• The Journal of Fisheries Business Administration
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• v.33 no.2
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• pp.31-48
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• 2002

This paper is aimed to analyze how to evaluate the choice of optimal management measures and level of control in fisheries management under the costly and imperfect management system by comparing with costless and perfect management system that is commonly assumed in the analysis of fisheries regulations. Fishermen would set the level of fishing efforts at the point where the marginal fishing profit for fishing effort is equal to the marginal level of fine under costly and imperfect management system. Therefore, under the case where the marginal fishing profit is higher than the marginal level of fine, the level of fishing efforts would be made at the point which is higher than the level of fishing efforts made under costless and perfect management system and is not a point where the economic profit is maximized in regulated fisheries. From this conclusion, the fishermens avoidance activities against regulations as well as the level of control in fisheries management substantially have an influence on the choice of fisheries management instruments. According to the analysis of optimal fisheries management policy, the economic profits in regulated fisheries are determined by the level of fisheries enforcement costs and total fishing profits, in which as enforcement costs increase the economic profits decrease. In addition, the economic profits vary in response to the level of control in avoidance activities. That is, as avoidance costs decrease, the economic profits increase. The determination of optimal level of control in fisheries management should be made at the point where the marginal regulation costs are equal to the marginal profits from regulated fisheries, in which marginal regulation costs are different according to the type of management measures. And the level of profits changes in response to different levels of avoidance activities. The management measure that can maximize the difference between the marginal regulation costs and marginal profits from regulated fisheries should be chosen as an optimal fisheries management instrument.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.547-556
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• 2016

A fishing lamp is the instrument for attracting distributed fish to a certain place, and is the lighting system mainly used in fishery. In the inshore fishing, most fishing lamps are used for squid and hairtail jigging fishing, and the light source of the fishing lamps mainly used is metal halide with 1.5 KW in electric power consumption. We will analyze the irradiance distribution according to depth because squid is attracted towards light. To analyze irradiance distribution by such fishing lamps, data for seawater Type-II among the seawater types defined in 1976 are applied to East Sea. However, the Type-II data have limitations in analyzing precise seawater transmission characteristics, due to insufficient information on deep seawater. This paper analyzed the irradiance distribution of fishing lamps using the measurement of transmission characteristics in the seawater in East Sea up to 100 m underwater instead of Type-II data, which is not sufficient for transmission. A compensation factor was drawn between the actual measurement data and Type-II data through seawater transmission characteristics simulation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.56-64
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• 2016

This study analyzed characteristics of officers' watch-keeping during fishing operation at the fisheries training ship KAYA (GT: 1,737 tons, Pukyong National University). It observed fishing works of three officers in wheel house of KAYA. The observations were carried out at the fishing ground 45 miles away from east of Jeju from 7 to 8 January 2010. The works and movements of the officers were recorded with three common video cameras and a 4-channel MPEG-4 Triplex DVR. Recorded data of the working circulation was analyzed by using the post-processing method. As a result of the traffic lines, the average (${\pm}S.D$) of working hour (min) and moving frequency (times), distance (m) and speed (m/min) during setting the net was 11.8 (0.9), 43.7 (8.1), 133.9 (35.8) and 10.5 (0.6), respectively. During trawling the net, it was 100, 241 (39.8), 615.7 (194.6) and 5.2 (1.6), respectively. During hauling the net, it was 17.6 (1.4), 41.0 (7.2), 196.9 (37.6) and 10.7 (0.8), respectively. In addition, it has a different tendency of the instrument usage frequency by the fishing works. During setting, the usage priority was CCTV, ECDIS, RPM and pitch controller, net monitor, GPS plotter, chart room, X-band radar, fish finder and public addressor. During trawling, it was CCTV, ECDIS, fish finder, X-band radar, net monitor, chart room, GPS plotter, RPM and pitch controller, auto pilot and steering, interphone, wind speed and direction indicator, No.1. VHF, navigation light control panel and public addressor. During hauling, it was CCTV, RPM and pitch controller, GPS plotter, public addressor, chart room, net monitor, X-band radar, auto pilot and steering and fish finder.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.311-326
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• 2005

The paper deals with the problem of selective harvesting in a prey-predator model with predator self limitation. Criteria for local stability and global stability for both the exploited and unexploited system are derived. The effort has been considered as a dynamic variable and taxation as a control instrument to protect the fish populations from over exploitation. Finally, the optimal taxation policy is discussed with the help of control theory.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.2
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• pp.469-480
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• 2019

The purpose of this study is to enhance the cultural heritage value of the Juk-Bang-Ryeum (Bamboo Weir) and prove the originality through the review of historical literature. The main industry of Korean was agriculture and fishery from ancient. In the ancient, fishery instruments are not enough due to the lack of fishing technology. The Juk-Bang-Ryeum was considered as important national resources and asset. It give us many implications about the wisdom of our ancestors because of it's scientific principle of the structure. It is surely a cultural heritage to preserve in the future because it is considered as important community asset as well as more natural and environment oriented fishing method. In the literature, the origin of 'Juk-Bang-Ryeum' can be found as 'Eo-Ryang' or 'Bang-Ryeum'. The records on this terminology go back to the Corea Dynasty, but their documentary records are rare, and most of them are records of the Chosun Dynasty. In this study, we surveyed mainly the literature records about the southern coast region in the period of Chosun Dynasty. This study contributes for preserving the cultural assets of our ancestors who pursued eco-friendly fishery method, and it is also of great significance to produce objective data based on records for the registration of the World Record Heritage.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.1
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• pp.21-29
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• 1993

The magnetic compass as a principal navigational instrument has been long used to fix ship's position and to determine ship's course. Particularly, in the small fishing vessels the studies on performance and rational usages for magnetic compass are requried to improve the safety and productivity of the small fishing vessels even though gyro compass is developed nowadays. For this purpose, the author examined the present condition of the magnetic compasses which are intalled on 219 small fishing vessels, and carried out a series of performance survey for each compass of them and also found the measured values of deviation by installation position of compass, respectively. The results obtained are summarized as follows: 1. The small fishing vessels less than 4 tons among the 219 small fishing vessels from 1 to 10 tons investigated were 50% of them. Only 1% of them were equipped with the deviation correctors, and 14 fishing vessels used the magnetic compasses which are more than 20 years old. 2. According to the compass installation position, the measured values of the deviation of the compass installed on the top bridge and the compass bed in bridge were ascertained to be the smallest, and those values of the compass installed on the bridge deck above engine room were larger and irregular. 3. The concomitant angle of the magnetic compasses installed on the experimented 4 fishing vessels were measured to be 6$^{\circ}$ to 16$^{\circ}$ and not accorded with the Korean standard values.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.12
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• pp.425-435
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• 2018

The purpose of this study is to investigate the cultural value as well as business value of Juk-Bang-Ryeum(fishing instrument made by bamboo weir) by the investigation of remains in Gyeongnam Sacheon area and reviewing various historical literatures. The research will contribute to make back data necessary for the registration of World Heritage(UNESCO) and Globally Important Agricultural Heritage Systems(FAO). Fisheries, along with agriculture, have been great significance in human history. In particular, the Fisheries has been considered very important industry due to the geopolitical characteristics of our country surrounded by the sea. We can imagine may types of fishing practices and instruments at the agricultural age. Nonetheless, there are a few fishery heritages such as collecting and hunting tools that remains today. Fortunately, there are many Juk-Bang-Ryeum which is actually operate now from the past 500 years ago at the The Sacheon and Namhae areas. We could found some literature records about it in the historical ancient literatures. We could also infer that Juk-Bang-Ryeum was an important fishery resource of the country for a long time. It was built on the basis of scientific principles to capture fishes using the rapid tide of the natural geological straits, and it prove the wisdom of our ancestors. We also could found some unique cultural heritages that was important to the local community. Naturally, it has been managed as an important asset for the residents. In addition to such historical and humanistic values, it also has business and educational value. It can be useful to understand scientific fishery principles as well as fishery experience field. It has business value as an important tourism resource in the region in connection with historical relics and geological environment resources. In conclusion, it is a valuable asset to be handed down as a valuable cultural heritage.

• The Journal of Fisheries Business Administration
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• v.33 no.2
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• pp.127-152
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• 2002

This study intends to review the development of Large Purse Seine Fisheries in Korea and Japan, and subsequent changes in the fisheries regime as well as management conditions and to examine reorganization directions. In the Northeast Asian Fishing Area, each country has done mutual operation, which causes the fishery competition and controls fishery development. Besides, Exclusive Economic Zon(EEZ) established in 1996 resulted in the prominent changes of fishery development as well as fishery relationship among each country, demands reorganization of fisheries. In the Large Purse Seine fisheries, Korea and Japan are not decreasing, they are stable. In other words, the increase in one country does not necessarily make the decrease in the other country. This is a difference from the case of the bottom fishery. Japan is the highest in the cost, the management is getting worse due to decreasing fish price and shortage of labor. In the case of Korea, the stagnant productivity has been compensated by the rising fish price, but the fishery of low productivity to cut down the size. In addition, during the 1990s the environment of fishery is getting worse because of the free import fishery, shortage of labor, etc. Following the new fisheries paradigm, each country should reorganize its fisheries structure. The principle for reorganization of fisheries structure in each country should be focused on the establishment of sustainable fisheries. The reorganization of fisheries structure for each country by EEZ establishment does not mean only dividing fishing ground and fisheries resources by countries, but means that countries should cooperate together in fisheries management for long-run benefits from fisheries.

• The Journal of Fisheries Business Administration
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• v.31 no.1
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• pp.1-12
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• 2000

The experience of many countries strongly suggests that bad governments and institutions have been a serious, if not the most serious, obstacle to economic growth and industry-structural adjustments. All public sectors pursue a mix of both predatory and productive activities-bad governments emphasizing the former, while good governments finding a way of promoting the later. In fishery public policy studies, much confusion exists about the roles of policy illustration and prescription. In general fishery public sectors involve collective actions by numerous individuals under conditions of uncertainty, complexity, bounded rationality, and imperfect information structure. All collective fisheries action organizations consist of a center(e.g., government), which leads fishery group actions, and peripheral participants(e.g., fishermen), which are controlled by the government. A paradigm is developed that gives both theoretical and empirical meaning to the constitutional determination of fisheries political preference function or fishery public sector governance structures. Three relevant spaces are specified: policy instrument, results, and constitutional. The collective-choice rules of the constitutional space structure the tradeoff between public and special fishery interest groups. Fishery public sectors seeking sustainable reductions in wasteful rent-seeking fishing activities should select constitutional principles and institutional structures that tend to promote resource sustainability. In particular, the effects of internal and external events on fisheries may result in a greater or lesser concentration of interest group power. Thus, the structure of the fishereis political power must be assessed in any prescriptive evaluation of alternative fishery governance weights.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.4
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• pp.337-348
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• 2017

The tension of warp from trawler and sea-floor contact can generate tilt and wake turbulence around otter boards. Preliminary measurements of otter board tilt and 3-D flow velocity during bottom trawl operations were taken using a vector instrument to investigate the effects of wake turbulence at the trailing edge of the otter board. Tilt data (i.e., yaw, pitch, and roll) at 1 Hz and flow data (velocities in the towing, lateral, and vertical directions) at 16 Hz were analyzed to determine their periods and amplitudes using global wavelet and peak event analyses. The mean period (${\pm}standard$ deviation) of the tilt from the peak event analysis ($5{\pm}2s$) was longer or double than that of flow velocity ($3{\pm}2s$). The two periods also had a significant linear relationship. The turbulence rate of flow was 30-50% at the trailing edge and was closely related to roll deviation. The frequency of phase difference ratios (i.e., peak time differences between tilts and flow periods) was significantly different from random occurrence in two trials, possibly due to side tidal effects. However, in the other trials, flow peaks were random, as shown by the even peak times between tilts and flows. Future studies should focus on reducing tilt variation, wake turbulence, and bottom contact to stabilize otter board motion.