• Title/Summary/Keyword: Fisheries oceanography

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On The Variation Of The Mixed Layer Depth And The Heat Flux In The Sea Of Japan

  • Shim, Taebo;Kim, Kuh
    • 한국해양학회지
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    • v.16 no.2
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    • pp.49-56
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    • 1981
  • Annual variation of the surface mixed layer depth (MLD) in the southern part of the Sea of Japan is investigated based upon the oceanographic and meteorological data taken during 1971∼1975 by the Fisheries Research and Development Agency and the Central Meteorological Office of Korea. It is found that the variation of the MLD is strongly correlated with the heat exchange between the atmosphere and sea. The MLD and heat flux vary within ranges comparable to those in the Kuroshio region found by Bathen(1972) and Wyrtki(1965)

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Geochemical Indicators for the Recovery of Sediment Quality after the Abandonment of Oyster Crassostrea gigas Farming in South Korea (굴(Crassostrea gigas)양식 중단 이후 퇴적물 질 회복에 관한 지화학적 지표 탐색)

  • Sim, Bo-Ram;Kim, Hyung Chul;Kang, Sungchan;Lee, Dae-In;Hong, SokJin;Lee, Sang Heon;Kim, Yejin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.53 no.5
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    • pp.773-783
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    • 2020
  • In order to evaluate the recovery of fishing ground environment after the cessation of aquaculture farming, we examined the variation in sediment quality over time using different geochemical factors and investigated whether these factors are indicators of sediment quality recovery. The study area was an oyster Crassostrea gigas, farm in Tongyeong, Geyongsangnam-do, South Korea, where aquaculture activities had been carried out for 20 years, and the changes in water and sediment environment were monitored for 14 months after the abandonment of the farm. The mean water depth was 14 m, with a tidal range of 3 m, and seawater current velocity ranged from 4.7 to 7.0 cm/s. After the abandonment of the farm, total organic carbon and total nitrogen concentrations in the surface sediments decreased significantly over time compared to those in the control site; in particular, immediately after farm abandonment, acid-volatile sulfide concentrations decreased relatively rapidly. Carbohydrate and protein concentrations in the sediments showed no significant changes; however, lipid concentrations markedly decreased. Further studies on other aquaculture taxa and various aquaculture areas are needed to establish new policies for environmental management of fishing grounds, such as relocation of fishing grounds and determination of optimal fallowing periods.

Review of Oceanography of the Subarctic North Pacific Ocean (북태평양어장의 해양환경)

  • 장선덕
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.7 no.1
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    • pp.9-27
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    • 1971
  • Oceanography of the Subarctic North Pacific Ocean is reviewed. The submarine topography and the current systems in the region are explained. Recent serial observation data reveals that. though the upper mixed layer of low salinity is relatively thick. the pattern of the property distribution in winter is essencially similar to that in summer. Alaskan Stream Extension Water. which influences the abundance and the location of demersal fishes. extends northward to 58${\circ}$ N Lat in the Bering Sea. A southeastward intrusion of the Bering Borcal Cold Water causes the formation of a sharp oceanic front. where the demersal fishes such as Alaska pollacks and cods arc concentrated. The Alaska pollacks seem to avoid the low salinity water of the Alaskan Coastal Water.

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Review of Oceanography of the Subarctic North Pacific Ocean (북태평양어장의 해양환경)

  • 장선덕
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.7 no.1
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    • pp.8-8
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    • 1971
  • Oceanography of the Subarctic North Pacific Ocean is reviewed. The submarine topography and the current systems in the region are explained. Recent serial observation data reveals that. though the upper mixed layer of low salinity is relatively thick. the pattern of the property distribution in winter is essencially similar to that in summer. Alaskan Stream Extension Water. which influences the abundance and the location of demersal fishes. extends northward to 58${\circ}$ N Lat in the Bering Sea. A southeastward intrusion of the Bering Borcal Cold Water causes the formation of a sharp oceanic front. where the demersal fishes such as Alaska pollacks and cods arc concentrated. The Alaska pollacks seem to avoid the low salinity water of the Alaskan Coastal Water.

Application of Single Cell Gel Electrophoresis for Detection of DNA Single Strand Breaks in DNA of Fish Blood Cell (어류혈구세포에 있어서 Single Cell Gel Electrophoresis를 응용한 DNA Single Strand Breack의 측정)

  • KIM Gi Beum;LEE Richard F.;MARUYA Keith A.
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.36 no.4
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    • pp.346-351
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    • 2003
  • Single-cell gel electrophoresis (comet assay) was used to detect DNA single strand break in blood cells from several marine fish species. Three fish species were collected from Georgia coastal area. Mummichog, Fundulus heteroclitus showed higher DNA damage than sea bass, Lateolabrax japonicus and trout, Oncorhynchus masou masou under the same experimental conditions. Mummichogs had more alkaline-labile sites on their DNA than other fish species. The comet assay with mummichog blood cells at pH 12.5 showed a dose-response curve with the increasing concentrations of hydrogen peroxide. While the isolated leucocytes showed no increase of DNA damage after in vitro exposure to 2-methyl-1,4-naphthoquinone (MNQ), erythrocytes showed dose-dependent DNA damage. These results indicate that the comet assay can be applied successfully as a bioassay using erythrocyte for environmental monitoring.

A Numerical Model on the Inflow into the Japan Sea: the Formation and Transport of the Tsushima Warm Current (동해 해수유입에 대한 수치모델: 대마난류 형성 및 수송량)

  • NAM Soo-Yong;SEUNG Yong-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.1
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    • pp.58-64
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    • 1992
  • A barotropic model is run over the Northwest Pacific Ocean to examine the formation and transport of the Tsushima Warm Current. The results indicate that the Tsushima Warm Current is a downstream extension of the Taiwan Warm Current. Local wind does not change the amount of transport of Tsushima Warm Current but it changes much the initial flow pattern of Tsushima Warm Current such that for southerly wind, the transport is through the Taiwan Strait but for northerly wind, it is through the eastern side of Taiwan.

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Comparative lectin binding patterns of Cochlodinium polykrikoides Margalef

  • Rhodes, Lesley L.;Cho, Yong-Chul;Cho, Eun-Seob
    • Journal of the korean society of oceanography
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    • v.35 no.3
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    • pp.153-157
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    • 2000
  • Four different FITC-conjugated lectins were used to visually evaluate lectin binding activity by optical staining quality using confocal laser scanning microscopy (CLSM) of Cochzodinium polykrikoides in nature (wild type) and culture (cultured type). Cells from the field and cultures treated with ConA fluoresced only at the outer cell wall, and the abundance and distribution of the fluorescent signal were similar. Treatment with PWM and HPA did not elicit fluorescence at the cell surface, but the wild type exposed to HPA showed greater binding than did the cultured cells, possibly due to greater concentrations of glucosamine. The wild type cells treated with LBL lectin showed a strong green fluorescence on the cell surface, whereas cultured cells did not. Signal intensity and abundance were greater than for any other lectins tested in this study. These results suggest that wild type and cultured type are significantly different based on surface sugar production. In particular, the wild type cells apear richer in galactosamine-like moieties. Neither glucose nor mannose-like moieties were present in either wild types or cultured cells.

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Influence of atmospheric aerosol on satellite ocean color data in the East/Japan Sea (동해에서 대기에어로졸이 해색위성자료에 미치는 영향)

  • Yamada, Keiko;Kim, Sang-Woo
    • Proceedings of KOSOMES biannual meeting
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    • 2009.06a
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    • pp.53-54
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    • 2009
  • The influence of atmospheric aerosol on satellite ocean color data were evaluated using SeaWiFS monthly standard mapped image products. The atmospheric optical thickness (AOT) was increased in spring and summer, and it showed the strong positive correlation with remote sensing reflectance, normalized waterleaving radiance /solar irradiance, at 555 nm (Rrs555) which is a component of the satellite chlorophyll estimation. Such the high AOT and high Rrs555 pixels showed overestimation of satellite chlorophyll in spring, especially in the area which showed large phytoplankton absorption which 1s expressed by low remote sensing reflectance at 443, 490 and 510 nm (Rrs 443, Rrs490 and Rrs510).

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Long-term Environmental Changes and the Interpretations from a Marine Benthic Ecologist's Perspective (I) - Physical Environment

  • Yoo Jae-Won;Hong Jae-Sang;Lee Jae June
    • Fisheries and Aquatic Sciences
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    • v.2 no.2
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    • pp.199-209
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    • 1999
  • Before investigating the long-term variations in macrobenthic communities sampled in the Chokchon macrotidal flat in Inchon, Korea, from 1989 to 1996, we need to understand how environmental factors in the area vary. As potential governing agents of tidal flat communities, abiotic factors such as mean sea level, seawater, air temperature, and precipitation were considered. Data for these factors were collected at equal intervals from 1976 or 1980 to 1996, and were analyzed using a decomposition method. In this analysis, all the above variables showed strong seasonal nature, and yielded a significant trend and cyclical variation. Positive trends were seen in the seawater and air temperatures, and based upon this relationship, it was found that the biological sampling period of our program has been carried out during warmer periods in succession. This paper puts forth some hypotheses concerning the response of tidal flat macrobenthos communities to the changing environment including mild winters in succession.

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