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A Historical Consideration on the Evolution of Competition in Offshore Fisheries (근해저인망류어업에 있어서 업종별 경합관계 형성에 관한 사적고찰)

  • 김병호
    • The Journal of Fisheries Business Administration
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    • v.35 no.1
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    • pp.23-56
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    • 2004
  • The offshore trawl fishery is seeking its survival way to overcome current management conditions in red, resulted from the bilateral agreement with China and Japan. However, this movement magnifies conflicts between fisheries on the contrary and it is thought to be impossible to get over current situations. For all that, this study is aimed at investigating how this current situations have occurred. The management freedom as response to the change in fishing conditions of a certain fishery, in case of Korea, is affected by institutional regulations. The example of this is controls on fishing gears, fishing vessels, and fishing grounds. The most exposure of this control is a segmentation of institutional fisheries. The initial segmentation of the offshore trawl fishery in Korea was occurred in the period of Japan's colonization when the degree of use of fishing grounds was limited geographically. At that time, fisheries were divided by fishing areas, but it did not divide the fishery itself. The large - sized fishing vessels were developed politically to be more competative to Japanese fishing vessels since 1950s. During this time, the trawl fishery was merged into current Eastern trawl fishery and South - Western trawl fishery. It was also inevitable to divide into the pair trawl and single trawl fishery as a result of the physical mergency between Western trawl and Southern trawl fishery. In order to develop the trawl fishery, new licenses were issued on the shrimp trawl fishery, through which it was expected to boost the trawl fishery. As opposed, the shrimp trawl fishery was changed into the mid - sized trawl fishery, targeting on the eastern fishing areas and the large - sized trawl fishery was developed since the late of 1970s with the development of filefish processing industry. The large trawl fishery that led in development of offshore trawl fishery since the late of 1950s was started to divide into a pair trawl and single trawl according to the fishing method and capital power. It finally became an institutionally independent fishery in 1980s, respectively. Looking into these historical process, the segmentation of the trawl fishery is thought as a result of the lack of long - term perspective and as a production of trial and error resulted by unprepared policy. As a result, these segmentation of fisheries roles as critical obstacles in harmonization of fisheries and in overcoming of current situations. Therefore, the review of this institutional segmentation of the offshore trawl fishery should be taken for an optimal redistribution of fishing grounds suits with business and fishing technology. For this, the fishery must be divided into large capitalized fishery and small - mid fishery with consideration of capital, fishing method, and the condition of use of fishing grounds. In addition to this, by limiting outline of fishing ground that the large fishery can harvest, it must allow for the small - mid fishery to catch with its own boundary. Furthermore, by launching buyback programs on the trawl, eastern trawl, pair trawl, it can provide broader fishing grounds where the fishery can harvest with management freedom.

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Efficiency of the Korean Bottom Survey Trawl for Snow Crab Chionoecetes opilio

  • Choi, Jung Hwa;Somerton, David A.
    • Fisheries and aquatic sciences
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    • v.15 no.4
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    • pp.337-343
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    • 2012
  • The Korean bottom trawl survey was conducted using a trawl designed by the National Fisheries Research and Development Institute (NFRDI). The capture efficiency and size selectivity of this trawl for snow crab Chionoecetes opilio was investigated by experimental tows. An auxiliary sampling net (underbag) was attached beneath the trawl net to capture crabs escaping under the trawl footrope. Experimental tows were made by the same vessel speed (3.4 knots) as in the bottom trawl survey, but toing time was shortened from the standard 30 min to 10 min to reduce possible trawl distortion due to the high catch rate of mud and debris in the underbag. In averaged over 17 tows conducted between 110-383 m depth, trawl efficiency of both males and females combined increased from about 10% at 20 mm (carapace width) to about 70% at 100 mm, with a width of 50% capture equal to 78 mm.

The Research on the Korean Distant Water Trawl Fisheries (한국 원양트롤어업의 경영실태에 관한 연구 : 기지식 트롤어업을 중심으로)

  • 성락곤;옥영수
    • The Journal of Fisheries Business Administration
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    • v.32 no.2
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    • pp.127-148
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    • 2001
  • Korean distant water trawl fisheries were sector of most important distant water fisheries with tuna long liner fisheries during the development age in Korea. Nevertheless Korean distant water trawl fisheries have suffered from catches and Income problem. It was caused to the strengthen regulation of costal countries, the rapid liberalization trend of trade on the fishing products and the shortage of cheap manpower, etc. In this situation, Korean government is inclined to convert big adjacent trawl fisheries of distant water trawl fisheries for structure adjustment In domestic fisheries. that is analyzed to incorrect method because the efficiency of management indicator in adjacent trawl fisheries was bad than distant water trawl fisheries. Then this policy of Korean government needs to convert anything else. Also it was compared with one of Japan to the efficiency of management indicator of Korean distant trawl fisheries. The result of analysis, Korea was better than Japan in some factor, especially labor cost Then if Korean government will put weighted policy on this viewpoint, Korean distant water trawl can more grow.

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The Development of Midwater Trawl Net in North Pacific Ocean (북태평양(北太平洋) 중층(中層)트롤그물의 발달(發達))

  • Kwon, Byeong-Guk;Chang, Ho-Young
    • Journal of Fisheries and Marine Sciences Education
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    • v.6 no.1
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    • pp.11-19
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    • 1994
  • The North Pacific midwater trawling which is one of the important fishing methods for Korean fishing industry is working in the Bering Sea and the sea near Kamchaka Peninsula. The catch by Korean midwater trawlers had been recorded about 300 thousands $^{M/_T}$ a year. Six types of midwater trawl net-ordinary midwater trawl net, super-V trawl net, super mesh trawl net, rope trawl net, super plus trawl net and kite trawl net-have been widely used by large trawlers above 1,500gt in size since 1982. Regarding the fishing efficiency, the super plus trawl net and kite trawl net were acknowledged as higher than other nets. Maximum mesh size of super-plus trawl net and kite trawl net ranges about 20m, whereas the length of net about 150m, and high-tech polyethylene is used as the material of rope part. The problems involved in the North Pacific midwater trawl net may be summarized as follows ; (1) The dimension of fishing gear is too big compared with the towing power of trawler. (2) The mesh size of the rope part is too big compared with that of the common netting part. (3) The net is often torn out in the connecting position of the rope part and the netting part. (4) The net is not matched with the trawler and the otter board in many trawlers, so the shape of the trawl gear in the water is instable. (5) The fish school located near head rope, ground rope and side rope in the net recorder is not caught in practice because of the net instability.

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Analysis of Resistance Distribution of the Midwater Trawl Net (중층 트롤 그물의 저항 분포 해석)

  • 박진영
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.35 no.3
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    • pp.250-265
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    • 1999
  • Quality and distribution of the TEA(Total Enclosed Area), TSA(Twine Surface Area), solidity ratio and resistance according to the partial nets of the midwater trawl net were examined through experiment at the sea to standardize a design of the midwater trawl net.The results can be summarized as follows;1. The TEA, TSA and resistance of the trawl net were increased definitely according to increasing the scale of the trawl net, and this is the most important factor to design the trawl net.2. As the result of analysis of the distributions of the bag net was smaller than the others. Because TEA for rear end of the wing net is decreased suddenly, we can judge that the trawl net was towed irregularly. 3. The resistance distribution of the partial net was increased suddenly from central part of the bag net and was showed large value in the codend.4. The resistance of the net from the position one of three to gab net and codened charged 75% at all resistance of net.

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Development of Trawl Monitoring System ( 1 ) - Distance Measuring System between Trawl Doors - (트롤 모니터링 시스템의 개발에 관한 연구 ( 1 ) - 트롤 전개판의 전개 간격 계측 시스템 -)

  • Shin, Hyeon-Ok;Lee, Chun-Woo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.33 no.3
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    • pp.189-193
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    • 1997
  • We make an ultrasonic system as a trial to measure the distance between trawl doors, and carried out a water tank ($24{\times} 24$m, water depth 1 m) experiment for confirming the practical use of the system in October 1996. This system calculates the distance between the pinger (50 kHz) and the transponder (50 kHz/70 kHz) attached each one on the trawl door by measuring the time-difference of receiving with two channels receiver on the trawler. This paper assums that both the length of the warp from the stern to the trawl door is same. At results the system shows a good relation between the distance and the time-difference of receiving while the location of the pinger is moved in variously in the water tank, and it was found that the method of measuring techniques on the prototype system could be applied to the measurement of the trawl door opening in the field experiment.

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Hydroacoustic Investigation of Demersal Fisheries Resources in the Southeastern Area of the Cheju Island , Korea - The Composition of Trawl Catches and the Influence of Net Efficiency on the Fish School Target Strength- (제주도 동남해역의 저서어업자원 조사연구 - 트롤 어획물의 조성과 어구 효율이 어군반사강도에 미치는 영향 -)

  • Lee, Dae-Jae;Lee, Won-Woo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.32 no.3
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    • pp.257-265
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    • 1996
  • The combined hydroacoustic and bottom trawl surveys were conducted in the Cheju southeastern area by the training ship "KAYA" belong to Pukyong National University in July 1995 and the traning ship "NAGASAKI MARl]" belong to Nagasaki University in April 1994, respectively. The main purpose of the investigations was to provide the basic data for the management and the biomass estimation of commercially important demersal fish stocks in this area. Fish samples were collected by bottom trawling from 10 trawl stations randomly selected in the survey area, and the species and length compositions of trawl catches were examined. The fish school target strength for demersal fish aggregations was related to the catchability of trawl net with a 90 mm mesh codend. The most abundant species in the 1995 trawl stations were Japanese flying squid, sword tip squid and red horsehead and that of the 1994 trawl stations Japanese flying squid and blackmouth goosefish. The average weight per cubic meter of trawl catches collected by bottom trawling in the Cheju southeastern area were $1.0791{\times}lO^-4$kg/$m^3$ in the 1994 survey area and $1.3636{\times}lO^-4$kg/$m^3$ in the 1995 survey area, respectively. The catch data by cover net suggest that the efficiency of trawl net could affect the weight normalized target strength values for demersal fish aggregations. That is, the average target strength per unit of weight dropped from - 33.1 dB/kg using the total catch by codend and cover net to - 30.5 dB/kg using only the catch data by codend, and a change of2.6 dB/kg was observed.ange of2.6 dB/kg was observed.

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Mathematical Models that Underlie Computer Simulation of the Trawl Doors for Mid-Water Trawls

  • Gabryuk, Victor Ivanovich;Kudakaev, Vasilii Vladimirovich
    • Ocean and Polar Research
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    • v.42 no.1
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    • pp.77-88
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    • 2020
  • This paper presents the coordinate systems used for trawl doors modeling, and provides matrix equations of connection between these systems. The projections of the forces acting on the door into axes of various coordinate systems were obtained, which were used in the door equilibrium equations. Six equilibrium conditions for the door as a solid were obtained: formulas that allow for the door area in plan to be determined; its weight in water; its mass; three moment equations for determining the position of the warp and backstrops fastening points to the door with triangular and quadrangular backstrop arrangements. It was found that the moment equilibrium equations of trawl doors are generally incompatible, which was not found by any of the authors who have previously conducted research into trawl doors. Using the Kronecker-Capelli theorem, the compatibility equation is obtained. This equation includes the coordinates of the backstrop fastening points to the door, which means that these points cannot be randomly selected. The technique of determining the warp and backstrops' fastening points position to the door is described. Conditions of directional (by angle of attack) and roll (in angle of roll) stability of the doors' equilibrium are presented. The equations presented in this paper comprise a mathematical model that allows, when designing the doors, to select optimal parameters, as well as to carry out adjustments for trawling purposes to ensure the stable movement of the doors and the entire trawl system.

Model Test on the High Performance of the Midwater Pair Trawl Net (쌍끌이중층망의 전개성능 향상을 위한 모형실험)

  • 권병국
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.31 no.4
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    • pp.340-349
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    • 1995
  • There are several problems in a fishing by the midwater pair trawl net which is used in Denmark; steeply decreasing of the net height with the towing speed increasing, the larger volume of the fishing gear in comparison with the size of the trawler, and catching of a float in a mesh, etc. To prevent steeply decreasing of the net height with the towing speed increasing and catching of a float in a mesh, it is sometimes more useful to use the kite instead of floats. This paper describes the hydrodynamic drag and the opening efficiency of the midwater pair trawl net and the midwater kite pair trawl net obtained by the model test in the circulation water channel. The results can be summarized as follows; 1. The hydrodynamic drag of the midwater kite pair trawl net is about 0.7 times smaller than that of the midwater pair trawl net. 2. The net height, mouth area and filtering volume of the midwater kite pair trawl net are smaller then those of the midwater pair trawl net when the towing speed is below 2.5knots, almost the same at 2.7knots, and are larger over 3.0knots. The net width of the midwater kite pair trawl net is same as that of the midwater pair trawl net. 3. The shapes of net mouth of both net are an oval steeply flatted with the towing speed increasing. The filtering volume of the midwater kite pair trawl net is larger then that of the midwater pair trawl net by 3% at 3.0knots, 11% at 4.0knots, and 16% at 5.0knots respectively.

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Restructuring of the Off-Shore Otter Trawl Fishery in Korea (우리나라 근해저인망어업의 축소재편에 관한 고찰)

  • KIM, Dae-Young;KIM, Byoung-Ho
    • Journal of Fisheries and Marine Sciences Education
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    • v.16 no.1
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    • pp.124-141
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    • 2004
  • This study focuses on the off-shore trawl fishery, specifically on its restructuring and new regulations governing its operation since the 1990s. This fishery has an important role in terms of fishing capacity and production amount and is dependent on close diplomatic relations with adjacent fishing countries. The off-shore trawl fishery has been shrinking since the 1990s. In addition to a decrease in stock and an increase in imports, there are vessel buyback programs and a decrease in fishing grounds related to a tri-lateral agreement among Korea, China and Japan which have sped up the shrinking of the fishery. In this processing, costs exceed the increase of revenue. Excess investments in fishing gear and salary for crews have lowered profits in this fishery. Considering the above, the off-shore otter trawl fishery should stop increases in production and restructure the fishery by coordinating fishing gear restrictions and fishing areas, and down-sizing management capacity.