• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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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.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.154-165
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• 2013

The species composition of the fish community was studied in four streams where fish kills have previously occurred in recent years; Worun Stream, Seo Stream, Jangnam Stream, and the Anyang Stream. The number of fish species varied from 22 to 86% compared to the number of fish species pre-fish kill. The recovery of fish populations in the streams seems to be determined by water quality and the presence of artificial structures in the streams. The Jangnam Stream, where alkaline pH caused a fish kill, showed a high recovery of fish species due to improvements in water quality. Anyang Stream had a low number of species, possibly because dissolved oxygen concentrations were intermittently low. Artificial structures in streams had a negative impact the recovery of fish species, particularly for benthic fish species. It appears that fish populations can recover rapidly when water quality improves or the movement of fish community is unimpeded. However, water quality and artificial structures in many streams in Korea still present adverse conditions for fish survival, deterring the recovery of fish populations. To conserve fish populations in streams, habitat all owing unimpeded movement for fish and controls on pollutant inputs are needed.

• Fisheries and Aquatic Sciences
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• v.2 no.1
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• pp.17-24
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• 1999

The blooms caused by Fibrocapsa japonica have occurred regularly in New Zea1andean coastal waters, and no fish kills and economic impacts have been reported. However, Fibrocapsa japonica in Japan killed caged juvenile fish and has been regarded as a harmful micro algae. In this comparative study a New Zealand isolate was found to be morphologically similar to a Japanese isolate, although slightly larger on average than. Optimal temperatures for growth differed, with fastest growth rates occurring at $22-24^{\circ}C$ for the New Zealand strain and $16-22^{\circ}C$ for the Japanese strain, with a decrease in growth rate exhibited by the latter at $25^{\circ}C$. Both isolates had low salinity optima of 20-25 PSU, although they grew between 15 and 30 PSU. Growth declined significantly for both strains above 30 PSU.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.4
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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.

• Environmental Analysis Health and Toxicology
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• v.11 no.3_4
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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.

• ALGAE
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• v.30 no.1
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• pp.49-58
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• 2015

In September 2007, reports of respiratory irritation and fish kills were received by the Florida Fish and Wildlife Conservation Commission (FWC) from the Jacksonville, Florida area. Water samples collected in this area indicated a bloom of Karenia brevis, the dinoflagellate that produces brevetoxin, which can cause neurotoxic shellfish poisoning. For the next four months, K. brevis was found along approximately 400 km of coastal and Intracoastal waterways from Jacksonville to Jupiter Inlet. This event represents the longest and most extensive red tide the east coast of Florida has experienced and the first time Karenia species other than K. brevis have been reported in this area. This extensive red tide influenced commercial and recreational shellfish harvesting activities along Florida's east coast. Fourteen shellfish harvesting areas (SHAs) were monitored weekly during this event and 10 SHAs were closed for an average of 53 days due to this red tide. The length of SHA closure was dependent on the shellfish species present. Interagency cooperation in monitoring this K. brevis bloom was successful in mitigating any human health impacts. Kernel density estimation was used to create geographic extent maps to help extrapolate discreet sample data points into $5km^2$ radius values for better visualization of the bloom.

• Journal of Pharmacopuncture
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• v.3 no.2
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• pp.1-25
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• 2000

We were trying to study the validity of Puffer fish's poison(Tetrodotoxin- TTX) to make a traditional Korean Medical treatment. The following conclusions were made after literary studies. 1. The first record of the puffer fish dates back 2000 years ago in the Chinese text Book of Mountain and Sea and other texts from the similar period. 2. Puffer fish's poison IS known as tetrodotoxin which is an amino perhydroquinazoline compound. It has a chemical formula of $C_{11}H_{17}N_3O_8$ in the hemiacetal structure and has the molecular weight of 319. 3. Tetrodotoxin (TTX) plays a role as potent neurotransmitter blocker by blocking the $Na^+$ -gate channel which hinders the influx of $Na^+$ ion into the cell. 4. Symptoms of the puffer fish poisoning ranges from blunted sense in the lips and tongue, occasional vomiting in the first degree to sudden descending of the blood pressure, apnea, and other critical conditions in the fourth degree. Intoxication of the puffer fish poison progresses at a rapid pace as death may occur after an hour and half up to eight hours in maximum. Typical death occurs after four to six hours. 5. Ways to treat the puffer fish poisoning include gastric irrigation, induce vomiting, purgation, intravenous fluid injection, and correcting electrolytic imbalance and acidosis. In cases of dyspnea, apply oxygen inhalation and conduct artificial respiration. 6. Tetrodotoxin (TTX) may be applied in treating brain disorders, ocular pain, excess pain in the large intestine and ileum, and relieving tension of the skeletal museles, neuralgia, rheumatism, arthritis, and etc. 7. In terms of Oriental medicine, the puffer fish poison has characteristics of sweet, warm, and poisonous. It's known efficacies are to tonify weakness, dispel damp, benefit the lower back, relieve hemorrhoid, kills parasites, remove edema, and so forth. And the puffer fish eggs processed with ginger are said to be effective against tuberculosis and lung cancer, thus, it's validity must be investigated and further research should be followed.

• Journal of Environmental Science International
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• v.18 no.1
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• pp.9-14
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• 2009

Pfiesteriaand Pfiesteria-like organisms were reported to be linked to major fish kills(involving well over a billion fish) in North Carolina and Maryland estuaries on the U.S. east coast during the 1990s. Occurrences of these species have been recently reported from Korean waters including Chinhae Bay and the coast of Yeosu. In this study, the life cycle of Cryptoperidiniopsis brodyi and Pfiesteria piscicida were examined using DAPI staining. Their excystment and growth were stimulated directly by the addition of prey cells such as Rhodiminas salina. Amoeboid stages in C. brodyi and P. piscicida were never observed in culture, even after addition of filter-sterile fish mucus and tissue. The dominant life cycle stages consisted of motile flagellated zoospores and cysts. A typical dinoflagellate life cycle was demonstrated by direct observation and DAPI staining.

• Journal of Food Hygiene and Safety
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• v.17 no.4
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• pp.193-200
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• 2002

Three species of fish such as yellow tail (Seriola quinqueradiata), bastard halibut (Paralichthys olivaceus) and black rockfish (Sebastes schlegeli) were exposed to the dinoflagellate, Cochlodinium polykrikoides, and quality changes of fish after death were investigated during the extended storage. The volatile basic nitrogen (VBN) and aerobic plate counts (APC) were determined in the muscles of fish, arid organoleptic change was evaluated in the kills, skins and muscles. APC in all the fish species did not change in 6 hours of storage, but increased gradually thereafter. VBN contents in the muscles continuously increased throughout the storage of fish. Slightly higher levels of APC and VBN were observed in the tested fish than control fish, which had been exposed to air until died and stored in seawater without treating C. polykrikoides. After 12 hours of storage, APC and VBN contents in the muscles did not exceed the initial spoilage limit, 10$^{5}$ CFU/g fur APC and 30 mg/100 g for VBN, in all of the fish including control fish. Organoleptic change in fish treated with C. polykrikoides did not greatly differ from the control fish. After 8 hours of storage, distinctive deterioration of muscle was detected organoleptically in the treated fish and the control fish. The compiled result indicated that moribund fish exposed to C. polykrikoides bloom should be handled properly in 6 hours of storage after death of fish.

• Interdisciplinary Bio Central
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• v.2 no.2
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• pp.5.1-5.9
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• 2010

Flavobacterium columnare (F. columnare), the dermotropic Gram negative yellow pigmented bacteria was isolated from different sites of skin ulcerations in the Nile tilapia (Oreochromis niloticus) and Nile catfish (Clarias gariepinus) collected from an earthen pond located at an aquaculture station in Sharkiya Province, Lower Egypt during an acute episode of mass kills during the early summer of 2009. An acute infection with F. columnare was behind the emergent event of mass mortalities among both populations. Many of the Nile tilapias exhibited typical signs of hole - in- the head like lesions from which F. columnare together with the myxosporean spore, Myxobolus tilapiae (M. tilapiae) were retrieved. Most of the cohabitating infected Nile catfishes exhibited severe form of saddle back like ulcer. The identities of the retrieved isolates were confirmed using morphological, biochemical and molecular tools. The research lead us to conclude that the two diverse etiological agents (F. columnare and M. tilapiae) under the triggering effect of the abrupt change in the water quality measures (abrupt rise in the water temperature, ammonia, pH, sharp decrease in dissolved oxygen) have synergized together to induce the above mentioned pathology with the consequent reemergence of fish mass mortalities.