• Title/Summary/Keyword: Fish school

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Shape of the model pound net affected by wave and fish behavior to the net - Shape and tension of the model pound net affected by wave - (파동에 의한 모형정치망의 형상변화와 어류대망행동 - 파동에 의한 모형정치망의 형상과 장력변화 -)

  • Lee, Ju-Hee;Kwon, Byeong-Guk;Yun, Il-Bu;Kim, Sam-Kon;Yoo, Je-Bum;Kim, Boo-Young;Kim, Byung-Soo;Lee, Hye-Ok
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.43 no.2
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    • pp.101-115
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    • 2007
  • The pound net fishery is very important one in Korean coastal fishery and it need to grasp the characteristics of the net affected by many factors. It is considered that the structure and the shape of the pound net can be changed by the direction and speed of current, wave height, depth and conditions of sea bed. However, most of all, the speed of current and wave height influence more upon the pound net than any other factors to deform and flutter. In this study, author carried out the experiments with a model of double one-side pound net made by the similarity law as 1:100 scales at a real experimental area, and additionally the model net experiments were conducted in the circulating water channel in Pukyong National University. The author analyzed the data of transformation of shape and tension of the model pound net to recognize the characteristics of the current and wave acting on it. Regardless of the direction of flow affecting on the fish court net or bag net, the deformed angle and depth to the side panel and bottom of box nets becomes bigger as the wave gets higher and the period of wave is faster. The tension in both upward or downward tends to be changed by the speed of wave. Those value of changes occurred similarly in either fish court net or bag net. Generally, when bag net is located at upward of flow, the value of tension was bigger 10% than any other location or nets. Regardless of the setting direction, the tension of the pound net is increased in proportion to flow speed, wave height and period of wave, and it becomes bigger about 15-30% at upward to flow than downward. Where the flow is upward in the court net, the tension in the wave increased to 37% compared to the one in the flow only in the condition of flow of 0.1-0.3m/s. Where the flow is upward in the bag net, the tension in the wave increased to 52% in the flow of 0.1m/s, and the tension increased to 48% in the flow of 0.2-0.3m/s.

Analysis of Physical, Chemical and Biological Parameters, Based on Long-Term Monitoring (2004 $\sim$ 2007), in Daejeon Stream (대전천 수계의 장기 모니터링 (2004$\sim$2007)에 의한 물리적, 화학적, 생물학적 평가 변수 분석)

  • Lee, Min-Jung;Choi, Ji-Woong;Kim, Hyun-Mac;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.42 no.3
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    • pp.364-373
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    • 2009
  • We evaluated stream health, based on integrative approaches of qualitative habitat evaluation index (QHEI), chemical water quality and the index of biological integrity (IBI) using fish assemblages in Daejeon Stream during August 2004 - October 2007. The QHEI values in this study averaged 78.2 (n=28, range: 47$\sim$124), indicating "fair" condition based on the criteria of US EPA (1993). The highest value was in the headwater site (S1) that was 112 (good), whereas the value in S3, mid and downstream was SS (fair-poor) that was the lowest owing to a disturbance on the bed and an artificial bank. Concentrations of chemical parameters such as BOD, TP and conductivity increased from the upstream to the downstream due to higher inputs of organic matters and nutrients from the urban area. Conductivity and TP showed a dilution of stream water by rainwater during summer monsoon. Analysis of fish compositions showed that total number of species was 24 and Zacco platypus was predominated (82%). The mean IBI was 17 (range: 12$\sim$30) during four years and the IBI values also decreased from S1 to S4. These results indicated that ecological health was degradated distinctly as the stream goes down through the city-center. We concluded that Daejeon Stream running through the city are influenced by chemical impact such as an influx of domestic sewage as well as the quality of habitat.

Efficacy of fumagillin against Telohanellus kitauei Infection of Israel carp, Cyprinus carpio nudus (향어의 장포자충증에 대한 Fumagillin의 예방 및 치료 효과시험)

  • Lee, Jae-Gu;Kim, Hyeon-Cheol;Park, Bae-Geun
    • Parasites, Hosts and Diseases
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    • v.31 no.1
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    • pp.57-66
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    • 1993
  • The potential of fumagillin dicyclohexylamine salt to treat and prevent intestinal giant-cystic disease in Israel carp, Cyprinus carpio nudus, was monitored in field experimental studies. In experiment 1 (therapeutic), most fish were already naturally infected with more advanced stage of Relohqnellu: kitnuet. Fumagillin was administered to ash (mean body weiht of 830 g for a Penod of one month at a dose of 10.62 mg in the first group and 5.3 mg in the second group per fi sh per day. In experiment 2 (fprophylactlcl), most flesh also were already naturally infected with an early developmental stage of the protozoa and fish (average body weight of 484 g) were administered fumagillln for 45 days at a dose of 3.95 mg per fish per day. In both experiments, the cumulative mortalities of fish and the extrusion rates of the polar filaments of the spores were significantly decreased in a dose-independent fashion. In experiment 2 no dead fish were observed. No adverse side effects of the drug were observed among fish from any dosage group. In experiment 2, an oval or dot-like concave lesion of most cysts developed at the 7th day and the vegetative form was never observed at the 17th day postmedication and the cysts were grossly reduced in size as compared with the control group, beginning at the 24th day until the end of the study. In contrast, it was scarcely effective to the cysts in experiment 1. Taking the seasonal development of the protozoa into consideration, the above results revealed that oral administration of fumagillin at 3.95 mg/500 g body weight/day for a month Is the optimal dose for the treatment and prevention of thelohanellosls caused by T kitnuei among C. carpio nudus.

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Pygidiopsis summa (Digenea: Heterophyidae): Status of Metacercarial Infection in Mullets from Coastal Areas in the Republic of Korea

  • Sohn, Woon-Mok;Na, Byoung-Kuk;Cho, Shin-Hyeong;Lee, Won-Ja;Park, Mi-Yeoun;Lee, Soon-Won;Choi, Seung-Bong;Huh, Beom-Nyung;Seok, Won-Seok
    • Parasites, Hosts and Diseases
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    • v.54 no.4
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    • pp.497-502
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    • 2016
  • To know the infection status of zoonotic trematode metacercariae in brackish water fish, we surveyed mullets collected from 18 coastal areas in the Republic of Korea. The metacercariae of Pygidiopsis summa were detected in 236 (68.2%) out of 346 mullets examined. They were found in mullets from 15 areas except for those from Boseong-gun (Jeollanam-do), Pohang-si, and Uljin-gun (Gyeongsangbuk-do). Especially in mullets from Taean-gun (Chungcheongnam-do) and Geoje-si (Gyeongsangnam-do), their prevalences were 100% and 95.5%, and the average metacercarial density was more than 1,000 per fish. They were also detected in mullets from 3 coastal lakes, Gyeongpoho, Songjiho, and Hwajinpoho, in Gangwon-do, and their average densities were 419, 147, and 672 per infected fish, respectively. The metacercariae of 5 other heterophyid species, including Heterophyes nocens, Heterophyopsis continua, Metagonimus sp., Stictodora fuscata, and Stictodora lari, were found in the mullets examined. The metacercariae of H. nocens were detected in 66.7, 100, 28.6, 81.6, 3.9, 61.5, and 27.3% of mullets from Muan-gun, Shinan-gun, Haenam-gun, Gangjin-gun, and Boseong-gun (Jeollanam-do), Hadong-gun, and Geoje-si (Gyeongsangnam-do), and their metacercarial intensities were 64, 84, 119, 99, 1, 24, and 24 per fish infected, respectively. From the above results, it has been confirmed that P. summa metacercariae are heavily infected in mullets from coastal areas of Korea. It is suggested that residents who frequently consume raw mullet dish can be easily infected with heterophyid flukes.

Evaluation of Yeongsan Lake Ecosystem Using Various Environment Parameters (다각적 수환경지표를 이용한 영산호의 생태영향 평가)

  • Choi, Ji-Woong;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.41 no.2
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    • pp.155-165
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    • 2008
  • The purpose of this study was to evaluate the ecosystem of Yeongsan Lake using physical, chemical, and biological indicators. We evaluated the integrative ecosystem health using Lentie Ecosystem Health Assessment (LEHA) model, Qualitative Health Evaluation Index (QHEI) model, and chemical water quality. The models of LEHA and QHEI were modified as 10 and 7 metries attributes, respectively. Also, we analyzed bioaccumulation of total mercury on various fish tissues by method of U.S. EPA 7473 using Direct Mercury Analyzer (Model DMA-80). Model values of LEHA model averaged 19 (range: $14{\sim}26$, n=15), which indicated a "poor" condition, and had slightly spatial variations. Values of the QHEI in the all sites averaged 72, which were judged as a "fair" to "good" condition. The QHEI values varied from 48 (fair condition) to 99 (good condition) and showed large longitudinal gradients between the upper and lower reach. Conductivity and salinity were increased from the up-lake to downlake reach. Analysis of total mercury in fish tissues showed that levels of total Hg ranged between 0.002 and $0.087\;mg\;L^{-1}$ depending on the types of tissues. Overall, the ecosystem health in the Yeongsan Lake was judged as a "poor" and the effects of bioaccumulation on the fish tissues were minor. Therefore, it is necessary to keep an efficient management for the lake environment to maintain their ecological health.

Behavioral analysis of Pacific cod (Gadus macrocephalus) released to the entrance of Jinhae Bay, Korea (진해만 입구에 방류한 대구(Gadus macrocephalus)의 행동 분석)

  • SHIN, Hyeon-Ok;HEO, Gyeom;HEO, Min-A;KANG, Kyoungmi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.55 no.1
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    • pp.29-38
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    • 2019
  • In order to investigate the behavioral characteristics of Pacific cod (Gadus macrocephalus) released at the entrance of Jinhae Bay, Korea, the direction and range of movement, swimming speed of the fish were measured with an acoustic telemetry techniques in winter, 2015. Three wild Pacific codes WC1 to WC3 (total length 66.0, 75.0, 76.0 cm; body weight 2.84, 2.79, 3.47 kg, respectively) were tagged with the acoustic transmitter. WC1 tagged with an acoustic transmitter internally by surgical method, WC2 and WC3, externally with the acoustic data logger and a micro data logger for recording audible sound waves including timer release unit. The movement routes of the tagged fish were measured more than five hours using VR100 receiver and a directional hydrophone. The directionality of the fish movement was tested by Rayleigh's z-Test, the statistical analysis, and a statistical program SPSS. Three tagged fishes were individually released on the sea surface around the entrance to the Jinhae Bay on 10 to 24 January 2015. WC1 moved about 13.32 km with average swimming speed of 0.63 m/s for six hours. The average swimming depth and water depth of the seabed on the route of WC1 were 7.2 and 32.9 m, respectively. The movement range of WC2 and WC3 were 7.95 and 11.06 km, approximately, with average swimming speed of 0.44 and 0.58 m/s for 5.1 and 5.3 hours, respectively. The average swimming depth of WC2 and WC3 were 18.7 and 5.0 m, and the water depth on the route, 34.4 and 29.8 m, respectively. Three fishes WC1 to WC3 were shown significant directionality in the movement (p < 0.05). Movement mean angles of WC1 to WC3 were 77.7, 76.3 and $88.1^{\circ}$, respectively. There was no significant correlation between the movement direction of fish (WC1 and WC2) and the tidal currents during the experimental period (p >= 0.05). Consequently, three tagged fishes were commonly moved toward outside of the entrance and headed for eastward of the Korean Peninsula, approximately, after release. It may estimate positively that the tidal current speed may affect to the swimming speed of the Pacific cod during the spring tide than the neap tide.

Study of Elementary and Middle School Students' Consumption of Foods Cooked at High Heat (초등학생과 중학생의 고온가열조리식품 섭취실태조사 연구)

  • Lee, Joon-Kyoung;Yoon, Ki-Sun
    • Korean journal of food and cookery science
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    • v.26 no.6
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    • pp.685-698
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    • 2010
  • Acrolein is a highly toxic, reactive mutagenic aldehyde. Humans are exposed to acrolein vapors from overheated cooking oil, cigarette smoke, and combustion of organic products. In this study, we investigated elementary and middle school students' consumption of foods cooked at high heat, such as fried, direct fire, and indirect fire cooked foods. The subjects of this survey study were 265 fifth grade students and 396 middle school students nationwide. According to the results of the frequency test, broiled fish was the most frequently consumed, followed by fried fish, indirect cooked samgyebsal, and other fried foods, which were eaten more than three times per month. The total intake of foods cooked at high heat per child over 1 year was in the following order: Fried chicken(7.50 kg) > Samgeybsal(6.57 kg) > Broiled pork ribs(4.18 kg) > Broiled fish(4.12 kg) > Bulgogi(3.31 kg) > Fried dish(3.18 kg) > Pork cuttlet(3.17 kg) > Jeyukbockeum(3.13 kg) > Charcoal-broiled beef ribs(2.74 kg) > Roasted whole chicken(2.05 kg) > Dackochi(1.87 kg) > Tangsuyuk(1.87 kg) > Fried fish(1.83 kg) > Hamburger patties(1.21 kg) > Fried potato(1.01 kg) > Barbecue(0.95 kg) > Doughnut(0.80 kg) > Corn dog(0.66 kg) > Croquette(0.51 kg). The favorite cooking method was indirect fire cooking for beef, pork, and fish, whereas frying was preferred for chicken. The results of this study provide important data for assessment of acrolein exposure via foods cooked at high heat temperature. The results also indicate that children might be exposed to acrolein through consumption of foods cooked at high heat temperature, suggesting the need to promote education of proper food consumption behavior.

The conciousness of primary school children and their parents about school food service and food preference of children in Korea and Japan (한.일 양국 초등학교 아동과 학부모의 학교급식에 관한 의식 및 아동의 식품기호도 비교연구)

  • Yoo, Young-Sang
    • Journal of the Korean Society of Food Culture
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    • v.11 no.1
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    • pp.13-21
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    • 1996
  • To find out the reference data of the school food service system, I serveyed four primary schools in Seoul, Korea and Nara, Japan respectively. The school children and their parents of whom arbitrary selected two classes among each primary school, were taken the questionaire about the present school food service system and their favorate food. The results were as follows; 1) 74.8% of Korean and Japanese children, and 92.5% of their parents were in favor of school food service. 2) Korean childrin wanted more amount of food and less salty taste. 3) Korean and Japanese children and their parents believed that the school food service system correct children's unbalanced diet. 4) Korean children wished more kinds of foods, western-styled cooking and that the food would be served in warm state. 5) Korean parents wanted that school food service system should be natural and better quality food material, and teacher should educate good eating habit. 6) Korean school children prefer yogurt, cuttle-fish, chicken, bean-curd, tomato, orange, dried laver, sweet potato, pine-mushroom in each food group. In conclusion, school food service system should be enough to meet children's good nutrition status, and the menu would be selected with consideration of children's preference and Korean traditional diet habit. Good table manner and eating all kinds of foods should be targht by school food service system as well as preparing good quality of food.

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Acute toxicity of four alkylphenols (3-tert-butyl-, 2-isopropyl-, 3-propropyl-, and 4-isopropyl-phenol) and their binary mixtures to Microtox, with comparisons to Ceriodaphnia dubia and Pimephales promelas

  • Park, Kyungho;Leonard I. Sweet;Brian E. Olseski;Peter G. Meier
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2003.06a
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    • pp.158-161
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    • 2003
  • Toxicity evaluations of 3-tert-butyl-, 2-isopropyl-, 3-isopropyl- and 4-propyl-phenol and their binary mixtures were performed with the Microtox$\^$(R) / assay and compared to invertebrates and fish. The single chemical, 4-isopropylphenol, exhibited the greatest relative toxicity to the Microtox organism (Vibrio fischeri). The relative electrophilicity (LUMO) of the phenols, in contrast to the lipophilicity (Log P), was strongly correlated with toxicity to V fischeri (r$^2$=0.96, p<0.01). In contrast, relative electrophilicity alone could not explain variances in toxicity of the phenols to Ceriodaphnia dubia. Results suggest that electrophilicity in conjunction with lipophilicity provide better correlation with toxicity to C. dubia and Pimephales promelas. Microtox results from the binary mixture toxicity tests of selected phenolics indicate a mechanism of interaction governed by suppression/antagonism.

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Development of the Endocrine Disruptor Experiment in Teaching Program for Teenagers

  • Yeo, Min-Kyeong;Lim, Eun-Hee
    • Journal of Environmental Science International
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    • v.17 no.8
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    • pp.827-831
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    • 2008
  • We investigated the education process of an environmental experiment in middle and high school. The major objective was that students understand about biological toxicity of endocrine disruptor. We used bisphenol A in environmental experiment to educate them about the effects of endocrine disruptor. The test animal was zebrafish (Danio rerio, wild type) which is very easy to use in the school experiment class. We educated the high school students (n=25) in Suwon through this teaching program. Finally we analyzed the effect of research education between two groups, education students (test) and non-education students (control). This experiment showed there were some positive effects on environmental reorganization of students. They understood the affect of endocrine disruptors in fish and man. Specifically, understanding the importance of preservation of ecosystem increased in the test-education group.