Moroccan Sahara (21–28° N) in different seasons of 1994–2007 are analyzed. In this region, the pelagic eggs and larvae of over 100 fish species belonging to 62 families have been recorded. In cold periods, off the coast of the Moroccan Sahara there is peak in the spawning of fish of the subtropical fauna. The majority of them are European pilchard Sardina pilchardus, common scad Trachurus trachurus, and Atlantic mackerel Scomber japonicus. In warm periods there is intensive spawning of fish of the tropical fauna. Among them, dominants are round sardinella Sardinella aurita, West-African scad Trachurus trecae, and Atlantic bonito Sarda sarda. The spawning biomass of principal commercial fish is calculated by the quantity of eggs laid by females. The environmental factors are indicated that influence the fluctuation of abundance and distribution of ichthyoplankton in the region under consideration.     

First record of the non-indigenous jellyfish <Emphasis Type="Italic">Blackfordia virginica</Emphasis> (Mayer, 1910) in the Baltic Sea

Marine invasions are of increasing concern for biodiversity conservation worldwide. Gelatinous macrozooplankton contain members, which have become globally invasive, for example the ctenophore Mnemiopsis leidyi or the hydromedusae Blackfordia virginica. B. virginica is characterised by a large salinity tolerance, with a brackish-water habitat preference, and by a metagenic life history strategy with an alternation between sexually reproducing planktonic medusae and asexually reproducing benthic polyps to complete the life cycle. In this study we analysed 8 years of ichthyoplankton survey data (2010–2017) from the Kiel Canal and 14 ichthyoplankton summer surveys in the central Baltic Sea (2008–2017). We report the first presence of B. virginica in northern Europe, namely from the southwestern Baltic Sea and the Kiel Canal. In the Kiel Canal, B. virginica was first sporadically sighted in 2014 and 2015 and has developed persistent populations since summer 2016. Changes in size-frequency distributions during summer 2016 indicate active recruitment in the Kiel Canal at salinities between 7 and 13 and temperatures?>?14 °C. Close vicinity to and direct connection with the southwestern Baltic Sea, where B. virginica was observed during 2017, indicate that the Baltic Sea and other brackish-water habitats of Northern Europe are at risk for colonisation of this non-indigenous species. Our results highlight that monitoring activities should consider gelatinous macrozooplankton for standard assessments to allow for the detection of non-indigenous species at an early stage of their colonisation.     

Population structure and variability of Pacific herring (<Emphasis Type="Italic">Clupea pallasii</Emphasis>) in the White Sea,Barents and Kara Seas revealed by microsatellite DNA analyses

Pacific herring, Clupea pallasii, have recently colonised the northeast Atlantic and Arctic Oceans in the early Holocene. In a relatively short evolutionary time, the herring formed a community with a complex population structure. Previous genetic studies based on morphological, allozyme and mitochondrial DNA data have supported the existence of two herring subspecies from the White Sea and eastern Barents and Kara Seas (C. p. marisalbi and C. p. suworowi, respectively). However, the population structure of the White Sea herring has long been debated and remains controversial. The analyses of morphological and allozyme data have previously identified local spawning groups of herring in the White Sea, whereas mtDNA markers have not revealed any differentiation. We conducted one of the first studies of microsatellite variation for the purpose of investigating the genetic structure and relationship of Pacific herring among ten localities in the White Sea, the Barents Sea and the Kara Sea. Using classical genetic variance-based methods (hierarchical AMOVA, overall and pairwise F _ST comparisons), as well as the Bayesian clustering, we infer considerable genetic diversity and population structure in herring at ten microsatellite loci. Genetic differentiation was the most pronounced between the White Sea (C. p. marisalbi) versus the Barents and Kara seas (Chesha–Pechora herring, C. p. suworowi). While microsatellite variation in all C. pallasii was considerable, genetic diversity was significantly lower in C. p. suworowi, than in C. p. marisalbi. Also, tests of genetic differentiation were indicating significant differentiation within the White Sea herring between sympatric summer- and spring-spawning groups, in comparison with genetic homogeneity of the Chesha–Pechora herring.     

The species composition and ecological features of pea crabs of the genus <Emphasis Type="Italic">Pinnixa</Emphasis> White, 1846 (Brachyura: Pinnotheridae) in Peter the Great Bay,the Sea of Japan

This paper provides an overview of pea crabs of the genus Pinnixa White, 1846 (Brachyura: Pinnotheridae) that occur along the Russian coast of the Sea of Japan. Three species of the genus have been recorded for this area: P. tumida Stimpson, 1858, P. rathbuni Sakai, 1934, as well as P. banzu Komai, Nishi & Taru, 2014, which is the first record for the fauna of Russia. All species clearly differ ecologically: P. tumida was found in Posyet Bay in the intestine of the burrowing holothurian Paracaudina chilensis (Müller, 1850); P. rathbuni, in burrows of the echiuroid Urechis unicinctus (von Drasche, 1881); and P. banzu, in tubes of the polychaete Chaetopterus cautus Marenzeller, 1879. The paper also provides a definitive key to Pinnixa species and data on the size, behavior, symbionts, and parasites of P. rathbuni and P. banzu.     

Peculiarities of summer phytoplankton spatial distribution in Onega Bay of the White Sea under local hydrophysical conditions

The species composition and phytoplankton biomass, concentrations of chlorophyll “a” (Chl) and nutrients in the surface water layer, and accompanying hydrophysical conditions were studied in Onega Bay of the White Sea in June 2015. The temperature and salinity of surface water layer and the water column stability varied greatly in the bay. The nutrients' concentrations exceeded the limiting threshold necessary for the phytoplankton development. The phytoplankton abundance was relatively low, averaged as 13.46 ± 9.00 mg C/m³ (total phytoplankton biomass), 0.78 ± 0.43 mg/m³ (concentration of chlorophyll “a”), and 0.18 ± 0.27 mg C/m³ (picophytoplankton biomass). The highest phytoplankton biomass has been registered along the frontal zones. Three phytoplankton communities that differed significantly in their structure have been found.     

Materials on the flora of Bacillariophyta in rivers of the white sea basin in the Republic of Karelia

A total of 290 species and varieties of Bacillariophyta including 32 that were new for the flora of Karelia and 18 that were new for the flora of Russia, have been recorded in phytoplankton in nine rivers of the White Sea basin. The genera Aulacoseira, Pinnularia, Eunotia, and Navicula s. l. are the richest in taxonomy. The maximum species diversity was recorded in the Suma (73), Kolezhma (91), and Chirko-Kem (146) rivers. The following species are the most widespread in the rivers that were under study here: A. ambigua, A. subarctica, A. subborealis, {tiA. tenella}, Asterionella formosa, and Tabellaria flocculosa.     

The Distribution of Macrozoobenthos Taxa,as Potential Indicators of Vulnerable Marine Ecosystems in the Western Bering Sea: 1. Anadyr Bay Area

The composition of common species in some macrozoobenthos groups that are considered as potential indicators of vulnerable marine ecosystems (VME), in the Anadyr Bay area, Bering Sea have been determined based on the results of four benthic surveys using a benthic grab sampler (1985, 2005) and a bottom trawl (2008, 2012). These are soft corals (Gersemia rubiformis), sponges (Myxilla incrustans, Halichondria panicea, and Semisuberites cribrosa), ascidians (Halocynthia aurantium and Boltenia ovifera), bryozoans (Cystisella saccata and Flustra foliacea), barnacles (Chirona evermanni), and the brittle star (Gorgonocephalus eucnemis). The distribution of these animals has been mapped. Aggregations of immobile sestonophages (the former five groups) are formed on hard coarse-grained and mixed sediments in waters with higher hydrodynamic activity (along the southwestern and northeastern coasts of the Anadyr Bay, mainly at depths of 80–90 m). In some cases, sponges and bryozoans in the southern part of the area can descend to a depth of 250 m (in the Navarin Canyon). The mobile filterer G. eucnemis forms aggregations mainly on soft sediments in the central part of Anadyr Bay, at depths of 50–270 m, in the area of a localized spot of near-bottom cold water. According to the results of trawl surveys conducted in 2008 and 2012, the mean biomass of the sponges, the brittle star G. eucnemis, and the sea squirt B. ovifera did not change, whereas the mean biomass of the barnacle Ch. evermanni and sea peach H. aurantium decreased by 6.5 and 3.7 times, respectively. Since the level of trawl fishing activity in the region is not high, the hypothesis has been proposed that the decrease in the abundance of the latter two species is presumably caused by the natural dynamics of their population or can be related to the factor of randomness, as these species are caught in their mosaically distributed local aggregations.     

Ichthyoplankton of Rockall-Hutton seamounts

Species composition and quantitative distribution of ichthyoplankton in areas of the Rockall-Hutton seamounts are considered in a comparative aspect, and the spawning biomass of the blue whiting Micromesistius poutassou, the main commercial item of this region, is calculated. Maximal catches of eggs and larvae were recorded in spring 2006 and minimal catches were recorded in spring 2003. The highest number of species was recorded in March–April 2006 and the lowest number was recorded in March–April 2003. In the seasons under consideration, M. poutassou had the most mass of the commercial fish in the plankton; haddock Melanogrammus aeglefinus and gurnard Eutrigla gurnardus were less numerous. Of the noncommercial species, the larvae of myctophids (fam. Myctophidae) and of other mesopelagic fish occurred more frequently in the ichthyoplankton. The species and quantitative composition of ichthyoplankton was considerably more numerous at the Rockall Seamount than at the Hutton Seamount, which is explained by specific oceanographic features of the region and the more southern location of this seamount. According to the data of the ichthyoplanktonic method, the spawning biomass of M. poutassou exhibited a tendency for an increase in the period of 2002 to 2006.     

Molecular genetic markers of intra- and interspecific divergence within starfish and sea urchins (Echinodermata)

A fragment of the mitochondrial COI gene from isolates of several echinoderm species was sequenced. The isolates were from three species of starfish from the Asteriidae family (Asterias amurensis and Aphelasterias japonica collected in the Sea of Japan and Asterias rubens collected in the White Sea) and from the sea urchin Echinocardium cordatum (family Loveniidae) collected in the Sea of Japan. Additionally, regions including internal transcribed spacers and 5.8S rRNA (ITS1–5.8S rDNA–ITS2) were sequenced for the three studied starfish species. Phylogenetic analysis of the obtained COI sequences together with earlier determined homologous COI sequences from Ast. forbesii, Ast. rubens, and Echinocardium laevigaster from the North Atlantic and E. cordatum from the Yellow and North Seas (GenBank) placed them into strictly conspecific clusters with high bootstrap support (99% in all cases). Only two exceptions–Ast. rubens DQ077915 sequence placed with the Ast. forbesii cluster and Aph. japonica DQ992560 sequence placed with the Ast. amurensis cluster–were likely results of species misidentification. The intraspecific polymorphism for the COI gene within the Asteriidae family varied within a range of 0.2-0.9% as estimated from the genetic distances. The corresponding intrageneric and intergeneric values were 10.4-12.1 and 21.8-29.8%, respectively. The interspecific divergence for the COI gene in the sea urchin of Echinocardium genus (family Loveniidae) was significantly higher (17.1-17.7%) than in the starfish, while intergeneric divergence (14.6-25.7%) was similar to that in asteroids. The interspecific genetic distances for the nuclear transcribed sequences (ITS1–5.8S rDNA–ITS2) within the Asteriidae family were lower (3.1-4.5%), and the intergeneric distances were significantly higher (32.8-35.0%), compared to the corresponding distances for the COI gene. These results suggest that the investigated molecular-genetic markers could be used for segregation and identification of echinoderm species.