• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.159-167
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• 1998

The environmental characteristics in shellfish farms were investigated in the western part of Jinhae Bay, 1996. During summer, anoxia and high nutrient concentrations were found in the bottom waters of shellfish farms. The concentrations of particulate organic species in seawaters were enriched, showing an average 57.44 uM for POC, an average 5.45 uM for PON, and an average 0.42uM for PP. The sediments environment in the farms was very polluted. The concentrations of COD and AVS were more than 20 mg/g.dry and 0.5 mg/g.dry, respectively. The total sedimentation rate was high as an average $7.81g/m^2/day$ with organic matter contents of $26\%$. Oxygen consumption rate was similar to polluted area as an average of $439mg/m^2/day$. Nutrient release rates were an average of $8.25mg/m^2/day$ for nitrogen and an average of $1.38mg/m^2/day$ for phosphorous. The cluster analysis through environmental data in summer indicated that DO, nutrient in the bottom water, and AVS in the sediment were important factors to characterize the polluted environmental site.

• Journal of Environmental Science International
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• v.29 no.3
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• pp.273-282
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• 2020

Residence time is defined as the time taken for a material in a system to leave the system. The residence time characteristics in shellfish aquaculture determine the dispersion of excretion from aquaculture farms, along with the supply of food by seawater exchange. In this study, we estimated the spatial distribution of average residence time in the shellfish farming area using a particle tracking model. As a result, a relatively short average residence time of about 20 days or less was calculated in most areas, but an average residence time of more than 40 days was calculated in the inner areas. Relatively long average residence times were calculated along the west coast compared to the east coast, with the longest average residence time of more than 50 days in the northwestern areas. It can be inferred that the disturbance of the benthic ecosystem caused by shellfish farms is likely to be large because of the relatively weak dispersion of excrement from shellfish farms located on the west coast, especially in the northwest region. This distribution of average residence time is important for understanding the potential effects of seawater exchange on the environmental sustainability of shellfish farms, along with the seawater circulation characteristics of Jaran Bay.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.436.2-437
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• 1998

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.460-466
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• 2016

From 2013 through 2015, we investigated the contamination status and antimicrobial resistance patterns of pathogenic Vibrio parahaemolyticus in commercially valuable seawater and shellfish (Oyster Crassostrea gigas, short-neck clam Venerupis philippinarum, ark shell Scapharca broughtonii and mussel Mytilus galloprovinciallis) from the southern coast of Korea. The detection rate of V. parahaemolyticus was highest in short-neck clams (23.7%), followed by ark shells (19.2%), oysters (15.9%), mussels (13.6%), and seawater (8.6%). The following percentages of PCR assays of shellfish were positive for the thermostable direct hemolysin-related hemolysin gene (trh) : oysters (12.8%), short-neck clams(11.8%), and ark shells (3.4%). Similar assays for the thermostable direct hemolysin gene (tdh) resulted in positive results for short-neck clams (5.9%) and ark shells (3.4%). Antimicrobial resistance was present in 100% of 8 tdh (+) and 2 trh (+) V. parahaemolyticus isolates challenged with ampicillin. However, all pathogenic V. parahaemolyticus were sensitive to 14 other antibiotics. To ensure the safety of shellfish consumption, the continuous monitoring of the prevalence and distribution of virulence factors of V. parahaemolyticus in shellfish farms is needed.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.24-33
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• 2000

The value of beauty and the resources in the southern coastal sea is most important not only ecologically but also economically in Korea. Since 1980s, intensive use and consequent coastal water pollution have caused an increase in the frequency of red tides outbreak in this area. In this study, seawater and sediment were collected in summer and winter of 1998 and 1999, respectively. The status of seawater eutrophication, sediment oxygen demand(SOD), and nutrients release from sediment were measured. There was an obvious trend that COD and total phosphorous concentrations of summer sediments obtained from aquaculture farms were higher than those of winter sediments. It was concluded that sediments accumulated in the shellfish farms of southern coastal sea caused oxygen deficit in the bottom layer of seawater and played an important role for eutrophication.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.424-436
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• 2013

Organic enrichment was investigated in surface sediments from the Yeoja and Gangjin Bays of Korea, which contain dense shellfish farms, in order to evaluate the contamination status and temporal changes in shellfish farming along these coasts. The degree of organic enrichment was determined using geochemical indicators (chemical oxygen demand, ignition loss, acid volatile sulfide, total organic carbon in sediments, and total nitrogen in sediments, ammonium and nitrate in pore water, and bioluminescence inhabitation for sediments). Temporal changes in organic enrichment conditions were detected by comparing our 2012 data to those previously reported from a survey conducted in 1999/2000. Organic enrichment was significantly higher in September than in May and July, in Gangjin Bay than in Yeoja Bay, and significantly higher in shellfish farms than in reference sites not used to culture shellfish. Ammonium concentrations in pore water were two orders of magnitude greater than nitrate concentrations, suggesting that these bays represent nitrogen-reducing environments.

• Journal of the korean society of oceanography
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• v.38 no.1
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• pp.17-23
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• 2003

We report the distribution of $^{210}$ Pb and various metallic elements (Al, Fe, Mg, Ca, Ti, Mn, Sr, Ba, Zn, V, Cr, Zr, Ni, Cu, and Y) in the sediment cores from six shellfish-farming bays in the South Sea of Korea. The $^{210Pb}$ inventories in Deukryang, Gwangyang, and Goseong Bay cores were comparable to those expected from the known fallout input. However, the $^{210}$ Pb inventories were two times higher in Jinju, Gangjin, and Hansan-Koeje Bay cores, suggesting an important role of other sources such as fluvial inputs. Based on the enrichment factor analyses, non-detrital fractions of all the measured elements were found to be insignificant. The Mn was highly enriched only in the surface sediments of the Jinju and Goseong Bay, which implies that the surface-sediment environment of these bays is efficiently oxidizing Mn remobilized from either pore waters or bottom seawaters. These data set provides the sources of heavy metal in sediment around shellfish farms and the current level of metallic elements for the future monitoring.

• Journal of Environmental Science International
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• v.26 no.6
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• pp.691-710
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• 2017

This study was performed to investigate the geochemical and benthic environment of three shellfish farms in Suncheon Bay during the period of September 2014 ~ April 2015. Three sampling stations were selected; St.1 is the shellfish farm of razor clam near Jangsan area. St.2 is the shellfish farm of small ark shell near Hwapo area and St.3 is the shellfish farm of razor clam near Yongdu area. Razor clam was the dominant species at St.1, small ark shell and granulated ark shell were dominant at St.2 and St.3, respectively. Granulated ark shell inhabited St.3, although it is not cultured at that station. This station's exposure to air during the ebb tide and sediment composition likely provides the appropriate habitat for granulated ark shell species. Analysis of the number of different species showed that 8 benthos species were found to be distributed at St.1, 18 species at St.2, and 13 species at St.3. Among three stations, the highest Ignition Loss (IL), Chemical Oxygen Demand (COD) and Acid Volatile Sulfide (AVS) values were obtained from the sediment at St.2. The analysis of pore water from St.2 also showed the highest values of Total Organic Carbon (TOC), ammonia ($NH_4^+$), Dissolved Inorganic Nitrogen (DIN) and phosphate ($PO_4^{3-}$). These results are related to the fact that species dominance and richness is the highest in St.2.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.233-240
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• 1982

Some environmental parameters on the shell-fish farms in Deukryang and Gamagyang Bays during summer in 1981 were determined to find an eutrophication level for the conservation of the farm. Chlorophyll-a content in the seawater in the Deukryang Bay in September was $1.0{\sim}5.0{\mu}g/l$ with an average of $2.5{\mu}g/l$ In the superficial bottom muds, contents of COD were 5-10 mg/g, ignition loss $5-9\%$, phaeophytin pigment $2{\sim}5{\mu}g/g$, and sulfide 0.1-0.3 mg/g dry mud in both bays. High contents of both organic matters and sulfide were found in the innermost area of the Deukryang Bay and in the north western part of the Gamagyang Bay. All quantities including chlorphyll-a in the water are little less than or similar to those of Hansan-Geoje Bay, one of the most productive shellfish farms in the southern coastal waters in Korea . Eutrophication on both water and bottom mud was under way like other shellfish farms but pollution indices on the bottom mud calculated from the data of CODs and phaeophytin pigments shelved 6-11, which is much lower than those of Jinhae Bay and of the Hansan-Geoje Bay. This means that the bottom muds are in an early stage of eutrophication, unlike the Jinhae and Hansan-Geoje Bays though the water, similar to the other bays, shows a middle stage of eutrophication.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.3
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• pp.260-264
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• 1983

Organic matters as COD, ignition loss, phaeophytin pigment, and sulfide in the superficial bottom mud in the shellfish farms during summer in 1981 were determined to find an eutrophication level for the conservation of the farms. Both the Goseong Bay and the Jaran Bay, which are productive shellfish farms, are located along the southern coast of the Korean Peninsula. The Goseong Bay is 8m deep with a narrow mouth and approximately $17.5km^2$ in area, and the Jaran Bay 10m deep with $27.3km^2$. The bottoms are silty. Major shellfishes cultured are the oyster by the off-bottom method and the arkshell in the bottom. COD contents were $12.5{\sim}19.5\;mg/g$ dry mud, ignition loss $6.70{\sim}11.83\%$, phaeophytin pigment $6.8{\sim}11.0{\mu}g/g$ dry mud, and sulfide $0.18{\sim}0.64{\mu}g/g$ dry mud. There were no significant differences in the determined quantities between two bays. All quantities except the sulfide which is a little over than an eutrophication level, 0.3 mg/g dry mud, shows that the bottom muds are in an early stage of eutrophication. In addition, there was no particular increase in quantities of aforementioned four paramenters in comparision with those of 1976. It means that the eutrophication in the Goseong-Jaran Bay makes slow progress.