• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.1
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• pp.25-32
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• 2010

A Sanitary survey in an Important shellfish-growing area of Biin Bay in Seocheon-gun Korea, was conducted to evaluate bay conditions and compliance with the bacteriological criteria for areas designated for the production of shellfish for export. Seawater samples were collected monthly at 55 sampling stations established in the survey area from January 2006 to December 2008. Bacteriological water quality did not change in response to a small rainfall (10.0 mm), but it increased abruptly in response to rainfall to 62.5 mm The most probable number (MPN) value for total coliforms and fecal coliforms in 1, 980 seawater samples ranged from <1.8 to >1, 600 MPN/100mL and from <1.8 to 330 MPN/100mL, respectively. The geometric mean and estimated $90^{th}$ percentile value for total coliforms ranged from 2.0 to 10.3 MPN/100mL and from 7.0 to 42.6 MPN/100mL respectively. The geometric mean and estimated percentile value for fecal coliforms ranged from 1.8 to 4.0 MPN/100mL and from 1.9 to 18.3 MPN/100mL, respectively. Accordingly, the bacteriological water quality of Biin Bay met the National Shellfish Sanitation Program (NSSP) and Korea Shel1fish Sanitation Program(KSSP) criteria for areas designated for shellfish production for export in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.3
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• pp.155-162
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• 2008

The seawater in the Taean area was surveyed to evaluate the conditions of the bay and compliance with the bacteriological criteria for a designated area for shellfish production for export. Samples of seawater were collected monthly at 34 sampling stations established in the survey area from January 2002 to December 2004. The bacterial density in the coastal area close to a pollution source located to the northeast of the survey area was higher than in the open sea to the west. The bacteriological counts in the water did not change with 16.5mm of rainfall, but increased abruptly after 65.4mm of rainfall. The total coliform and fecal coliform most probable numbers (MPNs) of 1,224 seawater samples in the survey area were <1.8-2,400 and <1.8-790 MPN/100 mL, respectively. The geometric mean and estimated 90th percentile of total coliforms were 1.9-3.4 and 2.7-26.3 MPN/100mL, respectively, and for fecal coliforms were <1.8-2.6 and 1.8-12.0 MPN/100mL, respectively. The bacteriological water quality in the Taean seawater area met the National Shellfish Sanitation Program criteria for an approved area and the Korea Shellfish Sanitation Program criteria for a designated area for shellfish production for export.

• Journal of Korean Society on Water Environment
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• v.34 no.2
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• pp.157-163
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• 2018

This study aims to determine the pollution levels of nine kinds of heavy metals (As, Cd, Cu, Cr, Hg, Mn, Ni, Pb, and Zn) in Lake Shihwa, which is susceptible to the inflow of pollutants, and the levels of heavy metal exposure in its fish and shellfish. Shihwa Lake's water quality did not exceed the short-term standard for protection of marine ecosystems, but concentrations of As, Cu, Cr, Hg, Ni, and Zn exceeded the long-term standard for protection of a marine ecosystem. In comparison to findings in prior research, performed in 2010, levels of Cr, Ni, As, and Zn are now 4.1 times lower. However, when compared to Saemangeum Lake, the environment is similar to that of Lake Shihwa, Cu, Ni, Hg, Mn, and Zn were 244.4 times higher. The levels of Pb, Cd, and Hg in fish's muscles did not exceed the average values set by the marine safety standard. However, when compared to the fish from the Korean coast, the levels of heavy metals were 9.7 times higher, on average. The levels of heavy metals in fish's livers were on average 26.8 times higher than in the muscles. In the case of shellfish, the levels of Pb, Cd, and Hg did not exceed the standard values, but in comparison to the shellfish from the south coast, the levels of heavy metals were 6.2 times higher on average. In particular, Mn (153.5 times higher) from fish and Cd (14.7 times higher) from shellfish were found in high amounts, indicating a concerning level of these specific heavy metals.

• Journal of Environmental Science International
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• v.17 no.9
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• pp.969-980
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• 2008

This research was performed to simulate shellfish production systems and sales in Gamak Bay, South Korea. To study the way the shellfish system generates maxima, a numerical model was developed to simulate the model under a control and a number of different scenarios. The program calculates the EMERGY flows by multiplying the flows of energy and materials by the appropriate solar transformity. In this study, an energy systems model was built to simulate the variation of sustainability for oyster aquaculture. The results of the simulation based on 2005 data that as oyster production yield slightly increases, money and assets increase to a steady state. When the program is run control simulation, the system reaches carrying capacity after 8 years. The simulation of models with price of purchased inputs increased with 3.5% inflation rate per year showed maximum benefit of shellfish production occurs after 6 years but amounts are less than control simulation, and then decreases slightly in money and yield results. The results with 3.5% inflation and increase of oyster price annually showed steady and slightly increase of money and yield.

• 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.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.18-25
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• 1990

Paralytic Shellfish Poison (PSP) is mainly produced by marine dinoflagellates such as Protogonyaulax sp. and Pyrodinium sp.. The PSP was known to be accumulated in digestive gland of shellfish as result of feeding toxic dinoflagellates. PSP illness when occurs when one eats PSP intoxicated shellfish. Therefore PSP is becoming as serious problem in food hygiene and shellfish cultivation industry. The purpose of this study was to develop detoxification method for utilization of PSP intoxicated sea mussel and prevent from PSP illness. The PSP was extracted with 0.1 N HCl solution from the submitted sea mussel, then the toxicity was measured by mouse assay according to Official Methods of Analysis of the Association of Official Analytical Chemists. No detoxification effect was observed by adding extracted juice of garlic and ginger. When the sea mussel homogenate was heated at various temperatures, the PSP toxicity was not changed significantly at below $70^{\circ}C$ for 60 minutes but it was decreased as the heating temperature was increased. For example, when the sea mussel homogenate was heated at 100, $121^{\circ}C$ for 10 minutes, the toxicity was decreased about 67 and 90%, respectively. When the sea mussel containing 645 $\mu$g PSP per 100g of edible meat was processed according to general shellfish canning procedure, the toxicity was decreased as the level of PSP undetected by mouse assay.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.6
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• pp.893-899
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• 1996

The studies on the detoxification of paralytic shellfish poison (PSP)-infested blue mussels, Mytilus edulis and oyster, Crassostrea gigas were performed for using of available processing resource. Toxic blue mussel and oysters from Nampo in Masan Bay, Hachong in Koje Bay and Woepori in Koje were used for experimental samples. The toxicity of low toxic blue mussel $(A,\;84{\mu}g/100g;\;B,\;166{\mu}g/100g;\;C,\;295{\mu}g/l00g;\;D,\;557{\mu}g/100g)$ and oyster $(740{\mu}g/100g)$ were reduced below the regulation limit of PSP $(80{\mu}g/100g)$ or undetected level by mouse bioassay after boiling at $98^{\circ}C$ for 10 min and retorting at $115^{\circ}C$ for 70 min, while the toxicity of high toxic blue mussel $(E,\;8,760{\mu}g/100g)$ remained beyond the regulation limit after boiling and retorting at same condition. These results suggested that the regulation limit of PSP could be level up from $(80{\mu}g/100g)$ to about $160{\mu}g/100g$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.614-622
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• 2010

The sanitary quality of a shellfish-growing area in Gangjinman, Korea, was assessed through a bacteriological examination of seawater form January 2007 to December 2009. The range of the geometric mean (GM) and the estimated 90th percentile for most-probable-number (MPN) values for fecal coliforms in samples collected in the designated area were 2.0-2.4 and 6.1-11.5 MPN/100 mL, respectively. Therefore, the bacteriological quality of seawater in the designated area in the Gangjinman area met the National Shellfish Sanitation Program (NSSP, USA) guidelines for approved areas. Also, the sanitary status of shellfish harvested from the designated area met the Korean Shellfish Sanitation Program (KSSP) fecal coliform criterion (<230 MPN/100 g). However, the degree of bacteriological contamination increased rapidly, and water quality exceeded the criteria for approved areas when large amounts of rain fell before the sampling date. Fortunately, fecal pollutants did not affect the bacteriological quality of a buffer zone established between the shoreline and the designated area. These results indicate that the current buffer zone established around the designated area protects the designated area properly.

• Journal of Microbiology
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• v.44 no.4
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• pp.403-408
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• 2006

The purpose of this study was to determine the efficacy of a nucleic acid sequence-based amplification (NASBA) method of detecting noroviruses in artificially and naturally contaminated shellfish. We used 58 fecal samples that tested positive for noroviruses with electron microscopy (EM) to develop an NASBA assay for these viruses. Oligonucleotide primers targeting the polymerase coding region were used to amplify the viral RNA in an isothermal process that resulted in the accumulation of RNA amplicons. These amplicons were detected by hybridization with digoxigenin-labeled oligonucleotide probes that were highly specific for genogroup I (GI) and genogroup II (GII) of noroviruses. The expected band of 327bp appeared in denaturing agarose gel without any nonspecific band. The specific signal for each amplicon was obtained through Northern blotting in many repeats. All fecal samples of which 46(79.3%) belonged to GII and 12(20.6%) belonged to GI were positive for noroviruses by EM and by NASBA. Target RNA concentrations as low as 5pg/ml were detected in fecal specimens using NASBA. When the assay was applied to artificially contaminated shellfish, the sensitivity to nucleic acid was 100pg/1.5g shellfish tissue. The potential use of this assay was also confirmed in naturally contaminated shellfish collected from different ponds in Guangzhou city of China, of which 24 (18.76%) out of 128 samples were positive for noroviruses; of these, 19 (79.6%) belonged to GII and 5 (20.4%) belonged to GI. The NASBA assay provided a more rapid and efficient way of detecting noroviruses in fecal samples and demonstrated its potential for detecting noroviruses in food and environmental samples with high specificity and sensitivity.

• Genomics & Informatics
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• v.10 no.3
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• pp.206-211
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• 2012

DNA barcoding has been widely used in species identification and biodiversity research. A short fragment of the mitochondrial cytochrome c oxidase subunit I (COI) sequence serves as a DNA bio-barcode. We collected DNA barcodes, based on COI sequences from 156 species (529 sequences) of fish, insects, and shellfish. We present results on phylogenetic relationships to assess biodiversity the in the Korean peninsula. Average GC% contents of the 68 fish species (46.9%), the 59 shellfish species (38.0%), and the 29 insect species (33.2%) are reported. Using the Kimura 2 parameter in all possible pairwise comparisons, the average interspecific distances were compared with the average intraspecific distances in fish (3.22 vs. 0.41), insects (2.06 vs. 0.25), and shellfish (3.58 vs. 0.14). Our results confirm that distance-based DNA barcoding provides sufficient information to identify and delineate fish, insect, and shellfish species by means of all possible pairwise comparisons. These results also confirm that the development of an effective molecular barcode identification system is possible. All DNA barcode sequences collected from our study will be useful for the interpretation of species-level identification and community-level patterns in fish, insects, and shellfish in Korea, although at the species level, the rate of correct identification in a diversified environment might be low.