• Journal of fish pathology
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• v.7 no.2
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• pp.113-117
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• 1994

The antimicrobial activity of Artemisia princeps var. orientalis essential oil against a partial fish pathogenic bacteria was examined. The growth of Aeromonas hydrophila, Aeromonas salomonicida, Aeromonas sorbia, Edwardsiella tarda and Streptococcus sp. (yellowtail) were inhibited at concentrations of 1,000 to 2,000 ppm. The A. salmonicida was inhibited at 1,000 ppm, A. hydrophila, A. sorbia, E, tarda and Streptococcus sp. (yellowtail) at 1,500 ppm, but Vibrio anguillarum, Vibrio ordalii, Edwardsiella ictaluri and Streptococcus sp. (SF 1) were grown on 100-2,000 ppm.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.1
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• pp.30-38
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• 2014

Hydro-acoustic survey was carried out to investigate the spatial characteristics of fish distribution near two artificial reefs (AO: large octagonal semi-sphere and AC: combined custom built) having different types in Jeju marine ranching area. The survey system consisted of scientific echo sounder (EK60), DGPS system, and ECDIS (Mecys). Field survey was conducted on August and October 2012 with star survey and line transect survey line method, and species composition was investigated from gill net fishing survey. The acoustic signals from individual fishes and small fish schools were mainly recorded around AO, but large and strong signals from large fish school were mainly detected in the top layer of and the water column near AC. The echogram suggest that the fish aggregation for the two types of AO and AC exist the significant difference in fish species and spatial distribution pattern.

• The Korean Journal of Zoology
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• v.11 no.1
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• pp.1-4
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• 1968

1. Infectious glochidia are attached only on the young fish of Zacco platypus which ranged from 2 to 4 cm in total body length. 2. The attachment of the glochidia on the fish was found at the beginning of April. 3. The glochidia per infectious fish are shown to be 1.6 in average number. 4. the glochidia were dropped from the infectious fish completely from late April through early May. 5. Most glochidia released from mother shell are attached on the fins on infectious fish, and also on the eyes, nose, mouth and gill. 6. The largest number of the glochidia was attached on the caudal fins of infectious fish, and the next was pectoral fins.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.6
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• pp.899-908
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• 2023

Droughts can alter the dynamics of aquatic ecosystems, including fish communities. This study compared the variations in fish communities in Juam reservoir before and after drought events. Fish sampling was conducted five times from April 2021 to April 2023 using three different sampling methods (kick net, cast net, and gill net). The water level in the reservoir reached its peak (103.73 EL.m, 62.2% capacity) in September 2021, before the drought, and dropped to its lowest point (88.84 EL.m, 17.6% capacity) in April 2023. The dissolved oxygen content in the reservoir decreased from 27 to 6.3 mg/L between the period with the lowest water level (April 2023) and the period with the highest water level (September 2021). In September 2021, 466 fish were collected, but after one year of drought, the number of individuals decreased to 105. Further, the number of fish collected and water levels were positively correlated. Dominant species exhibited a population decline of over 60% with decreasing water levels. These findings highlight the importance of fishery resource management during drought periods.

• Journal of fish pathology
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• v.4 no.2
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• pp.87-94
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• 1991

In the late summer of 1990 and 1991, mass mortality occured among cage-cultured grouper, Epinephelus septemfasciatus in south cost of Korea. The moribund fish didn't feed and became pale or dark chestnut colour and irregularly swimmed due to the loss of equilibrium, finally the diseased fish fell down side away on the bottom or the surface of cage showing the bent of body and died. The diseased fish showed the extensive hemorrahge in brain, the swelling of spleen and bile duct as the specific syptoms of internal organs. So the gill, skin and other organs of the diseased fish were examined for the presence of pathogenic parasites and bacteria. The parasitic Trichodina sp. were detected only from the gill lamella of the diseased fish, but these parasites seemed to be not a direct causative agents that induced the gross mortality of the cultured grouper. because these parasites were also observed in normal grouper, yellowtail, red seabream and rock bream co-cultured with the diseased grouper in same or near cages. In the viral examination, although isolation of the causative agent by the use of estabilshed cell Lines, RTG-2 and CHSE-214, was not succeed, the normal grouper inoculated intramuscularly with the filtered homogenate of the organs of the diseased fish showed the same external and internal signs with the naturally infected grouper. They died within a week. By using the naturally and the artificially infected fishes, electron microscopic observation revealed numerous hexagonal or polygonal particles in the cytoplasm of liver cells. Based on the these results, we suggest that the mass mortality of the cultured grouper would be occurred by the infection of a viral agent.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.283-289
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• 2003

The effect on kidney, gill, and hepatopancreas of juvenile olive flounder, Paralichthys olivaceus were investigated by histological method under limit concentration of effulent of PCBs for 60 days. The free surface of epithelial cell layer in the renal tubules of kidney showed a strong positive reaction in alcian blue during all exposure period. There were also observed swelling of hemocyte in glomerulus and macrophage. At 60 days after exposure, epithelium of the renal tubules was fused and some of organism $(20\%)$ showed damage of glomerulus and eosinophlic cell in epithelium of the renal tubules. The phenomena such as the activation and increase of the chloride cell, and swelling of hemocyte in the capillary of gill were observed during all exposure period. At 60 days after exposure, swelling of the gill filament and mucous cell appeared in gill and some of organism $(30\%)$ showed swelling of the gill lamellar. Swelling of hemocyte in the capillary of hepatopancreas was observed and the free surface of epithelial layer of the bile duct showed positive reaction in alcian blue during all exposure period. Degenerated zymogen in the pancreas and swelling of the hepatocyte were occurred at 60 days after exposure.

• Journal of Life Science
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• v.24 no.2
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• pp.186-190
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• 2014

Carbonic anhydrase isozymes (CAs) are widespread zinc-containing metalloenzyme family. The enzyme catalyzes the reversible interconversion of $CO_2$ and $HCO_3$. This reaction is the main role of CA enzymes in physiological conditions. CA III, one of the CA isozymes, has been identified in many tissues. It is distinguished from the other isozymes by several characteristics, particularly by a lower specific activity and by its resistance to acetazolamide. However, the physiological function of CA III in fish is unknown. In this study, we examined the detection of CAs in the Shaggy sea raven Hemitripterus villosus, using SDS-PAGE, isoelectric focusing (IEF), and western blot analysis. We detected a significant protein band with molecular weight about 30 kDa from the tissues of H. villosus by SDS-PAGE and western blotting. A specific band of CA III with pI 7.0 was detected by IEF and western blotting in gill and muscle. The immunoreaction of anti-CA III expressed in the gill of H. villosus was much stronger than other tissues. One explanation for this result is that the fish gill is the only organ that is exposed to the external environment and that plays an important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO{_3}^-$, for the maintenance of systemic pH. This is the first report on the identification of a carbonic anhydrase III-like protein from H. villosus.

• Journal of Aquaculture
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• v.19 no.1
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• pp.19-24
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• 2006

The objective of this study was to develop an efficient control method for the Alella macrotrachelus parasitic cultured black porgy, Acanthopagrus schlegeli utilizing the superior osmoregulatory ability of the host fish. The average number of the parasites on a fish was 5 worms (all female), which were attached to the cartilage of gill filament by their bulla. Morphologically, the parasite was tripartite with each length of $1822.1{\pm}521.5{\mu}m$ for the trunk $1825.0{\pm}495.8{\mu}m$ for the cephalothorax, and $134.2{\pm}43.1$ for the bulla. In histological observations, it was found that the female parasite took gill lamellae. Damage and loss of gill lamellae by the parasite caused hemorrhage and anemia in the fish. All parasites died within 48 hours by osmotic shock of freshwater or $5{\sim}15\%_{\circ}$ seawater treatment. These results suggest that Alella macrotrachelus could be controled by hyposmotic treatment.

• Korean Journal of Veterinary Research
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• v.47 no.3
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• pp.299-302
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• 2007

Neoheterobothrium hirame (N. hirame) is a large blood-feed gill-worm infecting the highly prized olive flounder. The present study was reported the occurrence and elimination of Neoheterobothrium infection from young cultured oliver flounder in the western coast of Korea. Flounder (weight 18-25 g, length 10-15 cm) were obtained from a cultured farm at Taean of Korea at May 2006. A lot of flounder died with serious anemia. We isolated N. hirame from the buccal cavity wall of dead flounder. Adult parasites were 5-15 mm in total length, with 4 pairs of clamps on the pedunculated haptor and isthmus region embedded in host tissue, while immature and sub-adults were identified the attachment to the gill filaments, rakers and arches with the clamps. All fish with infection were treated with 8% NaCl-supplemented seawater for 1 and 10 min at $22^{\circ}C$, respectively. The significant reduction in mortality (6.7%) was observed among fish treated with 8% salt water for 10 minutes, when compared with that of non-treatment group (100%).

• Journal of fish pathology
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• v.25 no.1
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• pp.31-37
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• 2012

The objective of this study was to investigate the antioxidant enzyme (superoxide dismutase, SOD; glutathione, GSH; glutathione peroxidase, GPx) activities in liver and gill of rock bream, Oplegnathus fasciatus fed the experimental diets for 40 days. The experimental diets were prepared by adding with 30, 60 120 and 240 mg/kg to a commercial diet. In the liver, there were significant increases in SOD at 30~240 mg/kg. GPx activities of liver also were significantly increased at 30~120 mg/kg. The increased activities of SOD and GSH in the gills were observed in the 120 and 240 mg/kg, hence, GPx activity of gill exposed to lower concentrations of zinc (60~240 mg/kg) showed significant augmentation.