West Kamchatka Research Articles

Distinct mechanisms controlling and influencing the supply of clay-sized sediments to the northern shelf of the Sea of Okhotsk since the Last Glacial Maximum

The Sea of Okhotsk is a transitional zone between East Asia and northwestern Pacific Ocean. As a result, its massive thick sediments contain numerous important records of geological past, such as the mechanisms of materials and energy exchanges. However, the scarcity of studies tracing the provenance of clay-sized sediments in the sea has limited the progress of reconstructing the paleoclimate of East Asia. In this study, clay mineral analysis was conducted on 31 surface stations and the LV87–54-1 core. These results were combined with grain-size to provide reliable evidence for distinct mechanisms controlling the influx of clay-sized sediments into the northern shelf of the Sea of Okhotsk since 23 ka. Results of provenance analyses suggested that clay-sized sediments in the northern shelf mainly originated from its northwestern shelf, the Okhotsk–Chukotka volcanic belt, and the Kamchatka Peninsula. Clay-sized sediments of the northern shelf was primarily transported from the northwestern shelf and the Okhotsk–Chukotka volcanic belt after 23 ka, while those analogues from the Kamchatka Peninsula increased after 11.7 ka. Based on variations in clay mineral ratios, sediments from the northwestern shelf were mainly transported by the North Okhotsk Countercurrent, wherein rapid millennial-scale variations were influenced by the high-latitude Arctic Oscillation (from the Last Glacial Maximum to the Last Deglaciation) and the low-latitude East Asian summer monsoon (including the Holocene), respectively. By contrast, the influx of clay-sized sediments from the western Kamchatka Peninsula might be mainly controlled by the intensity of the West Kamchatka Current. From the Last Glacial Maximum to the Last Deglaciation, north and northwest geostrophic winds dominated in winter, and the West Kamchatka Current shifted eastward. Since the Holocene, weakened north and northwest geostrophic winds, but strengthened east winds caused a series of rapid millennial-scale variations in the West Kamchatka Current.

Description of regression models for predicting the dynamics of pink salmon returns in the Kamchatka region based on climate-oceanological and population-genetic data

Several regression models for predicting returns of pink salmon in the Kamchatka region are presented. The data for 1990–2023 were analyzed. Among available climatic and oceanological indices, the most suitable for using as predictors for forecasting of pink salmon returns were the Pacific Decadal Oscillation (PDO) index, Western Pacific Cyclonic Index (WP), Arctic Oscillation (AO) index, and the sea surface temperature anomaly in the North Pacific. Multi-dimensional models of the «stock–recruitment» type were built on identified statistical patterns, which allowed to estimate potential abundance of the pink salmon returns to northeastern and western Kamchatka. Besides, methods for predicting the abundance of pink salmon returns on the data of fish counting in the sea are considered, using the materials of TINRO trawl surveys conducted in the Bering and Okhotsk Seas in the fall seasons of 2012–2023. To determine the abundance of pink salmon originated from West Kamchatka, genetic identification of regional composition of juveniles in mixed trawl catches was used. All tested methods have a high level of determination, but simpler regressive models are more prospective for practical forecasting of general trend in dynamics of pink salmon stocks in the Kamchatka region due to very weak generalization ability of more complicated models.

Features spawning of pollock <I>Gadus chalcogrammus</I> in the northern part of the sea of Okhotsk in the 2010s

A significant amount of data collected during spring complex surveys in the northern part of the Sea of Okhotsk allowed us to characterize pollock spawning in the period 2011–2020. It was found that, on average, during the period under review, caviar accumulations of various densities occupied up to 90% of the surveyed water area. In the spring period caviar on the early stages of development was found on a larger area of the studied landfill, with the exception of some marine stations, where it was absent from catches. At the same time accumulations of caviar on the late stages of development occupied a smaller area, and the densest concentrations indicating the beginning of spawning were noted in the waters off southwestern Kamchatka and above the Swan Hill. In the waters off the West Kamchatka coast 75% of the caviar was located above depths of 50–150 m and only 22% – outside the shelf. A similar distribution of caviar was noted in the North Okhotomorsky district – 76% developed within the shelf and 31% – over the deep-water part of the district. In the Shelikhov Bay the densest concentrations of caviar were located above the deep-water trough during all years of research.

Assessment of the regional composition of juvenile chum salmon mixed aggregations in the Sea of Okhotsk based on results of genetic assay

Genetic differentiation of chum salmon in the basin of the Sea of Okhotsk is demonstrated. Eight microsatellite loci (Ssa20.19, One101, Oke3, Oki1b, Oki23, Ogo2G, Oke11, Ots102) were used as genetic markers. Four original genetic regions of chum salmon reproduction have been figured out: West Kamchatka and northern part of the continental coast of the Sea of Okhotsk, Sakhalin, Ithurup (the Kuril Islands), the Amur basin, where the part of juvenile fish was found as a result of genetic identification in the mixed aggregations in the early period of marine feeding. The resolution ability of the reference database was within the limits 74.9–94.6 %. It was demonstrated based on results of the genetic identification, that juveniles from West Kamchatka and northern part of the continental coast of the Sea of Okhotsk dominate in the northern part of the Sea of Okhotsk. Majority of individuals examined in the central zone of the survey area (54 %) was from the Kuril Islands. A number of juvenile chum salmon from the Amur River basin and Sakhalin were recorded at the stations in vicinity of Sakhalin coast.

On the issue of optimizing snow crab fishing in the Gulf of Shelikhov, the Sea of Okhotsk

Existance of commercial snow crab aggregations for target fishing has been discovered in the Gulf of Shelikhov, the Sea of Okhotsk, based on the survey data for 2014 and 2021–2022. Sites of higher densities of snow crab have been figured. Analysis of sex ratio and size composition of the catches was made, and the catch values per an fishing effort and stock abundance of commercial males were estimated. In order to involve mentioned snow crab stock of the Gulf of Shelikhov, a ban for the fishing of snow crab has been recommended in the West Kamchatka subzone southward from 59°15´ N.

Commercial resources of saffron cod <i>Eleginus gracilis</i> in the Russian waters of the Far-Eastern Seas

Saffron cod Eleginus gracilis, being a typical representative of the elittoral ichthyocene, is an important commercial species in the coastal areas of the Far-Eastern Seas. Small- and medium-sized vessels equipped with both active fishing gears as Danish seine or trawl and fixed nets are used for fishery of this species, it is also popular for amateur and sport fishing from the sea ice. The portion of saffron cod in the total landing is the largest in the Karaginsky fishing subzone (8.1 %) and West-Kamchatka fishing subzone (3.6 %). Annual catch of the species in the Far-Eastern Seas fluctuated in 2003–2022 from 16.7 . 103 to 50.6 . 103 t, on average 33.9 . 103 t. The bulk of this value was caught in the waters at Kamchatka, mostly at its western coast where the average catch was 10.5 . 103 t annually in the last decade. The main fishing grounds of saffron cod are located within the Kamchatka-Kuril, West-Kamchatka, East-Sakhalin and Karaginsky fishing subzones, whereas the stocks at Primorye and sparsely populated coasts of the western Okhotsk Sea and northwestern Bering Sea are underexploited. The saffron cod CPUE reaches 4.5 t per hour of trawling on the shelf of West Kamchatka. The biomass of saffron cod is estimated recently as 197.4 . 103 t in the West-Kamchatka subzone, 100.4 . 103 t in the Karaginsky subzone, 32.8 . 103 t in the West Bering Sea fishing zone, 17.2 . 103 t in the Petropavlovsk-Commander subzone, 17.1 . 103 t in the East-Sakhalin sunzone, and 8.7 . 103 t in the North Okhotsk Sea subzone. The species is distinguished by significant fluctuations of commercial stocks caused by both environmental impacts on its recruitment and fishing pressure. The strong year-classes appear usually in relatively warm or moderate environmental conditions. In modern times, abundance and biomass of almost all exploited stocks of saffron cod in the Far-Eastern Seas excess their average long-term level or fluctuate around, so the state of their populations is considered as quite satisfactory.

Juvenile feeding of pacific salmon in the lower part of the Pymta River in May–September, 2019–2020

Comparative analysis of feeding in the lower part of the Pymta River (West Kamchatka) is carried out for juvenile Pacific salmon individuals of different age representing four species with a short or long freshwater period of their life cycle (chum salmon Oncorhynchus keta, sockeye salmon O. nerka, coho salmon O. kisutsch and Chinook salmon O. tschawytscha) for the period from May to September in 2019–2020. Spectra of food, stomach fullness indices and degree of food similarity between juveniles of different species and age classes are demonstrated. The feeding in all mentioned species was biotop-dependent. There were frequent changes in the composition of the forage consumed in the course of observations of Pacific salmon juveniles in the Pymta River basin, and the indices of stomach fullness varied extensively. The results of the analysis indicate extensive trophic adaptability in juvenile Pacific salmon in the ecosystem of the Pymta River.

New Data on the Neogene Volcano-sedimentary Complex of the Icha Depression: The Tyrkachyn Section (West Kamchatka)

New Data on the Neogene Volcano-sedimentary Complex of the Icha Depression: The Tyrkachyn Section (West Kamchatka)

Oil and Gas Potential of the West Kamchatka Coast and Its Relation to the Structural and Tectonic Setting of the Sea of Okhotsk Region Based on Geophysical Data

Oil and Gas Potential of the West Kamchatka Coast and Its Relation to the Structural and Tectonic Setting of the Sea of Okhotsk Region Based on Geophysical Data

Spatial distribution and biological characteristics of the Okhotsk Sea Pollock in the winter-spring period

The data on the biology and fishing of pollock in the northern part of the Sea of Okhotsk collected during its monitoring on fishing vessels in the winter-spring period 2001–2021 are analyzed. Analysis of the dislocation of the fishing fleet makes it possible to trace the formation and distribution of pollock clusters. A significant amount of the collected material made it possible to characterize the dynamics of gonad maturation and the change in the size and age structure of individuals in commercial subzones. Pollock fishing usually began in the Kamchatka-Kuril subzone and partly in the North Okhotsk subzone in the area of the Swan Upland, with gradual development northward into Shelikhov Bay, Pritaui district and the North Okhotsk shelf. The basis of the catches was pollock at the age of 5–8 years at the pre-spawning stages of the development of sexual products. By-catch of juveniles varied from 0,5% (2009) to 63,5% (2018), averaging 23,5% in the North Okhotsk subzone, 34,8% in the West Kamchatka subzone and 15,5% in the Kamchatka-Kuril subzone.

The Boundary Areas Structure of the Malko-Petropavlovsk Fracture Zone from Local Seismic Tomography and Earthquake Foci Mechanisms Data

Abstract —This study continues analysis of the new seismic tomographic structure of the suprasubduction complex of the central zone of Kamchatka, obtained from the dense local networks data of 2018–2020, and is devoted to the analysis of the velocity structure in the Malko-Petropavlovsk fracture zone margins and around them. The seismic tomographic model involves about 98,000 P- and S-wave travel times from 2963 local earthquakes from August 2018 to July 2020. The resolution of this model makes it possible to trace the feeding systems of volcanoes of the South Kamchatka and East Volcanic Belt to the slab surface, as well as to identify subvertical structural faults. To construct the orientations of the compression and extension axes we used the foci mechanisms of 41 earthquakes with М ≥ 4.5 from the catalog of the International Seismological Center for the period 1979–2019. Along the Malko-Petropavlovsk fracture zone, the Avacha transform fault is clearly traced in the geometry and mutual arrangement of velocity anomalies almost throughout the entire depth of the model. Comparison of seismic anomalies with a map of the directions of the compression and extension axes distribution from the earthquake foci mechanisms showed the correlation between the change in the value of the velocity anomalies along the Avacha transform fault with the axes direction change by almost 180°. A near-surface low-velocity anomaly to the depths of 25–35 km was found along the western border of the Malko-Petropavlovsk zone under the southern tip of the Sredinny Ridge. This anomaly probably marks the axes junction zone boundary of the ancient volcanic front along the Sredinny Ridge and the modern active Eastern Volcanic Belt, which formed as a result of the Kronotsky paleoarc accretion. To the west from the Sredinny Ridge southern tip, another low-velocity anomaly was revealed. This anomaly was traced to a depth of ~150 km, has a contrasting southern boundary confirmed by the distribution of the compression and extension axes directions by the earthquake foci mechanisms and apparently marks the southern boundary of the West Kamchatka block.

Distribution features and discovery prospects of hydrogen accumulations in the groundwater gases of the North-East of Russia

The paper presents data on hydrogen distribution in the free gas of groundwater sources and in water and gas bearing objects of oil and gas bearing artesian basins in order to preliminary estimate the prospects for possible identification of its deposits in the Earth’s interior in the North-East of Russia. The hydrogen content in the groundwater exceeding 0.1 vol% is shown to be rare. Its highest values – up to 47.18 vol% – are observed in the wells of the Anadyr and the West Kamchatka artesian basins. The study of geological and hydrogeological features of hydrogen occurrences leads to the conclusion that hydrogen comes from localized sources in the zones of the deep faults limiting the depressions. These depressions constitute artesian basins, the mantle of which includes rock layers with reservoir properties (porous, fractured), interstratified with the strata of basic and/or ultrabasic volcanic rocks (andesites, basalts, dolerites). It is concluded that such basins hold prospects for the preservation of significant hydrogen accumulations.

The database on oceanography of the eastern Okhotsk Sea

Database for the data of oceanographic observations in the eastern part of the Okhotsk Sea (on the shelf of West Kamchatka and in adjacent waters) obtained in 1888–2020 is created in KamchatNIRO (Petropavlovsk-Kamchatsky) that introduces many previously inaccessible data into scientific circulation and thus provides new possibilities for exploration of this area. The database is heterogeneous in its temporal and spatial resolution. The 1961–1990 period is better covered by the data, whereas the observations in the last three decades (1991–2020) are slightly less numerous. Spatial density of observations increases from the open sea to the coast and from the north to the south; the densest net of stations is located at the southwestern coast of Kamchatka.

Assessment of stock abundance and commercial perspective for cherry salmon (Oncorhynchus masou) in the water bodies of West Kamchatka

The paper presents generalized information for the ten-year period (2011–2020) on the stock abundance status of some West Kamchatka cherry salmon populations. Data on spawning stock abundance and catch statistics from scientifi c and recreational fi sheries are given. The sex and age structure is considered. Dynamics of body length and weight and absolute fecundity are analyzed. The results of the study make it possible to consider the West Kamchatka cherry salmon as a recreational fi shery object for the nearest decade.

Biomass of Ophiuroidea и Echinarachnius parma on a plot of the West Kamchatka shelf in 2013–2017

According to the results of bottom grab surveys carried out in 2013–2016, data on the biomass (g/m2) of the dominant sea urchin species Echinarachnius parma and the complex of brittle stars on a plot of the West Kamchatka shelf are given. The average biomass of Echinarachnius parma for the surveyed plot varied over the years and in 2013 was 45.298 ± 25.582 g/m2, in 2014 – 48.784 ± 26.561 g/m2, in 2015 – 19.557 ± 11.678 g/m2, in 2016 – 18.957 ± 13.192 g/m2. In terms of biomass on the surveyed plot (g/m2) the main role among the echinoderms belongs to fl at sand dollars, and in terms of population density (ind./m2) – to brittle stars. 11 species of brittle stars from 4 families were noted. In terms of population density the most common species among the brittle stars are Amphiodia craterodmeta and Ophiura quadrispina.

Walleye pollock of the Okhotsk Sea: history of fishery and current status

The purpose of the workis to review the history of the development of walleye pollock stocks in the of Okhotsk sea, to analyze the fishery and the state of its stocks.Methods:literature data, materials of long-term surveys by VNIRO (1997–2002) on the walleye pollock spawning grounds of Western Kamchatka, as well as the R/V «Professor Kaganovsky» in the spring of 2022 were used. Fishery statistics of OSM Monitoring.Results:The maximum walleye pollock catch (0.91 million tons) in the North Sea of Okhotsk subarea was achieved in 1995. In the period 1998–2001 annual catches averaged 510 thousand tons, in 2002–2008 decreased to 210 thousand tons. Over the past decade, there has been a gradual increase in catch from 286 thousand tons in 2009 to 383 thousand tons in 2020. Pollock catches in the West Kamchatka and Kamchatka-K uril subzones after high fishery rates achieved in 1996–1997 (1.2 million tons), began to decline, falling in 2004 to 191 thousand tons, after which a tendency to their increase appeared. In the period 2016–2019 catches walleye pollock of East Okhotsk sea stabilized at the level of 617–618 thousand tons, in 2020 the catch amounted to 681 thousand tons. The walleye pollock stock in the East Sakhalin subzone is currently at a low level, its gradual recovery began in the mid-2000s in 2019–2020. its catch was 110 thousand tons.Novelty:New data on walleye pollock stocks in the Okhotsk Sea are presented. Based on the results of a trawl survey conducted in the spring of 2022, the total number of walleye pollock in the Okhotsk Sea was estimated at 56.043 billion ind., biomass — 13.497 million tons, while the commercial stock was estimated at 10.413 million tons and 21.964 billion ind. Maps of the distribution of adult walleye pollock and eggs in the Okhotsk Sea in the spring of 2022 are given.Practical significance:data on the status of walleye pollock stocks in the Okhotsk Sea will be used to prepare TAC materials, as well as recommendations for rational fishery.

By-catch in the specialized fishery of target crab species near Kamchatka

Results of the assessment of by-catch in the specialized fishery of target crab species are presented. The studies covered three fishing areas: off Western Kamchatka (Kamchatka-Kuril and West Kamchatka sub- zones) and off the southeastern coast of Kamchatka (Petropavlovsk-Komandorskaya subzone). In addition to the target object, the catches included both non-target species of crabs and representatives of other groups of animals: fish and invertebrates. The by-catch of fish included representatives of several genera, the most common being Pacific cod (Gadus macrocephalus), Irish lords (Hemilepidothus sp.) and snailfishes (Careproctus sp.). Among invertebrate representatives in the by-catch, octopuses (Octopus sp.) most often prevailed by weight in the fishery of red king crab (Paralithodes camtschaticus) off Western Kamchatka and Tanner crab (Chionoecetes bairdi) off Eastern Kamchatka.

Catches structure of hydrobionts in the trap survey of crabs in the Okhotsk sea

In the world, annually the level of emissions from fisheries in the seas reaches 10.8% or 9.1 million tons per year, and according to Russian experts, only in the trawl and snurry fisheries of the Russian Far East, annual emissions are about 1.2 million tons. Therefore, the purpose of this work is to analyze the structure of catches of the main commercial species of crabs and by-catch of other invertebrates and fish. The collection of biological materials and fishing statistics was carried out in the course of research work from July 27 to October 5, 2021 on the research vessel (RV) Zodiak in the northern part of the Sea of Okhotsk (North Sea of Okhotsk subzone SOM, 55°01ʹ58 °05ʹ N and 142°00ʹ-154°02ʹ E; West Kamchatka subzone ZK, 58°00ʹ-59°40ʹ N and 154°45ʹ-159°30ʹ E). In the SOM, studies have shown that, depending on the depth, the near-bottom temperature varied widely from –1.48 to 2.84 °С, in the WK — from 0.20 to 6.72 °С, which is generally typical for this season of the year and water areas. The number and distribution of the main objects of the crab fishery, namely the opilio snow crab in the SOM and the blue crab in the ZK, are at the average long-term level. A rare extensive research area made it possible to describe the true distribution of crabs. The structure of hydrobiont catches also included 13 trumpeter species and 13 fish species in two subzones of the Sea of Okhotsk. Since crab fishing in different periods of the year is carried out in different water areas and is mainly concentrated in a small area, structure of catches is likely will be less diverse.

TO THE ISSUE OF FISHERY MANAGEMENT OF GOLDEN KING CRAB <i>LITHODES AEQUISPIUS</i> IN THE EASTERN OKHOTSK SEA (THE WEST KAMCHATKA SUBZONE)

Analysis of molting state of male and reproductive state of female golden king crabs Lithodes aequispius in January–December on the continental slope of the Eastern Okhotsk Sea was accomplished based on the data collected in 1998–2006 and 2019–2020. Dominance of molting state of males and mature egg stage of females was revealed during one year. Results of the research of molting process and temporal dynamics in male aggregations obviously indicate of purposeless temporal banning of fishing golden king crabs within the West Kamchatka fishery subzone.

ПОТЕНЦИАЛЬНАЯ НЕФТЕГАЗОНОСНОСТЬ ЗАПАДНО-КАМЧАТСКОГО ПОБЕРЕЖЬЯ И ЕЕ СВЯЗЬ СО СТРУКТУРНО-ТЕКТОНИЧЕСКИМ СТРОЕНИЕМ ОХОТОМОРСКОГО РЕГИОНА ПО ГЕОФИЗИЧЕСКИМ ДАННЫМ

This article describes the peculiarities of the deep structure of sedimentary depressions of the West Kamchatka coast and the adjacent offshore areas of the Okhotsk Sea shelf, manifested in the observed potential fields, as well as in their transformations. To reveal geophysical regularities reflecting the structure of the deepest part of the crystalline basement within the analyzed objects, a pseudo gravity field calculated on the basis of analytical approximation was used. The regional and local components of the decomposition of the observed potential fields, calculated by two-dimensional adaptive energy filtering and presumably associated with different-depth structural-tectonic objects, were analyzed. On the basis of comparison of the investigated Pustoretsky depression with the «reference» Kolpakovskaya depression, which includes known gas-condensate fields (West Kamchatka oil-and-gas bearing region), conclusions about the similarity of their formation conditions and subsequent evolution were made. A regional geophysical model of the Pustoretsky depression has been compiled, which makes it possible to reasonably assume its formation in the zone of Cenozoic subduction processes caused by the interaction of lithospheric plates.