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

• 생태와환경
• /
• 제46권2호
• /
• pp.154-165
• /
• 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.

• Fisheries and Aquatic Sciences
• /
• 제2권1호
• /
• pp.17-24
• /
• 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.

• 상하수도학회지
• /
• 제20권4호
• /
• pp.573-584
• /
• 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
• /
• 제11권3_4호
• /
• pp.45-51
• /
• 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
• /
• 제30권1호
• /
• pp.49-58
• /
• 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.

• 대한약침학회지
• /
• 제3권2호
• /
• pp.1-25
• /
• 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.

• 한국환경과학회지
• /
• 제18권1호
• /
• pp.9-14
• /
• 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.

• 한국식품위생안전성학회지
• /
• 제17권4호
• /
• pp.193-200
• /
• 2002

Cochlodinium polykrikoides 적조로 폐사한 어류를 식품원료나 사료로 이용하기 위한 기초연구의 일환으로 방어(Seriola quinqueradiata), 넙치(Paralichthys olivaceus) 및 조피볼락(Sebastes schlegeli) 등 양식어류 3종을 이 적조에 노출하여 치사시켰다. 이 치사어류를 동 적조수에 저장하면서 저장시간에 따른 생균수, 휘발성염기질소 및 관능적 변화 등을 공기 중에서 질식시킨 후 신선한 해수에 저장한 어류와 비교하였다. 시험어 근육중 생균수는 저장 6시간 이후부터 증가하는 경향을 보였고, 휘발성염기질소는 지속적으로 증가하는 경향이었다. 치사 후 해수에 저장된 각 시험어 근육중 휘발성염기질소 및 생균수 함량의 변화는 적조해수에서 치사.저장한 시험구가 공기 중에서 질식시킨 대조구보다 약간 빠른 증가 경향을 보였으나, 시험구와 대조구간의 관능적 변화의 차이는 뚜렷하지 않았다. 적조로 폐사한 어류 3종을 해수에 저장하였을 때 12시간이 경과하여도 근육에서 초기 부패단계의 기준인 VBN 30 mg/100g 및 생균수 $10^{5}$ CFU/g을 초과하지는 않았으나 관능적 변화는 6시간 이후에는 변화가 나타나 적조 폐사어는 6시간 이내에 처리하여야 할 것으로 판단되었다.

• Interdisciplinary Bio Central
• /
• 제2권2호
• /
• pp.5.1-5.9
• /
• 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.