• 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 Aquaculture
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• v.17 no.1
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• pp.24-29
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• 2004

The high mortality of cultured turbot, Scophthalmus maximus was occurred from Gochang in June, 2003. Infect fish with iridovirus showed a lower feed intake and lethargic. These fish exhibited pale body color, extended abdominal and exophthalmus. Histopathological studies showed basophilic enlarged cells from kidney, spleen, gill, heart, muscle, stomach, intestine, liver and pancreas of these fish. In PCR amplification with red sea bream iridovirus (RSIV) specific primer set of a DNA fragment of 286 bp was obtained from infect turbot with the virus. The strain showed the high homologies with RSIV, LBIV (largemouth bass iridovirus), GSIV (giant seaperch iridovirus) and SBIV (sea bass iridovirus).

• Journal of fish pathology
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• v.18 no.2
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• pp.119-124
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• 2005

Two species of myxosporean parasites - Parvicapsula anisocaudata and an unidentified myxosporean were found in the lumina of renal tubules and the tubular epithelium, respectively, from cultured olive flounder, Paralichthys olivaceus in Korea. The latter was also seen in interstitial tissue of spleen and interrenal gland of the head kidney. Group of pseudoplasmodia of P. anisocaudata were firmly attached on the epithelium of renal tubules through pseudopodia. In the renal tubule epithelium, a group of unidentified myxosporean trophozoites, which were 2-3 times larger than intraluminal trophozoites of P. anisocaudata, was observed. The parasites being burst out into the lumen was occasionally encountered with partial break of the epithelium. Although infection of P. anisocaudata and unidentified myxosporean parasites did not induce any cellular reaction of the host, occlusion of renal tubules and rupture of renal epithelium would impact negatively on the renal functions of severely infected fish.

• Fisheries and Aquatic Sciences
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• v.3 no.2
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• pp.78-82
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• 2000

The influence of daily water temperature changes on chemiluminescent (CL) response of phagocytes, plasma glucose level and mortality in cultured gray mullet (Mugil cephalus) was investigated. Among three experimental temperature groups, the fish in group I and group II were maintained constantly at $27^{\circ}C$ and $29^{\circ}C$, respectively, and those in group III were suffered daily elevation of water temperature from $27^{\circ}C$ to $29^{\circ}C$ for 5 hours, then restored again to $27^{\circ}C$. After 1 week of maintaining at each experimental tank, the fish in group III showed significantly lower CL peak value (p < 0.01) and higher plasma glucose levels (p < 0.05) than those in group I and group II. The cumulative mortality of group III was $86.9\%$ within 3 days after being subjected to acute handling stress. On the other hand, the cumulative mortalities of group I and group II were $12.5\%$ and $19.2\%$, respectively. In conclusion, gray mullet farms, especially, in the vicinity of thermoelectric power plants should avoid stressing the fish during periods of high water temperature.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.1-9
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• 2009

Microbes within complex communities show quite different physiology from pure cultured microbes. However, historically the study of microbes has focused on single species in pure culture and most of microbes are unculturable in our labs, so understanding of complex communities lags behind understanding of pure cultured cells. Methodologies including stable isotope probing (SIP), a combination of fluorescence in situ hybridization (FISH) and microautoradiography (MAR), isotope micrarray, and metagenomics have given insights into the uncultivated majority to link phylogenetic and functional information. Here, we review some of the most recent literatures, with an emphasis on methodological improvements to the sensitivity and utilities of these methods to link phylogeny and function in complex microbial communities.

• Journal of fish pathology
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• v.2 no.2
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• pp.75-82
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• 1989

Dactylogyrosis due to Dactylogyrus sp. occured among cultured sea bass (Lateolabrax japonicus) in Geoje, Kyoung Nam Prefecture in July, 1988. Descriptions are given of the opisthohaptor, copulatory organ and also of the structures in Dactylogyrus sp.. Dactylogyrus sp. have one pair of minute anchor (length : $15-22{\mu}m$) and 14 larger hooks. Histopathological changes of the heavily infested gills are showed necrosis, epithelium of the gill filaments underwent hyperplasia with fusion of the lamellae and filamental clubbing. And a bacterial colony is invaded on the surface of lamellar epithelium.

• Journal of fish pathology
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• v.21 no.3
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• pp.271-278
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• 2008

The epidemiological study was performed to survey the prevalence of 5 bacterial, 6 viral and 5 parasitic disease of cultured olive flounder, Paralichthys olivaceus in Pohang, Ulsan∙Gijang, Keoje and Wando area of Korea from February to December, 2007. The disease frequency of size groups were as follows; Among the 1,218 fish samples, less than 10 cm (67.6%), 11~20 cm (70.2%), 21~30 cm (73.4%), 31~40 cm (77.6%), above 41 cm (88.2%). The highest detection rates of pathogens were recorded in samples from August and Ulsan. The detection rates of parasites, bacteria or viruses were 43.2%, 38.8% and 24.4%, respectively. The distribution of specific diseases showed that detection rates of diseases occurring the most frequently during the study period were Trichodina (33.1%), viral nervous necrosis virus (16.0%), Vibrio (9.7%), Scutica (10.1%), Ichthyobodo (5.7%).

• Journal of fish pathology
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• v.13 no.2
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• pp.75-86
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• 2000

Monogeneans(Phylum Platyhelminthes) have been known as common parasites onto the skin and gills of cultured freshwater fishes. Infestation with these parasites result in a great loss in aquaculture industry. Some classification studies on these parasites have mostly been conducted in Japan but rarely in Korea. For the purpose of classifying monogenean parasites infesting two Korean freshwater fishes, eel (Anguilla japonica) and catfish(Parasilurus asotus), samples captured from March 1998 to April 2000 were examined. Here we report for the first time in Korea that four different species of monogeneans are identified: Pseudodactylogyrus bini and P. anguillae in eels; Ancylodiscoides infundibulovagina and Ancylodiscoides sp. in catfish.

• Journal of fish pathology
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• v.13 no.2
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• pp.143-146
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• 2000

The effectiveness of bronopol and bithionol in treating Ichthyobodo sp. infestation in cultured olive flounder was investigated, and compared them with formalin. Bath with formalin at 200 ppm or bithionol at 100 ppm for 1 h showed complete removal of Ichthyobodo sp. from all the experimental fish. Baths with lower concentrations of formalin (50 and 100 ppm) or bithionol (25 and 50 ppm) significantly reduced infection intensities of Ichthyobodo sp. On the other hand, baths with bronopol or intubation of bithionol at various concentrations were not effective against Ichthyobodo sp. infestation.

• Journal of fish pathology
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• v.25 no.3
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• pp.143-150
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• 2012

Infectious haematopoietic necrosis virus (IHNV) is an important fish pathogen that infects both wild and cultured salmonids. Since the first isolation of IHNV from rainbow trout and masu salmon in 1991, a series of IHN disease outbreak has been reported in Korea. In 2011, we isolated two IHNV isolates from rainbow trout cultured in Korea. The full open-reading frame (ORF) encoding the glycoprotein (G) of them were sequenced and the amino acid sequences were phylogenetically analyzed. Phylogenetic analysis of the G revealed that both IHNV isolates were grouped into an Asian genogroup containing Korean IHNV isolates and Japanese IHNV isolates. However, based on their sequence variation, they were divided into different subgroup. While one isolate was similar to other Korean isolates, the other isolate showed a high level of similarity with Japanese isolates, suggesting the possibility of influx of new IHNV strain into Korea.