• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.119-123
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• 1985

The author carried out an experiment to find out the response of rockfish, Sebastes schlegeli(Hilgendorf) to the color lights. The experimental tank($360L{\times}50W{\times}55H\;cm$) was set up in a dark room. Six longitudinal sections with 60 cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50 cm level. Light bulbs of 20 W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in the order of blue, white, yellow and red in day time, and yellow, blue, white and red at night time. The gathering rate of fish on illumination period was not constant and fluctuated with irregularity. The difference of the gathering rate on two different colors of light was great and the difference was larger in day time than in night time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.191-196
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• 1984

The author carried out an experiment to find out the response of filefish, Navodon modestus(Gunther) to the colored lights. The experimental tank($360L{\times}50W{\times}55Hcm$) was set up in a dark room. Six longitudinal sections with 60 cm intervals are marked in the tank to observe the location of the fish. Water depth in the tank was kept 50 cm level. Light bulbs of 20W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before thor were employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in the order of blue, white, yellow and red. The gathering rate of fish on illumination period was not constant but varied randomly. The difference of the gathering rates on two different colors of light was rather in significant, however the difference was larger in the day time than in the night time.

• Journal of fish pathology
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• v.9 no.1
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• pp.87-93
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• 1996

To examine the effectiveness of $\beta$-glucan in non-specific defence mecanisms of Korean catfish(Silurus asotus), the activities of peripheral neutrophils and serum lysozyme were evaluated after once or twice $\beta$-glucan injections. The number of peripheral neutrophils increased after the injection. The increased number in neutrophils in twice $\beta$-glucan injections maintained longer than in single glucan injecton. But the neutrophils did not showed any remarkable changes in PAS-positive reaction. Peripheral neutrophils from fish injected glucan had enhanced phagocytic activities but there was no significant difference in phagocytic index for the glucan and control groups. An elevation of lysozome activity was also observed in the fish received twice glucan but neither single glucan or physiological saline injection could not evoked an increase of lysozyme activity. These results suggest that $\beta$-glucan can enhance the resistance of Korean catfish against to bacteria infection through the activation of peripheral neutrophils and lysozyme.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2002.10a
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• pp.156-156
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• 2002

The goal of this study is to develop a biomarker used in monitoring abnormal behaviors of Japanese medaka (Oryzias latipes) as a model organism caused by hazardous chemicals that are toxic and persistent in the ecosystem. A widely used insecticide, diazinon (O, O-diethyl O- (2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate), is highly neurotoxic to fish, and it is also well known that it causes vertebral malformation and behavioral changes of fish at relatively low concentrations. The fish behaviors were observed on a real time basis using an image processing and automatic data acquisition system. The genes potentially involved in the abnormal behaviors were cloned using suppression subtractive hybridization (SSH) technique. The untreated individuals showed common behavioral characteristics. When the test fish was affected by diazinon at a concentration of 0.1 and 1 ppm, some specific patterns were observed in its behavioral activity and locomotive tracks. The typical patterns were enhanced surfacing activity, opercular movement, erratic movement, tremors and convulsions as reported previously. The number of genes up-regulated tty diazinon treatment were 97 which includes 27 of unknown genes. The number of down-regulated genes were 99 including 60 of unknown genes. These gene expression patterns will be analyzed by the artificial neural networks such as self organization map (SOM) and multilayer perceptron (MLP), revealing the role of genes responsible for the behaviors. These results may provide molecular biological and neurobehavioral bases of a biomonitoring system for diazinon using a model organism such as fish.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.1
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• pp.6-10
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• 1984

The author carried out an experiment to find out the response of rock trout, Hexagrammos otakii (Jordan et starks) to the color lights. The experimental tank (360L$\times$50W$\times$55H cm) was set up in a dark room. Six longitudinal sections with 60cm intervals are marked in the tank to observe the loction of the fish. Water depth in the tank was kept 50cm level. Light bulbs of 20W at the both ends of the tank projected the light horizontally into the tank. Two different colored filters were selected from four colors of red, blue, yellow, and white, and they were placed in front of the light bulbs to make different colors of light. Light intensity were controlled by use of auxiliary filters intercepted between the bulb and the filter. The fishes were acclimatized in the dark for 50 minutes before they were 3employed in the experiment. Upon turning on the light, the number of fish in each section was counted 40 times in 30 second intervals, and the mean of the number of fish in each section was given as the gathering rate of the fish. The colors favourited by the fish was found in the order of white, yellow, red and blue in day time, and red, yellow, blue and white at night time. The gathering rate of fish on illumination period was small and comparatively fluctuated with stability. The difference of the gathering rates on two different colors of light was great.

• Korean Journal of Ichthyology
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• v.31 no.3
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• pp.159-164
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• 2019

Species composition and seasonal variation of fish eggs and larvae were investigated from 2017 to 2018. During the study period, the fish eggs were identified as belonging to 6 taxa. The dominant species of fish eggs were Engraulis japonicus, Leiognathus nuchalis, and Konosirus punctatus. These three species accounted for 96% of the total number of individuals collected. The collected larval fishes were identified into 17 taxa, 11 families, and 5 orders. The dominant species of larval fish were Engraulis japonicus, Leiognathus nuchalis, and Konosirus punctatus. These three species accounted for 70% of the total number of individuals collected. The diversity index of the larval fishes was the highest in summer (H'=1.78) and the lowest in winter (H'=1.34). The economically important species in this area were Engraulis japonicus, Konosirus punctatus, Sebastes schlegelii, Cynoglossus joyneri and Stephanolepis cirrhifer.

• The Journal of Fisheries Business Administration
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• v.48 no.4
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• pp.1-10
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• 2017

The study analyzed the current status of fisheries port market and presented the direction of developments. The fisheries port market has become increasingly widespread due to the aging of the facilities and the scale of the fish product trade, and the number of distribution workers has also increased. The problems of fisheries port market are as follows. First, the transaction structure was changed as the proportion of aquaculture products increased. Second, the trading structure has changed, but it has failed to keep pace with the changes in the production structure. Third, the volume and amount of fish traded in aquaculture products and fish stocks increased. As a result, the growth rate of the fisheries port market is decreasing and profitability is deteriorating. The development direction of the fisheries port market is as follows. First, it is necessary to standardize the fisheries port market facilities, according to the type of fish products. Second, it needs to diversify its trade targets such as processed fish products and imported fish products. Third, it is necessary to diversify the business of the fisheries port market in order to increase profitability.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.989-996
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• 2008

Recently, a few types of fish-cage in open sea are researched. This fish-cage has to operate monitoring system for keeping an optimum living condition for fish. The most efficient monitoring system is WVMS(Wireless Vision Monitoring System) for fish-cage in open sea. WVMS should be able to transmit video signal and communicate with each controller. So. it needs to be based on WLAN(Wireless LAN) which has characteristic of higher transfer-rate, In this paper, we propose a structure of WVMS using WLAN equipments for maritime environment and prove its effectiveness. We present the propagation loss model of WVMS's communication channel. measured by field test, and discuss its validity compared with the predictive value based on the Friss propagation model and Plane earth reflection model. We present the number of frames that is received from WLAN modem connecting with underwater-camera in field test spots. As a result, we confirmed that proposed WVMS is suitable for maritime environment and it is possible to be applied to fish-cage in open sea on 'seogwipo'.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.348-362
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• 2023

This study analyzed the monitoring results of fishways at 16 weirs constructed on four large Rivers to provide data helpful for the operation and management of fishways. The average utilization rate of the fishways at the weirs was confirmed to be 64.9%. When comparing the dominant species in the mainstream and fishway monitoring results, differences were observed in 9 weirs (56.3%). This indicated that the species prevalent in the mainstream were not necessarily the ones most frequently using the fishways. The average number of individuals using the fishways per day was 336. When classifying the fish species using the fishway by life type, 92.3% were primary freshwater fish, and migratory species accounted for only 5.6%. Analysis based on the season of fishway usage revealed that an average or higher number of fish species used the fishways from May to October, with the highest number of individual users occurring from June to August. Between May and July, 80% of the fish species using the fishways were in their spawning period, while during other season, less than 40% were species that move during the spawning period. The fishways that showed a significant alignment between the spawning period and the fishway passage period were Rhinogobius brunneus, Leiocassis nitidus, Squalidus chankaensis tsuchigae, Pseudogobio esocinus, Acheilognathus rhombeus, and Pungtungia herzi, in that order. When comparing the fishway monitoring results of the Gangjeong-Goryeong Weir and the Dalseong Weir with the upper part water level of the weir, both the number of fish species and individuals using the fishway showed positive correlations with the upper part water level of the weir. This suggests that a higher water level of the weir increases the inflow discharge within the fishway, leading to increased use by fish (number of individuals in Gangjeong-Goryeong Weir, P<0.001; number of species in Dalseong Weir, P<0.05). This study summarized and analyzed the results of fishway monitoring at 16 weirs built on four large Rivers, considering fishway efficiency, operation and management, monitoring period, and regulation of water level in the upper part of the weir. It is thought that this will help understand the status of fish use in fishways on large River and aid the construction, operation, and management of fishways in the future.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.52-61
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• 1999

Seasonal variation in species composition of fish with depth was determined by analysis of bimonthly samples collected by a beach seine at the shallow water (St. 1 < 1.5m) and by beam trawl at the two stations (St. 2, 5~7m and St. 3 > 15 m) from October 1997 to August 1998 off Ippa-do in Asan Bay. Of forty species identified, 13 species at St. 1,28 species at the St. 2 and 30 species at the St. 3 were collected. The fish density was also increased with depth. Favonigobius gymnauchen occupied 55.7% at St. 1 and 38.9% of the number of individuals at St. 2. Almost of fish collected at these two stations were juveniles, and they were principally collected in August and in November. At St. 3, relatively large fishes were collected. Among them Pholis fangi and Chaeturichthys stigmatias predominated in the number of individuals. Abundance was low, but a large number of species were collected in winter. Principal component analysis revealed that the species composition at the shallower stations was different from that at the deeper station. The number of species and abundance of fish in Asan Bay was lower than in the other western coastal waters of Korea. Species composition in the study area of sandy bottom was different from that in the inner Asan Bay of mud bottom.