• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.4
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• pp.285-289
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• 1997

A Held experiment was carried out to confirm the effect of underwater sound on the luring of fish school of rudder fish in a set net at the coast of Cheju Island. The effects of the acoustic emission on the luring of fish school were observed at a cage around a set net fishing ground using a manufactured underwater speaker. Underwater sounds that were emitted for the luring of fish school were the pure sounds of which frequency were 300Hz and 400Hz, engine noise and swimming sound. The results of the observation are as follows : 1. The input and output wave forms of a manufactured underwater speaker in water tank were similar to those in measurement frequencies. The result of the observation indicated that it could be used for the purpose of the sound emission in measurement frequencies. 2. The effect of the emitted pure sound of 300Hz, 400Hz was remarkable for the luring of fish school in 2 minutes after the sound emission. The reaction of fish school was more sensitive to the pure sound of 400Hz than 300Hz. 3. The effect of the emitted engine noise was more remarkable than that of the pure sound for 3 minute continuously. On the feeding sound, fish formed a shoal and swimmed, but didn't gather around the underwater speaker. 4. The feeding and swimming sound spectra on rudder Hsh showed similar sound pressure distribution each other, they appeared low sound pressure in frequencies of 200-600Hz.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.2
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• pp.174-184
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• 1998

In order to accumulate fundamental. data for control of fishes’ behavior at the real fishing ground, the fitness of the numerical model for describing the behavior of fishes was examined by the marine fish. Mullet, Mugil cephalus were used as experimental fishes. The numerical model of fishes’ behavior presented in our earlier paper was modified on the vertical movement of fish school. For the comparision of parameters of the modified numerical model between mullet and rainbow trout, the estimated values of parameters were identified with dimension. The fitness of the modified numerical model was examined by the comparision between experiment and simulation on the several indexes represented by fishes’ swimming characteristics. The obtained result are summarized a follows : 1. The non-dimensional parameter a’ of propulsive force and kb’ of interactive force by the experiment without model net showed a similarity, but the non-dimensional parameter k sub(c’) of schooling force for rainbow trout was lager than one for mullet and the non-dimensional parameter k sub(w’) of repulsive force for mullet was lager than one for rainbow trout. 2. The non-dimensional parameter a’ and k sub(b’) for rainbow trout by the experiment with model net were a little lager than ones for mullet, but non-dimensional parameter k sub(c’) and k sub(w’) for mullet were lager than ones for rainbow trout. 3. The non-dimensional parameter k sub(c’) and k sub(b’) showed the largest and the smallest value among the non-dimensional parameters for rainbow trout and mullet, respectively. 4. The fitness of the modified numerical model was confirmed by means of the compulsion between experiment and simulation on the swimming trajectory of fishes, the mean distance of individual from wall, the mean swimming speed, the mean swimming depth and the mean distance between the nearest individuals. Especially, the similarity of mean swimming depth was improved by using the modified numerical model.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.13 no.2
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• pp.1-4
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• 1977

The author determined the relationship between the hauling veloicty and the hydrodynamic resistance of the sablefish pot shaped conic frustum like, and induced the formulae to determine the diameter of the main line and the net horse power of the pot hauler. The results are summarized as follows: 1. The maximum hydrodynamic resistance (with its weight in water) of the pot T(kg), when the bottom webbing is covered by a cloth to imitate the catches are scattered on the bottom, is eatimated as $$ T=120v^{1.1} (0.3{\leqq}v{\leqq}0.8) $$ where v denotes the hauling velocity of the pot in m/sec. 2. When P. P. 3 strand rope is used as main line, the diameter d(mm)is recommended to satisfy the formula $$ d=72 \frac{D}{H} V^{1.1} where H denotes the depth of the fishing ground and D the intervals of the pots linked to the main in m respectively. 3. The pot hauler must displace the net horse power p(ps) of $$ P= \frac{75}{120} \frac{D}{H} v^{2.1}$$

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.53-73
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• 2007

There exists historically intimate relationship between the fisheries of the three countries of Northeast Asia in terms of the same fishing ground and similar resources. This means that if one of the countries fail to manage their fisheries properly, it will harm the others. Especially, if the EEZ straddling and Trans-Boundary Fish Stocks aren't managed by the cooperation of the three countries, the exhaustion of resources will be more likely to be accelerated. Considering the aspects mentioned, this paper refers to the necessity of fisheries cooperation between Korea, China, and Japan. Next, it analyzed the joint control cases of Norway/Russia Management of Shared Fish Stocks in the Barents Sea, Management of South Tasman Rise in Orange roughy, Agreement on Fisheries between the European Economic Community and the Kingdom of Norway, Conservation and management of pollack resources in the central Bering Sea, and drew a conclusion for ourselves. Last of all, it suggests a step-by-step strategy of promoting joint control between three countries, and the plan of the establishing and managing the organization of joint fisheries control. About the joint control, "The Joint Statement of promoting collaboration between Korea, China, and Japan" has been announced at ASEAN in October 7th, 2003 and the summit talk of the three countries. In the joint statement, the three countries came to an agreement which says, "Cooperation in Fishery Resource Conservation : The three countries will cooperate, bilaterally or trilaterally, to promote the sustainable use and conservation of fishery resource through the effective fishery management". Not only the consistent collaboration between the government is necessary, but also continuous exchange and related study on a Non-governmental level is also needed for the viable outcome in the near future. When deducting the result for the joint fisheries control, this writer hopes the contents of this study will be helpful.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.581-586
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• 2013

The sea traffic volume in Southwest sea including Wando area have increased every year. However the improvement of the facilities for convenience and safety in port and sea was not enough to meet the increasing demand of traffic and passengers' need. This study dealt with the situations and status of passenger ship traffic system in Wando area. In addition to, questionnaire survey of passenger ship user in Wando area was carried out in order to research the improvement of marine traffic system. On the basis of the result, navigation risks in the area was analysed. The institutional system such as passenger ship fare, enhanced traffic system that can improve marine traffic environment in the area were suggested and examined. The urgent issue was the scattered fishing ground near fairway which makes narrow passage and can cause risky passeger ship's navigation. In the side of passeger ship's operation, the wage of cargo handling was relatively expensive that needed to be improved.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.1
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• pp.6-12
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• 1998

The moving behaviour of Yellowtail Seriola quinqueradiata schools in the main-net of a large scale set-net was investigated in relation to the catching function of the funnel-net by a scanning sonar. The investigation was took place in the Kishihata set-net fishing ground located in Nanao city Ishigawa prefecture, Japan from Nov. 9 to Nov. 13, 1992. The obtained results are summarized as follows; 1. Fish schools showed the greatest number at the playground in the morning and at the bag-net in the afternoon. The fish schools remained long time in the main-net. 2. The rate of fish school through the funnel-net was smaller than that of fish school which is though the playground and bag-net. Because the Yellowtail school changed the shape of school in passing the funnel-net. 3. The rate of entering the bag-net was 24%, among the fish school heading to the outer funnel-net. But, the rate of escaping to the playground was 27%, among the fish school heading to the inner funnel-net. It seems that the structure of the outer funnel-net was not enough to lead the fish to the bag-net. However, the structure of the inner funnel-net was very effective at preventing escape. 4. It is appropriate to haul the net in the morning in considering the number of accumulated fish in the bag-net during the survey.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.541-547
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• 2010

Marine accidents do not correspond with another accidents because of a serious loss of lives and property. The many marine accidents can be attributed to human error like as carelessness and decision faults, and hence there is a strong need for decision-support tools for marine navigation. Much of researchers have introduced the techniques about the tools, but they hardly consider environmental factors (water depth, the width of waterway, a fishing ground, a current, the number of surrounding marine accidents, marine obstacles, etc), which are very important to the decision making of officers. In a previous research, we proposed the conceptual model of environmental risk assessment of ship navigation using fuzzy. This paper describes the detailed design of the environmental factors based on the opinion of navigation experts, and shows the validity of the conceptual model through a prototype system.

• Korean Journal of Ichthyology
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• v.31 no.3
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• pp.178-182
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• 2019

This is the first report of Brachirus annularis (Pleuronectiformes: Soleidae) from Korea. A specimen of B. annularis (229.0 mm standard length) was firstly collected by drift gill net at a fishing ground locating between Jejudo and Geomundo Islands, the southern coast of Korea on 31 March, 2019. This species was characterized by having five large, deep colored patches on the ocular side of body, each patch outlined by dark brown ring, united dorsal and anal fins jointed with caudal fin, and short pectoral fin. We add this species to the Korean fish fauna and propose its new Korean names, "Eol-luk-seo-dae-sok" and "Eol-luk-seo-dae" for the genus and species, respectively.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.194-201
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• 2022

Purpose: This study investigated the relationship between climate factors and the catches in Korean offshore fisheries in recent three decades (1981 to 2010). Method: This study focused on seven types of fish species preferred in Korean cuisine. In the study, 10-year moving averages were used so that long-term trends could be easily identified. Results: Both air temperature and sea surface temperature (SST) on the coast of Korea rose in the period (p < 0.05). The rise in SST was significantly correlated with the rise in air temperature (p < 0.05), but not with precipitation. In the 2010s compared to in the 1981, catches of anchovy and squid greatly increased (p < 0.05), while catches of Alaska / walleye pollock has been almost extinct over the past 30 years. As such, cold-water fish species decreased or disappeared, and their fishing ground was replaced by warm-water fish species. Conclusions: These findings indicate that fish species caught in offshore fisheries of Korea have changed due to climate change, especially warming. This suggests that the warming of the Korean Peninsula may have a significant impact on the supply of fishery products and food security to Koreans in the near future.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.4
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• pp.399-406
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• 2023

This study presents an analysis of bycatch data concerning Pacific white-sided dolphins (Lagenorhynchus obliquidens) along the Korean coast from 2016 to 2021. A total of 503 bycatches were examined, encompassing data on year, month, body length, sex, latitude (N), longitude (E), and fishing gear. Bycatch was the most frequent in waters with a longitude of less than 130°E, particularly in the southern coastal region at a latitude of 35.5°N, with a higher likelihood of bycatch in lower latitudes. Since 2017, a decreasing trend in bycatches has been observed. The sex distribution of bycaught dolphins showed a predominance of males (40%), followed by females (31%), with an unclassified category at 29%, though no statistically significant differences were found (p > 0.05). Seasonal analysis indicated that bycatch predominantly occurred during the winter months, with significant monthly variations (p < 0.01). Pacific white-sided dolphins were primarily ensnared in gill nets and, to a lesser extent, in stationary nets. Statistical analysis by gear type revealed a significant preference for gill nets (p < 0.001). Considering body length composition in relation to latitude, it is suggested that Pacific white-sided dolphins may utilize the southern waters of the East Sea as a potential nursery ground, though this was not confirmed at a significant level, emphasizing the need for further in-depth monitoring and ecological investigations. Given that there are approximately 27 different types of gill nets associated with the majority of bycatches, more detailed research is warranted to divide these gear types into finer subcategories for estimating bycatch relationships, ultimately leading to the development of effective conservation and management strategies.