• 수산해양기술연구
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• 제47권2호
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• pp.108-117
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• 2011

In order to offer data about fisheries resources management and prediction of catch on large purse seine fisheries, the fluctuation of the fisheries condition and distributions of fishing ground for mackerel were analysed with monthly catch data for 1990.2009. The overall catch has decreased to about 70% since 1997, with approximately 70% of the mackerel (Scomber japonicus) catch and monthly fluctuations showing a similar pattern. Monthly distribution of fishing ground is like distribution of mackerel in large purse seine fishery. The main fishing grounds are near Jeju Island and the Yellow sea with the main fishing season existing between October to December. The catches fluctuations and distribution of fishing ground were related to the effect of regime shifts. Therefore, in order to prediction of catch on large purse seine fisheries should be studied these relationships.

• 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.

• 수산해양기술연구
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• 제35권3호
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• pp.227-236
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• 1999

Temperal and spacial analysis for catches have been drawing up a catch distribution chart and analysing catches and CPUE(Catch Per Unit Effort) using catch data with purpose of obtaining basic data to establish a selective method of effective fishing the tuna purse seine fishing ground.The temperature profile section and catch was surveyed to analyse the effect of catch in relation to the fishing ground environment.The results are as follows ;1. As for the catch variation between 1983 and 1984, the catch mainly took place on150^{\circ}E$, and after that it moved eastward enlarging the range of catch. In the monthly catch variation between January and February, the catches mainly happened on 135$^{\circ}$~ 150$^{\circ}$E, and then moved to the gradually westward. However, from July it moved to the South and from October Southeast.2. As to the eatch ratio for the school associated with the drifted object, the pelagic migrating school and the school associated with the biological objects, the catch ratio for the school associated with the drift objects was the highest. The catch ratio for the school associated with the drifted object was high in June, July and November whiles between January and March for the pelagic migrating school.3. SST(Sea Surface Temperature) was around 28~29^C$ on the observing line of 137^{\circ}E$ and the catches took place in the north equatorial counter-current situated on around $5^{\circ}~6^{\circ}N$. SST in the northern summer was 1^C$higher than winter and it was about 29~30^C$. The catch happened with the center of north equatorial counter-current. The reason why the catch mainly took place on the north equatorial counter-current is that main catch of tuna purse seine was the school associated with drift objects. It is thought that the fishing grounds are made in waters that have many drift objects like drift logs from the coast.

• 수산해양기술연구
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• 제41권4호
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• pp.263-270
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• 2005

This paper summarizes characteristics of the Korean tuna purse seine fishery in the Western and Central Pacific Ocean (WCPO). Major fishing area for the Korean tuna purse seine fleet consisted of the waters of Micronesia, Papua New Guinea and Solomon Islands and adjacent high seas between $130^{\circ}E-180^{\circ}$ The center of the Korean tuna fishing ground was in the vicinity of $180^{\circ}$ during the El - $Ni{\tilde{n}}$o event but was formed in $150^{\circ}-160^{\circ}$E during the La - $Ni{\tilde{n}}o$ event. As compared with other major purse seine fleets in WCPO, the Korean fleet set more on unassociated schools of tuna, while Japan, USA and Chinese - Taipei fleets accounted for more than 50% of sets on log - associated schools. In general, CPUES for log - associated schools were higher than those for unassociated schools and catch composition showed that yellowfin ratio was higher in unassociated shools than log - associated schools. Length frequency represented higher percentage of mid - sized yellowfin than Japanese and USA fleets. Daily set numbers and CPUE were high before 7 am and remained almost constant from 7 am to 3 pm but decreased rapidly after 3 pm and 5 pm, respectively. Catch composition per set indicated that pure skipjack school was caught most frequently, followed by mixed school and pure yellowfin school as the least, but CPUE was highest for the mixed school.

• 수산해양기술연구
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• 제58권4호
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• pp.317-325
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• 2022

Korean tuna purse seine fishery in the Western and Central Pacific Ocean (WCPO) began to operate in earnest in the early 1980s. Since then, the total catch has shown an increasing trend and the target species are skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacare) and bigeye tuna (Thunnus obesus). Based on the operational data of Korean tuna purse seine fishery from 2016 to 2020, the catch rates of target species (skipjack and yellowfin tunas) were analyzed by operation time for set types (free school and FAD sets). In the case of the free school sets, they were usually made from sunrise to sunset, and the catch rate was high before and after sunrise for skipjack tuna and before sunset for yellowfin tuna. On the other hand, for the FAD sets, more than 90% of them were made just before sunrise, and there were few operations during the daytime. The purpose of this study is to examine whether there are differences in the catch rate of skipjack and yellowfin tunas by operation time and by school type for Korean tuna purse seine fishery in the WCPO, which could be helpful in understanding its fishing characteristics and providing useful information for developing the stock indices of the target species.

• 수산해양기술연구
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• 제21권1호
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• pp.41-61
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• 1985

선망 어업은 우리나라 연안 어업에 있어서 매우 중요하며, 그 주 대상 어종은 고등어류이고 주 어장은 쓰시마 난류역이다. 이들의 어장과 해황과의 관계를 조사하기 위하여 크기별 고등어 어획량의 평균 분포(1974~1982)를 파악하고, 주요 어장인 제주도 동쪽 및 서쪽에 대한 해양 관측을 1983년 7월과 10월에 각각 실시하였다. 그 결과, 고등어류의 주요 어장은 역시 한국 남해의 쓰시마 난류역이었으며, 주어기는 5월과 9~10월이었다. 또 고등어류의 어획량은 체장 27~31cm(2~3세)인 소.중 고등어가 약 90%를 차지하였으나, 2~3월에는 체장 22cm (1세)의 콩 고등어가 약 40~70% 이었다. 계절적인 어장의 위치를 쓰시마 난류의 지표수인 15$^{\circ}C$ 등온선의 북상 또는 남하 위치로 알 수 있었다. 제주도 동쪽 및 서쪽의 주어장은 쓰시마 난류수와 한국 연안수 혹은 황해 저층 냉수와의 사이에 형성되는 조경역 이었다. 또 이들 어장의 투명도 및 수색, 태양광의 투과율의 분포는 수온과 염분의 분포 및 플랑크톤 습증량의 분포와 비슷하였다.

• 수산해양기술연구
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• 제43권1호
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• pp.12-27
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• 2007

This fundamental studies on for the productivity improvement and laborsaving of purse seine fishery. Given the difficulty posed from the distortion of net shape caused by the external forces, such as tide, at the time of shooting and pursing, we set the 4 steps of 0, 2, 4 and 6cm/sec in flow velocity in the flume tank for the experiment in order to examine those characteristics. We used two model seines designed on the scale of 1 to 180 based on the power block seine, which is the mackerel purse seine generally used in the near sea of Jeju Island and triplex seine, which is the mackerel purse seine of one boat system fishing expected in the future, for the experiment, and interpreted the characteristics of several motion in water, such as the shape of seine, the change in tension and area during pursing and its the analysis results are as follows. Though the experiment could be conducted up to 6cm/sec of flow velocity that was defined, the experiment could not go on because of the severe distortion in the seine at the flow velocity in excess of 6cm/sec. As for the depth of leadline and reduction rate of side area of seine when the pursing is connected, P seine turned out to be slightly higher than T seine, and the hauling speed and reduction rate of upper area of seine were found similar to each other. The correlation between the hauling time (Ht) and depth of lead line (Dhp, Dht) of P seine and T seine can be expressed by the equation, that is, Dhp=(0.99Pt-7.63)Pt+69.01, Dht=(1.03Pt-7.73)Pt+66.74. The correlation between the hauling time and hauling velocity (Hpp, Hpt) can be expressed by the equation, that is, $Hpp=-0.06Ht^2+0.88Ht+0.78,\;Hpt=-0.05Ht^2+0.81Ht+0.98$ here, Pt is pursing time. And the correlation between the pursing time and the reduction rate of side area (sArp, sArt) can be expressed by the equation, that is, $sArp=-0.48Pt^2+14.79Pt-16.74,\;sArt=-0.45Pt^2+14.56Pt-16.48$. The reduction rate of upper area of seine (tArp, tArt) can be expressed by the equation, that is, $tArp=0.34Pt^2-0.66Pt-0.74,\;tArt=0.34Pt^2-0.27Pt-1.80$. In addition, the correlation between the pursing time and tension of purse line (Tep, Tet) can be expressed by the equation, that is, $Tep=2.79Pt^2+2.26Pt-0.60,\;Tet=2.14Pt^2+8.08Pt-27.50$.

• 수산해양교육연구
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• 제8권1호
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• pp.92-107
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• 1996

1982~1989년간의 연안어업 자원조사 보고서, 1993년 연안어업의 자원이용 실태 평가 보고서와 설문조사한 자료 등을 이용하여 연안 낭장망어업의 어획성능과 소형어의 혼획실태 및 남획의 대처방안에 대하여 연구한 결과를 요약하면 다음과 같다. 1. 낭장망어업의 허가처분 실태는 1993년도에는 연안어업 873건, 구획어업 146건이었으나 1994년 수산업법이 개정된 이후에는 연안어업 757건, 구획어업 302건으로 연안어업 건수가 감소된 반면 구획어업 건수는 증가하였다. 2. 낭장망어업의 경영체당 순이익은 1991년도를 기준으로 할 때, 안강망과 해선망에 비교해서 훨씬 높은 수준에 있다. 3. 통당어획량은 1982년부터 1989년까지에서는 점차 증가하였으나, 1990년 이후에는 점차 감소하는 경향이었다. 4. 어종별 혼획율은 큰 변동이 없었으며, 지역별로는 서해안인 경기, 충남지역에서는 새우류 및 배도라치의 혼획율이 높았으며 남해안인 전북, 전남, 경남지역에서는 멸치와 배도라치의 혼획율이 높게 나타났다. 5. 소형어의 어종별 혼획율은 까나리, 멸치, 밴댕이, 배도라치 등은 각각 89.6%, 69.4%, 63.4%, 51.2%로 높게 나타났으나 새우류는 꽃새우 21.7%, 젓새우 18.8%로 적게 나타났다. 6. 월별 혼획율은 멸치, 밴댕이등은 4월과 8~11월에 높았으며 새우류는 4월과 9월에 높게 나타났다. 7. 낭장망어업에 의하여 어획되고 있는 소형어 남획의 대처 방안으로서는 소형어가 가장 많이 어획되는 시기인 4월과 8~11월에는 조업회수를 줄이는 방법, 소형어가 그물코를 통과할 수 있는 만큼의 큰 그물코를 사용하는 방법, 정착성 어류의 서식지가 아닌 조업구역을 설정하는 방법 등이 있다.

• 수산경영론집
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• 제33권2호
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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.

• Ocean and Polar Research
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• 제39권3호
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• pp.195-203
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• 2017

The purpose of this paper is to estimate the optimal $CO_2$ emission in the maximum economic yield (MEY), maximum sustainable yield (MSY), and open access (OA) using a bioeconomic model. The results are as follows; in the case of $E_{MEY}$, $E_{MSY}$, and $E_{OA}$ levels, $CO_2$ emissions are estimated at $150,704,746CO_2/kg$, $352,211,193CO_2/kg$, and $301,409,492CO_2/kg$ respectively. We show that the $E_{MEY}$ is more efficient than the other levels. That is, the level of $E_{MEY}$ signifies the optimal economic fishing usage as the most economically efficient usage for large purse seine fishery catching mackerel species. The emission of $CO_2$ in $E_{MEY}$ is the lowest level. Also, the impacts of climate changes such as ocean temperature increase, ocean acidification, and the combined impact thereof show that the biomass of mackerel decreases.