• Journal of fish pathology
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• v.18 no.1
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• pp.81-89
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• 2005

The toxic effects of pentachlorophenol (PCP) on haematological parameters in olive flounder (Paralichthys olivaceus) after chronic exposure to dietary PCP (0.1, 0.5 and 1.0 mg/kg diet) for 2, 4 and 6 weeks were studied. A significant decrease in total RBC count, haemoglobin concentration and hematocrit value was noted in fish exposed to PCP compared to the non-exposed fish. The PCP treatment group showed significantly lower concentration of serum total protein and albumin, and significantly higher serum chloride, magnesium and total bilirubin levels compared with those in the control group. However, PCP had no major effects on serum glucose, total cholesterol, phosphate and calcium ions in flounder. These results demonstrated that PCP have induced adverse haematological impacts in the olive flounder, Paralichthys olivaceus. Because we found damages in blood-forming function and disruption in blood homeostasis due to chronic exposure to PCP, it is needed to develop further experimental studies for the risk assessment of this environmental pollutant.

• Korean Journal of Veterinary Research
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• v.57 no.1
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• pp.67-69
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• 2017

In the present study, Aeromonas (A.) hydrophila was isolated from a captive-bred adult freshwater stingray (Potamotrygon motoro) reared at a commercial aquarium in Korea. The stingray had bites on its fins, hemorrhages on the ventral part, and congested internal organs. A bacterium was isolated from kidney and subsequently identified as A. hydrophila. Based on phylogenetic analysis results, the isolate in the present study (SNUAh-LA1) was most closely related to A. hydrophila AH10 (China) and A. hydrophila AKR1 (Korea). It is most likely that the pathogen infection resulted from Potamotrygon motoro cohabiting with ricefish (Oryzias latipes).

• Fisheries and Aquatic Sciences
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• v.24 no.11
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• pp.351-359
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• 2021

The red sea bream iridovirus (RSIV) belonging to genus Megalocytivirus is responsible for red sea bream iridoviral disease (RSIVD) in marine and freshwater fishes. Although several diagnostic assays for RSIV have been developed, diagnostic sensitivity (DSe) and specificity (DSp) of real-time polymerase chain reaction (PCR) assays are not yet evaluated. In this study, we developed a TaqMan probe-based real-time PCR method and evaluated its DSe and DSp. To detect RSIV, the probe and primers were designed based on consensus sequences of the major capsid protein (MCP) genes from megalocytiviruses including RSIV, infectious spleen and kidney necrosis virus (ISKNV), and turbot reddish body iridovirus (TRBIV). The probe and primers were shown to be specific for RSIV, ISKNV, and TRBIV-types megalocytiviruses. A 95% limit of detection (LOD_95%) was determined to be 5.3 viral genome copies/µL of plasmid DNA containing the MCP gene from RSIV. The DSe and DSp of the developed real-time PCR assay for field samples (n = 112) were compared with those of conventional PCR assays and found to be 100% and 95.2%, respectively. The quantitative results for SYBR Green and TaqMan probe-based real-time PCR were not significantly different. The TaqMan probe-based real-time PCR assay for RSIV may be used as an appropriate diagnostic tool for qualitative and quantitative analysis.

• Fisheries and Aquatic Sciences
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• v.25 no.6
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• pp.320-326
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• 2022

Most of the emerging diseases that threaten humans are caused by RNA viruses which are extremely mutable during evolution. The fish RNA virus, viral hemorrhagic septicemia virus (VHSV) can infect a broad range of aquatic animal hosts, but the transmissibility of VHSV to mammals has not been thoroughly investigated. Therefore, our study aimed to investigate the potential adverse effects of VHSV in mammals. Briefly, the survival of VHSV was determined using only minimum essential media (MEM-2) and mammalian SNU-1411 and hepa-1c1c7s cells at 15℃ and 37℃. Mice (Mus musculus, 27.3 ± 1.9 g) were intravenously injected with VHSV (2.37E+05 TCID₅₀·mice^-1) in triplicate. Clinical signs and survival rates were examined at 14 days post-challenge, and infection was confirmed in the surviving mice. The 50% tissue culture infective dose (TCID₅₀) and polymerase chain reaction analysis were used to determine viral titers and the infection rate, respectively. The titer of VHSV suspended in MEM-2 at 15℃ was reduced by only one log after 8 days, whereas the virus maintained at 37℃ was inactivated 8 days post-inoculation (dpi). There were no recognizable cytopathic effects in either SNU-1411 or hepa-1c1c7s cells inoculated with VHSV at 15℃ and 37℃. VHSV in those cell lines at 37℃ was rapidly decreased and eventually inactivated at 12 dpi, whereas virus at 15℃ remained at low concentrations without replication. In vivo experiment showed that there were no signs of disease, mortality, or infection in VHSV-infected mice. The results of this study indicate that it is highly unlikely that VHSV can infect mammals including humans.

• Journal of Korea Trade
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• v.27 no.2
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• pp.47-60
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• 2023

Purpose - This paper assesses the trade potential and efficiency of Korea and China in the aquatic products trade. Trade efficiency and potential are the main factors that affect the growth of a country's trade. In this study, a time-varying stochastic frontier trade gravity model was constructed to analyze the trade potential and efficiency between Korea and China. By integrating the results of trade theory and empirical analysis, measures and suggestions were proposed to encourage the release of trade potential of fish exports between Korea and China. Design/methodology - In this paper, GDP per capita instead of economic size was chosen as an explanatory variable, and population size and relative distance were selected as explanatory variables to measure trade potential. For trade non-efficiency terms, regional organizations, political factors, and economic factors were mainly considered, and variables such as free trade agreements, political stability, regulatory quality, government efficiency, currency freedom, investment freedom, financial freedom, and trade freedom were selected. Panel data for South Korea and 14 aquatic products trading partners (including China) from 2002 to 2020 were used in the empirical analysis. Findings - In the past 19 years, South Korea's export trade potential of aquatic products to China has never been lower than 70%. It was above 90% from 2006 to 2018, and has been at a high level for a long time. This shows that China's aquatic product market has large potential for development. Originality/value - This study examines the effectiveness and potential of South Korea's exports of aquatic items to China in a methodical and comprehensive empirical manner. The evaluation of the export trade potential of South Korea's aquatic goods to China is more precise when the effects of regional organization, political, and economic variables are taken into account in the trade non-efficiency term of the stochastic frontier gravity model. At the same time, we propose to increase the scale of South Korea's aquatic products trade from the perspective of China's demand. This issue of trade studies is underexplored both empirically and in theory, although the issue has long been important to Korean and world trade.

• Fisheries and Aquatic Sciences
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• v.5 no.2
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• pp.141-143
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• 2002

The treatment efficacy of oral administration of praziquantel against the blood-sucking monogenean Microcotyle sebastis under the commercial rockfish-culture conditions was evaluated. The quantity of praziquantel added to the food was calculated so that the amount of praziquantel ingested daily by fish was 200mg or 400mg/kg body weight (bw). The fish were fed a moist-pelleted fish meal supplemented with praziquantel at an rate of 0 (control), 200 or 400 mg of praziquantel per kg bw, respectively, for 3 times at an interval of 24 h. On 1 day to 8 days after the treatment, 10 fish were taken randomly from each net-pen daily (80 fish in each group in total), and the efficacy of each treatment was confirmed. Abundance of worms were significantly reduced in groups fed praziquantel-supplemented diets. The results clearly demonstrated that feeding the praziquantel-supplemented diet was effective for controlling M. sebastis infestation in practical commercial rockfish-culture systems without imposing any handling stress.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.3
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• pp.241-246
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• 2014

Viruses in the genus Megalocytivirus have been subdivided into four subgroups. Among these subgroups 2 and 4, represented by the red sea bream iridovirus (RBIV) and the olive flounder iridovirus (FLIV), respectively, are non-exotic. subgroups 1 and 3, represented by the red sea bream iridovirus (RSIV) and the infectious spleen and kidney necrosis virus (ISKNV), respectively, have not been detected in Korea and are known as exotic. Shellfish are filter-feeders, and can thus filter and accumulate Megalocytivirus in their digestive glands, allowing us to track viral contamination in surrounding aquatic environment. In this study, we developed a high-resolution melting (HRM) analysis to differentiate among subgroups of Megalocytivirus accumulated in shellfish, and confirmed the convenience and efficiency of this method. More than two subgroups of Megalocytivirus were found in the digestive gland of a single shellfish. We classified all Megalocytivirus viruses from shellfish in Korea into subgroups 2 and 4, although proportions of subgroups were different among regions. Compared to nucleotide sequencing analysis, HRM analysis is a simple and rapid method for differentiating of Megalocytivirus subgroups.

• Fisheries and Aquatic Sciences
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• v.5 no.4
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• pp.311-313
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• 2002

Proteolytic activity of live Uronema manum was analyzed by fluorescence polarization (FP) technique. Protease activity was measured by a decrease in FP value using fluorescein isothiocynate (FITC)-casein as a protein substrate. The results demonstrated an inverse linear relationship between fluorescence polarization (FP) values and live ciliate concentration over the range $1\times10^4\;to\;2\times10^5$ cells/well. However, the FP values of $10-10^3$ live parasites were not different significantly from that of control. Time-dependent decrease in FP value was shown in the wells containing live U. marinum. In the present study, FP assay had the benefit to provide measurements of substrate hydrolysis by live parasites in real-time, and did not require separations, precipitations, or transfers of reaction mixture.

• Journal of muscle and joint health
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• v.6 no.2
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• pp.317-324
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• 1999

The purpose of this study was to identify the relationship between self-efficacy and adherence of aquatic exercise in patients with chronic arthritis. Subjects were 54 patients with rheumatoid arthritis and osteoarthritis who had participated in the 6-week aquatic exercise program. The results indicated that the relationship between self-efficacy and aquatic exercise adherence in patients with chronic arthritis was statistically significant. A significant difference of self-efficacy was found between adherers and non-adherers and self-efficacy of adherer was higher than that of non-adherer(t=5.21, p=.000). Self-efficacy was significantly associated with the total duration of an aquatic exercise adherence(r=.44, p=.001). Based on these results, self-efficacy was the important factor which affect adherence of aquatic exercise in patients with chronic arthritis. Further study was suggested to identify the relationships among self-efficacy, exercise barrier and other possible factors.

• Fisheries and Aquatic Sciences
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• v.20 no.3
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• pp.4.1-4.6
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• 2017

Juvenile Anoplopoma fimbria (mean length $16.8{\pm}2.2cm$, and mean weight $72.8{\pm}5.4g$) were exposed for 2 months with different levels of ammonia (0, 0.25, 0.50, 0.75, 1.00, and 1.25 mg/L). Growth performances such as daily length gain, daily weight gain, condition factor, and hepatosomatic index were significantly decreased by ammonia exposure. Hematological parameters such as red blood cell (RBC) count, hematocrit, and hemoglobin were also significantly decreased. In plasma inorganic components, calcium and magnesium were significantly decreased by ammonia exposure. In plasma organic components, there was no alteration in cholesterol and total protein. In enzyme plasma components, glutamic oxalate transaminase (GOT) and glutamic pyruvate transaminase (GPT) were significantly increased. The results of this study indicated that ammonia exposure can induce significant growth reduction and blood biochemistry alterations of A. fimbria.