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.     

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.     

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.     

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.     

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,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.     

On the Morphology of Arrowhead Flounders of the Genus Atheresthes in the Pacific Waters of the Northern Kuril Islands and Southeastern Kamchatka

This paper presents the results of studies on the morphology of arrowhead flounders, the Kamchatka flounder Atheresthes evermanni (35 specimens), and the American arrowtooth flounder A. stomias (37 specimens) collected in Pacific waters of the northern Kuril Islands and southeastern Kamchatka in 1998–1999. The morphology of the discussed species is compared with that of arrowtooth flounders from other areas. From this comparison, available information on the sharp increase in the density of the American arrowtooth flounder in the surveyed area (since 1997), and similarities in size compositions of the fish in Kuril and Aleutian waters, a conclusion has been made about the penetration of this species from Aleutian Pacific waters into the area of the northern Kuril Islands and southeastern Kamchatka. This is a result of expansion of the geographical range of this species due to general water warming in the northwestern Pacific during the second half of the 1990s.     

Feeding of the Snailfish Careproctus cf. cyclocephalusin Pacific Waters of the Northern Kuril Islands

This paper describes the feeding habits of the snailfish Careproctus cf. cyclocephalus (Scorpaeniformes, Liparidae). The diet consisted mostly of crustaceans, among which decapods predominated comprising up to 69.3% of the mean biomass of food organisms. Small shrimp (Eualus biunguis and E. townsendi) dominated the diet making up over 40.9% of the total stomach fullness index.     

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.     

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.     

Specific features and dynamics of catches of twoline eelpout Bothrocara brunneum (Zoarcidae) in pacific waters near Kuril Islands and Kamchatka

We provide data on the occurrence, spatial-bathymetric distribution, and size composition of twoline eelpout Bothrocara brunneum and species accompanying it in catches in Pacific waters of the northern Kuril Islands and southeastern Kamchatka. This comparatively numerous and relatively large representative of the fam. Zoarcidae (maximum length of 74 cm, body weight 2.98 kg) in the study period (1992?C2002) was found everywhere at depths 198 to 824 m at the near-bottom temperatures of 0.5?C4.2°C. However, its maximum by density concentrations with catches to 150?C160 kg per hour of trawling were constantly recorded on the beam of the Fourth Kuril Strait and at a site southward of it in two ranges of depths-400?C600 and 700?C800 m at near-bottom values of temperature 2.1?C3.0°C. The ratio between the depth of catches and sizes of the twoline eelpout was analyzed. It was shown that the amount of its catches in Pacific waters of the northern Kuril Islands and southeastern Kamchatka is subject to some interannual, seasonal, and diurnal dynamics.     

Distribution and Size and Sex Composition of the Mud Skate Bathyraja taranetzi in the Pacific Waters off the Northern Kuril Islands and Coasts of Southeastern Kamchatka in the Summer Period

Journal of Ichthyology - In the summer period, the mud skate Bathyraja taranetzi lives at depths from ~100 to 757 m in the Pacific waters off the northern Kuril Islands and southeastern Kamchatka;...     

Ontogeny and potential function of poacher armor (Actinopterygii: Agonidae)

Many vertebrates are armored over all or part of their body. The armor may serve several functional roles including defense, offense, visual display, and signal of experience/capability. Different roles imply different tradeoffs; for example, defensive armor usually trades resistance to attack for maneuverability. The poachers (Agonidae), 47 species of scorpaeniform fishes, are a useful system for understanding the evolution and function of armor due to their variety and extent of armoring. Using publically available CT-scan data from 27 species in 16 of 21 genera of poachers we compared the armor to axial skeletal in the mid body region. The ratio of average armor density to average skeleton density ranged from 0.77 to 1.17. From a defensive point of view, the total investment in mineralization (volume * average density) is more interesting. There was 10 times the material invested in the armor as in the endoskeleton in some small, smooth plated species, like Aspidophoroides olrikii. At the low end, some visually arresting species like Percis japonica, had ratios as low as 2:1. We categorized the extent and type (impact vs. abrasion) in 34 Agonopsis vulsa across all 35+ plates in the eight rows along the body. The ventral rows show abrasive damage along the entire length of the fish that gets worse with age. Impact damage to head and tail plates gets more severe and occurs at higher rates with age. The observed damage rates and the large investment in mineralization of the armor suggest that it is not just for show, but is a functional defensive structure. We cannot say what the armor is defense against, but the abrasive damage on the ventrum implies their benthic lifestyle involves rubbing on the substrate. The impact damage could result from predatory attacks or from intraspecific combat.     

Feeding habits the Pacific cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> in oceanic waters of the Northern Kuril Islands and Southeast Kamchatka

This study examines the feeding habits of the Pacific cod Gadus macrocephalus in waters off the eastern coast of the northern Kuril Islands and southern Kamchatka. In November–December 1996, the cod primarily consumed fish, which made up 47.6% of the total food mass. The proportion of cephalopods, fishery offal discarded from fishing vessels, and decapods did not exceed 18.5, 17.4, and 12.2%, respectively. Among fishes, the main prey item of the cod was atka mackerel (15.4%); among cephalopods, octopus (16.8%); among fishery offal, heads of atka mackerel (14.2%); and among decapods, majid crabs (6.4%). The rather low percentage of walleye pollock (7.3%) in the cod diet was due to the decline of the east-Kamchatka walleye pollock stock.     

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.     

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.     

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.     

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.     

The First Record of a Spawning Ground of the Mud Skate Bathyraja taranetzi (Dolganov, 1983) and the Okhotsk Skate B. violacea (Suvorov, 1935) in Pacific Waters off the Northern Kuril Islands

Russian Journal of Marine Biology - A spawning ground of the Mud Skate Bathyraja taranetzi and the Okhotsk Skate B. violacea was recorded for the first time from Pacific waters off the northern...