Kuril Research Articles

First Data on Ecology and Biology of Arctoraja sexoculata (Arhynchobatidae) from the Area off Kuril Islands

First information on the Arctoraja sexoculata frequency of occurrence, ecology, and biology, from the area off the middle Kuril Islands has been provided. It is estimated that the Arctoraja sexoculata is a common bycatch species in trawl fishing for the commander squid Berryteuthis magister in this water area. The locations of catch events for this species were localized off the Ketoy and Simushir Islands and in the Diana Strait at the depths of 250–490 m at a water temperature near the bottom of 1.8–2.5°С. It is supposed that the species belongs to the mesobenthal ichthyocene. In the catches, A. sexoculata represented by individuals of 26–90 cm length and 0.1–5.6 kg body mass. The species probably reaches the age of maturity for the first time at 8–9 years old and over. Its highest life expectancy is 16 years. The individuals of 50–90 cm length become predators consuming predominantly cephalopods and fishes, in the same time isopods and ctenophores among the food items were rarely recorded.

Estimation of the maximum sustainable yield of giant grenadier <i>Albatrossia pectoralis</i> (Macrouridae) in the Russian Far East using Bayesian surplus production model JABBA

Statistical estimates for the exploitable stock of giant grenadier are determined, by fishing zones in the Russian Far East, and interannual dynamics of the species biomass is considered using historical data on catches and abundance. The assessments relationship with reference points of the biomass dynamic models is examined for the first time. With using the Bayesian approach, a priori assumptions about virgin biomass, which were made earlier on results of scientific surveys extrapolated to unsurveyed areas, are accounted in JABBA model; some errors in the catch and abundance indices are revealed. The parameters of instantaneous rate of recruitment and initial depletion of population are determined. Overfishing is not detected yet in any fishing zone, but a negative trend of the biomass dynamics is noticed for the Western Bering Sea fishing zone since 2015 (if the stock estimations based on surveys are realistic). The decline is reasoned by implementation of too high target for exploitation rate of vulnerable biomass (φF = 0.10) that is higher than such target for other fishing zones (< 0.08 or even 0.01 for the stocks exploited with the total allowable catch limits). That’s why annual catches exceeded the surplus production in the Western Bering Sea fishing zone in 2012 and since 2015 to nowadays. The sum of median estimations for the maximum sustainable yields in all fishing zones is about 47.4 . 103 t that exceeds the values of total annual catch. The instantaneous rate of recruitment is almost equal in the neighboring fishing zones in the western Bering Sea and at East Kamchatka (0.086–0.085 by median, with 95 % credible intervals from 0.05 to 0.14) and is much higher at Kuril Islands with the maximum in the North-Kuril fishing zone. The latter case is possibly conditioned by partially external recruitment. Therefore, population structure of giant grenadier should be clarified for correct modeling of the recruitment; until then, the stocks assessments by fishing zones are available.

HOLOCENE EXPLOSIVE ERUPTION ON THE VETROVOY ISTHMUS (ITURUP ISLAND) AS A SOURCE OF THE 2000 cal BP MARKER TEPHRA LAYER IN THE CENTRAL KURIL ISLAND ARC

Geochemical study of volcaniclastic material and radiocarbon dating of charred plant debris from Holcene deposits of the Guram site, which is located in vicinity of Vetrovoy Isthmus at Iturup Island, demonstrate that explosive eruption (VEI 4-5) occurred there by 2000 years ago. Geochemical and age similarity with the tephra of marker layer CKr that was distinguished at Iturup, Urup, Simushir, Rasshua, and Matua islands of the Kuril Island Arc led to the conclusion that this eruption is supposedly a source of this tephra. The data presented are proposed as a motivation for revision of volcanic hazard at Iturup Island.

Fish Species Composition of Bottom Gillnet Catches by Japanese Fishing Vessels Operated in Russian Zone of Kunashir Strait in 1998–2014

Overall, 85 fish species assigned to 56 genera, 27 families, and 13 orders were observed in the bottom net catches from the Kunashir Strait in 1998–2014. The highest number of species (18) represented the family Pleuronectidae, while the family Cottidae involved the lower number of species (14). Thus, 35 species were found in the Nemuro Strait (including the Kunashir Strait) for the first time. Considering the information in the literature, the total number of fish species in the strait separating the Southern Kuril Islands from the Hokkaido Island increased to 173.

Pb-Sr isotopes of the Kurile arc provide evidence for Indian-type oceanic crust in the Pacific basin

Pb-Sr isotopes of the Kurile arc provide evidence for Indian-type oceanic crust in the Pacific basin

The Holocene Explosive Eruption on Vetrovoi Isthmus (Iturup Island) as a Source of the Marker Tephra Layer of 2000 cal. yr BP in the Central Kuril Island Arc

Geochemical study of volcaniclastic material and radiocarbon dating of charred plant debris from Holocene deposits of the Guram site, which is located in vicinity of Vetrovoi Isthmus on Iturup Island, demonstrate that an explosive eruption (VEI 4-5) occurred there about 2000 years ago. The geochemical and age similarity with the tephra of marker layer CKr that was distinguished on Iturup, Urup, Simushir, Rasshua, and Matua islands of the Kuril Island Arc led to the conclusion that this eruption is possibly a source of this tephra. The data presented are proposed as a motivation for revision of the volcanic hazard on Iturup Island.

Resistance of wild plants seeds from Sakhalin Oblast to ultra-low temperatures

We studied the response of seeds of 58 plant species to deep freezing in liquid nitrogen at a temperature of minus 196 °C. The seeds were collected on Sakhalin Island, Moneron Island and Kuril Islands: Kunashir, Paramushir, Urup, Iturup, Shikotan, Simushir, Chyornye Bratya, Shumshu, Ketoi, Shiashkotan, Kharimkotan, Ushishir. All studied seeds were of the orthodox type (seed moisture content was lesser than 12%). Seed viability was assessed by laboratory germination. It was shown that the seeds did not die after freezing. For 70.4% of the studied samples the seed germination level after freezing remained at the control level, for 19.7% it was higher than in the control group (which indicates the stimulating eff ect of liquid nitrogen), for 9.9% of the samples the germination was lower than in the control group. The morphology of seedlings obtained from the seeds that had been frozen did not diff er from the control group

Possible partial melting and production of felsic melt in a Jurassic oceanic plateau of the Izanagi Plate: Insights from 159 Ma plagiogranites from northern Japan

ABSTRACT A small tonalite – dacite body has been discovered in the Nakanogawa Group, Hidaka Belt, northern Japan, which is a Palaeogene subduction complex formed in the palaeo-Japan trench along the northeastern margin of Eurasia. The tonalites are characterized by extremely low K2O (0.2–0.3 wt.%) and relatively flat chondrite-normalized rare earth element patterns (La/Yb[N] ~2.3), similar to plagiogranites in ophiolites. The major-and trace-element characteristics are consistent with low-pressure partial melting of oceanic crust outside the garnet stability field. Zircon U – Pb dating of the tonalite yielded a weighted-mean 206Pb/238U age of 159.1 ± 1.6 Ma. Late Jurassic oceanic plateau-type basaltic rocks with a small amount of plagiogranitic rocks are distributed sporadically in subduction complexes along the palaeo-Japan arc – trench system. A similar zircon U – Pb age (151.6 ± 1.8 Ma) has been reported for greenstone in the Cretaceous subduction complex along the palaeo-Kuril arc – trench system. The tonalite – dacite block was probably derived from the subduction complex at the junction of the palaeo-Japan and -Kuril arc – trench systems. Thus, the greenstones and the tonalite body were likely part of a large oceanic plateau, which formed at the Izanagi – Pacific–Farallon ridge triple junction during the Late Jurassic – Early Cretaceous.

FEEDING OF THE FISH OF BLAGODATNOE LAKE (ITURUP Island, KURIL ISLANDS) IN SUMMER

The feeding of mass fi sh species is described according to the data of ichthyological samples in June- August 2001 from Blagodatnoye Lake (Iturup Island, Kuril Islands):whitebaits of Oncorhynchus keta, Hypomesus nipponensis, Pungitius spp., Gasterosteus nipponicus, Salvelinus malma curilus, S. leucomaenis, Cottus amblystomopsis, Gymnogobius urotaenia and Tridentiger brevispinis. Whitebaits of Oncorhynchus keta, Pungitius spp. and Gasterosteus nipponicus formed the basis of catches in terms of abundance and biomass in the coastal zone of the lake. Hypomesus nipponensis is typical of shallow lake waters and has been constantly observed in the coastal area. Four ecological groups of fi sh are distinguished by the type of food. The fi rst group includes whitebaits of Oncorhynchus keta only, which are the most separated from other species in terms of the ecological spectrum of feeding. The basis of the diet of whitebaits of chum salmon (85 %) is non-aquatic insects consumed from the surface of the water. Salvelinus malma curilus and Hypomesus nipponensis exerted the greatest competitive pressure on juvenile salmon, 11 and 10 % of their diet also consisted of extra- aquatic insects, respectively. Hypomesus nipponensis is a plankto- benthophage and belongs to the second group. The basis of the ecological food spectrum of this species was formed by zooplankton (43 %) and zoobenthos (30 %). A signifi cant contribution was also characterized by fi sh eggs (17 %). The third group includes the Japanese three- spined sticklebacks, the main food of which is fi sh eggs (59 %) and zoobenthos (34 %). All other fi sh species are included in a single group of predominant benthophages. The contribution of zoobenthos in the ecological spectrum of nutrition of these fi sh varied from 57.4 % in Gymnogobius urotaenia to 100 % in Tridentiger brevispinis.

АЛЬТЕРНАТИВНЫЙ МЕТОД ЭВАКУАЦИИ КРУПНЫХ ОСТЕОЛОГИЧЕСКИХ ОБЪЕКТОВ НА ПРИМЕРЕ ЧЕРЕПА PHYSETER MACROCEPHALUS

The article proposes an alternative method for evacuating large osteological objects of scientific and expositional value from hard-to-reach areas on a sea coast. On the example of a 1.2-ton skull of the largest toothed whale Physeter macrocephalus Linnaeus, found during the first season (2019) of the integrated long-term expedition «Eastern Bastion - Kuril Ridge» on the Urup Island (Kuril Islands), the process of evacuation and delivery of the object to the Zvenigorod biological station of Moscow State University is considered step by step. Difficulties and nuances arisen during the evacuation activities are described in detail, the knowledge of which can help in organizing such events.

Morphology and Specific Features of Formation of Thermal Lake Utinaya Banya (Iturup Island, Southern Kuril Islands)

Abstract —This paper describes a set of studies performed at a thermal manifestation (Lake Utinaya Banya) on the Iturup Island (Kuril Islands). These studies include bathymetric survey of the lake basin, geometric leveling across the lake, pitting, sampling of thermal waters from the lake and springs, hydrochemical research, and isotopic analysis of oxygen and hydrogen in the lake water. It is suggested by the shape of the lake basin (close to lenticular with a significant concentric depression), the underwater gas-hydrothermal vents, the bank along the perimeter of the lake basin, and the presence of several layers of clastic deposits at the top of the rampart that the lake was formed by a hydrothermal eruption. The lake temperature has remained constant over the years and ranges on average from 25 to 15 °C, depending on the season. The water of Lake Utinaya Banya is represented by acidic, sulfate calcium, and low-mineralized waters.

New species of calcareous sponges of the family Leuconiidae (Porifera: Calcarea: Baeriida) from Kuril Islands, NW Pacific

New species of calcareous sponges of the family Leuconiidae (Porifera: Calcarea: Baeriida) from Kuril Islands, NW Pacific

Magmatism in Kamchatka and the Kurile Islands

Magmatism in Kamchatka and the Kurile Islands

Japan's foreign policy in the settlement of territorial disputes

Territorial disputes are a key element of Japanese security, directly aff ecting Tokyo's relations with all three of its closest neighbors: China, Russia and South Korea. Because of its complex history of repeated invasions as well as militaristic expansion, Japan has accumulated a tangled legacy of confl icts and disputes with its neighbors over the three contiguous territories, namely Senkaku, Dokdo, and the Kuril Islands, claiming or disputing sovereignty over them. The disputes discussed in the article are a direct result of Japan's involvement in World War II and the often ambiguous language used in treaties and other documents signed at the end of it. The article presents Tokyo's position based on Japanese documents and the positions of Beijing, Seoul and Moscow based on the Cairo Declaration, the Potsdam Declaration and the San Francisco Peace Treaty. The author illustrated her arguments with maps. During the analysis physiographic and historical approaches were used. The author's examination of these disputes provides a clear picture of how the changing security environment has aff ected the position of Japan and its neighbors over time. In the 2000s, Tokyo introduced a special term — territorial diplomacy "redogayko" which goal was international recognition of the legitimacy of Japanese sovereignty over disputed territories. The Ministry of Foreign Aff airs of Japan conducts an active policy to inform the world community about the rights of Tokyo to the Senkaku Islands, Takeshima, and the socalled "Northern Territories". During the analysis of the positions of the concerned countries the author concludes that Japan successfully defends the ownership of the Senkaku Islands, but so far has no proper results with Dokdo and the Kuril Islands. Russia's attitude to these disputes cannot be passive. First, Moscow is a direct party to one of them. Second, South Korea and China are basing their arguments on Japan's imperial past and, like Russia, on World War II documents.

Partial Melting under Shallow-Crustal Conditions: A Study of the Pleistocene Caldera Eruption of Mendeleev Volcano, Southern Kuril Island Arc

Abstract The southern part of the Kuril Island Arc is one of the world’s most active modern volcanic zones, with widespread felsic caldera volcanism, but it has been less well studied compared with other arcs. The Mendeleev caldera-forming eruption (40 ka) on Kunashir Island, southern Kurils, is one of the most explosive Pleistocene eruptions to have occurred in this region. This study aimed to establish the origin and storage conditions of magma preceding the Pleistocene caldera eruption of Mendeleev volcano. Mineralogical and melt inclusion analyses reveal that the primary melts had felsic compositions and that the early stage of magmatic evolution involved amphibole breakdown into a two-pyroxene, plagioclase, and Fe–Ti oxide assemblage under pressure–temperature conditions of 107–314 MPa and 807–932°C. The caldera-forming products are represented by dacitic pumice composed of plagioclase + augite + hypersthene+ quartz + Fe–Ti oxides and melt with uniform low-K rhyolite composition. Pre-eruptive magma was stored in a reservoir at 77–195 MPa (3.0–7.6 km depth) and 830–890°C under H2O-saturated conditions. The mechanism of magmatic evolution implies the following two-step scenario: (1) generation of magma by the partial melting of an amphibole-bearing substrate accompanied by the formation of early Mg-rich clino- and orthopyroxene, plagioclase, Fe–Ti oxides, and peritectic rhyolitic melt; and (2) crystallization of late plagioclase and quartz directly from these partial melts. Local or regional extension during the Pleistocene, accompanied by increasing heat flow in the supra-subduction mantle, generated an active mafic intrusion into the upper crust. This process was accompanied by abundant subaerial eruptions of basaltic volcanoes and could have caused intense heating and partial melting of upper-crustal rocks. Our results indicate that the partial melting of amphibole-bearing substrates in island arcs may serve as a universal mechanism for the generation of silicic magmas during powerful caldera eruptions in young island arcs.

ADDITION TO THE MOSS FLORA OF THE SOUTHERN KURILE ISLANDS (RUSSIAN FAR EAST)

As a result of identification the moss collections from Shikotan, Kunashir, Iturup and Urup islands (Southern Kuril Islands, Russian Far East) collected by T.I. Koroteeva, V.E. Fedosov, A.V. Shkurko, N.S. Liksakova, and A.K. Ezhkin in 2015–2021, new species for the islands were revealed: 6 ones for Urup, 8 for Iturup, 10 for Kunashir, and 19 for Shikotan. For the first time, 4 species new for the Kuril Islands were discovered, including three new for the Sakhalin Region (Forsstroemia cryphaeoides, Haplocladium intermedium, Rhizogemma staphylina, Meteorium buchananii). Another 3 species found in the islands are new for the Southern Kuriles (Dicranum fragilfolium, Gollania turgens, Hygroamblystegium varium). Most of the discovered species are rare in both the Sakhalin Region and the Russian Far East. To date, the moss flora of the Southern Kurils numbers 468 species and is the richest bryoflora in Russia.

The phylogenetic position of Maritrema afanassjewi Belopol'skaya, 1952 (Digenea, Plagiorchiida: Microphallidae), a parasite of the Ussuri brown bear, Ursus arctos lasiotus Gray, 1867 (Carnivora, Ursidae)

Adult digeneans of Maritrema afanassjewi Belopol'skaya, 1952 parasitize birds and mammals along the North Pacific coasts and were previously studied in terms of morphology. However, morphological features not supported by molecular characterization are considered an insufficient tool for the identification of evolutionary lineages of microphallid digeneans. Here we provide the first data on the phylogenetic position of this species inferred from sequences of the 28S rRNA gene and the ITS2 locus of the nuclear DNA, as well as additional morphometric data. The trematodes were isolated from the intestine of the Ussuri brown bear ( Ursus arctos lasiotus Gray, 1867) on Iturup Island (the southern Kuril Islands). This is the second record of M. afanassjewi in the brown bear. The phylogeny based on the 28S rRNA gene was poorly resolved for this parasite species. The analyses based on the ITS2 locus dataset showed that M. afanassjewi was a low-supported sister to Maritrema subdolum Jägerskiöld, 1909.

Characteristics of spawners of chum salmon <i>Oncorhynchus keta</i> from commercial stock of Iturup Island

Chum salmon spawners returned for spawning in the rivers of Prostor and Kurilsky Bays on Iturup Island (Kuril Islands, Sakhalin Region) were examined in the period from September 19 to November 4, 2022. Both females and males had mostly the age 3+ (68.8 % in the Prostor Bay and 62.2 % in the Kurilsky Bay). The portion of males in the age 2+ was in 3.8 times higher than the portion of females, with the average value of 19.2 %; the summary portion of older age groups (4+ and 5+) was 15.4 %. Chum salmon spawners were distinguished by relatively small body weight, similar for the fish of the same age in both bays, on average 2.27 and 2.57 kg for females and males of age 3+, respectively, that was lower than the weight of chum salmon spawners in the previous 8 years.

MERRA-2 reanalysis-aided sea fog detection based on CALIOP observation over North Pacific

Sea fog can lead to a dangerous meteorological hazard over oceans and coastal areas. Cloud-aerosol Lidar with Orthogonal Polarization (CALIOP) is an effective tool to detect sea fog, however it is ineffective for dense fog detection because the lidar signal has been fully attenuated before reaching the layer base. To address this issue by improving dense fog detection, a reanalysis-aided sea fog detection method using CALIOP lidar measurements and MERRA-2 reanalysis dataset is proposed taking the Northwestern Pacific (NP) as study area. In this method, CALIOP lidar measurements are used to locate the ceiling and base of the hydrometeor layers, and extract the candidate fog layers in the Marine Atmospheric Boundary Layer (MABL). Reanalysis dataset are used to identify real fog from the candidate fog layers based on the near-surface meteorological difference under different weather conditions (sea fog, stratus and stratus precipitation). Method validation using in-situ weather records from the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) and five climate stations, shows the detection accuracy and false alarm rate of 89.4% and 2.0%, respectively. Most importantly, about 87.4% of dense fogs are successfully discriminated with the aid of reanalysis data. Model application to CALIOP data from 2007 to 2019 shows pronounced spatial and seasonal characteristics of sea fog distribution over NP, with the highest frequency (>40%) found over the Kuril Islands, Sea of Okhotsk and Bering Sea from June to August. The example demonstrates that by using time series CALIOP observations and the proposed method, one may expect spatio-temporally complete sea fog information, which is important especially for remote regions with scarce in-situ measurements (e.g. polar regions). Our research proposes and proves a novel idea of sea fog detection from space by using satellite lidar and reanalysis data, which may benefit the sea fog forecasting and dynamics analysis, by providing unprecedented large-scale high-quality observations, especially over dense fog conditions.

Route assessment of state of the spawning stock in the lower ritral of the Utesny creek (Paramushir Island, northern Kuril Islands, Sakhalin Region)

The route survey in the lower part of the Utesny creek (Paramushir Island) was conducted to explore the state of spawning grounds for pink salmon Oncorhynchus gorbuscha and to examine their filling by spawners. The spawners were subjected to biological analysis with measuring their morphometric and physiological parameters. Besides, the data on granulometric composition of soils on the spawning grounds were updated.