• 수산해양기술연구
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• 제51권1호
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• pp.50-60
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• 2015

This paper conducted research on identifying the process of change in fishing gear and organizing the function of periodically-used fishing gear types through net plan and computer simulation by selecting the design of the four types of fishing gear used for the Korea tuna purse seiner in the Western and Central Pacific Ocean, which 1,000 G/T class and whose length over all 60 m class. In the late 1980s, the length of the tuna purse gear was 1,939 m and the design depth was 160 m, but currently, the length and the design depth are 2,515 m and 230 m, respectively. As a result of the simulation, the expansion of the fishing gear increased buoyance, sinking force, sinking depth, surrounded area, and purse wire continuously. Recently, the maximum tension of the currently used purse wire of tuna purse seiner is 23.5 tons and is close to 25.4 tons which is the maximum lift capacity of WS454 winch. The way to improve fishing gear should be proceeded to increase sinking speed rather than expand the size of fishing gear.

• Fisheries and Aquatic Sciences
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• 제18권2호
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• pp.221-227
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• 2015

We analyzed the small-scale purse-seine gear that is used along the North Coast of Java, Indonesia, using computer-aided tools to modify the gear. Data from the middle position of the leadline showed that the maximum depth reached by the net was 30 m. A similar result was also calculated. According to the calculated result, the mean sinking speed of the current gear at the middle position of the leadline was 0.13 m/s, and the maximum tension during pursing was 1,794 kgf. The best sinking performance was found in modified gear that used a 30.3 mm mesh knotless polyester net. The maximum depth reached by the net was 38 m, and mean sinking speed was 0.16 m/s at the middle position of the leadline. The maximum tension during pursing was 1,044 kgf. Independent sample t-test results show that the mean sinking depth and sinking speed in the simulated and measured results did not differ (P > 0.05). These results are expected to improve the efficiency and selectivity of small-scale purse seine gear.

• 수산해양기술연구
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• 제53권3호
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• pp.228-239
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• 2017

This study investigated the drag coefficient and lift coefficient of thirteen kinds of knotless nettings used for large purse seine gear. By comparing the hydrodynamic characteristics with nets of the previous study, the characteristics of this study were derived as a purse seine gear. Thirteen kinds of nettings with different length of bar (l) and diameter (d) were used in the experiment, out of which six kinds used the 30 mm in mesh size and three kinds with 40 mm. The drag coefficient ($C_d$) also increased with increasing d/l. It can be expressed as $C_d=3.71499(d/l)+0.76595$ at a current speed 0.4 m/s and $C_d=4.30324(d/l)+0.69056$ at a current speed 0.5 m/s. Compared with previous studies, drag coefficient values were similar to knotless net of similar d/l and smaller than drag coefficient of knot net. Therefore, using knotless net in a purse seine has the advantage of reducing the resistance acting on the purse seine gear.

• 수산해양기술연구
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• 제52권1호
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• pp.1-8
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• 2016

In this study, numerical method was used to assess technical properties and improve the Vietnamese tuna purse seine. The data were extracted from the two national level projects. The study results showed that average lead-line sinking speed reached 0.139 m/s and 0.143 m/s and maximum sinking depth was 61.6 m and 65.8 m for The gears 2003 and 2014 respectively. The maximum tension on ring line of The gear 2003 was 4,742 kgf and 2014 was 4,219 kgf. The improved tuna purse seines I, III and IV showed similar sinking speed results with 0.220 m/s, 0.219 m/s and 0.219 m/s respectively. The average lead-line sinking speed of the improved gear II was lowest with 0.215 m/s. The maximum lead-line sinking depth of the four improved gears I, II, III and IV were 116 m, 112 m, 115 m and 114.9 m respectively. Maximum tension on ring line of the improved gears I, II, III and IV were 5,657 kgf, 5,406 kgf, 5,645 kgf and 5,654 kgf respectively. The improved tuna purse seine IV is the most suitable for Vietnamese tuna purse seine fishery, Which corresponds with tuna purse seiner scale and its fishing supporting equipment at the present.

• 수산해양기술연구
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• 제56권4호
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• pp.340-346
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• 2020

In this study, the risk factors of coastal purse seine fisherman were analyzed through a survey of fishery workers of coastal purse seine fishery and the accident compensation insurance data of the fisheries workers of the National Federation of Fisheries Cooperatives (NFFC). The classified fishing operation accident data was analyzed through 4M (Man, Machine, Media, Management) model of the National Transportation Safety Board (NTSB) and the accident prevention measures were presented using Harvey's 3E (Engineering, Education, Enforcement) model. The rate of accidents on coastal purse seinens each year was 75.8‰, 36.7‰ and 74.8‰ from 2015 to 2017. The accident frequency resulting from slipping was the highest, and the risk of a contact with gear was low. When comparing each insurance data, the average value of the contact with gear accident was the highest. This research result is expected to be important data in identifying and preventing safety hazards of coastal purse seiner fisherman in the future.

• 수산해양기술연구
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• 제53권1호
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• pp.12-18
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• 2017

Lots of fishery stocks are overexploited and the overcapacity exists in Korean fishing fleets. One of the reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the offshore large powered purse seine fishery from 1960s to 2010s. Gross tonnage and horse power per fishing vessel was increased annually. Fishing gear material was changed to the knotless webbing to settle faster. Fishing equipments was modernized and supply rate was also increased. Therefore the relative fishing power index in the offshore large powered purse seine fishery increased from 0.4 in 1970 to 1.0 in 1980, to 1.5 in 2000 and to 1.6 in 2010, but the rate of increase slowed down gradually. The results are expected to contribute to reasonable fishery stock management.

• Fisheries and Aquatic Sciences
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• 제14권2호
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• pp.138-147
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• 2011

Modeling fishing-gear systems is essential to better understand the factors affecting their movement and for devising strategies to control movement. In this study, we present a generalized mathematical modeling methodology to analyze fishing gear and its various components. Fishing gear can be divided into a finite number of elements that are connected with flexible lines. We use an algorithm to develop a numerical method that calculates precisely the shape and movement of the gear. Fishinggear mathematical models have been used to develop software tools that can design and simulate dynamic movement of novel fishing-gear systems. The tool allowed us to predict the shape and motion of the gear based on changes in operation and gear design parameters. Furthermore, the tool accurately calculated the swept volume of towed gear and the surrounding volume of purse-seine gear. We analyzed the fished volume for trawl and purse-seine gear and proposed a new definition of fishing effort, incorporating the concept of fished space. This method may be useful for quantitative fishery research, which requires a good understanding of the selectivity and efficiency of fishing gear used in surveys.

• 수산해양기술연구
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• 제25권2호
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• pp.61-69
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• 1989

한국 제주도와 대마도 주변해역을 중심으로 고등어와 정어리를 주어획대상으로 선단조업을 하고 있는 건착망어업의 어선의 성능, 어패의 크기, 어획성능, 조업해역별 단위노력당 어획량등을 조업어선의 톤급별로 분석, 검토한 결과는 다음과 같다. 1. 망선의 총톤수(x)와 건착망의 면적(y)간에는 y=538.8x+99657.3의 관계가 있었다. 2. CPUE의 계절변동지수는 11~4월은 기분보다 높고, 5~10월은 낮은 현상을 나타내었다. 3. 각 해역에 있어서 톤급별 어획성능지수는 톤급별, 해역별 CPUE는 1%의 유음수준에서 차가 인정되었다. 4. 톤급별 망어패의 효율은 A와 D급선 보다 B와 C급선이 높은 현상을 나타내었다

• 수산해양기술연구
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• 제27권4호
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• pp.247-254
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• 1991

1982~88년 사이 한국건착망 어업의 망선 48척의 어황일보에 의한 조업해구, 어종별 어획량의 자료를 이용하여 5개 해역별로 어획량의 특성을 분석하였다. 이들 해역중 제주도 연안해역(CC)은 양망회수와 어획량은 많으나 양망당어획량이 타해역보다 적으므로, 조업중 어구의 형상에 대해 계측한 자료를 이용하여 저층류에 의한 망형변화에 대해 분석한 결과를 요약하면 다음과 같다. 1. 건착망의 평균 CPUE는 31.6톤인데 음 10~4월은 평균보다 높고, 음 5~9월은 낮았다. 2. 건착망 어장 5개 해역중 CC해역은 양망회수비 42.4%로서 가장 높고 CPUE는 25.7톤으로 낮았으며, 각 해역별 CPUE는 1%의 유의수준에서 차가 인정되었다. 3. 고등어 CPUE의 계절변동지수는 음 11~1월에 평균 136.3%였고, 음 5~10월에 평균 63.7%였다. 4. 저층류에 의한 역조시 선망권의 직경은 가장 짧았고, 이때 납줄에 의한 포위면적은 더욱 좁아지며 어군의 포위효율은 낮아졌다. 5. 저층류에 의한 납줄의 형상은, 순조의 경우 유향으로 장원형이 되었고, 역조의 경우 유향과 직교되는 방향으로 장원형이 되면서 포위면적이 급히 축소되었으며, 망의 변형은 역조의 경우 가장 심하였다.

• 수산해양기술연구
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• 제55권1호
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• pp.82-93
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• 2019

The International Labor Organization (ILO) selected fishing as the most dangerous group of jobs in the world, and it is well known in Korea as a 4D industry. Offshore large purse seine accounts for the largest portion of the fishing industry in the coastal region with high death rate and the accident rate. The repeated disaster rate survey by the Korea Maritime Institute (KMI) shows offshore large purse seiner is the highest at 22.3 percent and coastal gill nets and offshore stow net are following at 12.4 percent and 11.9 percent in order. Therefore, risk factors occurring in offshore large purse seiners were analyzed based on data from the National Federation of Fisheries Cooperatives (NFFC) for three years from 2015 to 2017 and 4M (Man, Machine, Media, Management) 3E (Engineering, Education, Enforcement) techniques were used to provide a safe fishing environment. The number of accidents on offshore large purse seiners each year was more than 150, and the number of accidents on every fishing boats was as high as 17 percent in 2015. If the accident rate and the risk level were divided by insurance, the accident resulting from contact with machinery was the highest, and the risk of a contact with gear was low but frequently occurring. This was caused by collisions and contact with gear in situations where death and disappearance risk are not high, and accident types in situations where death and loss risk are considered to be contact with machinery, falls or other accidents. Through these analysis techniques, the frequency and risk of each type of accident on a offshore large purse seiners can be demonstrated, and it is expected to raise awareness of a safer fishing environment and contribute to the reduction of accidents.