• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.470-471
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• 2006

• Journal of fish pathology
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• v.22 no.1
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• pp.75-83
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• 2009

Disease surveillance was performed to monitor the prevalence of fish pathogens in wild marine fish caught in coastal offshore water from February to October in 2008. A total of 401 fish samples were collected at set net or fish market at landing port on the coast of Pohang, Geoje, Yeosu and Jeju. In this study, 17 kinds of fish pathogens were isolated from 152 fish samples. The detection rates of parasites, bacteria or viruses were 21.4%, 17.0% and 2.7%, respectively. The detected parasites were Scutica, Trichodina, Cryptocaryon, Dactylogyrus, Microcotyle, Benedenia, Bivagina, Heteraxin, Caligus, Epistylis and nematode. The dominant bacterial pathogens were Vibrio, Streptococcus, Photobacterium and Psuedomonas. Red sea bream iridovirus (RSIV) and lymphocystis disease virus (LDV) were detected in 6 species of fish virus examined in this study. The detection rates of fish pathogens from Scorpaenidae, Monacanthidae, Pleuronectidae, Sparidae and Carangidae investigated over 30 samples were 59.2%, 48.4%, 34.2%, 30.6% and18.2%, respectively.

• Journal of fish pathology
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• v.26 no.3
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• pp.283-287
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• 2013

The susceptibility of marine medaka, Oryzias dancena to fish pathogenic viruses (infectious pancreatic necrosis virus (IPNV), viral hemorrhagic septicemia virus (VHSV), hirame rhabdovirus (HIRRV), infectious hematopoietic necrosis virus (IHNV), and lymphocystis disease virus (LCDV)) was investigated. The cumulative mortalities of fish immersed with IPNV (experimental condition: $15^{\circ}C$ sea water (SW)), VHSV ($15^{\circ}C$ SW), HIRRV ($15^{\circ}C$ fresh water (FW)) were 30%, 40% and 60%, respectively. In the fish immersed with IPNV ($15^{\circ}C$ FW, $18^{\circ}C$ FW and SW), VHSV ($15^{\circ}C$ FW, $18^{\circ}C$ FW and SW), HIRRV ($15^{\circ}C$ SW), IHNV ($15^{\circ}C$ FW and SW), LCDV ($15^{\circ}C$ FW and SW, $18^{\circ}C$ FW and SW), and mock-challenged group, mortality rate was less than 10%. IPNV, VHSV and HIRRV were re-isolated from the dead fish. These results suggest that marine medaka is susceptible to IPNV, VHSV and HIRRV, although their susceptibility depends on the environmental conditions.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.187-191
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• 1998

Chemotherapy can not be applied for the control of fish viral diseases because viruses depend on host machinery for their replication. Although new control strategies including vaccination are under development, avoidance of virus introduction by rapid and correct diagnosis is the best way of fish viral disease control. Although observation of virus particles with an electron microscope is an easy method for virus detection, it take a few days for the sample preparation. In order to shorten the sample preparation time, microwave radiation was applied in the procedure. With this method, 15 seconds was enough for fixation of virus infected fish samples or cultured cells inoculated with infectious hematopoietic necrosis virus, which takes 2-4 hours with routine methods. Also four minutes was enough for polymerization of embedding resin which takes 24-48 hours with routine methods. Samples prepared with microwave were good enough for direct electron microscopic observation and immunogold labeling assay.

• Journal of Aquaculture
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• v.10 no.1
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• pp.9-15
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• 1997

The pathogenic organisms occurred in cultured marine fishes in Kamak Bay were investigated from March to November in 1993. The samples were collected at 7 sampling stations once a month. Nine species of pathogenic organisms (Vibrio sp., Edwardsiella sp., Flexibacter sp., Streptococcus sp., Micrococcus sp., Caligus sp., Trichodina sp., Lymphocystis and Staphylococcus sp.) were identified as pathogenic organisms from four different species of fish (Sebastes schlegeli, Paralichthys olivaceus, lateolabrax japonicus and Pagrus major) collected in the study areas. Most of pathogenic organisms were found at over 20^{\circ}C$ of sea water temperature from June to October in 1993. On the test of drug sensitivity, Vibrio sp. (KS-9303) was sensitive to oxytetracycline and chloramphenicol ; Edwardsiella sp. (KP-9315) to oxytetracycline ; Flexibacter sp. (KP-9318) to oxytetracycline, chloramphenicol and oxolinic acid ; Streptococcus sp. (KP-9319) to erythromycin, chlorampheicol and oxytetracycline. However, all these 4 isolated bacteria were resistant to ampicilin, steptomycin, sulfamethoxazole and nitrofurazone.

• Journal of fish pathology
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• v.37 no.1
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• pp.97-110
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• 2024

The Serranidae is high-quality fish species with good meat quality and is traded at high price, and is attracting attention in South Korea as a cultured species that creates high added value. However, the high-density fish farming for mass production increases the risk of mass mortality due to infectious diseases, leading to enormous economic losses. Therefore, in order to safely prevent and protect farmed fish from serious infectious diseases, it is necessary to conduct disease monitoring on a regular basis. In this study, Hyporthodus septemfasciatus, Epinephelus moara, and the hybrid longtooth grouper (E. moara ♀×E. lanceolatus ♂) were collected once a month from fish farm of Garorim and Aquabiotech Co., Ltd for a total of six months, from July to December 2023. We investigated infections of five species of bacterial diseases, including Flavobacterium columnare, six species of viral diseases, including LCDV (lymphocystis disease virus), and parasitic pathogens in grouper farms. As the result, Vibrio vulnificus and V. harveyi were detected in H. septemfasciatus in August, in the case of viral diseases, NNV was detected in H. septemfasciatus from July to August using RT-PCR or PCR. Finally, In the case of parasitic diseases, Tricodina sp. was detected in E. moara and the hybrid longtooth grouper from August to December.

• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.474-482
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• 2019

Disease monitoring in wild aquatic animals is necessary to obtain information about disease occurrence, disease agents, and the transmission of diseases between wild and cultured species. In this study, we monitored viral diseases in wild marine fish and crustacea caught by trawl in Korea in April and October 2018. We monitored the viral diseases in 977 fish from 39 different species and 287 crustacea from 14 different species. In fish, we collected kidney and spleen to detect viral hemorrhagic septicemia virus (VHSV), red sea bream iridovirus (RSIV), marine birnavirus (MABV), hirame rhabdovirus (HRV), and lymphocystis disease virus (LCDV). In crustacea, we monitored white spot syndrome virus (WSSV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), taura syndrome virus (TSV), infectious myonecrosis virus (IMNV), yellowhead disease virus (YHDV), and white tail disease virus (WTDV) using pleopods, pereiopods, gills, muscle, and hepatopancreases. Although none of the viral diseases tested in this study were detected in the samples, these results will help disease control between aquaculture species and wild aquatic animals.

• Journal of fish pathology
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• v.21 no.3
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• pp.259-270
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• 2008

Disease surveillance was performed to monitor the prevalence of fish pathogens in wild marine fish caught in coastal offshore water in Korea. A total of 333 of fish samples were collected at set net or fish market at landing port in Pohang (East Sea), Taean (Western Sea), Goseong and Tongyeong (Southern Sea) and 21 species of pathogens causing clinical infections to farmed fish were investigated. The detection rates of fish pathogens from Mugili formes, Tetraodontiformes, Pleuroneciformes, Sorpaeniformes, erciformes and Clupeiformes were 90.9, 61.1, 47.6, 43.6, 37.2 and 11.8%, respectively. Comparing with prevalence of diseases seasonally, both the detection rates of bacteria and parasite were higher than those of virus in April but the detection rates of parasites were distinctively higher than those of bacteria in August with high water temperature. Virus were detected in fish samples caught in the Western and Southern Sea in April. The detected parasites were Trichodina, Ichthyophthirius, Dactylogyrus, Microcotyle, Bivagina, Caligus, Alella and Myxobolus. Among the bacterial pathogens, Vibrio, Streptococcus, Photobacterium, Psuedomonas were predominant. Viral nervous necrosis virus (VNNV) and flounder lymphocystis disease virus (FLDV) were detected from the 6 species of fish virus examined in this study.

• The Journal of the Korea Contents Association
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• v.22 no.3
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• pp.71-80
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• 2022

In the past, fish diseases were bacterial in aqua farms, but in recent years, the frequency of fish diseases has increased as they have become viral and mixed. Viral diseases in an enclosed space called a aqua farm have a high spread rate, so it is very likely to lead to mass death. Fast identification of fish diseases is important to prevent group death. However, diagnosis of fish diseases requires a high level of expertise and it is difficult to visually check the condition of fish every time. In order to prevent the spread of the disease, an automatic identification system of diseases or fish is needed. In this paper, in order to improve the performance of the disease identification system of Paralichthys olivaceus based on deep learning, the existing pre-processing method is compared and tested. Target diseases were selected from three most frequent diseases such as Scutica, Vibrio, and Lymphocystis in Paralichthys olivaceus. The RGB, HLS, HSV, LAB, LUV, XYZ, and YCRCV were used as image pre-processing methods. As a result of the experiment, HLS was able to get the best results than using general RGB. It is expected that the fish disease identification system can be advanced by improving the recognition rate of diseases in a simple way.

• Journal of fish pathology
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• v.25 no.3
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• pp.263-270
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• 2012

This study surveyed for the prevalence of parasites, bacteria and viruses in four fish species, olive flounder (Paralichthys olivaceus), red sea bream (Pagrus major), black sea bream (Acathopagrus schlegeli) and black rockfish (Sebastes schlegeli) in 2010. The survey was aimed to compare the pathogens detected from wild and cultured fish for an epidemiological study. Anisakis sp. was predominantly detected from wild olive flounder and red sea bream (58.6% and 41.7% respectively), but not from the cultured fishes, suggesting anisakid infection is rare in cultured fish. The wild fish get in contact with the anisakids through their prey such as small fishes or crustaceans which carry the anisakids; whereas the cultured fish are fed with formulated feed, free of anisakids. Bacterial detection rates from the wild fishes examined in the study were lower than those of cultured fishes. Vibrio sp. dominated among detected bacterial population in cultured olive flounder (18%). Since vibriosis is known as a secondary infection caused by other stressful factors such as parasitic infections, handling and chemical treatment, it seems that cultured olive flounder are exposed to stressful environment. Viruses diagnosed in the study showed difference in distribution between wild and cultured fishes; hirame rhabdovirus (HRV) (0.1%) and lymphocystis disease virus (LCDV) (3.9%) were detected in the cultured olive flounder, but not in the wild fish, and marine birnavirus (MBV) (1.7%) and red sea bream iridovirus (RSIV) (3.2%) were detected from the wild and cultured red sea bream, respectively. From the survey conducted, it can be concluded that even though some pathogens (Trichodina sp., Microcotyle sp., etc.) are detected from both the wild and cultured fish, pathogens such as Anisakis sp., Vibrio sp. and LCDV showed difference in distribution in the wild and cultured host of same fish species and this can be attributed to their environmental condition and feeding.