• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.474-476
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• 2000

뱀장어 양식에 사용하는 치어는 아직 인공 생산 기술이 개발되지 않아 (Takahash and Sugimoto, 1978; Yu et al., 1993) 강 하구에 도달한 실뱀장어를 포획하여 이용하고 있으며, 실뱀장어 포획 정도가 한 해의 양식을 좌우하는 실정이다. 그러나 주로 양식되는 극동산 뱀장어 A. japonica의 실뱀장어 확보가 어려워지자 대체자원으로 아직은 자원량이 풍부하고 가격이 싼 유럽산 A. anguilla과 북미산 뱀장어 A. rostrata를 이용하려는 노력이 활발하지만, 이들 종간 구분이 제대로 이루어지지 않아 문제시되고 있다. (중략)

• Korean Journal of Ichthyology
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• v.17 no.4
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• pp.271-278
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• 2005

The ichthyofauna and fish community were studied in Miho Stream from May 2004 to August 2005. During the surveyed period 41 species belonging to 10 families were collected. Twelve of the species (29.3%) are endemic to Korea. Exotic fishes were Carassius cuvieri, Lepomis macrochirus, and Micropterus salmoides. Dominant species was Zacco platypus (54.7%). Comparing the present result with that of Son (1982), the indices of diversity,evenness and richness were lower and the dominance index was higher; Lampetra reissneri, Anguilla japonica, Acheilognathus macropterus, Coreoleuciscus splendidus, Pseudopungtungia nigra, Gobiobotia naktongensis, Lefua costata, Pseudobagrus koreanus, Monopterus albus and Iksookimia choii did not appear; Carassius auratus, Rhodeus uyekii, Rhodeus notatus, Acheilognathus lanceolatus, Pseudogobio esocinus, Hemibarbus longirostris, Microphysogobio yaluensis, Cobitis lutheri, Iksookimia koreensis, Pseudobagrus fulvidraco, and Rhinogobius brunneus, remarkably decreased, and Z. platypus, Pseudorasbora parva, and Squalidus gracilis majimae increased.

• Korean Journal of Ichthyology
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• v.4 no.1
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• pp.80-86
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• 1992

The ichthyofauna at the Dongchang Stream(a second tributary of the Naktong River) was surveyed from autumn to winter 1991. The fishes collected were 21 species, 18 genera belong to 7 families, and 9 species of them were found to be endemic species to Korea ; Squalidus gracilis majimae, Coreoleuciscus splendidus, Microphysogobio yaluensis, Cobitis longicorpus, Cobitis rotundicaudata, Niwaella multifasciata, Liobagrus mediadiposalis, Coreoperca herzi and Odontobutis platycephala. The dominat species were Zacco temmincki(37.3%)and Odontobutis platycephala(16.9%). and rare species were Pseudorasbora parva, Hemibarbus longirostris, Acheilognathus limbatus, Microphysogobio yaluensis, Cobitis rotundicaudata, Misgurnus mizolepis and Anguilla japonica. The indices of species diversity, eveness and dominant were 0.934, 0.707 and 0.293, respectively.

• Journal of fish pathology
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• v.3 no.2
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• pp.61-66
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• 1990

Experimental infection and histopathological study using a deleterious aquatic fungus (Saprolegnia diclina type I) were carried out in the eels (Anguilla japonica) to know what pathological changes the fungus would produce in the affected eels. The eels in group A and B which were treated with fish net were not susceptible to experimental infection. In group C which the cuticle was scraped by artificial treatment, the aquatic fungi were invading all the eel bodies including the desquamated lesions. Histopathologically, the affected eels were markedly reduced in number of goblet cells and showed moderate damage of the clavate cells. Nodular formation involving ecchymotic hemorrhage was seen in some affected areas. The eels survived to 25 days after experimental infection.

• Development and Reproduction
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• v.22 no.3
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• pp.289-295
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• 2018

Large quantity of eggs fail to be fertilized and many of fertilized eggs are unable to hatch in the eel, Anguilla japonica. Larvae of eel absorb egg yolk up to 8 days after hatching but the majority of hatched larvae die before they reach the stage of first feeding in this species. Genes of key enzymes for yolk processing (cathepsin B, D, L and lipoprotein lipase - abbreviated as ctsb, ctsd, ctsl and lpl, respectively) could be associated with egg quality. In this study, we investigated differences in the expression of these genes between floating eggs and sinking eggs, and also the relationship between the gene expressions of the enzymes and fertilization rates in the fertilized eggs obtained from artificially matured female eels. Expressions of yolk processing enzyme genes did not show significant difference between floating and sinking egg groups. Expression of ctsb decreased when fertilization rate was high. Expression of ctsd, ctsl and lpl, however, did not show any significant differences. These results suggest that ctsb expression could be an indicator of egg quality, and that some proteins prone to be digested by ctsb could be very important in the process of fertilization and normal cleavage in this species. Further study should identify these critical proteins to improve our understanding on the quality of fish eggs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.1
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• pp.29-31
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• 1981

The eels Anguilla japonica were reared in an indoor aquarium of $1m{\times}1m{\times}0.67m$ from June 7 to August 8, 1980. The eels used for the experiment were the smallest ones which were left over from 1974 to 1976 groups, of which the others grew out years earlier. The eels were fed pelletized feed, with the results of 1.05 to 1.678 in feed coefficient, and 0.96 to $1.46\%$ in daily growth rate. The results are well comparable to those of paste feed, which has been being used in the eel farming industry up to date and will be as well used in the future, if any innovative way will not be developed. If pelletized feed can be used without any other hazards, the cost of feed will be remarkably reduced by eliminating costly $\alpha-starch$ which is absolutely necessary for the paste feed preparation, and also by preventing scattering of feed materials which is always associated with paste-feed during feeding time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.199-206
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• 1982

Histological changes occurred by freezing storage and subsequent thawing, and changes of muscle fiber after heating and drying of the eel (Anguilla japonica) were observed under microscope . The results are as follows : (1) After one month of freezing storage the muscular tissue produced considerable number of extracellular and intracellular ice crystals. The sample stored at the temperature of $-40^{\circ}C$ produced ice crystals inside the muscle cells while sample stored at $-20^{\circ}C$, outside. (2) No changes were observed in the hypodermic fat after thawing regardless of storage temperature, while insufficient recovering of muscle cells were detected in the muscular tissue. Muscular tissues which have been stored $-20^{\circ}C$ showed severe change in shape due to dehydration. (3) Microscopic observation on muscle homogenate showed loss of transparency due to free-zing, disfiguration and contraction by drying and water seperation, and elasticity by heating.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.623-628
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• 2010

The distribution of fluoroquinolones was investigated in the carp (Cyprinus carpio) and eel (Anguilla japonica) after an oral dose of 20 mg/kg body weight/day for 35 days. Blood samples were collected at 5 and 10 hours and 1, 2, 3, 5, 7, 9, 13, 20, 30, and 35 days after treatment. The fluoroquinolone concentrations were determined high- performance liquid chromatography with an ultraviolet detector. The recovery rates of fluoroquinolones in the fish samples ranged from 91.4-96.6, 91.2-96.5, and 90.4-98.6% for concentrations of 0.1, 0.5, and $1.0\;{\mu}g/g$, respectively. In the blood of carp, ciprofloxacin, enrofloxacin, norfloxacin, and sarafloxacin reached maximums level of 11.03, 9.37, 9.10, and $9.81\;{\mu}g/g$ 10 hours, 1 day, 10 hours, and 10 hours after treatment, respectively. In the eel blood, these reached maximum levels of 12.65, 11.18, 11.91, and $8.74\;{\mu}g/g$ all at 10 hours. Carp sample concentrations of ciprofloxacin, enrofloxacin, norfloxacin, and sarafloxacin were not measurable 20, 30, 20, and 20 days after treatment, respectively, in all experiments (

• Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.85-92
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• 2013

To determine the relative importance of two main factors, diet or culture environment, that affect the proximate composition and main nutritive ingredients (vitamin A, vitamin E, cholesterol, fatty acid composition) in cultured eels, we analyzed the composition of eels fed diets of formula feed (FF) produced by four different companies and of eels cultured at five different eel farms that provided only one of the four different FFs. The four commercial eel FFs did not markedly differ in proximate composition or major nutritive compounds, and consequently, these variables did not significantly differ in cultured eels fed the different FFs. The FF imported from Japan was marginally superior to the two domestic commercial FFs and the FF imported from Taiwan in terms of the proximate composition and main nutritive ingredients of both the FF itself and the eels cultured on it. However, proximate composition and main nutritive ingredients significantly differed among eels cultured at the five farms that used a different FF and among eels fed the four different FFs at the same farm. In conclusion, the difference in quality between domestic and Japanese FFs in terms of eel culture was small, whereas physical or chemical environmental differences among farms during eel culture may more strongly affect the proximate composition and levels of the main nutritive ingredients in cultured eels.

• Korean Journal of Veterinary Research
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• v.50 no.1
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• pp.29-35
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• 2010

Yersinia (Y.) ruckeri has been recognized as a serious bacterial pathogen to several kinds of fish, including rainbow trout. However, there are no reports about the characteristics and pathogenicity of Y. ruckeri isolated from farm-cultured eels. In this study, we isolated and characterized Y. ruckeri from the farm-cultured eel Anguilla japonica in Korea. We investigated the phenotypic and genotypic characteristics of Y. ruckeri and tested the virulence of Y. ruckeri isolates on experimentally infected eels. Examination of the flagellar morphology of Y. ruckeri by electron microscopy showed peritrichous flagella in its cell body. Biochemical reaction studies showed overall identical profiles between the isolates and the reference strain of Y. ruckeri in API 20E and API ZYM tests. We sequenced the 16S rRNA of the Y. ruckeri (1,505 bp) for the genotypic characterization (National Center for Biotechnology Information accession number EU401667). Comparison of the 16S rRNA sequences with previously reported Y. ruckeri strains revealed similar phylogenetic relationships. In the virulence assay of the Y. ruckeri on eels, the eels exhibited listlessness, but Y. ruckeri was reisolated from those of the gills and kidneys.