• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.383-388
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• 2005

To install a radar reflector on small ships, such as a small fishing vessel, a fishery buoy, and a barge ship for fishery, it is very important to develop the optimal system which may determine a proper installation location. For this, the response characteristics how waves have an effect on the small ships should be accurately analyzed. In this paper, we analyze the dynamic behaviors of small ships, which may be caused by irregular waves. To do this, we investigate how a barge ship responses to wavelength, water depth, and directions of incoming waves. The analyzed results shall be utilized to evaluate an effect on a radar cross section when we install an radar reflector on a barge ship for fishery and a small ship.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.229-232
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• 2022

Recently, production of offshore fisheries in Korea has been decreasing. Since production of offshore fisheries in 2016 fell below 1 million tons for the first time in 44 years, it has not recovered and has been decreasing. In order to cope with such a decrease in fishery resources, the TAC (total allowable catch) system is implemented internationally for fisheries resource management. Since 1999, South Korea has introduced the TAC system to perform resource management. In this paper, we propose an artificial intelligence-based fish classification and weight estimation system that can be used to investigate fishery resources of land observers essential for the implementation of the TAC system. The system consists of an app and a cloud server that automatically measures the body size and height of fish and takes photos using a terminal equipped with a lidar sensor. In the cloud server, fish classification is performed using a CNN-based efficientnet model and the weight of fish is predicted using automatically measured body length and body height information. Using this system, it is possible to improve the existing method in which the land observer manually writes after measuring the tape measure and weight in the stomach market.

• The Journal of Fisheries Business Administration
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• v.52 no.2
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• pp.1-31
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• 2021

This study is to evaluate the prior economic feasibility of the off-shore fisheries stock enhancement project. The main findings of this study can be summarized as follows: first, offshore fisheries stock enhancement project shall be implemented by dividing them into 1st·2nd·3rd projects for efficient promotion. The 1st·2nd·3rd projects will be conducted in a total of 50 locations (the eastern sea, the western sea, the southern sea, and the jeju sea areas), and the project period per unit will be five years, which will cost 1 trillion won. Second, according to the results of the survey on public awareness, the most consumed marine species in Korea over the past year were analyzed in the order of mackerel, hairtail, squid, yellow corvina, blue crab, and cod. The dominant response to the reason for consuming marine products in Korea was healthy well-being food and safe food. In addition, 67.9% of them have hesitated to purchase offshore fish species over the past year due to high prices, indicating that they are burdened by high prices. On the other hand, 79% of the respondents said that the government's policy was insufficient, according to a survey on whether the government's coastal marine resource creation policy was sufficient. Third, as a result of preliminary economic analysis of offshore fisheries stock enhancement project, the benefit-cost ratio is 4.01, net present price is 1,283.7 billion won, and internal rate of return is 91.7% per year, which means that the economic analysis ensures the feasibility of the projects. The results of this study provide useful information on securing or organizing budgets for offshore fisheries stock enhancement project by securing economic feasibility as a national infrastructure project that increases fishery income and public benefits such as consumption of marine products.

• The Journal of Fisheries Business Administration
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• v.45 no.2
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• pp.73-83
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• 2014

This study estimated quantitatively the loss of the fisheries due to China's illegal fishing that prevailed in the EEZ of the country in recent and has been an object to present a basic data in the implementation of government policy as to strengthen the enforcement capacity, setting up the direction of the crackdown of Chinese through to figure out an objective loss according to that. The analyzed result of this study setting a reasonable scenario, fisheries resources reduction is estimated about 67.5 million ton and the estimated amount of the loss is about 1.3 trillion won. This is 21.2% of about 318.3 ten thousand tons of the total fishery production of the country and accounts for 61.9% compared to coastal and offshore fisheries production. Therefore it is a very serious problem due to China's illegal fishing in Korea fisheries sector. It is significant to the point that estimating the qualitative and quantitative losses that can achieve a realistic and effective policy.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.376-384
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• 2016

Seasonal catch distributions of large purse seines and daily landings of coastal set nets were analyzed to understand the migration path of the Spanish mackerel Scomberomorus niphonius around Korean waters. The Spanish mackerel start to move toward the coastal region in the South and West Sea in May for spawning and stay until July, when spawning finishes. Afterwards, they start to migrate to the East China Sea and the southern East Sea and are found irrespective of the onshore and offshore regions. Therefore, they disappear from the offshore region during the spawning season in June and July, and a new recruitment population of age 0 begins to inflow into the coastal fishing grounds in the South Sea and West Sea in August, one month earlier than in the Japanese coastal region of the East Sea.

• 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.57 no.4
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• pp.302-315
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• 2021

In this study, factors such as improvement of a fishing process and safety, reduction of the labor force and headcount and development of the automation technology for offshore (eel and crab) pot fishing vessels were analyzed. A questionnaire survey was conducted to analyze and select the key factors using independent/paired sample t-test and correlation analysis, and a living lab was operated with ship owners, skippers and experts to discuss practical needs of the site. From the result of questionnaire survey and field requirements, it was possible to understand the level of awareness of ship safety, general safety equipment, fishing work process and fishing safety equipment from the point of view of the field. In addition, there were differences in the measurement results of each items because the working environment and experience were different according to the position of the ship owner and the skipper. The results of the questionnaire survey and various perceptions of field stakeholders were reflected when analyzing the fishing system and fishing process to choose the development equipment applicable to the field. From the analysis results, the selected development equipment based on the fishing equipment and process currently in operation are pot washing device, catch separation and fish hold injection device, length limit regulations and bait ejection device after use, automatic main line winding device, bait crusher, automatic (crab) pot hauling separator and so on.

• Journal of Ocean Engineering and Technology
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• v.24 no.2
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• pp.53-56
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• 2010

Oil spills and red tide can be very damaging to the environment and fishery farming. These catastrophic accidents must be detected as quickly as possible. In this paper, we report the results of applying the wavelet transform to SAR or marine radar images for the detection of the boundaries of an oil spill or red tide. The application of the wavelet transform to these phenomena looks quite promising in detecting the boundaries of oil spills and red tide areas.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.2
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• pp.107-115
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• 2018

In this study, we tested Japanese trolling lines in the Jeju fishery. This fishery simulates the natural marine environment with many seabed rocks, and has been redesigned and manufactured it to be suitable for the Jeju fishery. In order to ensure that the trolling lines were deployed at the inhabitation depth of hairtails, the conditions required for the fishing gear to reach the target depth were determined for use during the experiment. The experimental test fishing was conducted at the depth of 120 m water in front of Jeju Seongsanpo and in the offshore area of Jeju Hanlim. The fishing gear used in the test fishing is currently used in a variety of field operations in Japan. However, several problems were identified, such as twisting of the line during its deployment and excessive sinking of the main line. The fishing gear was, therefore, redesigned and manufactured to be more suitable for the Jeju fishery environment. For the fishing gear to accurately reach the target depth, depth loggers were installed at the starting point of the main line and at the 250 m and 340 m points of the line. Depth and time were recorded every 10 seconds. According to the daytime positioning of hairtails in the lower water column, the target depth of the fishing gear was set at 100-110 m, which was 10-20 m above the sea floor. At a speed of 1.9 knots and with a 9 kg sinker attached, the main fishing line was deployed and catch yields at depths of 100 m, 150 m and 180 m were recorded and analyzed. When the 180 m main line was fully deployed, the time for the hairtail trolling lines to arrive at the appropriate configuration had to be 5 minutes. At this time, the depth of the fishing gear was 16-23 m above the sea floor, in accordance with the depths at which the hairtails were during the day. In addition, in order to accurately place the fishing gear at the inhabitation water depth of hairtails, the experimental test fishing utilized the results of the depth testing that identified the conditions required for the fishing gear to reach the target depth, and the result was a catch of up to 97 kg a day.

• Korean Journal of Environmental Biology
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• v.40 no.1
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• pp.25-53
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• 2022

In this study, trends in research methods and topics of seabird and marine fish migration were examined. Based on the framework of existing animal migration studies, future research directions were proposed in relation to the migration of seabirds and fish. In terms of research methodology, with the development of science and technology, tracking techniques using radio telemetry, acoustic telemetry, RFID (radio-frequency identification), satellite tracking, and geolocators are widely used to study seabird and fish migration. Research is also conducted indirectly through a population survey and the analysis of substances in the body. Research contents are largely classified into extrinsic factors that affect migration(such as environmental variables and interspecific competition), intrinsic factors such as hormones, anthropogenic activities including fishery and offshore wind farm, and the effect of global climate change. In future studies, physiological factors that influence or cause migration and dispersal should be identified concerning intrinsic factors. For the analysis of migration ability, it is necessary to study effects of changes in the magnetic field on the migration ability of seabirds and fish, interspecific differences in spatiotemporal migration ability, and factors that influence the migration success rate. Regarding extrinsic factors, research studies on effects of anthropogenic disturbances such as fishery and offshore wind farm and global climate change on the migration and dispersal patterns of marine animals are needed. Finally, integrated studies on the migration of seabirds and fish directly or indirectly affecting each other in various ecological aspects are required.