• Title/Summary/Keyword: Southeast sea of Korea

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A report on the mass summer mortalities of the farmed Pacific oysters, Crassostrea gigas and Bay scallops Argopecten irradians in the local waters of Goseong Bay, Korea

  • Han, Jong Cheol;Jo, Qtae;Park, Young Cheol;Park, Tae Gyu;Lee, Deok Chan;Cho, Kee-Chae
    • The Korean Journal of Malacology
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    • v.29 no.3
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    • pp.239-244
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    • 2013
  • Mass mortalities of farmed shellfish, mostly in summer season, thus named mass summer mortalities, have been a global issue in shellfish aquaculture. The 2013 mass summer mortalities in the confined waters of Goseong Bay, Goseong, Korea were quite a unique and intensive for two farmed species, the Pacific oysters, Crassostrea gigas, and bay scallops, Argopecten irradians. The mortalities were progressive from the bottom of the suspended oysters and caged scallops in the waters, reaching up to 80% for the oyster and 95% for the scallop in about 20 days after the first occurrence, early August, 2013. We monitored a wide range of environmental factors, including water temperature, dissolved oxygen (DO), salinity, turbidity, acidity (pH), organic and inorganic matters, chemical oxygen demand (COD), suspected pathogenic agent, and phytoplankton composition throughout the water column where the two species were suspended or caged. Our survey concluded that the hypoxia or anoxia might be a major cause of the mortalities. Here, we detailed the mortalities and ways to arrive at the conclusion.

Seasonal variation of physicochemical factor and fecal pollution in the Hansan-Geojeman area, Korea

  • Park, Young Cheol;Kim, Poong Ho;Jung, Yeoun Joong;Lee, Ka Jeong;Kim, Min Seon;Go, Kyeong Ri;Park, Sang Gi;Kwon, Soon Jae;Yang, Ji Hye;Mok, Jong Soo
    • Fisheries and Aquatic Sciences
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    • v.19 no.4
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    • pp.17.1-17.9
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    • 2016
  • The seasonal variation of fecal coliforms (FCs) and physicochemical factors was determined in seawaters of the Hansan-Geojeman area, including a designated area for oyster, and in inland pollution sources of its drainage basin. The mean daily loads of FCs in inland pollution sources ranged from $1.2{\times}10^9$ to $3.1{\times}10^{11}$ most probable number (MPN)/day; however, the pollutants could not be reached at the designated area. FC concentrations of seawaters were closely related to season, rainfall, and inland contaminants, however, within the regulation limit of various countries for shellfish. The highest concentrations for chemical oxygen demand (COD) and $chlorophyll-{\alpha}$ in seawaters were shown in the surface layer during August with high rainfall, whereas the lowest for dissolved oxygen (DO) in the bottom layer of the same month. Therefore, it indicates that the concentrations of FC, COD, DO, and $chlorophyll-{\alpha}$ of seawaters were closely related to season and rainfall.

Antimicrobial Resistance of Escherichia coli Isolates from Mussel Mytilus galloprovincialis Farms and Inland Pollution Sources in the Changseon Area, Korea (창선 해역의 지중해담치(Mytilus galloprovincialis) 양식장 및 육상오염원에서 분리한 대장균(Escherichia coli)의 항생제 내성)

  • Kwon, Soon Jae;Lee, Ka Jeong;Jung, Yeoun Joong;Park, Sang Gi;Go, Kyeong Ri;Yang, Ji Hye;Mok, Jong Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.5
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    • pp.564-572
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    • 2016
  • In this study, we isolated and characterized Escherichia coli from mussels and inland pollution sources in or in proximity to the Changseon area on the southern coast of Korea in 2014. A total of 147 strains of E. coli were isolated from 54 mussels and 32 pollution-source samples. The susceptibility of the isolates to 24 antimicrobial agents was analyzed. The resistance of E. coli isolates to rifampin was highest at 100%, followed by cephalothin (98.6%), tetracycline (91.8%), amikacin (81.0%), ampicillin (79.6%), cefazolin (79.6%), streptomycin (73.5%), piperacillin (70.7%), gentamicin (37.4%), cefoxitin (35.4%), cefamandole (34.7%), tobramycin (29.9%), amoxicillin/clavulanic acid (24.5%), nalidixic acid (21.8%), trimethoprim (19.0%), chloramphenicol (17.7%), cefotaxime (12.9%), trimethoprim (10.9%), ceftazidime (10.2%), aztreonam (7.5%), imipenem (2.7%), cefepime (2.0%), and cefotetan (0.0%). In addition, the antimicrobial resistance of E. coli isolates from inland pollution sources was slightly greater than or similar to that of isolates from mussels.

New Records of Three Sergestid Shrimps (Crustacea: Decapoda: Penaeidea) from the Korean Waters of the Yellow Sea

  • Kim, Jung Nyun;Choi, Jung Hwa;Lee, Jeong-Hoon;Kim, Joo Il
    • Fisheries and Aquatic Sciences
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    • v.16 no.3
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    • pp.199-205
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    • 2013
  • Three species of pelagic sergestid shrimps, Deosergestes seminudus (Hansen, 1919), Sergia lucens (Hansen, 1922) and S. talismani (Barnard, 1947), were identified based on collections by the National Fisheries Research and Development Institute from the Korean coast of the Yellow Sea between 2003 and 2011. They are herein reported for the first time from the Yellow Sea. Morphological descriptions and illustrations with color photographs of all species are also given. With the addition of these species, the family Sergestidae in the Korean waters now comprises five species belonging to three genera. Finally, a key to the Korean genus and species of the family Sergestidae is presented.

Heterogeneous growth of the triploid Pacific oysters Crassostrea gigas created by chemical inhibition of polar body release

  • Jo, Qtae;Han, Jong-Chul;Hur, Yong-Baek;Byun, Soon Kyu;Moon, Tae-Seok
    • The Korean Journal of Malacology
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    • v.30 no.4
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    • pp.443-447
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    • 2014
  • Triploids have several potential advantages over diploids in aquaculture, drawing an elevated commercial reaction into the realistic application of the techniques despite we are still in the early stage of triploid industry for the Pacific oysters Crassostrea gigas. We traced the growth performance of the triploid C. gigas for over a year from hatchery spats, which was created by manipulations of chemicals (Cytochalasin B, CB or 6-Dimethylaminopurine, 6-DMAP). The growth was clearly marked by an initial longer dormancy and following a great magnitude of heterogeneity. The dormancy was almost 9 to 10-month long or even longer and was considered as a downside of the creation. The heterogeneity was magnified by appearance of extraordinarily growing oysters in part during summer season, which could be a representative upside of the triploids. Overall, however, the results were not as positive as were expected. The longer dormancy and following heterogeneity observed in our practice could be marked as an additional negative sign of the chemical use. The present study, thus, might be highly indicative in the introduction of biological cross between tetraploid and diploid to produce natural triploid embryos.

Antimicrobial Resistance of Escherichia coli Isolated from Oysters Crassostrea gigas and Major Inland Pollution Sources in the Jaranman-Saryangdo Area in Korea (자란만사량도 해역의 굴(Crassostrea gigas) 및 육상오염원에서 분리한 대장균(Escherichia coli)의 항생제 내성)

  • Kwon, Ji Young;Kwon, Soon Jae;Yang, Ji Hye;Mok, Jong Soo;Jeong, Sang Hyeon;Ha, Kwang-Soo;Lee, Hee Jung;Jung, Yeoun Joong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.52 no.6
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    • pp.605-616
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    • 2019
  • This study evaluated the abundance and antimicrobial resistance of Escherichia coli in oysters Crassostrea gigas and major inland pollution sources sampled in 2014-2015 from Jaranman-Saryangdo on the southern coast of Korea. The ranges of the geometric mean of E. coli concentrations in oysters and major inland pollution sources were <20-29.8 MPN/100 g and 7.5-137.2 MPN/100 g, respectively. We isolated 247 strains of E. coli (28 from oysters and 247 from major inland pollution sources) and examined the antimicrobial resistance patterns of all isolates. Isolates from both sources were highly resistant to rifampin (99.5-100%) and cephalothin (70.8-78.6%). The resistance rate was higher in E. coli isolated from oysters those from inland pollution sources. Multiple resistance against at least four antimicrobials was observed in 85.7% and 21.0% of the oyster and major inland pollution sources isolates, respectively.

Distribution and Species Composition of Larval Fish during Winter Season in Jinhae Bay, Korea (동계 진해만에서의 자어 분포 및 종조성)

  • Lee, Jeong-Hoon;Kim, Jung-Nyn;Nam, Kimun;Kim, Chang-Won;Kim, Joo-Il
    • Korean Journal of Ichthyology
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    • v.26 no.2
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    • pp.133-138
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    • 2014
  • We investigated the spacial distribution and species composition of fish larvae during winter season (January 2013~March 2013) in Jinhae Bay, Korea. During the study period, a total of 12 larvae species belonging to 8 families were collected, and the dominant species were Pholis crassispina, Clupea pallasii, Liparis tanakae, Hexagrammos otakii. These four species accounted for 93% of the total number of individual collected. High density and species diversity occurred around Jam-do and eastern area of Chilcheon-do, suggesting that these areas are the main spawning ground of fish larvae in Jinhae Bay.

The Prison and the Sea

  • Mrazek, Jan
    • SUVANNABHUMI
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    • v.11 no.1
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    • pp.7-40
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    • 2019
  • The essay reflects on the work of Adrian Lapian (1929-2011), an Indonesian scholar of archipelagic/maritime Southeast Asia and its "sea people-sea pirates-sea kings." The essay suggests that Lapian's writing mirrors navigation at sea, and the constant re-orientation and ever-changing, multiple points of view that are part of it. This is contrasted to Foucault's "panopticism" and academic desire for discipline. Taking cue from Lapian's writing and from the present author's experience of seafaring, the essay envisions Southeast Asian studies as a fluid, precarious, disorienting, even nauseating multiplicity of experiences, dialogues, and moving, unstable, and uncertain points of view; a style of learning that is less (neo)colonial, more humble, and closer to experiences in the region, than super-scholarship that imposes universalizing, panoptic standards, theories and methods (typically self-styled as "new") that reduce the particular into a specimen of the general, a cell in the Panopticon. The essay concludes with reflections on certain learning initiatives/traditions at the National University of Singapore, including seafaring voyages-experiences, encounters, and conversations that make students and scholars alike to move and see differently, to be touched, blown away, rocked, swayed, disoriented, swallowed, transformed, and feel anew their places, roots, bonds, distances, fears, blindness, powerlessness.

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Temporal changes in the abundance of the fish-killing dinoflagellate Karlodinium veneficum (Dinophyceae) in Tongyeong, Korea

  • Park, Tae-Gyu;Ok, Yu-Ran;Park, Young-Tae;Lee, Chang-Kyu
    • ALGAE
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    • v.26 no.3
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    • pp.237-241
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    • 2011
  • The toxic dinoflagellate Karlodinium veneficum has been implicated in numerous fish kill events around the world. Since this species commonly co-occurs with other morphologically similar dinoflagellates, field monitoring of this species in natural waters via light microscopy only has been problematic. In this study, we investigated temporal changes in K. veneficum's abundance in the waters of Obido, Tongyeong, using a species-specific real-time polymerase chain reaction (PCR) assay. The field survey, from April to December 2010, revealed K. veneficum occurred at low densities (12 to 425 cells $L^{-1}$) during this time and that cell numbers peaked in June (early summer in Korea), indicating this species generally occurs in the warmer season (mostly at $16.9-22.3^{\circ}C$ and 33.4-34.5‰) in the Obido area.

Assessment of the Bacteriological Safety of Seawater and Oysters Crassostrea gigas in Yongnam-Gwangdo Area, Korea 2014-2016 (2014-2016년 경남 용남·광도해역 해수 및 굴(Crassostrea gigas)의 세균학적 위생평가)

  • Yoon, Hyun Jin;Kwon, Ji Young;Lee, Ka Jeong;Kwon, Soon Jae;Mok, Jong Soo;Kim, Poong Ho;Jung, Yeoun Joong
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.5
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    • pp.535-541
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    • 2018
  • This study evaluated the sanitary state of seawater and shellfish in Yongnam-Gwangdo area from January 2014 to December 2016. The sampling stations for sanitary survey in Yongnam-Gwangdo area were composed of 41 seawater stations and 5 oyster Crassostrea gigas stations. The samples were collected monthly at each station. Shellfish-borne disease is associated with bacteria and viruses in the presence of fecal coliforms. Bacteriological pollution levels of shellfish increase with seawater quality. Therefore, fecal coliforms are very important criteria for evaluating the safety of fisheries in coastal areas. The geometric mean and the estimated 90th percentile ranges of total and fecal coliforms for seawater were 1.8-11.7, 2.8-233.6, <1.8-6.7 and 1.8-100.2 MPN/100 mL, respectively. The range of E. coli levels for oysters was <20-1,300 MPN/100 g. Based on various standards, the sanitary condition in Yongnam-Gwangdo area was evaluated as follows: clean area (Korean criteria), conditionally approved area (US criteria) and class B (EU criteria).