scholarly journals Ricker analysis of dynamics for two populations of walleye pollock in the Japan Sea

Trudy VNIRO ◽  
2020 ◽  
Vol 180 ◽  
pp. 156-173
Author(s):  
Yu. I. Zuenko ◽  
V. A. Nuzhdin
Keyword(s):  
Climate Change ◽  
Carrying Capacity ◽  
Japan Sea ◽  
Walleye Pollock ◽  
The North ◽  
Optimal Value ◽  
The Japan Sea ◽  
Analysis Of Dynamics ◽  
Local Ecosystem ◽  
Two Populations

Recent changes in reproduction are considered for two populations of walleye pollock which spawn in the Japan Sea at the coasts of Primorye and Hokkaido. Interannual dynamics of reproduction for both populations corresponds to the stock-recruitment dependence described by Ricker curve that determines the maximum recruitment with an optimal value of stock equal to the carrying capacity of the biotope for the species and the lower recruitment if the stock is either lower or higher than this optimal value. However, instability of the Ricker curve parameters is noted, and their recent changes were unfavorable for reproduction of both populations and caused decreasing of their stocks, with sharp decline in the early 1990s. Basing on authors results and cited data, climate change in the Japan Sea region is determined as the reason of this decreasing, in particular weakening of winter monsoon. In spite of a common nature, mechanisms of the climate change influence on two studied populations are completely different: reproduction of the Hokkaido population worsened because of increasing transfer of its eggs and larvae out of the Japan Sea in conditions of the strengthening Tsushima Current, that was explained in the terms of Ricker curve as decreasing of population fecundity, but reproduction of the Primorye population worsened because of unfavorable for pollock reconstructions in the local ecosystem located in the south periphery of the Subarctic zone in conditions of increasing water temperature that was explained in the terms of Ricker curve as shrinkage of carrying capacity for pollock (from approximately 150 .103 t to almost zero level). Note that the carrying capacity did not shrink but slightly extended (to 500 .103 t) for the Hokkaido population located in the north periphery of the Subtropic zone. Features of climate warming influence onto subarctic and subtropic ecosystems are discussed.

New insights into the latitudinal ventilation variations in the Japan Sea since the Last Glacial Maximum: A radiolarian assemblage perspective

2020 ◽  
Author(s):  
Zhi Dong ◽  
Xuefa Shi ◽  
Jianjun Zou ◽  
Yanguang Liu ◽  
Ruxi Dou ◽  
...  
Keyword(s):  
Deep Water ◽  
Coastal Upwelling ◽  
Sediment Cores ◽  
Japan Sea ◽  
Volume Transport ◽  
The North ◽  
Radiolarian Assemblage ◽  
Basin Scale ◽  
Japan Sea Proper Water ◽  
The Japan Sea

<p>The formation of intermediate and deep water plays a key role in regulating climate changes at a variety of time scales through the heat redistribution and carbon cycling. The Japan Sea has unique water-mass characteristics in the North Pacific with its own deep-water formation within the Sea itself called Japan Sea Proper Water (JSPW). Latitudinal ventilation changes in the Japan Sea were reconstructed using radiolarian assemblage from three sediment cores, extending from the southwestern, central to northwestern Japan Sea. Here, we present downcore faunal records spanning the last 25 ka as well as other existing ventilation records in the Japan Sea, and provide reliable evidence to evaluate the potential controlling mechanism that lead to onset and interruption of JSPW ventilation. Taking all together, we argue that radiolarian assemblage records have revealed a distinct basin-scale transition in deep-water conditions from anoxic to oxic during the deglaciation related to changing surface hydrography. However, it should be recognized that there is significant potential for bias in the timing of the ventilation changes among regions. Deep ventilation in the central Japan Sea has been in an interglacial mode during the Bølling/Allerød presumably related to northward volume transport of the Tsushima Warm Current. Moreover, the decrease of JSPW Assemblage at the B/A in southwestern Japan Sea was attributed to higher export productivity, facilitating suboxic deepwater condition through enhanced consumption of oxygen, which was probably caused by coastal upwelling. In contrast, the weakening ventilation of the northwestern Japan Sea during the B/A and YD periods was probably caused by the blocking effect of the sea ice. Note: This study was supported by the National Natural Science Foundation of China (Grant No. 41420104005, U1606401) and National Program on Global Change and Air-Sea Interaction (GASI-GEOGE-04).</p>

scholarly journals Distribution of Walleye Pollock Theragra chalcogramma off Southwestern Hokkaido in the Japan Sea in Spring.

1996 ◽  
Vol 62 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Shogo Takagi ◽  
Tatsuaki Maeda ◽  
Yoshihiko Kamei ◽  
Toshikuni Nakatani ◽  
Tetsuya Takatsu ◽  
...  
Keyword(s):  
Japan Sea ◽  
Walleye Pollock ◽  
Theragra Chalcogramma ◽  
Walleye Pollock Theragra Chalcogramma ◽  
The Japan Sea

scholarly journals Reconstruction of Tsunami Occurrence on Okushiri Island, Southwestern Hokkaido, Japan

2021 ◽  
Author(s):  
Atsushi Urabe ◽  
Yoshihiro Kase ◽  
Gentaro Kawakami ◽  
Kenji Nishina ◽  
Yasuhiro Takashimizu ◽  
...  
Keyword(s):  
Japan Sea ◽  
Tsunami Deposit ◽  
Fault Activity ◽  
Tsunami Deposits ◽  
Tectonic Zone ◽  
Tectonic Plates ◽  
Eastern Margin ◽  
The North ◽  
The Japan Sea ◽  
Okushiri Island

Abstract The eastern margin of the Japan Sea is located along an active convergent boundary between the North American and Eurasian tectonic plates. Okushiri Island, which is situated off the southwest coast of Hokkaido, is located in an active tectonic zone where many active submarine faults are distributed. Studying the records of past tsunamis on Okushiri Island is important for reconstructing the history and frequency of fault activity in this region, as well as the history of tsunamis in the northern part of the eastern margin of the Japan Sea. Five tsunami deposit horizons have been identified previously on Okushiri Island, including that of the 1741 tsunami, which are interbedded in the coastal lowlands and Holocene terraces. However, these known tsunami deposits date back only ~3,000 years. A much longer record of tsunami occurrence is required to consider the frequency of submarine fault activity. In this study, we cored from 7 to 25 m depth in the Wasabiyachi lowland on the southern part of Okushiri Island, where previous studies have confirmed the presence of multiple tsunami deposits on peat layer surfaces. The results indicate that the Wasabiyachi lowland comprises an area that was obstructed by coastal barriers between the lowland and the coast at ~8.5 ka and consists of muddy sediment and peat layers formed in lagoons and floodplains, respectively. In addition, event deposits and 15 tsunami horizons were observed among the turbidites and peat layers, dating back as far as 3,000 years. Combined with previous findings, Okushiri Island has sustained 20 tsunami events between ~7.5 ka and the present. These findings are critical for investigating the activities of submarine faults off the southwestern coast of Hokkaido, as well as for determining tsunami risks along the coast of the Japan Sea between North Tohoku and Hokkaido.

scholarly journals Analysis and revision of the Miocene boreal faunae of bivalve mollusks of the South Sakhalin

2020 ◽  
Author(s):  
В.Д. ХУДИК ◽  
Ю.Д. ЗАХАРОВ
Keyword(s):  
Japan Sea ◽  
Climatic Conditions ◽  
Bivalve Mollusks ◽  
The South ◽  
The North ◽  
Initial Stage ◽  
The Japan Sea ◽  
South Sakhalin ◽  
Early Neogene ◽  
Climatic Cooling

Приведены результаты изучения остатков фаун двустворчатых моллюсков из миоценовых отложений Южного Сахалина. Их анализ позволил выделить три бореальных комплекса моллюсков: невельский, раннечеховский и курасийский, фиксирующие периоды похолодания климата в миоцене региона. Изучение неогеновых представителей родов Lucinoma и Mya позволило обозначить среди них ряд таксонов, имеющих стратиграфическое значение. Установленное присутствие тепловодных двустворок в фаунах позднечеховского времени Южного Сахалина, очевидно, отражает собой начальный этап тенденции нарастающего потепления климата в миоцене региона с климатическим оптимумом в верхнедуйско-сертунайское время. Высказывается следующее мнение: неустойчивые климатические условия в позднем палеогене – раннем неогене северной части Япономорского региона могли быть основной причиной возникновения здесь одного из мощных центров эволюции морских малакофаун бореальных районов северной Пацифики. The results on the studying of the faunae of bivalve mollusks remains from miocene deposits of the South Sakhalin are presented. The analysis of the last ones allowed distinguishing the following three boreal assemblages of mollusks: Nevelskiy, early Chekhovskiy and Kurasiiskiy, recording the period of climatic cooling in miocene of the region. Studying of Neogene representatives of Lucinoma and Mya generas allowed identifying some taxa among them which have stratigraphic significance. The detected presence of warm water bivalves in the faunae of the late Chekhovsky time of the South Sakhalin appears to reflect the initial stage of the tendency of the intensifying climate warming happened during miocene, with climatic optimum during the Verkhneduysky – Sertunaysky times. An opinion is expressed that the unstable climatic conditions in the northern part of the Japan Sea region during late Paleogene – early Neogene could have been the main reason for originating of one of the high-potential centers of evolution of the marine malacofaunae of boreal regions of the North Pacific.

Oceanological studies in the northwest Pacific, Japan and Okhotsk seas in the 73th cruise of the RV Professor Gagarinskiy and 53th cruise of the RV Academic Oparin

2019 ◽  
Vol 59 (6) ◽  
pp. 1093-1096
Author(s):  
V. N. Karnaukh ◽  
A. F. Sergeev ◽  
V. B. Lobanov ◽  
P. Ya. Tishcenko
Keyword(s):  
Bottom Water ◽  
Japan Sea ◽  
Western Pacific ◽  
Northwest Pacific ◽  
The North ◽  
Water Composition ◽  
Sea Bottom ◽  
The Japan Sea ◽  
North Western ◽  
North Western Pacific

During the the 73th cruise of the RV Professor Gagarinskiy and 53th cruise of the RV Academic Oparin oceanological studies of the north-western Pacific, Japan and Okhotsk Seas were conducted. New data on the structure sea bottom, water composition as well as slope convection of the Japan Sea.

scholarly journals A computer database for falling snowflakes

1993 ◽  
Vol 18 ◽  
pp. 11-16 ◽  
Author(s):  
Ken-ichiro Muramoto ◽  
Kohki Matsuura ◽  
Toshio Harimaya ◽  
Tatsuo Endoh
Keyword(s):  
Winter Season ◽  
Japan Sea ◽  
Primary Data ◽  
Maximum Diameter ◽  
Fall Velocity ◽  
North East ◽  
The North ◽  
The Japan Sea ◽  
Computer Based ◽  
Average Size

A computer-based measurement system for characteristics of snowfall is described. To measure the size and velocity of falling snowflakes quantitatively, images of snowflakes were input to an image processor and the primary data were analyzed in real time. In this process, maximum diameter in a horizontal plane and falling velocity were recorded in previously set intervals, then stored on a disk. Since a lot of data were obtained during a full winter season, data had to be processed to make up a database after an experiment. Using this database, the data of the distribution of size and velocity of snowflakes can be retrieved at anytime.We observed snowflakes during winter months of 1986-92 in Sapporo and Toyama, which are located near the north east and middle of the Japan Sea coast respectively. The data indicate that the average size of snowflakes in Toyama was larger than that in Sapporo, while the number concentration of snowflakes in Sapporo was rather higher. The fall velocity tends to increase with increasing size of snowflakes, as observed in both areas.

scholarly journals Distribution and Maturation of Adult Walleye Pollock in Autumn in the Japan Sea off Southwest Hokkaido.

1999 ◽  
Vol 65 (2) ◽  
pp. 223-229
Author(s):  
Yoshihiko Kamei ◽  
Tetsuya Takatsu ◽  
Shogo Takagi ◽  
Toshikuni Nakatani ◽  
Toyomi Takahashi ◽  
...  
Keyword(s):  
Japan Sea ◽  
Walleye Pollock ◽  
The Japan Sea

scholarly journals Nematodes of common Hexagrammidae species from the Far-Eastern Seas of Russia

2014 ◽  
Vol 176 (1) ◽  
pp. 216-224
Author(s):  
Galina F. Solovyeva ◽  
Zoya I. Motora
Keyword(s):  
Japan Sea ◽  
Anisakis Simplex ◽  
The North ◽  
Pseudoterranova Decipiens ◽  
The Japan Sea ◽  
Pleurogrammus Azonus ◽  
Contracaecum Osculatum ◽  
Far Eastern ◽  
First Time ◽  
Far Eastern Seas

Nematoda parasites of five greenling species from the Far-Eastern Seas ( Pleurogrammus azonus , P . monopterygius , Hexagrammos octogrammus , H . lagocephalus , H . stelleri ) are investigated. The family Hexagrammidae is endemic for the North Pacific. In total, 10 species of nematodes are found: Anisakis simplex l., Pseudoterranova decipiens l., Hysterothylacium aduncum , Contracaecum osculatum l., Ascarophis filiformis , A. curvicauda , A. pacifica , Cucullanellus minutus , Cucullanus heterochrous , and Paracapillaria helenae , all of them have wide geographical and hosts distribution. Anisakis simplex l. and Pseudoterranova decipiens l. are the most common for all investigated host species. The highest species diversity of nematodes (7 species) is registered for arabesque greenling P. azonus , particularly its females; Contracaecum osculatum l. and Cucullanus heterochrous are found for the first time for this host in the Japan Sea. The parasites are dispersed irregularly in muscles of all parts of fish body. Large-sized (i.e. elder) fish is higher infected by larvae of P. decipiens .

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