Species composition and distribution of Zoarcidae in the northern part of the Sea of Japan from the data of trawl surveys

Species composition, ratio, distribution, and size composition of Zoarcidae on the shelf and the upper part of the continental slope of the northern part of Japan at depths of 5 to 700 m were analyzed on the basis of four trawl surveys. In the studied area, nine species of Zoarcidae were found: Bilabria sp., Bothrocara hollandi, Davidijordania lacertina, Lycodes japonicus, L. nakamurae, L. cf. yamatoi, L. tanakae, L. toyamensis, and L. cf. ushakovi. Data on catches, density of distribution at different depths, and size composition are listed for each species. Four species: B. hollandi, L. tanakae, L. nakamurae, and L. cf. yamatoi have the greatest biomass and numbers among zoarcids in the northern part of the Sea of Japan. It was shown that zoarcids from the northern part of the Sea of Japan, similar to most demersal fish, perform seasonal migrations from the depths of 200 to 500 m, which they inhabit in the summer period, to depths larger than 400 m in the winter. It was found that the most common species of Zoarcidae (B. hollandi, L. tanakae, L. nakamurae, L. cf. yamatoi, and L. toyamensis) dwell mainly in waters of the intermediate water mass and the upper part of the Sea of Japan water mass. These species are abundant at depths larger than 200 m, which permits assigning them to a mesobenthal ecological group. All of the studied species of Zoarcidae from the given region are stenothermal—the temperature range of their habitation is below 2°C, as a rule, from 0.3 to 2.5°C.     

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.     

Variation of coloration in <Emphasis Type="Italic">Lycodes yamatoi</Emphasis> Toyoshima, 1985 (Pisces: Zoarcidae) in the northern Sea of Japan

Specimens of eelpouts were found in the northern Sea of Japan that were externally similar to Lycodes yamatoi Toyoshima, 1985, but their coloration differed from the coloring known for this species. Comparative analysis of meristic characters and sequence comparison of mtDNA COI and cytb gene fragments did not reveal distinctions between specimens with different types of coloration. All studied specimens belong to L. yamatoi. The live color pattern of L. yamatoi is characterized by high variation, with two main types of coloration, “dark” and “bright.”     

New data on eelpouts (Pisces: Zoarcidae) from the south-western part of the Sea of Japan

On the basis of standard trawl survey made at the shores of the Republic of Korea in the Sea of Japan, species composition, ratio of species in catches, and size composition of eelpouts (fam. Zoarcidae) at depths 123–330 m is analyzed. Five species of eelpouts are found in the investigated region: Bothocara hollandi, Lycodes nakamurae, L. sadoensis, L. tanakae, and Petroschmidtia toyamensis. For the first time for the south-western part of the Sea of Japan, quantitative characteristics of distribution, size composition, and bottom temperature of capture are reported for each eelpout species. L. sadoensis is a common species in this region.     

Distribution and some features of the biology of the eelpout Lycodes tanakae Jordan et Thompson, 1914 (Perciformes: Zoarcidae) in the Tatar Strait, Sea of Japan

Based on data from studies that were performed in 2006, 2007, and 2009, we analyzed the distribution and some features of the biology of the eelpout Lycodes tanakae, which inhabits the Tatar Strait. The young of this species (<30 cm in TL) predominantly occur to the north of 50° N. The largest individuals (>71 cm in TL) are found to the south of 49° N and medium-sized fish occur throughout the studied area. In the Tatar Strait, L. tanakae inhabits the 50?C615 m depth range, but the majority of the eelpouts (67.9%) were caught from depths of 200?C600 m. Small individuals of this species (<30 cm in TL) occur at depths of 50?C200 m, while medium-sized and large fish (>30 cm in TL) can be found at all depth horizons that were surveyed. The mean linear size of L. tanakae increases with an increase in the depth of their habitat. The relationship between the spatial distribution of L. tanakae and water temperature regime is discussed. The nutritional spectrum of L. tanakae includes 18 food items, with fish and shrimp predominating. Young L. tanakae (<30 cm in TL) are benthophages, 41?C50-cm individuals feed mainly on cephalopods and fish.     

Seasonal migrations of pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> (Gadidae) off the eastern coast of Kamchatka

On the basis of materials of bottom trawl surveys of 1974–1992, data of commercial statistics of 1995–2005, as well as literature sources, on the dynamics of seasonal distributions of cod Gadus macrocephalus and its migrations off eastern Kamchatka are studied. In the southeastern part of the shelf of the peninsula, from Cape Lopatka to Kronotskii Bay inclusively, as compared to its northeastern part, in the cold period of the year, a considerable increase in the density of distribution and the commercial catch of the cod are recorded. In the warm period, the density of its distribution and catch, on the contrary, are higher in the northeastern part of the Kamchatka shelf, in Kamchatka Bay, as well as in the Karaginskaya commercial subzone. This suggests that the cod performs rather extended seasonal migrations during which its considerable part winters and spawns off the southeastern coast of Kamchatka and feeds off the northeastern coast, in Karaginskii and Olyutorskii bays, and, possibly, more to the northeast. At the same time, a noticeable part of cod does not perform extended migrations and throughout the year inhabits eastern Kamchatka bays and adjoining waters. Both types of migratory behavior are characterized by seasonal changes in the habitation depth: in the warm period of the year, cod inhabits comparatively small depths near the coast and, in the cold period, comparatively large depths in the external part of the shelf and the upper section of the continental slope.     

Summer distribution of the purplegray sculpin <Emphasis Type="Italic">Gymnocanthus detrisus</Emphasis> (Cottidae) in Waters of Primorsky Krai,Sea of Japan

Results of trawl catches show that in the summer period, in the waters of Primorsky Krai, Russia, Sea of Japan, the purplegray sculpin Gymnocanthus detrisus occurs at depths of 20 to 411 m, preferring the range 80–250 m. The temperature of the species’ habitat varies from 0.8 to 8.6 ° C, and the optimal one is 1.2–2.2 °C. G. detrisus occurs at the preferred depths more frequently in the southern area—the Peter the Great Bay, which is more favorable for foraging; in the area of North Primorsky Krai it was found both at greater and lesser depths. The latter is probably determined by the more limited spreading of waters with unsuitable temperatures for the species there. The body size of the purplegray sculpin grows with depth. Juveniles avoid depths over 200 m, where inflow of low-temperature waters is recorded. G. detrisus, which inhabits waters of Primorsky Krai, is represented mainly by females; the proportion of males exceeds that of females only in the 21–27 cm size group. This may be related to the lower growth rate in males after maturation as compared to females.     

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.     

Specific features of distribution and some features of biology of Korean flounder <Emphasis Type="Italic">Glyptocephalus stelleri</Emphasis> (Pleuronectidae) in waters off Kamchatka in the Sea of Okhotsk

According to materials of 1997–2002, the characteristic of the spatial-bathymetric distribution, size and age composition, size and sex structure, and feeding of the Korean flounder Glyptocephalus stelleri in the summer period in waters off Kamchatka in the Sea of Okhotsk (the site from 51°15′ to 57°20′ N, depths of 10–300 m) is given. It is shown that throughout the observation period, maximum catches of this flatfish were constantly observed at two sites of the western Kamchatka shelf (51°20′–53°00′ N and 55°00′–56°00′ N) in the zone exposed to the effect of anticyclonic gyres in the range of depths 101–200 m at the near-bottom temperature below 2°C. Unlike other habitat areas, off the coast of western Kamchatka, G. stelleri in the summer time is quite frequently found at negative temperature values, which is obviously determined by the specifics of thermal conditions of the eastern part of the Sea of Okhotsk. It was established that, in this species of flatfish, sex dimorphism is distinctly pronounced in sizes—males are considerably smaller than females whose relative number among individuals with a length larger than 50 cm reaches 100%. The main items of feeding of G. stelleri at the western Kamchatka shelf in the summer period are oligochaetes.     

Ichthyofauna composition in the mesobenthal of Peter the Great Bay (Sea of Japan)

Based on our data, 76 species of fish from 57 genera and 19 families are found in the mesobenthal of Peter the Great Bay. At depths greater than 200 m in the open part of the bay, no less than five species occur that are lacking closer to the coast; twenty species are capable of descending to a larger depth than was previously assumed. The species composition of fish in the mesobenthal is impoverished during the period of the hydrological summer and is considerably enriched in the cold time of the year, which is related to the wintering migrations of many species from shelf waters to the continental slope. Mass, common, and rare, as well as permanently occurring fish are determined for each hydrological season. The lowest fish biomass is observed in the warm time of the year, and the highest in winter and spring. Specific features of the spatial and temporal variation in the composition of mass fish in the mesobenthal are shown.     

Distribution and Some Biological Features of Antlered Sculpin Enophrys diceraus (Cottidae) in Russian Waters of the Sea of Japan

Journal of Ichthyology - In Russian waters of the Sea of Japan, antlered sculpin Enophrys diceraus occurs throughout the year at depths of 4–605 m and temperature of –1.4 to...     

Distribution and some biological features of skate <Emphasis Type="Italic">Bathyraja parmifera</Emphasis> (Rajidae,Rajiformes) in the northwestern part of the Sea of Japan

In the northwestern part of the Sea of Japan, skate Bathyraja parmifera in catches of the bottom trawl occurs at depths of 40 to 830 m at the near-bottom temperature of 0.4–4.9°C. Throughout the year, the skate performs migrations within the continental slope and, in the feeding period, inhabits mainly the depth range of 300 to 500 m. Maximal average density of aggregations of B. parmifera is observed in waters of northern Primorye; minimal average density is observed in Peter the Great Bay and on the Yamato Bank. In catches, skates with a length of 17–130 cm and a weight of 0.5–18.8 kg are recorded; however, fish with a length of 80–115 cm dominate. Individuals with a length of up to 40 cm feed mainly on amphipods, and larger immature and adult individuals feed on decapods, cephalopods, and fish. The value of the daily ration of B. parmifera with its growth decreases from 2.4 to 0.9% of the body weight. Specific ecological features of B. parmifera are a cause of its considerable underfishing by the bottom trawl; therefore, the total resource of this species in the considered region may be at the level of maximal estimates obtained during surveys and comprise no less than 20000 t.     

Lycodes nishimurai, a new deep-sea eelpout (Teleostei: Zoarcidae) from the Sea of Japan

A new zoarcid fish, Lycodes nishimuari, is described on the basis of four specimens from the Yamato Bank, the Sea of Japan, at depths of 642–669 m. Although this species resembles Lycodes diapterus, L. hubbsi, L. pectoralis, L. macrochir, and L. nakamurae in having a deep notch in the pectoral fin and a single lateral line on the body, it is distinguished from them by the following combination of characters: no scales on pectoral fin base; scales on dorsum before dorsal fin origin; suborbital, preopercular, and last postorbital pores with risen rim; whitish lips; no whitish transverse bars on body; pectoral fin membrane and anterior part of dorsal fin membrane without black spots; basal color of vertical fins black. Supplementary material to this paper is available in electronic format at .     

Intraspecies structure of beaked redfish <Emphasis Type="Italic">Sebastes mentella</Emphasis> of the Atlantic and Arctic oceans

On the basis of the results of complex interdisciplinary investigations of the population composition and structure of the beaked redfish Sebastes mentella of the Atlantic and Arctic oceans, its three populations are discerned relatively isolated from each other by the system of permanent marine currents—North Atlantic, Flemish-Cape, and Norway-Barents Sea. The population structure of the species in the southern part of its area corresponds to the model of a local stock. Interaction of the North Atlantic and the Norway-Barents Sea populations well correspond to the model of fluctuating stocks. Redfish aggregations in different biotopes (mesobenthal and mesopelagial) are intrapopulational epigenetic groups. In the period of warm and anomalously warm years, a part of mature specimens from the pelagial of the North Irminger Sea make an irreversible migration to the southern part of the Norwegian Sea and form there mixed aggregations of fish from the North Atlantic and Norway-Barents Sea populations. With consideration of the effect of climatic–oceanological processes, a principally new scheme is elaborated describing the process of seasonal migrations of redfish in the mesobenthal and mesopelagial. The previous views on direction of return migrations of redfish of the Norway-Barents Sea population are reconsidered. Juveniles from the western part of the Barents Sea and Spitsbergen not only supplement the demersal aggregations but also migrate to the pelagial of the Norwegian Sea.     

Catching of Greenland halibut <Emphasis Type="Italic">Reinhardtius hippoglossoides</Emphasis> (Pleuronectidae) on the shelf edge of the Laptev and East Siberian Seas

The first capture of the Greenland (or Black) halibut Reinhardtius hippoglossoides in the Arctic Ocean on the border with the East Siberian Sea (79°03′–79°08′ N 139°59′–141°16′ E, 259–277 m) and the repeated findings of the species in the Laptev Sea (78°03′–78°04′ N 132°56′–133°04′ E, 307 m; 78°33′–78°35′ N 138°44′–138°48′ E, 125 m) are reported. Fish (79 specimens with the length of 15.0–44.5 cm) were caught during four bottom trawlings on the edge of the continental shelf of the two seas in the transformed waters of Atlantic origin, as evidenced by the discovery of the indicator species of these waters—the Glacier lanternfish Benthosema glaciale (Myctophidae)—in one of the stomachs of halibut. The other captures of Greenland halibut in the Arctic were also reviewed.     

New data on the Blue-Eyed Searcher <Emphasis Type="Italic">Bathymaster signatus</Emphasis> (Bathymasteridae,Perciformes) from the northwestern part of the Bering Sea

Special traits of the biology of the Blue-Eyed Searcher Bathymaster signatus are considered on the basis of bottom trawlings in the northwestern part of the Bering Sea in July 2000 at depths of 136–400 m. Its spawning ends in June. Maturation occurs at the length of 27–28 cm. Individual absolute fecundity is 90 351 eggs, the diameter of oocytes is 1.4 mm, and the weight is 1.14 mg. The diet consists mainly of polychaetes followed by (according to significance) hermit crabs, shrimps, and gammarids.     

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.     

Occurrence of skate <Emphasis Type="Italic">Raja pulchra</Emphasis> (Rajidae,Rajiformes) in Russian waters of the Sea of Japan

According to data of long-term observations in Russian waters of the Sea of Japan, it was shown that skate Raja pulchra occurs only off the coasts of western Sakhalin. In all probability, it is a constant inhabitant of these waters during the course of the year; like the overwhelming majority of bottom and near-bottom fish, it performs seasonal bathymetric migrations in autumn, for wintering to the insular slope to a depth of 695 m, and in spring to shallow waters. Maximum length of R. pulchra recorded in catches is 106 cm. The main food items of R. pulchra are decapods and fish. The stock of R. pulchra off the coasts of western Sakhalin is assessed as 520 t.     

Concerning range expansion of the crabGeryon tridens in the Barents Sea

This paper presents data on 48 individuals of the rare high-boreal crab speciesGeryon tridens Krøyer, 1837, retrieved from the stomachs of cod caught in the southwestern part of the Barents Sea and adjacent waters in 1987–1997. There was only one large male with a carapace width of 58 mm; the other individuals were juveniles with carapace widths of 21–48 mm and masses of 3.2–27.5 g. The length: width ratio of the crab carapaceL=(0.85±0.06)H and the dependence of mass on carapace width (cm)W=0.4637H ^2.73 atr=0.99 were calculated. Analysis of the data provides evidence that this crab species is expanding its range to the northeast and is sustaining its invasion of the Barents Sea, where it was first recorded no less than 10–15 years. It is concluded that this species now permanently inhabits the region of the Finmarken and Rybach'ya banks, forming rather dense aggregations there, and, on sites of cod catches, it predominantly inhabits depths of 180–320 m, where the warm Atlantic waters dominate and sand-silt bottoms prevail. These bottoms are favorable for the sheltering of crabs, which have a burrowing mode of life.     

Spatial distribution and life‐history aspects of blackspot seabream Pagellus bogaraveo (Osteichthyes: Sparidae)

Spatial distribution and life history aspects of Pagellus bogaraveo in the eastern Ionian Sea were investigated using the data from 13 different studies carried out in the area from 1983 to 2010. The spatial patterns of the abundance, biomass and mean size showed that the species inhabits the shallow waters of the shelf (<170 m depth) as juveniles up to a certain size (<180 mm total length, L_T), moving to deeper waters of the slope (mainly 400–500 m depth) as adults. The spatial pattern of abundance indicated a continuous distribution of the species in deep waters, with hot‐spot areas of high values, whereas in shallow waters distribution was more discontinuous, with higher concentrations of juveniles in estuaries and brackish waters. The study of biological aspects of the species revealed (1) a difference in the increase in mass between males and females, (2) protandrous hermaphroditism, accompanied by the presence of primary females and males that do not change sex, (3) a sex ratio in favour of females >250 mm L_T, (4) the presence of hermaphrodites between 200 and 370 mm, (5) a long reproduction period from June to March, (6) a size at first maturity around 300 mm and (7) a diet composition of adults based mainly on fishes, and also on opportunistic behaviour in the food scarce environment of deep waters. The results suggest that the species' distribution and feeding strategies are the most appropriate for the oligotrophic eastern Ionian waters and that these conditions result in smaller sizes of the species in the east Mediterranean Sea compared to the west basin and the east Atlantic Ocean, with implications for the growth and reproductive biology of the species.