• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.716-720
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• 2023

This study was designed to analyze the effects of reducing water turnover in olive flounder Paralichthys olivaceus farms, focusing on olive flounder growth, decreasing electricity costs, and developing measures to ensure business stability. Daily water turnover was set at 18 in the control group and six in the experimental group. Juvenile fish were reared for 12 months. No significant differences in mean weight were observed between groups until five months. After five months, the mean weight of the control group grew significantly faster than that of the experimental group. Maintaining water turnovers leverl at six turnovers for the first five months after stocking juvenile fish and then increasing water turnover resulted in a 34.4% reduction in electricity costs compared to the control group. This approach presents a potential method to enhance the profitability of olive flounder farms and ensure stable productivity and profitability without sacrificing olive flounder growth.

• Korean Journal of Environmental Biology
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• v.19 no.2
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• pp.173-181
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• 2001

To find the appearance period and distribution of Edwardsiella tarda which causes severe damage to flounder (Paralichthys olivaceus) farms in Jeju-do, the rearing seawater (inflow, rearing water, outflow) and internal organs of flounders from 5 flounder farms were examined from June, 1997 to May, 1998. The number of bacteria in seawater was counted by plating the seawater on DSSS (Double Strength Salmonella-Shigella) agar plates or by plating after cultivation of bacteria. Bacteria in internal organs were counted by plating series of dilution of homogenized organ. The results are summarized as follows. E. tarda was detected in inflow seawater of five flounder farms in July, September and November, 1997 and February, March, April of 1998. In the rearing water and outflow water, the bacterium was detected throughout the year and the number of bacteria was much higher in summer than any other seasons. A large number of E. tarda in the internal organs were detected at farm B where a track-shaped tank was used, which has the characteristics of low circulation rate and bad discharge of excrement and residuals. In contast, none of E. tarda was detected at farm A where high circulation rate and good discharge of organic materials were applied. A few number of E. tarda at farm E were detected at the same condition as the farm A. A large number of E. tarda was observed in liver and intestines among the internal organs, and the number was higher from June to September in summer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.611-621
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• 2014

A nationwide survey was conducted to study the rate of Kudoa septempunctata parasitization in cultured olive flounder, Paralichthys olivaceus, in Korea in 2013. Of 1107 olive flounder sampled randomly from 89 culture farms in five different regions in Korea, K. septempunctata was detected only in Jeju, where 10 of 318 fish (3.14%) were PCR positive, with genomic concentrations of $4.67{\times}10^5$ to $1.48{\times}10^{11}$ rDNA copies/g by real-time PCR. Of the ten Kudoapositive fish, K. septempunctata spores with 5-7 polar capsules were detected only in four fish. No samples of K. septempunctata were detected in olive flounder from the other regions surveyed. Furthermore, K. septempunctata was not detected in 326 samples of olive flounder seeds sampled from 39 hatcheries in seven different regions in Korea. Therefore, the parasite infection is restricted to Jeju and K. septempunctata infection is not spread from hatcheries.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1646-1655
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• 2015

Korean government has issued the ratings standard for disease control of aquaculture farms according to the Aquatic Life Disease Control Act in 2008. There are five rating criteria within the enforcement regulations; period of disease free, performance of disinfection, environmental and hygienic management, keeping record of trade and sales, completion of education for disease control. There are no application has been applied on the basis of the rating criteria so far because detailed subcriteria and scoring indicators has not established for assessment process. In order to apply the ratings standard for disease control, we set up the subcriteria and new scoring for rating disease control level based on legal criteria in this study. This study was conducted on 90 targeted olive flounder farms in Jeju. The result of disease control level assessment on olive flounder aquaculture farms show the overall average of Jeju-do was 72.9 points and differed depending on the district; 74.7 in Jeju-si and 71.1 in Seogwipo-si, respectively. The Spearman correlation of each evaluation index show the disease control level score was correlated highly with the performance of disinfection(R=0.715, p<0.01), and environmental and hygienic management(R=0.661, p<0.01). The result of correlation analysis show that there is the highest correlation between the aquaculture farm status and the total mortality(R= -0.618, p<0.01). The reliability of the results are considered to be accurate in the Cronbach's alpha value of 0.727.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.2
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• pp.66-71
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• 2006

Fluoroquinoles have a wide range of antimicrobial properties and are effective in the treatment of bacterial diseases in fish. The use of fluoroquinoles continues to grow steadily. Fluoroquinolone antibiotics are probably the most important class used among synthetic antibiotics in human and veterinary medicines because of their broad activity spectrum and good oral absorption. This study was conducted to estimate the residue of antibiotics in four species of farmed fishes, including olive flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major), and sea bass (Lateolabrax japonicus), collected from fish farms located in the southern coastal area of Korea. The residues of fluoroquinolones were determined using high performance liquid chromatography (HPLC) with a fluorescence detector. Residuals of five fluoroquinolones in muscle tissue of farmed fish were analyzed. We found that enrofloxacin was the most common agent in fish muscle, and that ciprofloxacin was the next most common. The range of detected concentrations of fluoroquinolones in olive flounder muscle was 0-0.859 mg/kg in 32.6% of all samples. Enrofloxacin was commonly detected in sea bass muscle at a range of 0-0.143 mg/kg in 38.9% of all samples. Fluoroquinolones were detected in 6.9% of black rock fish muscle and in 16.6% of sea bream, although the detected concentration was below 0.01 mg/kg. The maximum detection value of enrofloxacin and ofloxacin in olive flounder at the time of shipping was 0.102 mg/kg and 0.09 mg/kg, respectively; no other antimicrobials were detected. We detected no antimicrobial substances in red sea bream.