• 수산해양교육연구
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• 제26권5호
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• pp.1037-1043
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• 2014

We extensively observed macroalgal assemblages of species composition and biomass of summer benthic marine algae at Dokdo in the East sea of Korea. A total of 102 species (12 Chlorophyta, 36 Phaeophyta, and 54 Rhodophyta) were identified in quadrats and were analysed qualitatively to define the variation patterns. Biomass in dry weight according to various depths ranged between 146.0 to 764.2 g m-2 at study sites. Mean biomass at the investigated sites was greater in the 10m depth range than in the 5 and 15m depths at Dongdo. The flora could be classified into six functional groups: coarsely branched form (51.0%), filamentous form (17.7%), thick leather form (15.7%), sheet form (5.9%), jointed calcareous form (4.9%) and crustose form (4.9%). The R/P, C/P and (R+C)/P value were 1.67, 0.50 and 2.17, respectively. The number of marine algae species and the biomass in Dokdo area were markedly reduced as compared with those in the previous studies. This result suggests possible future changes in the algal vegetation, considering coastal marine environment of this area.

• Animal Systematics, Evolution and Diversity
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• 제32권1호
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• pp.1-8
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• 2016

Vermamoeba vermiformis is a very important free-living amoeba for human health in association with Legionnaires' disease and keratitis. This interesting amoeba was firstly isolated from a freshwater of Dokdo (island), which was historically used for drinking water. Trophozoites and cyst forms of V. vermiformis strain MG1 are very similar to previous reported species. Trophozoites of V. vermiformis strain MG1 showed cylindrical shape with prominent anterior hyaline region. The average ratio of length and width was about 6.5. Typically, cysts of the strain MG1 showed a spherical or slightly ovoidal shape with smooth wall, and lacked cyst pores. Some cysts had crenulate-walled ectocyst, which was separated from endocyst wall. Further, 18S rRNA gene sequence of V. vermiformis strain MG1 showed very high similarity to other V. vermiformis species (99.4%-99.9% identity). Molecular phylogenetic analysis based on 18S rRNA gene sequences clearly confirmed that the isolate was one strain of V. vermiformis with maximum bootstrap value (maximum likelihood: 100%) and Bayesian posterior probability of 1. Thus, the freshwater of Dokdo in Korea could harbor potentially pathogenic amoeba that may cause diseases in humans.

• Ocean and Polar Research
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• 제35권4호
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• pp.313-322
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• 2013

The concept of effective control is a crucial element for the acquisition as well as maintenance of territorial title. The general meaning of the concept has been described as 'an intentional display of power and authority over the territory, by the exercise of jurisdiction and State functions, on a continuous and peaceful basis'. The concept has been developed through some significant international cases such as the Island of Palmas case (1928), Legal Status of Eastern Greenland (1933), Minquiers and Ecrehos case (1953), Burkina Faso/Mali case (1986) and Nicaragua/Colombia case (2012). In relation to Dokdo, the concept has an important bearing in regard to Korea's claims of territorial sovereignty over the island. This paper reviews the definition, components and ramifications of the effective control with regard to the acquisition and maintenance of territorial title through analyzing the relevant judgements of international courts and tribunals. Furthermore, it exams the legal ramifications of the current effective control on Dokdo and makes some suggestions for the strengthening of Korea's position on the island.

• 한국패류학회지
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• 제24권3호
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• pp.199-203
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• 2008

독도에 서식하고 있는 연체동물 중 지금까지 알려지지 않았던 31 종을 2006년 4월부터 2008년 8월까지 국립수산과학원 '탐구5호'를 이용한 독도 수중생태계 잠수조사 과정에서 확인하여 이들이 독도의 연체동물상에 추가됨을 보고 한다. 따라서, 현재까지 알려진 독도 서식 연체동물은 총 106 종이 된다.

• 한국수산과학회지
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• 제45권6호
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• pp.716-722
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• 2012

The larval occurrence of the red snow crab Chionoecetes japonicus was investigated near Dokdo in the East Sea of Korea, and the larval timing of the genus Chionoecetes in world oceans was reviewed. C. japonicus larvae were collected seasonally at 12 stations in February, May, August, and November in 2011. A Bongo net with a 303 mesh was deployed with a double oblique tow. Larvae appeared from February to August, but no larvae were found in November. Zoea I occurred at nine stations with a few zoea II in February, and were found until August. The larval densities in February were high near the northern. In May, megalopa were found at eight stations with a few zoea II. No larvae were caught in November. The larval abundance in the research area peaked in February. Overall, the larval duration of the genus Chionoecetes in the world's oceans persisted for a long time, and Chionoecetes larvae occurred during the warm season in each area. The cold temperature at the sea bottom, where gravid females are found, may prolong larval production along the distribution range of the genus Chionoecetes.

• 식물병연구
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• 제18권4호
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• pp.381-386
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• 2012

독도 생태 연구의 일환으로 2008-2009년 2개년간 독도의 토양을 채집하고 선충의 종류, 밀도, 식이습성군, 생태지수 등의 연구를 수행하였다. 독도에서 총 31종의 선충이 발견되었으며 평균 밀도는 $m^2$당 239,500마리(26,000-836,000)였고 biomass는 $103.9mg/m^2$(3.0-388.6)였다. 중요도는 Acrobeloides 속이 Prominence value(PV) 117.8로 가장 높았고 다음으로 Rhabditidae(PV = 81.9), Prismatolaimus(PV = 39.0), Aphelenchoides(PV = 31.4) 순이었다. Feeding Group별로는 세균성선충이 전체 선충 중에서 밀도로는 77%, biomass로는 62%를 차지하여 가장 중요한 그룹이었고 다음으로는 식물기생성선충과 식균성선충류였다. 동도 참소리쟁이에서 발견된 뿌리썩이선충은 신종으로 추정된다. 독도 선충의 생태적 분석 결과 Shannon and Wiener 지수(2.46), Simpson's diversity 지수(0.86), 종 균일도(0.73), 종 풍부성(1.30)을 볼 때 독도의 선충상은 종이 풍부하고, 다양한 것이 특징이며, 독도만의 독특한 생태계를 유지하고 있다고 하겠고 이것은 경작되지 않고 자연 그대로 보존된 원시적 환경의 특징이다. 이번의 조사 결과는 독도의 생태적 모니터링에 기초자료로 활용되어질 수 있을 것이다.

• Ocean and Polar Research
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• 제24권4호
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• pp.491-500
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• 2002

Magnetic anomalies in the Dokdo and it's surroundings were investigated with respect to structure and origin of the Dokdo and surrounding seamounts. After normal and diurnal correction of measured magnetic data, crossover correction was applied to reduce errors between sets of magnetic anomalies. The errors from crossover operation result in decrease of about 51%, from 62.2 nT to 30.1 nT in standard deviation. Reduction-to-the-pole, second vertical derivative and analytic signal processing were applied to explore magnetic anomaly signatures in detail. Magnetic anomalies are most complicated in the 1st-Dok seamount, show SWW-NEE linear pattern in the 2nd-Dok seamount and lower to the 3rd-Dok seamount. Different magnetic anomaly patterns in three seamounts imply that three volcanic seamounts were formed at different times and are composed of rocks that were produced in different conditions. It seems that the 3rd-Dok seamount was first to form and followed by the 1st-Dok seamount. The complicated magnetic and second vertical derivative anomaly patterns in the 1st-Dok seamount may be due to subsidiary cones around crater or the presence of intruded magma bodies below sea surface and the Dokdo is probably a marginal subsidiary part of crater.

• 한국수산과학회지
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• 제42권5호
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• pp.503-508
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• 2009

We investigated species composition and variation of benthic marine algae between 2003 and 2006 at Dokdo on the East Sea. The total number of benthic algae species identified was 96, which included 15 Chlorophyta, 30 Phaeophyta, 50 Rhodophyta and 1 Spermatophyta species. The representative species in this study were Ulva pertusa, Caulerpa okamurae, Codium adhaerens, C. frgile, Undaria pinnatifida, Ecklonia cava, Eisenia bicyclis, Dictyopteris undulata, Padina arborescens, Sargassum horneri, Hildenbrandtia rubra, Lithophyllum okamurae, Amphiroa dilatata, Corallina officinalis, C. pilulifera, Prionitis cornea, Grateloupia elliptica, Plocamium telgairiae, Chondrus ocellatus, Chondracanthus intermedia, Chondria crassicaulis, Polysiphonia morrowii, Melobesioidean algae and Phyllospadix sp. Wet weight biomass according to various depths ranged between 1,094.8 to $2,595.3\;g\;m^{-2}$ during the study period. Mean biomass at the investigated sites was greater in the 15m depth range than in the 5 and 10m depths. Vertical distribution was characterized by Ulva intestinalis, U. linza, Endarachne binghamiae, Bangia atropurpurea, Gloiopeltis furcata and Chondria crassicaulis at intertidal zone, Amphiroa dilatata, Corallina pilulifera, Gelidium amansii, Eisenia bicyclis and Ecklonia cava at 2m depth, Ecklonia cava, Eisenia bicyclis, Padina arborescens, Undaria pinnatifida and Sargasum horneri at 5m depth, Ecklonia cava, Sargassum horneri and Padina arborescens at 10m depth, Ecklonia cava, Myagropsis myagroides, Padina arborescens and Sargassum horneri at 15m depth. The R/P, C/P and (R+C)/P value were 1.67, 0.50 and 2.17, respectively.

• 한국수산과학회지
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• 제48권6호
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• pp.929-939
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• 2015

We studied the characteristics of age and growth of the Goldeyes rockfish Sebasetes thompsoni in the Ulleungdo and Dokdo areas by using 730 otoliths from February 2013 to February 2014. The lowest value of the marginal index was found in June once a year. The spawning period was estimated as April. Therefore, the duration from fertilization to the complete formation of the first annual growth ring is fourteen months. From the parameters calculated using the weighted average length of the year ring formation, the growth of S. thompsoni was demonstrated by the von Bertalanffy growth equation as $L_t=34.68(1-e^{-0.2113(t+0.7683)})$ for females and $L_t=29.79(1-e^{-0.2163(t+1.7964)})$ for males, $L_t=32.84(1-e^{-0.25(t+0.57)})$ for combined sex. Comparing with growth performance index(${\Phi}$) from these 4 offshore areas, parameter of S. thompsoni in Ulleungdo area was 2.4087, that of in Tong-yeong was 2.2835, that of in Aomori was 2.4077 and in Niigata was 2.3927. As a result, the value of Dokdo and Ulleungdo areas showed the highest.

• Ocean and Polar Research
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• 제41권2호
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• pp.47-61
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• 2019

The Dokdo coast is known for its high biodiversity. However, few studies have examined the biodiversity and macrobenthic community on the subtidal soft-bottom. Therefore, we collected macrobenthos (> 1 mm) using a Smith-McIntyre grab ($0.1m^2$) at 15 stations along the Dokdo coast in September 2016. The sediments consisted of badly sorted (1.7) coarse sand with gravel and the mean sediment grain size was $-0.4{\phi}$. In total, 177 macrobenthic species were collected; their mean density was $1,566ind./m^2$. The number of species and density of macrobenthic fauna decreased significantly with the mean grain size. The dominant species were the amphipods Melita denticulata (16.5%) and Melita shimizui (5.5%), polychaete Salvatoria clavata (5.4%), bivalve Glycymeris aspersa (4.4%), and ophiuroid Ophionereis dubia (4.3%). The dominant macrobenthos species on the subtidal soft-bottom differed from the coastal areas of the East Sea, suggesting that the difference in the sediment grain size affected the macrobenthos. Cluster analysis was performed to divide the study area into four groups, and environmental factors which correlated with species composition and distribution in the study area were the combination of the four parameters of salinity, dissolved oxygen, total organic carbon and depth. A future seasonal investigation is needed to understand the species composition and characteristics of the Dokdo macrobenthos.