• Title/Summary/Keyword: Yellow sea

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Preliminary Diagnosis for Pulsing Simulation of Low Trophic Ecosystem by Environmental Changes in Coastal Area (연안해역의 환경변화에 따른 저차 생태계 Pulsing Simulation 예비 진단)

  • Lee, Dae-In
    • Journal of Environmental Impact Assessment
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    • v.21 no.3
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    • pp.461-468
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    • 2012
  • In general, long-term changes of ecological factors take a pulse form in which they interact with other factors and go through a repeated increasing and decreasing cycle. The coupling of the two approaches the grid model and the box model in ecological modeling can lead to an in-depth understanding of the environment. The study analyzes temporal variations of major storages with an energy system model that formulizes effectively the relationships among nutrients, phytoplankton, and zooplankton in the Yellow Sea and the East China Sea. An increase of light intensity and standing stock of nutrient increase the magnitude and frequency of pulsing. Also, an immense reduction of nutrient concentration can cause extinction of the pulsing and bring about a steady state. It is concluded that the nutrient loads in freshwater discharge from the Yangtze affect the cycles of major ecological components as well as water quality variables and play an important role in the marine ecosystem.

Vertical Temperature Profile in the Yellow Sea according to the Variations of Air Temperature

  • CHO Kyu-Dae;CHO Kwang-Woo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.21 no.1
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    • pp.1-10
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    • 1988
  • The vertical temperature profiles of the Yellow Sea in summer are investigated by means of the nine air temperature (AT) patterns which are classified with the AT of winter and summer. The sea surface temperature (SST) is high when the AT of summer is high, and vice versa. The gradient of thermocline in the offshore region is higher than that in the coastal region and is not always favorable with the AT patterns. The relation between sea bottom temperature (SBT) and the AT of winter is favorable when the SBT is averaged in the coastal and offshore stations. In addition, the SST of coastal stations is higher than that of offshore stations because of the strong mixing by the tidal current in the coastal region. The correlation between the AT and the SST of August is favorable (r=0.44-0.69), while the correlation between the AT of February and the SBT of August is not favorable except the stations, A2 (r=0.57) and B2 (r=0.61).

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Distribution and Occurrence of Swimming Crab, Portunus trituberculatus Larvae in the Mid-western Coast of Korea in the Yellow Sea (우리나라 서해중부 연안의 산란철 꽃게유생 분포 및 출현량)

  • Jo, Hyun-Su;Park, Won-Gyu;Kwon, Dae-Hyeon;Cha, Byung-Yeul;Im, Yang-Jae
    • Journal of Fisheries and Marine Sciences Education
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    • v.25 no.4
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    • pp.991-997
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    • 2013
  • Distribution and occurrence of swimming crab, Portunus trituberculatus larvae were investigated in the mid-western coast of Korea in the Yellow Sea. P. trituberculatus larvae were collected in July and August from 2010 to 2012. Bongo net with 303 mesh was deployed once with a double oblique tow. Zoea I (ZI) densities were highest in all sampling months. Then densities of later larval stages decreased dramatically. In general, larval densities at the stations in northern parts and coastal areas were higher than those at the southern and offshore area. Because egg bearing seasons of P. trituberculatus in the study area are between April and August, larval densities, particularly, of ZI may be underestimated. Considering higher densities of ZI and lower ones of later stages, larvae may be transported to growing area and returned to the parental populations. Larval densities and sea surface temperature were not correlated.

Maturation and Spawning of the Pacific Cod Gadus macrocephalus in the West Coast of Yellow Sea of Korea (한국 서해에 출현하는 대구(Gadus macrocephalus)의 성숙과 산란)

  • Choi, Dong Hyuk;Youn, Byoung Il;Kim, Maeng Jin;Lee, Seung Hwan;Lee, Seung Jong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.54 no.1
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    • pp.46-52
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    • 2021
  • The maturation and spawning of Pacific cod Gadus macrocephalus were inversigated using 2,415 samples collected monthly from January 2017 to December 2019, in the Yellow Sea of Korea. We analyzed monthly changes in gonadosomatic index (GSI), maturity stage, egg diameter (mm), the relations fecundity and total length (cm). The spawning period was February to March. Fecundity varied between 334,836 and 2,099,600 eggs. The relationship between the fecundity and TL of fish was expressed in F=186.86TL2.0954 (R2=0.7359). The percentage of sexually mature females estimated from a logistic function was over 50%, 75% and 97.5% for the size (TL) 39.3, 44.8 and 57.7 cm.

Standardization of Catch per Unit Effort (CPUE) for Yellow Croaker (Larimichthys polyactis) in the East China Sea (동중국해 참조기자원에 대한 단위노력당어획량(CPUE)의 표준화)

  • Lee, Dong-Woo;Lee, Jae-Bong;Kim, Yeong-Hye;Jung, Suk-Geun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.41 no.5
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    • pp.346-352
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    • 2008
  • Yellow croaker (Larimichthys polyactis) is a major target species of large pair trawl fishery in the East China Sea. To standardize catch per unit effort (CPUE) of yellow croaker for the large pair trawl fishery, generalized linear model (GLM) was applied to evaluate and eliminate the influence of the explanatory factors (year, month, horse power and gross tonnage of vessel) on daily catches per boat collected and compiled by National Fisheries Research and Development Institute (NFRDI) from 1990 to 2007 at the fishery auction places of Busan, Masan and Incheon in Korea. Results of GLM showed that all of the factors significantly influenced on CPUE, explaining 36% of the total deviance. The standardized CPUE indicated that the abundance of yellow croaker in 2000's was 1.7 times higher than the CPUE in 1990's.

Oceanographic Conditions of Eishing Ground of Yellow Croaker (Pseudosciaena polyactis) in Korean Waters (한국연근해 참조기 (Pseudosciaena polyactis Bleeker) 어장의 해황 특성)

  • BAIK Chul-In;CHO Kyu Dae;LEE Chung Il;CHOI Kwang-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.37 no.3
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    • pp.232-248
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    • 2004
  • In order to utilize fisheries resources under a joint management scheme with adjacent nations, as well as detecting of fishing grounds, the factors which influence yellow croaker (Pseudosciaena polyactis) in Korean waters were studied using historical catch per unit effort and oceanographic data. The main fishing ground near Cheju Island was located along the thermal front formed between the Yellow Sea Bottom Cold Water (YSBCW) and northward moving warm current. When the YSBCW (index temperature: $10^{\circ}C)$ strongly extended southward, the fishing condition were worse than average. Especially, low temperatures greatly influenced stow net fisheries, which were operated in the deep water layer The concentration and dispersal of fishing ground and catch coincided with oceanographic features and the seasonality of water masses.

Proposed program for monitoring recent Crustal movement in Korean Peninsula

  • Hamdy, Ahmed M.;Jo, Bong-Gon
    • Journal of the Korean Geophysical Society
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    • v.5 no.4
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    • pp.283-292
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    • 2002
  • The Korean peninsula is located at the edge of the East Asian active margin. The seismic activity in the Korean Peninsula is relatively low compared with the neighboring countries China and Japan. According to the available Seismic information, the Korean Peninsula is not totally safe from the Earthquake disaster. Moreover, the area is surrounded by varies tectonic forces which is resulted from the relative movements of the surrounding tectonic plates "Pacific, Philippine Sea, Eurasian and South China". Nowadays South Korea has 65 GPS stations belong to 5 governmental organizations "each organization figure out its own GPS stations for different requirements" In order to minimize the seismic hazard in the Korean Peninsula a program for monitoring the recent crustal movement has been designed considering the uses of the available GPS station "some selected stations from the previously mentioned stations" and the tectonic settings in and around the Korean Peninsula. This program is composed of two main parts, the first part to monitor the crustal deformation around the Korean Peninsula with the collaboration of the surrounding countries "China and Japan" this part is composed of two phases "East Sea Phase and Yellow Sea Phase". These phases will be helpful in determining the deformation parameters in the East Sea and the Yellow Sea respectively While the Second part of this program, is designed to determine the deformation parameters id and around the main faults in the Korean Peninsula and the relative movement between the Korean Peninsula and the Cheju Island. Through out this study the needs of crustal movement center rose up to collect the data from the previously mentioned stations and Organizations in order to use such reliable data in different geodynamical application.

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The Prospect of the Development of Sea&Air Transportation Routes around the Yellow Sea Regions (환황해권 Sea&Air 수송의 발전 가능성 전망)

  • Kim, Tae-Seung;Won, Dong-Woo;Yun, Jung-Won
    • Journal of Korea Port Economic Association
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    • v.22 no.3
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    • pp.189-207
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    • 2006
  • As the development of Northeast Asian logistics hub becomes one of the national agenda for further development, the sea&Air transport around the Yellow Sea regions has drawn attention of many scholars and government officials. The Sea&air transport is a mode of transportation combining the advantage of high-speed in air transport with the advantage of low-price in sea transport. Hence the sea&air aims at a niche market between air and sea. This paper reviews the possibility of development of the sea&air transport in the aspects of competitiveness over other modes, future demand condition, and the change of the technology and transport environment. The result is that the sea&air is competitive in the aspect of time as well as cost, and sustainable in the aspect of future demand condition. But, it is not stable in the aspect of the conditions of technology or transport demand. Especially, the progress of air transport technology which is aiming at the door-to-door transport among mid- and small- cities, and the rapidly increasing strategic alliances of international airlines with Chinese airlines for the market of China will undermine the stability of the sea&air transport seriously As alternatives, this paper proposes the 3-stage development strategy of sea&air transport. First, at the stage of transshipement, the development of high speed vessels to reduce the time crossing the Yellow Sea and the proactive marketing strategy to induce Chinese-owned products should be emphasized. Second, the value added logistics activity which will secure the demand of the sea&air transport should be developed. Third, demand creation by developing the SCM hub in Incheon is final goal for the logistics hub strategy as well as the sea&air transport.

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