• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.960-968
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• 2015

This study examined the spatiotemporal distribution of demersal fish aggregations in the Northern East China Sea by conducting a trawl survey with hydroacoustic devices. A bottom trawl was used for this survey and fish density was determined from the catch data. Acoustic data were collected at frequencies of 38 and 200 kHz from November to December 2014 and converted into the nautical area scattering coefficient (NASC, $m^2/n{\cdot}mile^2$). In the catch data analysis, the range of catch per unit area by station was $26-8,055kg/km^2$ and for the acoustic data, that of the NASC was $0.45-34.80m^2/n{\cdot}mile^2$. The values were significantly correlated. The combined results of both surveys found that the density was highest at St. 5 ($33^{\circ}$ 10.3', $126^{\circ}$ 23.3') and lowest at St. 8 ($33^{\circ}$ 20.7', $127^{\circ}$ 36.3'). The application of hydroacoustic methods offers a new approach for estimating the biomass of demersal fish aggregations.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.499-505
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• 2011

The fishing grounds of Korean large-pair trawlers have shifted since exclusive economic zones (EEZs) were established in a fisheries agreement involving countries neighboring Korean waters. The distributions of marine ecosystems and fisheries resources have been changing with environmental changes such as global warming and with the shift in species targeted as a result of changes in fishing technology and fishing gear. This study analyzed variation in the species assemblages caught in Korean waters by large-pair trawlers as a result of these geopolitical and environmental changes. The data used in this study were obtained from the Fishery Production Statistics of Korea and the Port Sample Survey of the National Fisheries Research and Development Institute (NFRDI) from 1990 to 2007. Hierarchical clustering analysis (HCA) and correspondence analysis (CA) were used to explore the characteristics of the catch-species composition. The overall variation in the species composition of the catch of Korean large-pair trawlers showed that the proportions of croaker Johnius grypotus, small yellow croaker Larimichthys polyactis, eel Anguilla japonica, and blue crab Portunus trituberculatus decreased, whereas those of hairtail Trichiurus lepturus, Spanish mackerel Scomberomorus niphonius, anchovy Engraulis japonicus, and common squid Todarodes pacificus increased in Korean waters over the 18-year period. The results of the HCA of the annual catch data by species showed four different distributions of fish species according to year. Results of the CA showed that the species assemblages differed between the 1990s and 2000s.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.173-178
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• 1969

Few reports have been written regarding the measurement of stern trawler warp tension under conditions of a full catch. This report compares the tension imposed on the warps at the time the boat begins to tow the net and the tension at the time the cod end is filled with a large quantity of fish. The structure of the otter boards and trawl net used for the experiment was the same types as used by Koyama, Sakurai, and Sumikawa (1968). The warp tension was measured with a load cell tension meter. 3) This meter continuously records the tension on a pen oscillograph. The net towing speed was measured with the CM-lA type current meter, Toho Dentan Co. Ltd., Japan. The data collected in the experiment are shown in Table 1. This table indicates that shooting No. 2 and No. 11 show a large catch volume, and the types of fish caught are shown in Table 2. The tension meter recordings when the boat began to tow the net and when the cod end was filled with a large quantity are shown in Fig. 1 and Fig. 2. It is indicated that the barracouta Thyrsites atun (EUPHRASEN) causes little tension difference between the time before they enter the net and the time after they enter the net before hauling. Other types of fish influence tension similarly. According to these results, the warp tension measurements as recorded on a big stern trawler are more influenced by rough sea wave action than by the volume of fish caught.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.740-746
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• 2010

This study standardized the catch per unit effort (CPUE) of bigeye tuna (Thunnus obesus) caught by the Korean longline fishery in the Pacific Ocean. The study used a general linear model (GLM) to standardize the CPUE using catch and effort data aggregated by year, month, and $5{\times}5$ degrees of latitude and longitude in the tropical Pacific Ocean from 1982 to 2008 (except for 1988 and 1989). Explanatory variables in the GLM analysis included year, month, subtropical area, and number of hooks between floats (HBF). The study area and HBF were subdivided into three subtropical areas and six classes, respectively. During the study period, the standardized CPUE was significantly related to the nominal CPUE. The standardized CPUE declined sharply, as compared to the nominal CPUE, after the mid 1990s. In particular, the decline in the standardized CPUE in all subtropical areas in the 2000s was clearer than that of the nominal CPUE.

• Proceedings of the Technology Innovation Conference
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• 2004.02a
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• pp.288-315
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• 2004

This paper has examined the leapfrogging thesis with the case of catch-up in digital TV by the Korean firms. Despite the disadvantages implied by the technological regime of digital TV and the risks facing early entrants in trajectory choice and initial market formation, the Korean firms had achieved a 'path-creating catch-up' in the sense they chose a different path from the Japanese forerunning firms. As they have been closely watching the technological trends and the standard setting process, there was less risk of choosing the right or wrong technological trajectory. Also, despite the lack of sufficient capability and core knowledge base, the Korean firms had some complementary asset, such as the experience of producing analogue TV, and were able to develop the prototype digital TV and the ASIC chips, given the accesses to the foreign knowledge via overseas R&D posts and acquisition of a foreign company. To secure the initial market size, the Korean targeted the US market from the beginning, and their sources for competitive advantages were the speedy setting up the production system for mass production of products at the initial stage. The initial failure of the Japanese firms and the success of the Korean firms do suggest that the period of paradigm shift, like this toward digital technology, can serve as a window of opportunity for late-comers while penalizing the forerunner.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.3
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• pp.223-234
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• 1996

Distribution of Anchovy was analyzed from the experimental operations by the small anchovy drag net fishery in the coastal area of Yang yang - gun and Myongju - gun of Kangwon Province from October to December, 1994. Temperature ranged from $11.4^{\circ}C.$to $17.4^{\circ}C.$throughout the experimental period. Fishes caught by experimental operation vessels were composed of anchovy, Clupanodon Punctatus, Pleuronectidae, Tetraodantidae, Acanthopagrus Schlegeli etc., and the anchovy occupied more than 99.6% of the total catch. Anchovy was characterized by the most abundance of the catch for the individual less than 6cm and the gradual increase after October for those larger than 6cm. CPUE(catch per tow) of anchovy was 684kg in October, 784kg in November, 1,590kg in December and mean CPUE of 3 months from October to December was 1,066kg. Fishing grounds of anchovy were formed in coastal area, from $37^{\circ}$45'N to $38^{\circ}$04'N, off Kangwon Province. Distribution density of anchovy in Chumunjin - up, Kyohang - ri Sachon - myon, and Sachonjin - ri coasts was higher than the other areas. Anchovy caught in this surveyed area was recruited from July to September at the length class between 2cm and 3cm, and grew to the sizes between 4cm and Bem in October, between 5cm and tcm in November, between tcm and Bem in December. Recruitment of anchovy increased from July to September and suddenly decreased after September. Individual number of the population was the largest during the period from August to October and gradually decreased after October. Biomass continuously increased after August, and was the largest in December.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.1159-1170
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• 2016

This study examines the distribution and taxonomy of sea horses in South Korea, specifically sea horses that were caught in the Southern Sea, centering on Yeosu, South Korea. Specimen collection methods The samples were collected by set net, skimming nets, dragnets, and landing nets on a boat, as well as scuba diving. A total of 128 sea horses belonging to three species were collected. To investigate the exact distribution pattern, the catch per unit effort and the population density per $1,000m^2$ were calculated for each site in the Southern Sea. The result shows the highest catch by set nets was 29 sea horses a day in Site B at Dolsan-eup, Port Impo, and the highest catch by scuba diving was 8 sea horses a day in Site B at Gijang-gun, Busan. The highest population density was 61.2 sea horses in the coast of Gijang-gun, Busan. Genetic information analysis and morphological analysis were performed for determination of species. As a result, four Hippocampus trimaculatus, (flat-faced sea horses), 45 Hippocampus coronatus (Crowned sea horses), and 79 Hippocampus mohnikei (Japanese sea horses) were distinguished.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.161-167
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• 2006

The citrus leafminer (CLM), Phyllocnistis citrella Stainton, is an oligophagous pest of Rutaceae family, especially Citrus spp. occurring in most worldwide citrus-growing areas. This study was conducted to evaluate a sex pheromone chemical of CLM, (Z,Z)-7,11-hexadecadienal (7Z,11Z-16:Al) in monitoring CLM by trap types, the diel activity and the influence of some weather factors on trap catch. CLM was well attracted on a trap baited 7Z,11Z-16:Al 1mg. Sticky wing trap was more effective than bucket trap. Most caught CLM were attracted at 2$\sim$6 a.m. regardless of season, and activity time of CLM was affected by sunrise time as well as sunset time. The trap catch of CLM was more influenced by wind velocity than temperature for activity time of CLM. The number of caught CLM was fallen at below 13$^{\circ}C$, but there was little effect for trap catch at over that temperature. The average wind velocity at over 2.0 m/sec made the number of caught CLM drop down. The precipitation did not affect the number of caught CLM when the average wind velocity was lower than at 2.0 m/sec.

• Journal of Fisheries and Marine Sciences Education
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• v.15 no.2
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• pp.166-175
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• 2003

In order to offer fundamental data for the standard of comfilation of the budget on the compensation money for the reduction of fishing baot and index of investigation for computation on the average earnings of reduction of fishing boat, the fluctuation of actual outputs, expenses, earnings and the difference by type of coastal and off-shore fishery was investigated and analyzed. The results are as follows : 1. The average ouput money by large powered purse seine fishery was much with about 3,510 million won, but the average output money by off-shore gill nets fishery was little with about 8.4 million won. 2. The average catch by large powered purse seine fishery was many with about 296,000 M/T, but the average catch by eastern sea danish seine fishery was few with 4,600 M/T. 3. The average expense by large powered purse seine fishery was much with about 3,360 million won, but the average expense by diving fishery was little with 6.3 million won. 4. The average earning by large powered purse seine fishery was much with about 240million won, the average earning by offshore long line fishery was little with 18 million won. 5. The average earning rate by diving fishery was much with 31.62%, but the average earning rate by large powered purse seine fishery was little with 7.30%.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.22 no.4
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• pp.61-70
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• 1986

In accordance with a rapid growth of demani on aquatic animals, researches of the unused fishery resources On the deep sea b~d in the Korean Waters has been and will be required. The authors carried out a series of fishing experiments to investigate the available resources and to find the effective fishing method on the deep sea bed of the Korean East Sea. In the experiments, 19 kinds of traps which are different from each other in shape, mesh size and entrance diameter were used. The fishing experiments w~r;; carried out in four areas of 20Dm, 600.'11, 800m and 1000.'11 deep respectively, by the Pusan 402 (30:) GT) and the Pusan 403 (279GT), the training ships of National Fisheries University of Pusan, during August, 1986. The catc~ were analyzed with the size, the depth and the construction of traps. The results obtained can be summarized as follows: 1. Main species of the catch w~re pink shrimp, Pandalus bolelis, a kind of welks, Buccimum striatissimum and a kind of larg~ crabs. Chiono8cetes japonicus and the another species were few. 2. The CPUE value (expressed by the number of catch per trap in this paper) of pink shrimp was the highest in the depth of 20J-n around, and the value in the depth of 600.'11 or more decreased gradually with an increase of the depth. But, the value of Buccimum straitissimum was much higher in the depth of 6:J:)!1I or more than that in the depth of 200m around. On the other hand, the value of Chion:Jecetes japonjcus was very low in general. 3. The iniividual body size of the catch differed with the depth. Pink shrimps caught in the depth of 200m around were smaller than those in the depth of 600.'11 or more. In contrast with this, Baccimum striatissim:t.m caught in the depth of 200m around were larger than those in the depth of 600.'11 or more. 4. Depending on the selection curve in Ishida's method for the mesh size of trap webbing, the carapace length of pink shrimp and the shell length of Buccimum striatissimum which are equivalent to 100% relative catching efficiency can be estimated about 3.5cm and 6.5cm or so respectively. 5. The number of catch of pink shrimp and Buccimum striatissimum by the 60.'1'1.'11 entrance diameter of trap were less than that by the 90mm, 120mm and 150mm, even thogh the diffierence am~r, g 9:Jmm, 120.'11.'11 and 150:1'.'11 are not so large.