• 수산해양기술연구
• /
• 제52권4호
• /
• pp.386-393
• /
• 2016

It is essential to provide good environment for juvenile fish to grow and spawn in order to keep reproduction mechanism of fisheries resources. However, harvesting juvenile fish deprives adult fish of the opportunity to reproduce, thereby changing self-regulating renewable resources into non-renewable ones and preventing sustainable harvesting as well as reducing fishers' income. We reviewed the catch status of Korea on juvenile mackerel and analyzed how reducing the catch ratio of juvenile mackerel may affect the spawning stock and Korean fishermen's revenue. In addition, we analyzed the problem of caching juvenile mackerel in Korean fisheries and current efforts to protect and reduce the catch ratio of juvenile mackerel in Korea. Furthermore, we suggested future efforts to protect juvenile mackerel. The result of the study showed that reducing the catch ratio of juvenile mackerel from 44.4% to 30.0% would increase fishers' revenue by 60.6 billion KRW. We suggest the changing of purse seine fishery's catching methods from night operation to day operation, relocation of fishing vessels to move to other fishing grounds when fishing vessels meet high density of juvenile mackerel, and consumers' clever choice of consuming adult mackerel in order to accelerate the move toward protecting juvenile mackerel in Korea.

• 수산해양기술연구
• /
• 제37권3호
• /
• pp.232-239
• /
• 2001

제주도 연안 정치망의 어획성능을 향상시키기 위한 어구구조개량과 조업방식의 생력화에 대한 기초자료를 제공할 목적으로 현재 제주도 연안정치망 어장에 부설하여 조업을 행하고 있는 각망어구와 낙망어구의 어획성능을 비교하기 위해서 두 어장의 3년(1997~1999년)간 어획량을 분석하였는데, 그 결과는 다음과 같다. 1. 1997~1999년까지의 3년간의 총어획량은 각망어구가 18.7톤 낙망어구가 36.5톤으로 낙망구의 어획량이 2배 정도 많았다. 2. 1997~1999년까지의 오징어, 전갱이, 독가시와 방어의 어획량은 전체적으로 각망어구보다 낙망어구의 어척량이 1.8배 정도 많았다. 3. CPUE는 각망어구에서는 전갱이가 10.01k 오징어가 20.5kg, 독가시치가 18.0kg 방어가 2.2kg이며 낙망어구에서는 전갱이가 57.5kg, 오징어가 30.0kg, 독가시치가 25.0kg, 방어가 4.7kg였는데 전반적으로 낙망어구의 CPUE가 높게 나타났다. 4. 유어율은 각망어구에서는 전갱이가 64%, 오징어가 79%, 독가시치가 39% 방어가 14%이고 낙망어구에서는 전갱이가 18%, 오징어가 85%, 독가시치가 40%, 방어가 14%로 전체적으로는 각망어구의 유어율이 높게 나타났으나 여기서의 어획량은 낙망어구가 높게 나타났다.

• 수산해양교육연구
• /
• 제24권2호
• /
• pp.137-145
• /
• 2012

In order to survey the conditions of bycatch and discards for a gape net, a series of filed surveys was carried out total 10 surveys on two gape nets operated in the coastal area of Jindo during July to November 2008. The all catches in each survey were measured the body length, weight after sorted species. The analysis of catch data was conducted to separate 'first operation' and 'general operation'. In this study, the first operation defined as hauling the fishing gears that soaked over 10 hours because of setting on the previous day. The general operation means the haul of fishing gears conducted at intervals of one of or two hours after first operation. The bycatch in this study is defined as the other species except for anchovy, and bycatch rate refers to the proportion of bycatch to total catch. From the survey results, the average bycatch rates on first operations were 50% and 51% for Masa-ri and Supum-ri areas in Jindo, respectively. Also, the average bycatch rates on general operation were 2% and 3% for Masa-ri and Supum-ri areas in Jindo, respectively. The proportion of anchovy to total catch caught represented 75.5%. It needs the research on the selective fishing technology to reduce the bycatch on the gape net fishery.

• 수산해양기술연구
• /
• 제47권3호
• /
• pp.183-193
• /
• 2011

This study made a comparative analysis of behavioral reaction of squid to red (624nm), green (524nm), blue (460nm) & white LED light, its arrival time for the shadow section by making the shadow section in the central section of a water tank just like the bottom part of a squid jigging vessel, and on-site catching efficiency of LED fishing lamp with control fishing vessel. The color LED light showing the highest squidgathering rate as against the shadow section was found to be blue LED light with 39.3% rate under the dark (0.05lx) condition. Under the brighter condition than 0.05lx, white LED light was found to have the highest gathering rate of 41.5%. In addition, it was found that squid gathering rate was high at the shadow section which showed 6.3-fold brightness difference between the shadow section and bright section. As for the arrival time for the shadow section, blue LED light was found to be the fastest in attracting squids in 192.7 seconds under the dark condition while the red LED light was the fastest in luring squids in 164.6 seconds under the bright condition. The ratio of the squid-jigging operation and sailing in fuel consumption of the fishing vessel loaded with LED fishing lamp is about 7 to 1, showing most of the fuel is consumed more in sailing than in squid-jigging operation. As for a catch of squid, the control vessel loaded with MH (Metal Halide) fishing lamp had more catch of 600-7,080 squids than the vessel loaded with LED fishing lamp having a catch of 260-1,700 squids. In addition, even in the comparison of a catch per automatic jigging machine, the catch of the vessel loaded with MH fishing lamp excelled that of the vessel loaded with LED fishing lamp in 6 operations of squid jigging out of 9 operations. The ratio of hand-jigging and automatic jigging machine (one line) in the LED fishing lamp vessel was 1:1.1 excepting the case of having a catch only using an automatic jigging machine, showing almost the same with each other in catches, while in case of a MH fishing lamp vessel, its ratio against hand-jigging was 1 to 5.8, showing hand-jigging excelled in catches.

• 수산해양기술연구
• /
• 제41권3호
• /
• pp.188-198
• /
• 2005

This study was conducted to survey the catches of vertical bottom longline fisheries in the sea mount of central northern Pacific($30^{\circ}-42^{\circ}N$, $170^{\circ}-175^{\circ}E$), during the period of July 1 to August 25,2004 by commercial fishing vessel. The number of 57 test fishing was carried out in the central northern Pacific during 43 days and the total catches were 21,092.4kg as 19 fish species, CPUE/day and catches/day were 185 baskets and 490.5kg, respectively. Main fish species caught from the experimental fishing were Squalus mitsukurii (66.3%), Coelorhyrchus asperocephaius (11.7%) and Helicolenus avius (9.8%) and, average inside diameter for fish mouth was 4.0cm over. Catch ratio according to each fishing ground was the order of F, D, J, B and C. Catch ratio fur water depth was the order of 450-500m, 350-400m, 300-350m, 400-450m, 1000-1100m and 500-550m and, main species by water depth was Squalus mitsukurii for 300-400m, Etmopterus lucifer for 300-550m, Coelorhyrchus asperocephaius far 1,000m over. Catch ratio according to the kind of hooks was higher at the hook no.6 for Squalus mitsukurii and no. 5 for Etmopterus lucifer and, catch ratio by baits was higher at squid for Squalus mitsukurii, saury and eel for Helicolemus avius and saury for Etmopterus lucifer. Accordingly, it is thought that the extension of fishing hours is needed with the reduction of damage and loss for fishing gears during fishing operation.

• 수산해양기술연구
• /
• 제50권3호
• /
• pp.396-406
• /
• 2014

Shrimp beam trawl fishery is one of the important coastal fisheries in Korea. It has a regulation to the length of beam (8m) and wing net (7m) of shrimp beam trawl that has been used in the district of Junlanam-do and Gyungsangnam-do. This regulation was made in relation to the size of shrimp beam trawler of 3-ton class at that time. Now the shrimp beam fishing vessel has a limit not greater than 5 tons in gross ton. Recently, with improvement of fishing industry and fishing vessel fishermen asked the expansion of the length of beam and wing net, therefore it is necessary to investigate the effect of lengthening the beam and wing net length. Three different beams (8m, 10m and 12m in length) and three different wing net (7m, 10m and 13m in length) were made and the experiment was conducted near Narodo of Goheng by two fishing vessels of 4.98 and 4.88 tons in gross ton between June 2011 and October 2012. When the length of wing net was increased from 7m to 10m and 13m, the relative catch ratio in total biomass was increased 25% and 79% for shrimp, (17% and 22% in total), respectively. And when the beam length was increased from 8m to 10m and 12m, the relative catch ratio was increased 35% and 84% for shrimp, (21% and 37% in total), respectively. The force exerted to the iron guide of inhauler's with the beam length of 8m was about 30% greater than that with the beam length of 10m when hauling the shrimp beam trawl net.

• 수산해양기술연구
• /
• 제27권4호
• /
• pp.247-254
• /
• 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
• /
• 제54권4호
• /
• pp.279-286
• /
• 2018

The objective of this study was to quantitatively evaluate the influence of the netting hanging ratio on fishing performance of gillnet. A total of six tests was carried out using three kinds of gillnets with different horizontal hanging ratios (0.3, 0.5 and 0.7) on the basis commercial gillnet of mesh size of 60 mm used in Yeosu Dolsan. As a result of the test fishing operation, catches of the net with hanging ratio 0.3 and the shortest float length was 1.34 times larger than the net with hanging ratio 0.7. The caught species in experimental testes was lager in the net with hanging ratio 0.3 than the net with hanging ratio 0.7. The catch rate per unit area (CPUE) is on the silver croaker with the largest catches in tests as follows. The net with hanging ratio 0.3 net was $89.45g/m^2$, hanging ratio 0.5 net was $41.63g/m^2$, and hanging ratio 0.7 net was $24.50g/m^2$. The net with hanging ratio 0.3 (float line length of 45 m) exhibited the largest CPUE value.

• 한국자동차공학회논문집
• /
• 제2권2호
• /
• pp.42-48
• /
• 1994

Turbocharging is one of the best methods to improve the performance of diesel engines, because of its merits,-power ratio, fuel consumption and exhaust emissions. Most of them in small and medium diesel engines have adopted the pulse turbocharging method with twin entry vaneless radial turbines to maximize the energy utility of exhaust gas. This method requires the high performance of turbine under unsteady flow, and also the matching between turbine and diesel engine is most important. However, it is difficult to match properly between them. Because the steady flow data are usually used for it. Accordingly, it is necessary to catch the characteristics of turbine performance correctly over the wide range of the operation conditions under unsteady flow. In this paper, the characteristics of turbine performance under unsteady flow are represented at varying conditions, such as inlet pressure amplitude, turbine speed and frequence.

• 경영과정보연구
• /
• 제22권
• /
• pp.137-165
• /
• 2007

It seems high time to increase productivity by adopting e-business to overcome challenges posed by both external factors including the appreciation of Korean won, oil hikes and fierce global competition and domestic issues represented by disparities between large corporations and small and medium enterprises (SMEs), Seoul metropolitan and local cities, and export and domestic demand all of which weaken future growth engines in the Korean economy. The demands of the globalization era are for innovative changes in businessprocess and industrial structure aiming for creating new values. To this end, e-business is expected to play a core role in the sophistication of the Korean economy through new values and innovation. In order to examine business performance in e-business-adopting industries, this study analyzed the home shopping industry by closely looking into the financial ratios including the ratio of net profit to sales, the ratio of operation income to sales, the ratio of gross cost to sales cost, the ratio of gross cost to selling, general and administrative (SG&A) expense, and return of investment (ROI). This study, for best outcome, referred to corporate financial statements as a main resource to calculate financial ratios by utilizing Data Analysis, Retrieval and Transfer System (DART) of the Financial Supervisory Service, one of the Korea's financial supervisory authorities. First of all, the result of the trend analysis on the ratio of net profit to sales is as following. CJ Home Shopping has registered a remarkable increase in its ratio of net profit rate to sales since 2002 while its competitors find it hard to catch up with CJ's stunning performances. This is partly due to the efficient management compared to CJ's value of capital. Such significance, if the current trend continues, will make the front-runner assume the largest market share. On the other hand, GS Home Shopping, despite its best organized system and largest value of capital among others, lacks efficiency in management. Second of all, the result of the trend analysis on the ratio of operation income to sales is as following. Both CJ Home Shopping and GS Home Shopping have, until 2004, recorded similar growth trend. However, while CJ Home Shopping's operating income continued to increase in 2005, GS Home Shopping observed its operating income declining which resulted in the increasing income gap with CJ Home Shopping. While CJ Home Shopping with the largest market share in home shopping industryis engaged in aggressive marketing, GS Home Shopping due to its stability-driven management strategies falls behind CJ again in the ratio of operation income to sales in spite of its favorable management environment including its large capital. Companies in the Group B were established in the same year of 2001. NS Home Shopping was the first in the Group B to shift its loss to profit. Woori Home Shopping has continued to post operating loss for three consecutive years and finally was sold to Lotte Group in 2007, but since then, has registered a continuing increase in net income on sales. Third of all, the result of the trend analysis on the ratio of gross cost to sales cost is as following. Since home shopping falls into sales business, its cost of sales is much lower than that of other types of business such as manufacturing industry. Since 2002 in gross costs including cost of sales, SG&A expense, and non-operating expense, cost of sales turned out to have remarkably decreased. Group B has also posted a notable decline in the same sector since 2002. Fourth of all, the result of the trend analysis on the ratio of gross cost to SG&A expense is as following. Due to its unique characteristics, the home shopping industry usually posts ahigh ratio of SG&A expense. However, more than 80% of SG&A expense means the result of lax management and at the same time, a sharp lower net income on sales than other industries. Last but not least, the result of the trend analysis on ROI is as following. As for CJ Home Shopping, the curve of ROI looks similar to that of its investment on fixed assets. As it turned out, the company's ratio of fixed assets to operating income skyrocketed in 2004 and 2005. As far as GS Home Shopping is concerned, its fixed assets are not as much as that of CJ Home Shopping. Consequently, competition in the home shopping industry, at the moment, is among CJ, GS, Hyundai, NS and Woori Home Shoppings, and all of them need to more thoroughly manage their costs. In order for the late-comers of Group B and other home shopping companies to advance further, the current lax management should be reformed particularly on their SG&A expense sector. Provided that the total sales volume in the Internet shopping sector is projected to grow over 20 trillion won by the year 2010, it is concluded that all the participants in the home shopping industry should put strategies on efficient management on costs and expenses as their top priority rather than increase revenues, if they hope to grow even further after 2007.