Spatial distribution and some features of biology of the two-line eelpout Bothrocara brunneum (Zoarcidae) in the Sea of Okhotsk

According to data of integrated trawl surveys, specific features of distribution and some traits of biology of the two-line eelpout Bothrocara brunneum in the Sea of Okhotsk are shown. The species under investigation is spread over the entire sea, and the average density of its distribution averages 0.29 ind./km² or 0.11 kg/km². It is found at depths of 200–1995 m, mainly in the range of 300–900 m. Juveniles inhabit large depths, while large individuals are distributed over the entire slope. Optimal temperature of habitation is 1.5–2.3°C. The main center of reproduction is the slope of the northern part of the sea. In catches, individuals with a length of 6–71 (on average, 41) cm and a weight of 20–2600 (757) g occur. Sexual maturation takes place on reaching a length of 45–50 cm; at the same time, gravimetric increments begin to be ahead of linear ones. Sex ratio is 1 : 1. Sexual dimorphism with respect to sizes was not revealed. Spawning is extended: individuals with mature gonads are found in the summer-autumn period. In net catches, fish aged 4–8 years dominate, while fish aged 2–7 years dominate in trawl catches.     

Specific features of distribution and ecology of Lycenchelys fedorovi (Zoarcidae) in Pacific waters off the northern Kuril Islands

On the basis of material for 1993–2002, data are provided on occurrence, spatial-bathymetric distribution, and size composition of Lycenchelys fedorovi, as well as on species that occur simultaneously with it in catches in Pacific waters off the northern Kuril Islands. This relatively scarce, medium-sized representative of the family Zoarcidae (maximum length of 42 cm, body weight 200 g) during the period of studies occurred only at the site to the south of the Fourth Kuril Strait in the range of depths 220–775 m at the near-bottom temperature of 1.6–4.2°C. The dependence between the depth of catch and sizes of L. fedorovi was analyzed. It was shown that the size of its catches in Pacific waters off the northern Kuril Islands is subjected to some interannual, seasonal, and diurnal dynamics.     

Specific features of distribution,ecology, and dynamics of catches of blotched snailfish Crystallichthys mirabilis (Liparidae) in Pacific waters off the northern Kuril Islands and southeastern Kamchatka

Based on materials of 1992–2002, data on the spatial-bathymetric distribution and size-age composition of blotched snailfish Crystallichthys mirabilis and species accompanying it in catches in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are presented. This relatively large representative of the family Liparidae (maximum length in catches 50 cm, body weight 2150 g) is found throughout the examined area in the depth interval of 76–755 m at near-bottom temperature of ?1.2 to +4.2°C. Maximum catches (over 200–500 individuals or 180–280 kg per hour trawling) year round are recorded off the southeastern extremity of Kamchatka, from the oceanic side of the Shumshu and Paramushir islands and on the beam of the Fourth Kuril Strait in the bathymetric range of 151–350 m. The magnitude of its catches in the examined area is subjected to interannual, seasonal, and diurnal dynamics.     

Specific features of distribution, some features of biology, and the dynamics of catches of smooth lumpsucker Aptocyclus ventricosus (Cyclopteridae) in waters of the Pacific Ocean off the Kuril Islands and Kamchatka

On the basis of data on bottom trawl catches in Pacific waters off the northern Kuril Islands and southeastern Kamchatka (1992–2002), quantitative indices of occurrence of the smooth lumpsucker Aptocyclus ventricosus and the range of preferred habitation temperature are provided. Its spatial and vertical distribution are analyzed, and specific features of size composition and the relationship between the length and weight of the body and between the average weight and the capture depth are considered; the diurnal, seasonal, and long-term dynamics of occurrence and of the amount of average catches is presented; data on the species composition of fish present in catches parallel to A. ventricosus are cited.     

Specific features of distribution and ecology of two species of sea poachers of genus Podothecus (Agonidae) in pacific waters off the northern Kuril Islands and southeastern Kamchatka

According to materials of studies in 1992–2002, data on occurrence, spatial-bathymetric distribution, and size-weight composition of two species of sea poachers of the genus Podothecus (P. accipenserinus and P. sturioides) and species accompanying them in catches in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are provided. The distribution of these relatively large representatives of the family Agonidae (maximum length of the first species is 38 and that of the second species is 33 cm, body weight of both 200 g) noticeably differ. In the period of observations, P. accipenserinus was found in catches only to the north of the Fourth Kuril Strait at depths of 80–570 m at near-bottom temperature of ?0.70 to +4.25°C, while P. sturioides was found over the entire studied area in a wider bathymetric range (85–786 m) exclusively at positive values of near-bottom water temperature (0.10–3.55°C). However, more frequently and in greater amounts, both species of sea poachers were recorded in catches off the southeastern extremity of Kamchatka and from the oceanic side of the Shumshu and Paramushir islands. The relationship between the depth of catch and sizes of P. accipenserinus and P. sturioides was analyzed. It is shown that their occurrence and the magnitude of catches in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are subjected to some interannual, seasonal, and diurnal dynamics.     

Biological features of the sea raven Hemitripterus villosus (Hemitripteridae) in Pacific waters off the northern Kuril Islands and southeastern Kamchatka

Data on the spatial-bathymetric distribution and the size-weight composition of the sea raven Hemitripterus villosus in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are provided. This representative of the family Hemitripteridae is a comparatively scarce, large fish species (maximum length 75 cm, body weight 11.8 kg), which in the study period (1992–2002) was found practically everywhere at the site from 48°00′ to 52°00′ N in the depth interval of 83–496 m at near-bottom temperatures from ?1.2 to 3.5°C. However, during the year, the overwhelming majority of its individuals were recorded in two depth ranges—101–150 and 251–400 m, which is accounted for by seasonal changes in the habitation depths. With an increase in depth, the sizes of H. villosus increase in catches due to the fact that individuals with a body weight smaller than 1.7–1.9 kg reside mainly at depths of up to 300 m, and those with a body weight greater than 2.2–3.0 kg reside at larger depths. It is demonstrated that the occurrence and the amount of catches of H. villosus are subjected to some interannual, seasonal, and diurnal dynamics.     

Spatial distribution and dynamics of catches of Sebastes glaucus, S. iracundus, and S. polyspinis in Pacific waters off the Kuril Islands and Kamchatka

Based on studies of the years 1992–2001, quantitative indices characterizing the occurrence of three rare or little-studied species of rockfish (Sebastes glaucus, S. iracundus, and S. polyspinis) in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are provided. Specific features of distribution (spatial, vertical, and dependence on near-bottom temperatures) are considered. New data on the diurnal, seasonal, and multiyear dynamics of their catches and occurrence, as well as on the length and weight of the body, sex ratio, and sexual dimorphism in the amount and intensity of feeding are cited.     

Specific features of distribution and ecology of two species of armorhead sculpins of the genus Gymnocanthus (Cottidae) in Pacific waters of the northern Kuril Islands and Southeastern Kamchatka

Based on materials of 1992?C2012, data on the occurrence, spatial-bathymetric distribution, and size-weight composition of armorhead sculpin Gymnocanthus galeatus and purplegray sculpin G. detrisus and species accompanying them in catches in Pacific waters of the northern Kuril Islands and southeastern Kamchatka are provided. These comparatively numerous, medium-sized representatives of the family Cottidae (maximal length of the former species 49 cm, weight 1400 g and that of the latter, 48 cm and 1140 g) in the period of study occurred uniformly at depths of 76 to 596 m at a near-bottom temperatures of ?1.2 to + 4.5°C. Their maximum by density concentrations were constantly recorded at the beam of the Fourth Kuril Strait, from the oceanic side of the Paramushir and Shumshu Islands, and off the southeastern extremity of Kamchatka mainly in the lower part of the shelf (depths of 80?C200 m) at temperatures of ?1.0 to +2.5°C. Regularities of spatial-bathymetric distribution of different size groups of these species were analyzed. It was shown that the occurrence and the size of catches of both armorhead sculpins in Pacific waters of the northern Kuril Islands and southeastern Kamchatka are subjected to some inrterannual, seasonal, and diurnal dynamics.     

Specific features of distribution and ecology of sawback poacher Sarritor frenatus (Agonidae) in Pacific Waters of the Northern Kuril Islands and Southeast Kamchatka

According to materials of 1992–2002, data on the occurrence, spatial-bathymetric distribution, and size-weight composition of sawback poacher Sarritor frenatus and species accompanying it in catches in Pacific waters of the northern Kuril Islands and southeastern Kamchatka are provided. This comparatively numerous and relatively small representative of the family Agonidae (maximum length 31 cm, body weight 103 g) in the period of studies was found uniformly at depths of 78-790 m at near-bottom temperature of ?1.2 to ?4.2°C. In spring, summer, and winter months, maximum catches (over 500–1000 ind./h of trawling) were recorded in the southernmost and northernmost sites of the study area in a bathymetric range of 101–500 m; increased concentrations of this poacher were recorded also on the beam of the Fourth Kuril Strait near the southeastern extremity of Paramushir Island only in the autumn period. The ratio between the depth of catch and the sizes of sawback poacher is analyzed, and the data on the composition of its food in waters of the northern Kuril Islands is given. It is shown that the occurrence and amount of catches of this poacher in Pacific waters of the northern Kuril Islands and southeastern Kamchatka are subjected to some interannual, seasonal, and diurnal dynamics.     

Seasonal dynamics in the distribution of demersal fish species in the pacific ocean coast of the northern Kuril Islands and southeastern Kamchatka regarding the near-bottom water temperature

Based on the analysis of multiyear data on the distribution of demersal fish species regarding the near-bottom temperature in the Pacific Ocean coast of the northern Kuril Islands and southeastern Kamchatka, seasonal changes in the habitat temperature for 16 fish species were revealed (preference and weighted average values are given). Functional relationships between the fish catch value and near-bottom water temperature were determined. All the species under study were divided into three groups regarding the near-bottom temperature of habitat: cold water, eurythermal, and warm water.     

Temperature-dependent energy allocation to growth in Antarctic and boreal eelpout (Zoarcidae)

Antarctic fishes display slower annual growth rates than congeneric species from temperate zones. For an analysis of growth in relation to energy turnover, body composition was analysed in two benthic fish species to establish a whole animal energy budget. The Antarctic eelpout, Pachycara brachycephalum, was maintained at 0, 2, 4 and 6°C and the boreal eelpout, Zoarces viviparus at 4, 6, 12 and 18°C. At maximum food supply the weight gain was highest for P. brachycephalum at 4°C. Routine metabolic rate in acclimated Antarctic eelpouts did not differ between temperatures, whereas in Z. viviparus maximized growth benefited from a reduction of metabolic energy demands at 12°C. The lipid content of liver declined with increasing temperature in both species. The thermal window for growth is based on food conversion efficiency and the level of metabolic energy demand and is limited according to the level of aerobic scope available between pejus temperatures.     

Specific features of distribution and ecology of the Japanese dog poacher <Emphasis Type="Italic">Percis japonica</Emphasis> (Agonidae) in Pacific waters off the northern Kuril Islands and southeastern Kamchatka

According to materials of 1992–2002, data on the spatial-bathymetric distribution and size composition of the Japanese dog poacher Percis japonica in Pacific waters off the northern Kuril Islands and southeastern Kamchatka are provided. This comparatively scarce, medium-sized representative of the family Agonidae (maximum length of 46 cm) in the observation period was found in the lower part of the shelf and the upper bathyal over the entire study area from 47°50′ to 52°00′ N at depths of 76–770 m; however, its maximum catches (more than 200 individuals per hour of trawling) were constantly recorded in the spring and autumn months at the traverse of the Fourth Kuril Strait and at the eastern slope of the seamount of the northern link of the external Kuril Ridge, mainly in the range of 251–350 m at a temperature of 1.6–3.0°C. The relationship between the depth of catch and the average weight of P. japonica was analyzed. It was shown that the value of its catches in Pacific waters off the northern Kuril Islands and southeastern Kamchatka is subjected to some interannual, seasonal, and diurnal dynamics.     

A taxonomic study on Saxifraga ser. Radioflorae (Saxifragaceae) in Japan,the Kuril Islands and Kamchatka

Plants of Saxifraga ser. Radioflorae (A. M. Johnson) Zhmylev, now commonly regarded as belonging to the genus Micranthes, including Saxifraga fusca Maxim. and Saxifraga purpurascens Kom. (Saxifragaceae), distributed from Kamchatka to southern Japan through the Kuril Islands, are here taxonomically revised on the basis of floral morphology. The results suggest that the plants can be divided into three groups: 1) those from Kamchatka and the northern Kurils, 2) those from Kunashiri to the Japanese archipelago, through Hokkaido and Honshu, and 3) those from the southern Kurils from Chirpoi to Etorofu Islands. Leaf characteristics and habitat preferences also correlate with these groupings. The first group is identified as Micranthes ohwii ( = Saxifraga purpurascens Kom.), and the second group as M. fusca. The third group is similar to M. fusca in floral proportions, but has petals with non‐revolute margins, larger floral discs and disc and filaments developing throughout anthesis. The third group may be derived from M. fusca, adapted to the coastal environment.     

Aerobic mitochondrial capacities in Antarctic and temperate eelpout (Zoarcidae) subjected to warm versus cold acclimation

Capacities and effects of cold or warm acclimation were investigated in two zoarcid species from the North Sea (Zoarces viviparus) and the Antarctic (Pachycara brachycephalum) by investigating temperature dependent mitochondrial respiration and activities of citrate synthase (CS) and NADP⁺ -dependent isocitrate dehydrogenase (IDH) in the liver. Antarctic eelpout were acclimated to 5°C and 0°C (controls) for at least 10 months, whereas boreal eelpout, Z. viviparus (North Sea) were acclimated to 5°C and to 10°C (controls). Liver sizes were found to be increased in both species in the cold, with a concomitant rise in liver mitochondrial protein content. As a result, total liver state III rates were elevated in both cold-versus and warm-exposed P. brachycephalum and Z. viviparus, with the highest rates in boreal eelpout acclimated to 5°C. CS and IDH activities in the total liver were similar in Z. viviparus acclimated to 5°C and 10°C, but decreased in those warm acclimated versus control P. brachycephalum. Enzyme capacities in the total liver were higher in eelpout from Antarctica than those from the North Sea. In conclusion, cold compensation of aerobic capacities in the liver seems to be linked to an increase in organ size with unchanged specific mitochondrial protein content. Despite its life in permanently cold climate, P. brachycephalum was able to reduce liver aerobic capacities in warm climate and thus, displayed a capacity for temperature acclimation.     

Specific features of spatial distribution of Pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> in waters off the eastern coast of the northern Kuril Islands and the southern extremity of Kamchatka

Spatial distribution of Pacific cod Gadus macrocephalus inhabiting waters off the eastern coast of the northern Kuril Islands and the southern part of Kamchatka has been studied. It is shown that the redistributions of densities of the aggregation of cod during the year occur mainly within the area under consideration. The absence of considerable migrations of cod is related, in particular, to sufficient food availability of abundant hydrobionts: for small-sized groups of cod, the main food are juvenile wall-eyed pollack Theragra chalcogramma and, for medium-sized and large-sized groups, its adult individuals and also Atka mackerel Pleurogrammus monopterygius and squid Belonella borealis.     

Temperature-dependent pH regulation in stenothermal Antarctic and eurythermal temperate eelpout (Zoarcidae): an in-vivo NMR study

Temperature-dependent adjustments of intracellular pH are thought to play a major role in the maintenance of protein function. Comparative studies were carried out in two species from the same fish family (Zoarcidae), the stenothermal Antarctic eelpout (Pachycara brachycephalum) and the eurythermal eelpout (Zoarces viviparus), to find out whether pH regulation is modified by temperature in the closely related species and to what extent the respective pattern differs between eurytherms and stenotherms. Previous invasive studies had compared individual animals sampled at various temperatures and suggested that a decrease in intracellular pH (pHi) values occurs at rising temperatures, as predicted by the alpha-stat hypothesis of acid-base regulation. The present study used non-invasive in vivo ³¹P-NMR spectroscopy in non-anaesthetized, unrestrained fish for long-term online recordings in individual specimens. Control spectra obtained at T=0°C for P. brachycephalum and at 12°C for Z. viviparus indicated low stress conditions, as well as a high stability of energy and acid-base status over time periods longer than 1 week. Temperature changes had no influence on the concentration of high-energy phosphates like phosphocreatine or ATP. Temperature-induced pH changes were monitored continuously in a range between 0 and 6°C for polar, and 12 and 18°C for temperate eelpout. A pHi change of around -0.015 pH units/°C was observed within both species, in accordance with the alpha-stat hypothesis; however, extrapolation to the same temperature revealed different set points of pH regulation in the two species. These findings confirm that an alpha-stat pattern of pH regulation can be found in stenothermal Antarctic animals, at set points deviating from an alpha-stat pattern, however, in a between-species comparison.     

Feeding of the Snailfish Careproctus roseofuscus in Pacific Waters of the Northern Kuril Islands and Southeastern Kamchatka

The paper describes the feeding of two phenotypically different forms of the snailfish Careproctus roseofuscus (Scorpaeniformes, Liparidae) from the Pacific waters of the northern Kuril Islands and southeastern Kamchatka. The diet in the first form is comprised of actiniae. The second form mostly feeds on fish eggs and the amphipod Metopa majuscula Gurjanova. The second form is supposed to be confined to the biocenosis of Ophiopholis aculeata + Spongia.     

Age and growth of spiny dogfish <Emphasis Type="Italic">Squalus acanthias</Emphasis> (Squalidae,Chondrichthyes) in pacific waters off the Kuril Islands

On the basis of materials collected from catches of drift salmon nets in Pacific waters off the Kuril Islands from 2005 to 2006, the age and rate of growth of spiny dogfish Squalus acanthias are considered. Individuals with a length of 67–123 cm and weight of 1140–5970 g aged 10–26 years were represented in catches. In almost all age classes, the length of males was greater and the weight smaller than in females. The lifespan of females is slightly higher as compared to males-26 and 25 years, respectively. The values of K coefficient of the Bertallanffi equation of growth in males and females comprised 0.10 and 0.05 and the calculated values of the asymptotic body length comprised 116.3 cm and 147.2 cm. A relationship was found between the age of spiny dogfish and the spine size: its length (r _s = 0.693), base width (r _s = 0.815), and base length (r _s = 0.823).