• Animal cells and systems
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• 제6권3호
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• pp.215-219
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• 2002

In mid-April, 2000, hundreds of thousands of fish floated dead on the Chungnang River, one of the small branches of the Han River in Seoul. We examined the causes of the accident in detail, through analysis of monitorinq data from the Han River Monitoring Project, which employed the transplanted aquatic moss, Fontinalis antipyretica. This allowed investigation of another possible cause of the fish kill: release of trace metals into the river from industrial sources during the rainfall event. In addition, we aimed to verify the usefulness of aquatic mosses as bioindicators of the event. Water samples collected 48 h after the fish kill exhibited low pH and high Total-N and Total-p, indicating that acidic compounds rich in nitrogen and phosphorus might be a major contaminant. BOD and COD were also very high. On the whole, the conditions of the river water were degraded at that time. Distinct trends were not observed in the chlorophyll phaeophy-tinization quotient and photosynthesis rate of transplanted mosses. How-ever mosses sampled soon after the accident exhibited the lowest values for those variables (P < 0.01), suggesting that stress factors in the river were diluted out over time. Heavy metals with characteristics of industrial effluents (Cr, Pb, Zn, Fe, Cu, and Cd) increased (p ＜ 0.01), indicating that they were unlikely to be major causes of the accident.

• 상하수도학회지
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• 제20권4호
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• pp.573-584
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• 2006

This study was carried out to investigate the causes of fish kills in the Yudeung Stream in Daejeon, Korea using literature reviews, governmental and our water quality monitoring data of the study site, rainfall data, intensive water quality monitoring during rainfall events, sediment pollutant contents and laboratory bioassay tests. Fish kill in urban streams can be caused by combined effect of reduction in dissolved oxygen concentration, increase in toxic material or increase in turbidity in waterbody due to introduction of surface runoff or effluent of combined sewer overflows after rainfall from the watershed areas. Despite of extensive and intensive field surveys and laboratory tests, it was found that those conventional methods have limitations to identify causes of fish kills in urban streams. It would be necessary to use dynamic water quality modeling to predetermine the range and level of water pollution in the stream and automatic water quality monitoring system that can collect water samples and detect water quality continuously.

• 상하수도학회지
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• 제20권4호
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• pp.585-594
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• 2006

This study focused on the causes of fish kills and its prevention methods in Yudeung Stream, Daejeon, Korea. Intense field data, continuous water quality monitoring system and water quality modeling were applied to analyze the causes. Pollutant can be delivered to urban streams by surface runoff and combined sewer overflows in rainfall events. However, water quality analysis and water quality modeling results indicate that the abrupt fish kills in the Yudeung stream seems to be caused by combined effect of DO depletion, increase in turbidity and other toxic material. Excessive fish population in the study area may harm the aesthetic value of the stream and also has greater potential for massive fish kills. It is suggested to implement methods to reduce delivery of pollutants to the stream not only to prevent fish kills but also to keep balance of ecosystem including human uses. Frequent clean up of the urban surface and CSO, installation of detention basin will be helpful. In the long run, it seems combined sewer system has be replaced with separate sewer system for more effective pollutant removal in the urban area.

• Fisheries and Aquatic Sciences
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• 제3권2호
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• pp.111-117
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• 2000

To clarify the ichthyotoxic mechanisms of a harmful dinoflagellate Cochlodinium polykrikoides, hematological responses of the flounder Paralichthys olivaceus and red sea bream Pagrus major exposed to this algal bloom were investigated. The mortality of red sea bream was considerably larger than that of flounder, and the threshold lethal density of C. polykrikoides to the test fish was approximately 3,000 cells/ml. Blood $PO_2$declined in proportion to the increasing density of algal cells. The blood $PO_2$ of moribund fish was about $40-60\% of control test fish. Particularly, the fishes began to be killed when the blood $PO_2$ fell below 30-40 mmHg. However, the blood pH dropped almost 1.0 unit just before fish kill. Hemoglobin and hematocrit levels of fish exposed to C. polykrikoides of 5,000 cells/ml for 24 h and of moribund fish did not show great difference. The concentrations of plasma $Na^+$, $K^+$ and $Cl^-$ were slightly elevated to different magnitudes except $Ca^{2+}$ and plasma osmolality was also increased in Cochlodinium-exposed fish. In the plasma cortisol level, these values of moribund flounder and red sea bream were 4- 5 times higher than those of control fish. These results suggest that the drop of blood $PO_2$ was may be one of the principal causes of fish kill by C. polykrikoides, and the changes of other hematological parameters were secondary responses elicited by the decrease in blood $PO_2$.

• 한국어병학회지
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• 제31권2호
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• pp.109-113
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• 2018

The purpose of the present study was to determine whether the scuticocidal activity of olive flounder (Paralichthys olivaceus) head-kidney leucocytes can be enhanced by stimulation with polyinosine-polycytosine [poly (I:C)]. The growth of Miamiensis avidus was not affected by exposure to unstimulated or poly (I:C)-stimulated leucocytes alone, heat-inactivated immune serum alone, or unstimulated leucocytes plus heat-inactivated immune serum. However, leucocytes stimulated with poly (I:C) showed clearly high scuticocidal activity against M. avidus in the presence of heat-inactivated immune serum. Furthermore, numerous poly (I:C)-stimulated leucocytes occupied the surface of scuticociliates in the presence of the heat-inactivated immune serum, which led to lysis of scuticociliates. These results suggest that both of the stimulation of leukocytes and the immobilization of scuticociliates are necessary to kill scuticociliates by leukocytes.

• 한국어병학회지
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• 제34권2호
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• pp.249-253
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• 2021

Anisakiasis is a well-known zoonosis caused by ingestion of raw or thermally undercooked seafood product contaminated with live Anisakis nematode third stage larvae (L3). Several traditional processing techniques have been used to kill or remove the Anisakis larvae worldwide, but thermal processing or deep freezing are the most effective treatments to kill the Anisakis larvae. In this study, we investigated the survival of Anisakis larvae in several condiments (soy bean sauce, wasabi, vinegar, red pepper paste) commonly consumed when eating raw fish in Korea. We also examined several different media (NaCl solution, absolute alcohol, soju) to investigate their larvicidal effect. When directly exposed to various condiments, the most effective larvicidal effect was observed in the mixture of wasabi and soy bean sauce. When exposed to different NaCl solutions, the larvicidal ability became more effective as the concentration increased, but did not show 100% killing effect. In soju, the L3 were killed under less than 4 hr. We observed the larvicidal effects of several condiments in this study, but these results are thought to be carefully interpreted for actual use because all the condiments in this study showed the effect in hours and in general, the L3 are exposed to these condiments only for seconds before ingested in real situation.

• 생태와환경
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• 제46권2호
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• pp.154-165
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• 2013

본 논문은 최근 몇 년 동안 어류폐사가 발생했던 하천인 월운천, 서천, 장남천 그리고 안양천을 대상으로 어종의 변동을 조사하였다. 어류폐사의 영향을 받은 지역에서 종수의 회복률은 22~86%까지 이르렀는데, 인공구조물과 수질에 의한 영향을 받았다. 장남천에서는 알칼리성 pH로 인해 어류폐사가 발생하였으나 다른 두 하천(월운천, 서천)에 비해 수질의 회복 이후 빠른 종수의 회복을 보였다. 또한, 안양천에서의 낮은 종수는 간헐적으로 발생하는 용존산소고갈로 인한 수질악화의 영향이 크다. 이와 더불어 하천에 설치되어 있는 인공구조물은 특히 저서성 어종의 회복에 부정적인 영향을 주는 것으로 나타났다. 수질 또는 어류개체군의 이동이 회복될 때 어종의 빠른 회복이 예상되지만, 여전히 많은 하천에서 수질의 악화현상과 일부 노후화한 인공구조물의 존재는 어류의 서식환경을 악화시킬 수 있고 어류폐사 이후 하천에서 어종의 회복을 지연시키는 원인이 될 수 있다. 하천에서 어류군집의 보존을 위해서는 어류의 이동을 위한 통로와 유역으로부터의 오염원의 유입을 관리하여야 한다.

• 대한수의학회지
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• 제50권4호
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• pp.279-284
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• 2010

Combination therapy of antibiotics is leading to improved efficacy or safety profiles with decrease emergence of bacterial resistance. Because of this benefit, many of antibacterial combinations have been used in veterinary practice for the past few decades. The purpose of this study was to examine the in vitro activity of an amoxicillin alone and in combination with other antibiotics against pathogenic bacteria of fish origin. Based on the fractional inhibitory concentration (FIC) index (FIC $$\leq_-$$ 0.5), a synergistic interaction was shown in combination of florfenicol with amoxicillin or cefuroxime. The combination of florfenicol and amoxillin showed higher antibacterial activity than that of florfenicol and cefuroxime. Ratio of amoxicillin and florfenicol in combination was 1 : 1, which showed the antibacterial activity against bacterial isolates of fish as compared with other ratios. A synergetic effect of the combination (amoxicillin and florfenicol) was further confirmed in the time-kill curve study. The study showed a better in vitro antibacterial activity of a 1 : 1 combination of amoxicillin and florfenicol than the individual antibacterial against bacterial isolates of fish. In conclusion, the combination of florfenicol and amoxicillin may serve as a potential antibacterial therapy in fishes infected pathogenic bacteria.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2003년도 춘계 수산관련학회 공동학술대회발표요지집
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• pp.219-220
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• 2003

The success of recirculating system depends largely on the treatment efficiency of waste generated in the system. fine solids were suspected to be responsible for fish kill in a recirculating system. Clogging of biofilter may be induced by high solids concentration in recirculating systems. Also, the solids could generate more ammonia nitrogen and oxygen demand if not removed out of recirculating system as soon as possible (Weeks et al., 1992). (omitted)

• Environmental Analysis Health and Toxicology
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• 제11권3_4호
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• pp.45-51
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• 1996

Histopathological changes of gills and caudal fins isolated from fishes, Cyprinus carpio, Carassius auratus, and Hernibarbus labeo, which were killed by oxygen deficiency or toxic chemicals, were studied. The toxic chemicals were HCl, NaOH, chloroform, benzene, heavy metals(Cu, Cr, Zn, Pb, Hg), and o-dichlorobenzene. The exposure level was enough to kill the fishes within 30 minutes. Oxygen deficient water was prepared by aeration of nitrogen gas and the oxygen concentration was less than l ppm. Cryocutting was used for the rapid preparation of tissue slides and the tissues were stained by hematoxylin/eosin. In the fishes killed by hazardous chemicals, congestion and/or hyperplasia of secondary lamella and erosion of fin were found as the major histopathological changes. Whereas, these characteristics were not observed in gills or caudal fins of fishes killed by oxygen deficiency. These different bioindications appeared in the fishes killed by toxic substances or natural causes, can be used for the rapid identification of the causes of fish kills.