The First Finding of the Actinia Synandwakia hozawai in the Sea of Okhotsk

The finding of the actinia Synandwakia hozawai in the coastal waters of northern Sakhalin (Sea of Okhotsk) suggests a wider range of this species, which was previously only known to inhabit the coastal waters of eastern Japan. Data are presented on the morphology of the S. hozawai specimen from the Sea of Okhotsk and the types of its nematocysts.     

The karyotype of the flathead sculpin Megalocottus platycephalus platycephalus (Pallas, 1814) (Pisces: Cottidae) from Odyan Bay,Sea of Okhotsk

This study deals with the karyotype of the flathead sculpin Megalocottus platycephalus platycephalus (Pallas, 1814) (family Cottidae) from Odyan Bay of the Sea of Okhotsk. 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 the telomere parts of the short arms of two large subtelocentric chromosomes. Variations in the number of nucleolar organizer chromosomes and in the number of NO-staining blocks were found. Comparison of the karyotype of M. p. platycephalus with the karyotypes of previously studied species of the genus Myoxocephalus from the Sea of Japan and the Sea of Okhotsk revealed their significant similarity in the main features and difference in the number and localization of NORs.     

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.     

Occurrence of the Chilean devil ray Mobula tarapacana (Elasmobranchii: Batoidea: Myliobatiformes) in the Sea of Okhotsk: first record from cold temperate waters

The northernmost record for Chilean devil ray Mobula tarapacana, a circumglobal species that occurs in tropical, subtropical and limited warm temperate waters, is described. An adult female was caught incidentally in the Sea of Okhotsk on 17 September 2011. This specimen is the first confirmed occurrence of devil rays Mobula spp. in cold temperate waters.     

Restriction fragment variation of the mitochondrial gene of cytochrome b in some taxa of the Eelpout Family (Pisces, Perciformes, Zoarcidae) from the northern Sea of Okhotsk

The first analysis of restriction fragment length polymorphism (RFLP) of the mitochondrial gene of cytochrome b of fish from the Eelpout Family (Zoarcidae) from the northern Sea of Okhotsk has been performed. The mean genetic distances between the subfamilies Zoarcinae and Lycodinae, subfamilies Lycodinae and Gymnelinae, and subfamilies Zoarcinae and Gymnelinae are 11.14, 13.87, and 14.00%, respectively. Species of the genus Lycodes (Lycodinae) are characterized by a mtDNA small divergence (on average, 2.04%) and are divided into two groups on the basis of lateral line morphology. Magadania skopetsi, an endemic of Tauiskaya Bay of the Sea of Okhotsk, is genetically close to Hadropareia middendorffii from the same subfamily (Gymnelinae). The mtDNA sequences of species from the genus Lycogrammoides (Lycodinae) differ by 3.83%. The genetic differences between the eelpout Zoarces elongatus Zoarces sp. (d = 4.54%) suggest that the latter is a separate species.     

The distribution and abundance of scyphomedusae (Scyphozoa) of the family Ulmaridae in the pelagic zone of the Sea of Okhotsk and the Sea of Japan

The distribution and abundance of jellyfish of the family Ulmaridae was studied based on the data of trawl surveys conducted in the Sea of Okhotsk (1998–2006) and the Sea of Japan (2003) in the fall. The jellyfish Aurelia aurita mainly inhabits the waters of the Sea of Japan, while in the Sea of Okhotsk small quantities of this species were recorded in southern areas, and solitary individuals, off North Sakhalin. Aurelia limbata tends to shelf waters of the Sea of Okhotsk, being less abundant in the southern deepwater area and in the Sea of Japan. Phacellophora camtschatica, in contrast, aggregates mostly over deep basins, whereas in shallow areas a significant quantity of this species was found only off West Kamchatka. In the northern Sea of Okhotsk, the species A. limbata dominated in biomass and abundance among Ulmaridae. During the studied period, its biomass varied from 27 to 803 kg/km² and its abundance varied from 69 to 1706 ind/km². In the southern Sea of Okhotsk, as a rule, P. camtschatica prevailed (1–16 kg/km² and 6–46 ind/km²). In the Sea of Japan, the most abundant species was A. aurita (29 kg/km² and 104 ind/km²). The jellyfish size structure in catches is presented.     

Comparative analysis of the karyotype of the sculpin Myoxocephalus ochotensis (Pisces: Cottidae) from the Odyan Bay of the Sea of Okhotsk

The karyotype of the endemic Okhotsk Sea sculpin Myoxocephalus ochotensis Schmidt (Cottidae) from Odyan Bay was studied. The number and morphology of chromosomes were determined, 2n = 42 (2 metacentric, 20 subtelocentric, and 20 acrocentric chromosomes), NF = 44. Variability of chromosome number was not revealed; no difference between male and female karyotypes was found. The karyotype of the Okhotsk sculpin M. ochotensis was compared with karyotypes of the Far East Steller’s M. stelleri (Tilesius), snow M. brandti (Steindachner), and plain M. jaok (Cuvier) sculpins, and to the European shorthorn sculpin M. scorpius (Linnaeus) from White Sea. Their similarities and distinctions were shown.     

The species composition and quantitative distribution of the diatom genus Pseudo-nitzschia H. Peragallo, 1990 in Russian waters of the Sea of Japan and the Sea of Okhotsk

This paper studies the species composition and quantitative distribution of diatoms that belong to the genus Pseudo-nitzschia in the Russian waters of the Sea of Japan and the Sea of Okhotsk. In total, 11 species of this genus were found in the area, including 7 that are known as being potentially toxic. The highest concentrations of Pseudo-nitzschia microalgae (1.4 × 10⁶–2.7 × 10⁶ cells/L) were found in the summer and autumn in the Peter the Great Bay of the Sea of Japan and the lowest concentrations (2.5 × 10²–1 × 10⁴ cells/L) were found in the Sakhalinsky and Akademiya bays of the Sea of Okhotsk. The species diversity of potentially toxic diatoms was greatest (seven species) and the cell concentrations highest (over 6 × 10⁵ cells/L) in the Peter the Great Bay, Sea of Japan, and in the Aniva Bay, Sea of Okhotsk. The density of potentially toxic species was highest near the northeastern coast of Sakhalin Island, in the Amur River estuary, and in adjacent waters. This paper also presents geographical distribution maps of Pseudo-nitzschia species and maps of the density distribution of potentially toxic microalgae over the studied area and identifies potential amnesic shellfish poisoning areas.     

Feeding of Okhotsk sculpin Myoxocephalus ochotensis (Cottidae) in the Gulf of Shelikhov

Feeding of the Okhotsk sculpin Myoxocephalus ochotensis, an endemic of the northern part of the Sea of Okhotsk, is studied on the materials of two bottom trawl surveys in 2004–2005 in the Gulf of Shelikhov. The quantitative and qualitative characteristics of its food spectrum depending on the linear sizes are given. It is revealed that its food spectrum includes the crustaceans, mollusks, fishes, and polychaeta. In the composition of crustaceans being a basic food group, the gammarids and small species of shrimps are replaced by crabs and large shrimps as the fishes grow. It is found that the individuals of the Okhotsk sculpin with a length from 15 to 20 cm have a mixed type of feeding, and the fishes larger than 20 cm are predators to a greater extent.     

Some features of biology of butterfly sculpin Melletes papilio (Cottidae) in the pre-Kamchatka waters of the Sea of Okhotsk

Data on occurrence, spatial-bathymetric distribution, size-weight composition, size-sex structure, and food composition of butterfly sculpin Melletes papilio in the Sea of Okhotsk waters off the Kamchatka shores are given. This species is a relatively nonnumerous representative of fam. Cottidae with maximal length 42 cm and body weight to 960 g. In summer time, the species occurs practically over the whole study region at depths of 15 m to 285 m and water temperature near the bottom from ?0.9 to 10.7°C. However, the majority of individuals of this species occur within the depths range of 41–80 m in the cold intermediate water level at minimal positive (<2.0°C) and negative values of near-bottom water at sandy-silty grounds. The correlation between the harvesting depth and fish size has been analyzed. The variations of the feeding spectrum with growth of butterfly sculpin are described for the pre-Kamchatka waters of the Sea of Okhotsk.     

Finding of the shantar snailfish Liparis schantarensis (scorpaeniformes: Liparidae) in the taui bay region of the Sea of Okhotsk

Six specimens of the Shantar snailfish Liparis schantarensis are found in the Taui Bay region of the Sea of Okhotsk for the first time. The new location is approximately midway between two the previously known areas of habitation of the species. The mature males of Shantar snailfish show two peculiarities which were not noted for the species until now: the essential lengthening of rays of the anterior dorsal fin, and the presence of skin spines on the body.     

Variability of cytochrome b gene of mitochondrial DNA of pink salmon Oncorhynchus gorbuscha (Walbaum) from the rivers of the continental coast of the Sea of Okhotsk and Zavyalov Island

Data on the structure and variability of the nucleotide sequence of the cytochrome b (cytb) gene fragment of mitochondrial DNA (mtDNA) in pink salmon of adjacent generations from the rivers of the continental coast of the Sea of Okhotsk and Zavyalov Island were obtained. The differences between adjacent generations were discovered. By the marker studied, pink salmon of the even-year line are characterized by a high level of genetic variability. It is shown that reproductive isolation has led to accumulation of specific mutations of the mtDNA cytb gene in each line and, consequently, to their divergence. Analysis of the data showed that the share of intrapopulation genetic variability of northern Sea of Okhotsk pink salmon accounts for about 91%. The intergroup component that was calculated for adjacent generations of the species is relatively small and is 9%, which seems to be indicative of a relatively recent divergence of adjacent generations of salmon.     

Distribution of the Eelpout Lycodes soldatovi(Pisces: Zoarcidae) over the Continental Slope of the Sea of Okhotsk

The eelpout Lycodes soldatovi was found at depths of 153 to 1005 m in the Sea of Okhotsk; however, it usually inhabits the depth range of 400 to 800. The mean and maximum abundance and the biomass of this species were 198.5 and 1037 individuals per km² and 173.7 and 1275 kg/km², respectively. In view of the data on the distribution of young fish (up to 30 cm in total body length) and the reports on the absence of Lycodes larvae, a hypothesis was developed that this species spawns predominantly in the waters off western Kamchatka and eastern Sakhalin at the depth range of 700 to 900 m. Large individuals (>50 cm) exhibit higher migratory activity and are more tolerant of environmental conditions. That is why they are encountered throughout the distribution area of this species, even in subzero temperature areas. Lycodes soldatovi seems to be a typical inhabitant of the Sea of Okhotsk, except for the waters off the South and Central Kuril Islands and the Pacific waters off the North Kuril Islands.     

Molecular genetic analysis of the Shantar summer group of bowhead whales (Balaena mysticetus L.) in the Okhotsk Sea

The results of molecular genetic analysis (full-length sequences of the mtDNA cytochrome b gene and control region and the allelic composition of 14 microsatellite loci) of 65 tissue samples from the endangered bowhead whale (Balaena mysticetus) population of the Sea of Okhotsk are presented. The data obtained enable the suggestion that at present, the state of the Sea of Okhotsk bowhead whale population is relatively stable.     

Specific features of distribution and size indices of four poorly studied species of sculpins (Cottidae) in the Okhotsk Sea Waters off Kamchatka

Evidence on occurrence in catches and characteristic of the spatial-bathymetric distribution and size indices of four species of Cottidae—frog sculpin Myoxocephalus stelleri, brightbelly sculpin Microcottus sellaris, antlered sculpin Enophrys diceraus, and furseal sculpin Stelgistrum stejnegeri—in summer-autumn months in the Okhotsk Sea waters off Kamchatka (site from 51°15′ to 57°20′ N, depths of 11–100 m) are provided. The first three species occur mainly in the northern part of the shelf above 54° N at depths smaller than 30–40 m within a comparatively well warmed surface water mass of seasonal modification at near-bottom temperature values above 6°C at various solid grounds. Maximum catches of S. stejnegeri were recorded only at a site of the western Kamchatka shelf from 54°00′ to 54°20′ N on pebbly-stony ground in a narrow bathy-metric range of 41–60 m on the boundary between the well warmed surface water mass of autumn modification and the cold intermediate water mass at a water temperature below 2°C. Evidence on the size-weight indices of the studied species of Cottidae in trawl catches in the Okhotsk Sea waters off Kamchatka in the study period is provided.     

Carcinophyly of fish of the genus Careproctus (Scorpaeniformes: Liparidae) in waters of southeastern Sakhalin (Sea of Okhotsk)

In waters of southeastern Sakhalin (Sea of Okhotsk), clutches of snailfishes of the genus Careproctus containing eggs at different stages of development or prolarvae were found on gills of the largest individuals (mainly in males) of three species of crabs (Lithodidae)-Paralomis verrilli (clutches were found in 1.4% of individuals), P. multispina (0.8%), and Lithodes covesi (11.6%). With an increase in the carapace width of lithodid crabs, the amount of eggs of snailfishes deposited in them and their diameter increase. More frequently, clutches are located from the left side of the carapace of crabs. Two-side clutches occur in larger individuals of crabs. No direct relationship between the presence of clutches of snailfishes on gills of lithodid crabs with necrosis or reduction of gills was revealed. The form of relations between lithodid crabs and Careproctus snailfishes was defined as “lodging” with different degree of impact on the host.     

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.