Northwestern Sakhalin Research Articles

On finding of an abundant population of free-living stages of ergasilids (Copepoda, Cyclopoida) in the Lyutoga river of Southern Sakhalin

In the littoral zone of the oxbow of the Lyutoga River (Southern Sakhalin), which remains connected to the main channel, a high population density of parasitic copepods was found (103 ind./m2). Ergasilus briani Markewitsch, 1933, widely distributed in Eurasia, but not previously recorded in South Sakhalin and noted only for one water body in northwestern Sakhalin (Lake Sladkoe), demonstrated the highest population density (98 ind./m2). The abundance of the second species, Thersitina gasterostei (Pagenstecher, 1861) was significantly lower (5 ind./m2). T. gasterostei has previously been noted in South Sakhalin, but the present finding is the first for the Lyutoga River. The high abundance of free-living stages of ergasilids is presumably related to the reproductive peak and the hydrological nature of the collection site (littoral area with a slow current and strong overgrowing with macrophytes).

Preliminary assessment of the number and commercial stock of Yellowcheck Elopichthys bambusa (Richardson, 1845) (Cypriniformes, Cyprinidae) Amur river

Yellowcheck Elopichthys bambusa (Richardson, 1845) is a valuable commercial species. In 2020, after more than twenty years of a ban on fishing, the yellowcheck removed from the list of fish in the Red Book of Russia. Based on the data of scientific research surveys by nets (2437 catches) of 2010–2021, an increase in its number in recent years in the Russian part of the Amur River basin, compared with the end of the XX century, is shown. This is confirmed by the expansion of the species’ range both up and down the Amur, as well as by the occurrence of yellowcheck migrants in the coastal waters of northwestern Sakhalin. At the same time, in absolute terms, the number of this predator is small. In order to solve the issue of introducing yellowcheck into the fishery, it is necessary to conduct studies to research many aspects of its biology, and, above all, growth, age structure, age of mass maturation, as well as to research the influence of Chinese fishing the current state of its biological resources. The obtained preliminary estimates of the commercial stock’s biomass of yellowcheck (9,2 tons) and its minimal possible catch (1,7 tons) allows starting these works.

Ecogeographic Units and Management Units of Chum Salmon Oncorhynchus keta of the Amur Zoogeographic Province

—Using the example of chum salmon Oncorhynchus keta in the Amur zoogeographic province, we review the principle of subdividing the species into population groups. On the basis of zoogeographic zoning and biological boundaries of chum salmon groups defined by the spawning areas, taking into account the distribution, migration, and reproduction, as well as estimates of their differentiation using microsatellite DNA markers, we identified eight ecogeographic units in the Amur province. In the Amur zoogeographic region of this province, these included the summer chum salmon of the Amur-Amgun ecoregion and the autumn chum salmon of the Lower Amur (Amur-Amgun and Amur-Ussuri ecoregions); in the Shantar zoogeographic region of the province, the Uda-Tugur and Ulban groups; in the Sakhalin part of the Amur province, groups from the northwestern and northeastern Sakhalin, as well as summer and autumn chum salmon from the Poronai River. These ecogeographic units can be considered as basic spawning management units of chum salmon for this part of the species distribution range.

Morphologies and population genetic structures of the eight-barbel loach of the genus Lefua on southern Sakhalin

Coldwater, primary freshwater, fish such as the eight-barbel loach, Lefua nikkonis, are thought to have colonised Hokkaido from the continental Far East via Sakhalin Island during the Late Pleistocene. Lefua populations have been reported on southern Sakhalin, but detailed morphological and population structure analyses have not yet been completed. This information is important for reconstructing the colonisation history of L. nikkonis to Hokkaido. In this study, morphological analysis revealed that L. nikkonis and two continental congeners, Lefua pleskei and Lefua costata, are distinguishable from each other, and Lefua collected from southern Sakhalin is morphologically more similar to L. nikkonis. Random forest analysis, a machine learning classification method, classified all Sakhalin individuals as L. nikkonis. Haplotype analysis of mitochondrial DNA sequences revealed that all but one Sakhalin haplotype are shared with L. nikkonis and none is shared with the two continental congeners, which supports the hypothesis that Sakhalin Lefua are L. nikkonis. However, none of the Sakhalin haplotypes was distributed on northern Hokkaido. This discontinuous distribution of haplotypes across Sakhalin and Hokkaido suggests that the Sakhalin Lefua populations are not native. Some of the Sakhalin haplotypes were found only on Hokkaido’s Ishikari River system or the Tokachi River system, suggesting that they originated from these regions. Because previous field surveys reported wild Lefua only from northwestern Sakhalin, we concluded that native Lefua on southern Sakhalin may have gone extinct after they colonised Hokkaido in the Middle Pleistocene.

Genetic legacy of cultures indigenous to the Northeast Asian coast in mitochondrial genomes of nearly extinct maritime tribes

BackgroundWe have described the diversity of complete mtDNA sequences from ‘relic’ groups of the Russian Far East, primarily the Nivkhi (who speak a language isolate with no clear relatedness to any others) and Oroki of Sakhalin, as well as the sedentary Koryak from Kamchatka and the Udegey of Primorye. Previous studies have shown that most of their traditional territory was dramatically reshaped by the expansion of Tungusic-speaking groups.ResultsOverall, 285 complete mitochondrial sequences were selected for phylogenetic analyses of published, revised and new mitogenomes. To highlight the likely role of Neolithic expansions in shaping the phylogeographical landscape of the Russian Far East, we focus on the major East Eurasian maternal lineages (Y1a, G1b, D4m2, D4e5, M7a2, and N9b) that are restricted to the coastal area. To obtain more insight into autochthonous populations, we removed from the phylogeographic analysis the G2a, G3a2, M8a1, M9a1, and C4b1 lineages, also found within our samples, likely resulting from admixture between the expanding proto-Tungus and the indigenous Paleoasiatic groups with whom they assimilated. Phylogenetic analysis reveals that unlike the relatively diverse lineage spectrum observed in the Amur estuary and northwestern Sakhalin, the present-day subpopulation on the northeastern coast of the island is relatively homogenous: a sole Y1a sublineage, conspicuous for its nodal mutation at m.16189 T > C!, includes different haplotypes. Sharing of the Y1a-m.16189 T > C! sublineages and haplotypes among the Nivkhi, Ulchi and sedentary Koryak is also evident. Aside from Y1a, the entire tree approach expands our understanding of the evolutionary history of haplogroups G1, D4m, N9b, and M7a2. Specifically, we identified the novel haplogroup N9b1 in Primorye, which implies a link between a component of the Udegey ancestry and the Hokkaido Jomon.ConclusionsThrough a comprehensive dataset of mitochondrial genomes retained in autochthonous populations along the coast between Primorye and the Bering Strait, we considerably extended the sequence diversity of these populations to provide new features based on the number and timing of founding lineages. We emphasize the value of integrating genealogical information with genetic data for reconstructing the population history of indigenous groups dramatically impacted by twentieth century resettlement and social upheavals.

RECENT CHANGES IN PRODUCING OF THE INTERMEDIATE WATER IN THE OKHOTSK SEA AND ITS PROPERTIES

Data of long-term observations on the cold intrusions in the warm intermediate layer of the Okhotsk Sea are overviewed, considering these intrusions as fresh portions of the Intermediate water of local origin. They are formed in the process of the high-density Bottom Shelf water cascading from the northwestern shelf, mainly in the submarine canyon at northwestern Sakhalin. Transport of these new-formed portions is traced in the flows of cyclonic circulation of the Okhotsk Sea waters from the area of their origin to the southern Kuril Straits, that takes from 2 to 6 years. Similar intrusions are found in the Pacific, mainly at southern Kuril Islands, where they penetrate presumably through the Vries and Bussol Straits. Year-to-year variability of the Bottom Shelf water and the new-formed Intermediate water properties are analyzed in dependence on external factors. There is determined that the volume and density of the Bottom Shelf water depend on winter severity that could be quantitatively explained by the ice cover; all these parameters decrease recently. Salinity of the new-formed Intermediate water has similar changes. Besides, tidal mixing influences on its salinity, in particularly at the Kuril Straits, so the tidal 18.6-year cycle is presented in the salinity variations. On the contrary, variations of the minimal temperature in the cold-water lenses of the fresh Intermediate water of local origin do not correlate with the changes in their production because of auto-compensatory effect for temperature in the process of its cascading to different depths. The same effect is obviously applied to dissolved oxygen, that’s why the oxygen content in the upper intermediate layer at the area of cascading is rather stable and doesn’t correlate with the ice cover changes. However, ventilation of the medium and deeper parts of the intermediate layer decreases on the background of recent lowering of the Intermediate water producing, in particularly the production of the water with σq ≥ 26.8. On a distance from the area of cascading, the tendency to deoxygenizing spreads over the whole intermediate layer of the Okhotsk Sea.

Dynamics of the abundance and conditions of reproduction of mass species of pacific salmons (Oncorhynchus) on the northwestern coast of Sakhalin

The efficiency of reproduction of Pacific salmons of the genus Oncorhynchus in the rivers of the northwestern coast of Sakhalin Island is characterized on the basis of long-term data (1989−2014). Differences between the rivers in the northern and southern parts of the region under study have been revealed with respect to the channel type, faunistic composition of the aquatic biota, and prevailing species of salmons. A high spawning efficiency of pink salmon O. gorbuscha, high densities of filling of spawning grounds, and a relatively poor composition of the freshwater ichthyofauna have been recorded in the rivers of the northern part with the mountain–piedmont type of channel. Varied fish population and the high spawning efficiency of chum salmon O. keta have been recorded in the rivers of the southern part with the mainly lowland channel. The salmon spawning area in the rivers of the northern and southern parts has been estimated. The data on the dynamics of the abundance of salmons on the northwestern coast of Sakhalin are given. The total value of the passage of spawners to the rivers of northwestern Sakhalin that is required for effective reproduction has been estimated, ranging from 0.672 to 1.639 million specimens for pink salmon and approximately 0.43 million specimens for chum salmon.

Pathways of the Amur pink salmon <i>Oncorhynchus gorbuscha </i>to the areas of reproduction

Biannual sequence of high-numerous and low-numerous year-classes of pink salmon ( Oncorhynchus gorbuscha ) is disturbed rarely in the areas close to its spawning grounds where mostly local groupings are landed, as it is shown on the data of fishery statistics in many areas of Russian Far East for 1907-1986. The disturbances are related usually with by-catch of transitory fish, in particular for the Sakhalin-Kuril region. Dynamics of the pink salmon annual landings in the Amur correlates with its dynamics at northwestern Sakhalin, that allows to suppose the species migration from the Okhotsk Sea to its spawning grounds via northwestern Sakhalin. Besides, a part of the Amur pink is caught at the mainland coast of the Gulf of Sakhalin, but the landings in the Amur correlate well with this transitory area in even years only, when the run is stronger. The highest catches of pink salmon on the mainland coast of the Gulf of Sakhalin in 2015 could be ensured neither the Amur nor the Sakhalin groupings; a hypothesis on the Shantar groupings contribution is discussed. In general, high catches of pink salmon in Khabarovsk Region in 2015-2016 are possibly reasoned by its good survival and lowered fishery in the Sakhalin-Kuril region.

Tendencies of climatic and anthropogenic changes of the marine environments in the coastal areas of Russia in the Japan Sea for the last decades

Complex assessment of the marine environments changes in the coastal zone of the Japan Sea at Primorye and Sakhalin coasts is presented for the last 4 decades. Both natural and anthropogenic aspects of these changes are considered with the tasks: 1) to compare interannual variability of oceanographic parameters, as water temperature, salinity, and sea level, and reveal distinctions and common tendencies; 2) to define indicators of chemical pollution and find general features of interannual dynamics for polluting substances and water quality. The data of regular oceanographic observations at 11 coastal stations and the data of pollution monitoring in certain areas conducted by hydrometeorological service of Russia (Roshydromet) in 1980-2015 are analyzed. Cyclic fluctuations with the period of 2-5 years prevail in year-to-year variability of oceanographic parameters being observed on the background of long-term trends, more significant in the 21 st century. The sea surface temperature has a strong positive trend (up to 1.4 o per 35 years) at many stations, with exclusion of 5 ones located in northwestern Sakhalin and central Primorye; the average trend for the whole area is 0.7 о per 35 years. Majority of the stations have the significant positive trend in summer and fall, but Sovetskaya Gavan - in all seasons. For all stations, the lowest mean annual temperature was observed in 1980 and 1987, the highest one - in 1990. Salinity has a significant negative trend at all stations (up to -2.66 ‰ per 35 years), except Alexandrovsk-Sakhalinsky, with average value -1.3 ‰ per 35 years. The negative trend of salinity is more significant in spring and summer, though other tendencies could be seen locally in certain seasons. The sea level has a positive trend, significant at all stations in any season, with the maximal value in spring (on average 7 cm per 35 years that is 35-50 % of the range of seasonal fluctuations). Dynamics of pollution is described by frequency of high concentration (over the maximum permissible level) of organochlorine pesticides (HOPs), petroleum hydrocarbons (TPHs), phenols, detergents, and heavy metals. The high concentrations of TPHs and phenols are observed rather frequently, usually in the Tartar Strait and Peter the Great Bay (Golden Horn Bay, Diomid Bight, and Bosfor Vostochny Strait). In the latter area, the dangerous levels of dissolved oxygen content are observed, as well. Other pollutants don’t exceed frequently the maximum permissible level.

Vegetation and climate during the LGM and the last deglaciation on Hokkaido and Sakhalin Islands in the northwest Pacific

Abstract In the process of reviewing pollen data from Hokkaido and Sakhalin, three facts were confirmed. 1) The climate was revised to one colder than the Last Glacial Maximum (LGM) during the last deglaciation in the last glacial period, called the Kenbuchi Stadial, which was related to the southward shift of the summer position of the Kuroshio-Oyashio sea current boundary, which affected not only northern Hokkaido but also eastern Hokkaido and northwestern Sakhalin. 2) From marine isotope stage 3–8000 Cal. yr BP, grassland and mire that developed in Hokkaido were characterized by expanded spikemoss, which grows in snowpatch grassland and mire in the alpine zone of Hokkaido and northern Honshu today. 3) During the LGM, thermokarst depressions, so-called “alas,” likely formed in eastern Hokkaido along the Sea of Okhotsk based on the yield of the aquatic plants Menyanthes and Botryococcus in LGM sediments.

On biology of Kaluga sturgeon Acipenser dauricus (Acipenseridae) from the Viakhtu River (Northwestern Sakhalin)

Data on catch of three specimens of Kaluga sturgeon Acipenser daurucus in the channel part of the Viakhtu River (Sakhalin Island) are first presented; their morphometric indices are provided. According to data of histological study, females with a length of 121–127 cm and a weight of 12–20 kg have ovaries at III early stage of maturity. It was demonstrated that food resources of the Viakhtu River can provide spawning of immature individuals of Kaluga sturgeon in June–July. It was proved that the range of Kaluga sturgeon includes, as minimum, one of the rivers of the northwestern part of Sakhalin Island.

Geomorphological aspects of the problem of protecting the shores of the Sakhalin Island

The presence of the frozen grounds on the coasts including the barrier lagoon ones, thermo-abrasion observed on some sites, the presence of shore ice and icings lasting up to the end of May, allow to consider the shores of the north-western and eastern Sakhalin as subarctic type. It was determined that during last 50 years more than 15 км 2 of accumulated plain was lost as a result of shore erosion only in the north and south-east of Sakhalin Island. The spatial structure of erosion has existed in its general outline since the 1930s. Since 1940 the extension of eroded shores has enlarged nearly two times. The spatial rhythms of erosion with wave length about 30 and 60 km determine the main regularities of shore erosion pattern. The formation of non-uniformity of beach structure and accordingly the irregular distribution of its wave-decreasing properties along the shore were considered. On the seashore of Sakhalin more than thirty sites were found, where quasi-rhythmic forms of shore relief were observed. But all the deformations of underwater relief were observed only in the frames of rated close depth. The special attention was devoted to the changes of wave-suppression characteristics of the beach during beach deposits freezing and under the open sea influence. The freezing of the 40-50 cm of the upper parts of shore profile and decrease of wave-suppression characteristics (mainly drainage and roughness), caused by this, occurred during this period before the formation of the shore ice and icings (1.5–2 months). According to the observations the height of swash zone increases by 30–45%. The calculations showed that the height of wave run-up for bank slope of storm bar may increase owing to freezing by 2–2.5 times.

A detailed study of the rupture zone of the MW 5.8 March 16, 2010 Earthquake at Northwestern Sakhalin Island

An earthquake of magnitude MW = 5.8 occurred in the upper reaches of the Uanga and Pogibi rivers in northwestern Sakhalin at 9 h 44 min WT on March 16, 2010. The event is the largest for the northwestern part of the island during the entire history of instrumental seismological observations that have been conducted on Sakhalin since 1905. A macroseismic study showed that the earthquake was felt in much of northern Sakhalin and the Amur River area. This paper presents the results from a detailed study of the seismicity in the rupture zone, the space-time distribution of aftershocks, and their relationships to the active fault zones that exist in northern Sakhalin. Some new results were obtained that concern the interrelationships between the focal mechanism and the present-day geodynamic setting.

サハリン・カムチャッカ地域における新生代の古気候・地球環境変動

Cenozoic paleoclimatic and paleoenvironmental changes in the northwestern Pacific region, including Kamchatska, Sakhalin and northern Japan, can be summarized as followings: 1) Cenozoic paleoclimatic changes of Kamchatska are similar to those of the Hokkaido and Sakhalin. 2) Parallel communities of shallow-marine mollusks can be recognized throughout the Pelogene and Nogene in Sakhalin, Kamchatska and northern Japan. 3) The Oyashio-type cold water-mass might be first appeared at around 1 Ma as indicating by such shallow-water mollusca as Chlamys islandicus. These Cenozoic geological history and faunal changes of the northwestern Pacific region should be considered from a viewpoint of the Pacific gateway events such as onset of the Drake Passage at 23.5 Ma, enclosure of the Indonesian seaway at 17 Ma, the intermittent opening of the Bering landbridge after 5 Ma and so on.

Spatial differences in reproduction of capelin (Mallotus villosus socialis) in the coastal waters of Sakhalin

Capelin spawn in all main coastal areas of Sakhalin Island except the Amur estuary (i.e. in the northwest, southwest, and northeast of the Island, including Aniva and Terpeniya Bays). In all those areas, spawning stocks of capelin exhibit significant differences in population parameters (size–age composition, growth, fecundity), periods and intensity of spawning, and rates of egg mortality. The areas are distinguished also by the parameters of the spawning areas, oceanographic conditions, zooplankton biomass, numbers of pelagic and demersal fish species, and abundance of planktivorous fish and seabirds. Conditions are clearly best for reproduction and growth of capelin off northwestern Sakhalin Island.

サハリン（樺太）島の地質と地形 サハリン・マカロフとシュミット半島の新生界層序と貝類化石群からみた北西太平洋地域の古環境変遷

Basic Cenozoic geological data for the studied area in the Sakhalin Island such asroute maps showing sampling points, and columnar sections showing sampling horizons were compiled. The area studied are the Makarov and Korsakov regions of southern Sakhalin, and Shmidt Peninsula at northwestern Sakhalin. Micro-fossil biostratigraphy, geo-chemical analysis, and K-Ar dating were studied. As a result, the Oligocene/Miocene boundary, tectonic event and climatic fluctuation are discussed based on the newly established geologic age. The Cenozoic paleoenvironment related to the Pacific Ocean gateways is also discussed from the viewpoint of molluscan fauna.