• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.495-500
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• 2015

Currently the fish aquaculture industry of Korea is focused on the mass culture of flatfish (Paralichthys olivaceus) and and rockfish (Sebastes schlegeli) with completely controlled culture techniques. Recently, there has been considerable interest in new species development, such as the starry flounder (Platichthys stellatus). The value of starry flounder (Platichthys stellatus) as a raw fish increases with time because it is tasty, light, and bouncy. In this paper, the growth characteristics dependent on the LED wavelengths and the optimal growth conditions of the starry flounder were studied. In these experiments 4 different kinds of LED lighting, configurations were designed and prepared using red, green, blue and white, respectively. The fish aquaculture experiments were conducted over 10 weeks in four fish tanks, each installed with a different color of LED lighting. 10 starry flounders of 13 ~ 17g were placed into each tank. The effects of each color of light on the growth rate of the starry flounders were then examined. As a result, the starry flounders under the green LED lighting showed the highest growth rate, followed by the white, red, and blue LED lighting. Based on these results, a green light provides a suitable breeding environment for the starry flounder.

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.210-224
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• 2007

Fish community study by a gill net in four coastal waters of Southern Sea, Korea were simultaneously conducted to determine seasonal variation of species composition and abundance from March to November, 2006. A total of 68 species and 577,422.9 g by four study waters were caught during the survey period. The dominant species were Platycephalus indicus, Mugil cephalus, Cynoglossus robustus and Argyrosomus argentatus of 58.2% in total catch and they occupied 63.1% in IRD (index of relative distribution). By regional community, fishes that compromised 18 species and 53,148.8 g in Tongyeong Donam were caught and the dominant species were Platycephalus indicus, Hexagrammos otakii, Liparis tessellatus, Paralichthys olivaceus. In Yeosu Gyedong, fishes of 44species and 123,926.9 g were caught and the dominant species were Platycephalus indicus, Muraenesox cinereus. In Jangheung Sumoon, fishes of 44 species and 123,926.9 g were caught and the dominant species were Mugil cephalus, Platycephalus indicus, Cynoglossus robustus, Liparis tessellatus. And in Jindo Modo, fishes of 32 species and 171,426.3 g were caught and the dominant species were Platycephalus indicus, Argyrosomus argentatus, Cynoglossus robustus. Therefore, the species composition and abundance of fish by region were very different. These results seem to be related to differences of regional environmental condition, productivity, and fish ecological habits. And the fish catch in four study waters were high from April to July, and the number of fish species and diversity index had a tendency to increased from March to November. The ranges of environmental factors caught fish were $8.3{\sim}28.5^{\circ}C$ in temperature, 26.59~34.92 in salinity and also these factors were correlated to seasonal variation of fish.

• Journal of Aquaculture
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• v.18 no.2
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• pp.98-106
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• 2005

A feeding trial of two extruded pellets (EPI, 45% crude protein with 7% crude lipid and EP2, 47% crude protein with 10% crude lipid)${\times}$ two satiation rates (satiation and 80% satiation)${\times}$ three feeding frequencies (three, two and one meal a day) factorial design with three replications was carried out to investigate the optimum feeding frequency and satiation rate for growth of juvenile flounder. Flounder averaging 55 g were fed a extruded pellets for 58 days. Daily feed intake was affected by dietary composition, feeding frequency and satiation rate (P<0.05). Weight gain of fish fed the EP1 and EP2 was not affected by both dietary composition and feeding frequency (P>0.05), but affected by feeding satiation rate (P<0.05). Weight gain of fish fed the each of EP1 and EP2 twice daily with satiation was the highest among treatments, but was not significantly different to that of fish fed the diets three times daily with satiation feeding. Feed efficiency and protein efficiency ratio of the fish were not affected by dietary composition, feeding frequency and satiation rate (P>0.05). Moisture, crude protein and crude lipid contents of the muscle of fish were affected by satiation rate. Moisture and crude protein contents of the liver were affected by dietary composition. Based on fish performance results, it can be concluded that the proper feeding frequency for the growth of juvenile flounder grown from 55 g to 90 g is two meals a day with satiation feeding, regardless of dietary composition used in this study.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.42-49
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• 2009

This study analyzed the fatty acid and amino acid compositions of dorsal and fin muscles collected from olive flounder cultured using a formula feed(extruded pellets, EP) and compared them to those of fish cultured with a raw fish moist pellet(MP) feed as a control. The olive flounder in this study were cultured for 10 months with either the formulated extruded pellets(FEP), commercial extruded pellets(CEP), or the MP feed, and their average weight was 1.15 kg. The proximate compositions of the dorsal muscle were not different among the groups, whereas in the fin muscles of the fish fed with the MP diet, moisture content was higher and crude lipid content was lower. The major fatty acids in the dorsal and fin muscles of the fish fed with the MP, CEP, and FEP diets were palmitic acid and oleic acid. Finally, no significant differences were observed among the diet groups in the results for amino acid content or the sensory and textural properties of the muscle.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.199-204
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• 2006

Streptococcosis of olive flounder(Paralichthys olivaceus) is an important bacterial disease in Jeju island. In this study, we investigated monthly infection pattern of this disease in different size of the flounder fish. Even though the disease occurred throughout the year, the infection ratio was relatively higher in the months with warm water season. The infection was more prevalent in adult flounder over 30 cm total length compare to these of small size fish. Two infectious species of streptococcosis pathogens were detected by multiplex PCR assay. Detection ratios of Streptococcus iniae and S. parauberis reached up to 46% and 54%, respectively, from June 2003 to May 2005 in Jeju island. S. iniae occurred intensively from September to October, whereas S. parauberis reported from March to May. S. iniae and S. parauberis infections of cultured flounder share some common features, but clinical findings showed considerable differences between two diseases. Distended abdomen, protruded anus and ascitic fluid in the peritoneal cavity are evident lesions detected in S. iniae infection, whereas, flounders infected by S. parauberis showed prominent lesions such as darkened surface and haemorrhaging in the non-ocular side. Both streptococcosis pathogens were sensitive to antibiotics, such as ampicillin and amoxicillin. However, S. iniae strains were more sensitive to doxycycline, erythromycin and oxytetracycline than S. parauberis strains.

• Journal of fish pathology
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• v.23 no.3
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• pp.389-398
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• 2010

Effects of various concentration of yuzu Citrus junos Siebold ex Tanaka in the diets on growth, blood chemistry and disease resistance of olive flounder were determined. Fifteen hundred fish averaging 200~270g were fed on moist pellet containing yuzu at the concentrations of 0%(control), 2.5%, 5% and 7.5% for 3 months. After feeding trial, weight gain of fish fed 2.5% and 5.0% yuza diet was higher than those of fish fed 0% and 7.5% yuza diet but not significant(P>0.05). No differences in hematological and physiological indices of olive flounder were found among the experimental diets except for total cholesterol. Serum lysozyme activity was not significantly different among fish fed experimental diets but bactericidal activity of fish fed 7.5% yuza diet was significantly different from those of fish fed 0, 2.5 and 5% Yuza diets. Survival rates of fish fed 2.5% yuza diet at experimental infection with Edwardsiella tarda and Streptococcus sp. were higher than those of the other experimental groups but not significant. In conclusion, Dietary inclusion of 2.5~5% yuzu seems to have positive effects for fish health condition and disease resistance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.463-470
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• 1998

To improve muscle quality and prolong freshness of sashimi, the effects of freezing-thawing condition on physicochemical and rheological properties of plaice muscle were investigated. Muscle tested were frozen with quick freezing (liquid nitrogen gas) or slow freezing ($-15^{\circ}C$ air). Transition time of zone of ice crystal formation was within 10 minute for quick freezing and 110 minute for slow freezing. Time required for thawing to $0^{\circ}C$ in muscle temperature by various thawing methods was shortest with $25^{\circ}C$ tap water, followed by $15^{\circ}C$ tap water, $10^{\circ}C$ tap water, $25^{\circ}C$ air, $5^{\circ}C$ tap water and $0^{\circ}C$ cold water. Breaking strength of muscle was higher in quickly frozen sample than in slowly frozen sample. According to sashimi term, changes in breaking strength of muscle did not show any difference in quickly frozen sample, while showed significant difference in slowly frozen sample. The remaining content of ATP was not effected by freezing speed, and ATP content was apt to higher in quickly thawed sample than in slowly thawed sample. IMP was the majority of ATP and it's related compounds of sample after freezing and thawing. Collagen matrix was weakened markedly in slowly frozen sample than in quickly frozen sample.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.553-559
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• 1998

Electron micrographs of muscle of plaice killed instantly by spiking at the head clearly showed the A-band, I-band, Z-line and M-line in muscle strips, whereas these bands could not be distinguished from each other in electrically stimulated plaice muscle strips. As the electrical stimulation time increased, the continuity of Z-line disrupted rapidly. Electron microscopic observation showed that sarcoplasmic reticulum (SR) in unstimulated plaice had natural triad structures between Z-line. However these structures were disrupted in the electrically stimulated sample. These structures were clearly observed after storage for 10 hrs at $5^{\circ}C$ from all the samples. In association with the $Ca^{2+}$ translocation, $Ca^{2+}$-pyroantimonate deposits were observed at the inner part of SR immediately after spiked the plaice, However, $Ca^{2+}$-pyroantimonate deposits in electrically stimulated plaices were observed in the muscle strips and this phenomenon was clearly observed when electrical stimulation was prolonged.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.382-388
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• 2019

Streptococcosis caused by Streptococcus parauberis is a very important disease in farmed olive flounder Paralichthys olivaceus. For most fish pathogens, including S. parauberis, there are no analytical criteria to distinguish antibioticsusceptible strains from antibiotic-resistant strains. In this study, epidemiological cut-off ($CO_{WT}$) values were generated to classify 75 strains of S. parauberis isolated from 1999 to 2018 as wild type (WT) and non-wild type (NWT) using disc diffusion data and normalized resistance interpretation (NRI) analysis. The susceptibility of the isolates to 16 antibiotics was evaluated using CLSI guideline M42-A. The wild-type cut-off values for amoxicillin, erythromycin, oxytetracycline, and florfenicol for S. parauberis were ${\geq}35$, 31, 28, and 27 mm, respectively. The NWT ratios of S. parauberis strains to treatment with GEN, FFC, ENR, SXT, EFT, VAN, and CHL were 17% or less, indicating that these antibiotics may be used to treat streptococcosis caused by S. parauberis. For recent S. parauberis isolates, the NWT ratios for AMX, ERY, OTC and FFC are much higher than for strains isolated from 1999-2007. The $CO_{WT}$ data from this study will assist aquatic animal disease professionals in prescribing appropriate antibiotics for the treatment of streptococcosis caused by S. parauberis, which will help reduce the misuse and abuse of antibiotics in the aquaculture sector.

• Journal of fish pathology
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• v.35 no.2
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• pp.195-203
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• 2022

This study was performed to delineate pharmacokinetic residue characteristics of lincomycin (LM) in olive flounder at low water temperature (13℃), and to examine whether LM is effective against main Gram-negative pathogens. It was observed that the times for residue declined below the maximal residue limit (0.1 mg/kg) in the muscle was, respectively, 32, 33 and 55 days following 10, 20 and 40 mg/kg intramuscular LM injections. The in vitro MIC value of LM against Edwardsiella piscida was higher than 256 ㎍/mL and against Vibrio harveyi 32 ㎍/mL when examined with several clinical isolates. These results suggest that the withdrawal time of LM should be more than 30 days in consideration of the 10 mg/kg employed as the regular clinical dose. It was also found that LM administered to treat streptococosis in olive flounder is not likely to be effective against some pathogenic Gram-negative bacteria.