• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.4
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• pp.325-338
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• 2016

Properties of aggregation and spatial distribution of fish were examined based on three lines in the South Sea of Korea using three frequencies (18, 38, and 120 kHz) of a scientific echosounder. The vertical distribution of fish was displayed using acoustic biomass namely nautical area scattering coefficient (NASC). As a result, at 120 kHz high NASC showed from water surface to 20 meters in deep while at 18 and 38 kHz very high NASC presented in 70 ~ 90 meters in depth, especially at line 3. Among three lines, the line 2 had lowest NASC. The horizontal distribution of fish using three frequencies together exhibited high NASC between the eastern South Sea and center of South Sea. In especial, NASC ($801{\sim}1,920m^2/n{\cdot}mile^2$) was observed along coastal waters from Busan to Tongyeong, Geoje, and Namhae. In regard with the property of aggregation of fish schools, the volume back-scattering strength ($S_V$) of three lines presented close each other, however, the range of $S_V$ in the line 2 was shortest (-53.5 ~ -43.4 dB). The average distributional depth was deep in the order of L3 ($32.8{\pm}9.0m$), L1 ($45.2{\pm}9.5m$), L2 ($49.7{\pm}5.6m$). The average altitude was high in the order of L3 ($13.4{\pm}10.3m$), L1 ($17.0{\pm}12.6m$), L2 ($56.7{\pm}5.6m$). The average length, thickness, and area were large in the order of L1, L3, and L2. This means that small sized fish schools were distributed near water surface in the line 2 while relatively large and similar sized fish aggregations between line 1 and line 3 appeared however, fish schools at line 3 had lower distributional depth and smaller compared to those at line 1. Acoustic data were visualized for demonstrating the entire circumstances of survey area. Additionally, there was no correlation between acoustic and trawl results.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.243-250
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• 2002

According to Ocean Korea 21, a basic plan established by the Ministry of Maritime Affairs and Fisheries (MOMAF) of Korea in May 2000, Korea Research Institute of Ships and Ocean Engineering (KRISO) proposed a program for the development of a deep-sea unmanned underwater vehicle (UUV) to explore deep sea for scientific purpose. KRISO has launched a project in May 2001 under the support of MOMAF. The deep-sea unmanned underwater vehicle will be applied to scientific researches in deep-sea as well as in shallow water. For operation of underwater vehicles in shallow water near the Korean Peninsula, a special design is required because of strong tidal current. In addition, MOMAF requires the vehicle to be designed for the purpose of long range survey, a long-term observation, and precise works in a specific area. Thus, KRISO has planned to design the system with the functional combination of both ROV and AUV. This paper presents the design of the deep-sea unmanned underwater vehicle.

• Korean Journal of Plant Resources
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• v.25 no.3
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• pp.323-328
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• 2012

This paper describes the potential use of deep sea water to stimulate seed germination in both common and Tartary buckwheat. Treatment of 10% deep sea water at $25^{\circ}C$ would slightly enhance germination of buckwheat seeds compared to non-DSW treatment and other temperature. In this study, the significant effects of photoperiod and temperature on seedling growth were also found in the HL treatment for the number of leaf, plant height, and plant fresh weight and LL treatment for root length and leaf size. Common buckwheat (Suwon No.1) showed higher rate (93%) of flowering plants in the HS and LL (93% of flowering rates) than those revealed in the HS and LS treatment, while the low percentage(67%) of plant flowering plants was shown in the LS treatment. All plants (100%) of a Korean landrace, Ahndong-jaerae showed flowers in the HS and LS treatment. HL and LL treatment status did not occur in the plant's flowering. Any Tartary buckwheat (KW45) plant did not yet flowered when it was 21 days-old.

• Journal of the Optical Society of Korea
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• v.20 no.5
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• pp.547-556
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• 2016

A fishing lamp is the instrument for attracting distributed fish to a certain place, and is the lighting system mainly used in fishery. In the inshore fishing, most fishing lamps are used for squid and hairtail jigging fishing, and the light source of the fishing lamps mainly used is metal halide with 1.5 KW in electric power consumption. We will analyze the irradiance distribution according to depth because squid is attracted towards light. To analyze irradiance distribution by such fishing lamps, data for seawater Type-II among the seawater types defined in 1976 are applied to East Sea. However, the Type-II data have limitations in analyzing precise seawater transmission characteristics, due to insufficient information on deep seawater. This paper analyzed the irradiance distribution of fishing lamps using the measurement of transmission characteristics in the seawater in East Sea up to 100 m underwater instead of Type-II data, which is not sufficient for transmission. A compensation factor was drawn between the actual measurement data and Type-II data through seawater transmission characteristics simulation.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.3
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• pp.151-156
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• 2009

This study shows that the distribution density of snow crab, Chionoecetes opilio, was estimated using an underwater video monitoring system attached on the towing sledge. The field experiments were carried out at the coastal waters around Chuksan, East Sea, where ranged from 110 to 130m depth during September and October 2007. The sledge was towed for 40 minutes and the towing speed was controlled between 1.5 to 1.7 knot and each research areas were calculated to multiply towed distance by the detection width of the video monitoring system(1.2m), and then, distribution density of snow crab in each observations were estimated as a counted number of crab per 1,000$m^2$. The result shows that their survey, taken between two months, reflected similar results during survey period, and the maximum and mean distribution densities in September estimated to be 77.0(number/1,000$m^2$) and 19.9, respectively, and those of October were 36.0 and 21.8, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.4
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• pp.507-528
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• 2015

The Fish Collection Project collected 356 fish species from the Southern Sea of Korea during 2010-2012, 55 more than previously collected. The fishes belonged to 3 classes, 29 orders and 128 families. The 5 dominant orders, Perciformes, Scorpaeniformes, Pleuronectiformes, Tetraodontiformes, and Clupeiformes, accounted for ~80% of the identified species. Additionally, 126 species were collected from the Southern Sea for the first time, while 85 species that had been found in previous collections were not seen. The species variety of fish in the Southern Sea may be influenced by its unique oceanographic conditions such as increased water temperatures in coastal areas, so regular surveys would assist our understanding of the fish community. We suggest that various collection methods, including diving, be used to collect fish species inhabiting rocky shore or deep-sea areas, where commercial fishing gear is difficult to deploy.

• The Journal of Fisheries Business Administration
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• v.9 no.1
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• pp.1-27
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• 1978

The paper attempts to analize the economic situations of the coastal fishing business contering on the fishery right fisheries. Fisheries in Korea are usally divided in to three categories according to the distance fishing grounds; namely, coastal fisheries, off -shore fisheries and deep-sea fisheries. The fishery right fisheries fall into the category of the coastal fisheries, and include five typs of fisheries: 1. Class 1 common fishing 2. Class 2 common fishing 3. Class 3 common fishing. 4. Set-net fishing. 5. Aquarculture fishing. These fisheries have been stagnated mainly due to traditional fishing methods, unskilled labor forces, shortage of capital, and lack of the technological improvements. Owing to these factors their profitabilities of the fishing businesses have been steadly lowered. The main purpose of this paper is to point out the measures required in developing the fishery right fisheries. Economic performances were estimated for 1976 with data collected in the late 1977.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.178-186
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• 2003

Seasonal variation of phytoplankton was investigated with surface mixed layer ecosystem model in the East Sea. The model consisted of four compartments (phytoplankton, zooplankton, nutrient, detritus) forced by mixed layer depths, photosynthetically available radiation and nutrient concentrations. From model results we estimated entrainment rate $2.5-4.0\;m{\cdot}day^{-1}$ to reproduce the two annual blooms, and reproduced seasonal variation of phytoplankton at southern and northern regions by the difference of surface winter mixed layer depth (MLD) using the entrainment rate value $3.0\;m{\cdot}day^{-1}$. The spring blooms in the southern and northern regions closely related to deepening of a winter surface MLD. In the southern region where MLD was shallow and phytoplankton spring bloom occurs one month in advance to the northern region where MLD was deep. The amount of light increases within the MLD during the onset of stratification and water temperature increases faster in spring in the southern region than the northern region. Decrease of phytoplankton was mainly affected by zooplankton grazing in the southern region and by nutrient exhaustion in the northern region. The fall bloom in the two regions was caused by the nutrient availability and entrainment on the phytoplankton.

• Ocean and Polar Research
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• v.35 no.2
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• pp.123-125
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• 2013

According to the Intergovernmental Panel on Climate Change (IPCC), ocean warming and acidification are accelerating as a result of the continuous increase in atmospheric $CO_2$. This may affect the function and structure of marine ecosystems. Recently, changes in marine environments/ecosystems have been observed (increase in SST, decrease in the pH of seawater, northward expansion of subtropical species, etc.) in Korean waters. However, we still don't understand well how climate change affects these changes and what can be expected in the future. In order to answer these questions with regard to Korean waters, the project named 'Assessment of the impact of climate change on marine ecosystems in the South Sea of Korea' has been supported for 5 years by the Ministry of Oceans and Fisheries and is scheduled to end in 2013. This project should provide valuable information on the current status of marine environments/ecosystems in the South Sea of Korea and help establish the methodology and observation/prediction systems to better understand and predict the impact of climate/marine environment changes on the structure and function of marine ecosystems. This special issue contains 5 research and a review articles that highlight the studies carried out during 2012-2013 through this project.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.6
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• pp.341-350
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• 1988

The wind stress distribution over the East Sea of Korea was obtained from the shipboard observations of the Fisheries Research and Development Agency along the serial observation lines. These monthly and annual mean wind stress distributions were put into the simplified interface model which describes the latitudinal variations of the upper-layer thickness as function of the curl of the wind stress. The observed variations of the surface, zonally averaged winds indeed caused the upper-layer flow convergent and divergent at the latitudes that produced a tone of thick upper-layer or a deep permanent thermocline and the shallower depth with divergence. Thus, the wind field contributes positively to maintain the almost time-independent distribution of the interface of 'saddle like' feature in north-south direction over the study area.