• Fisheries and Aquatic Sciences
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• v.25 no.11
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• pp.549-558
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• 2022

The Indonesian Archipelago has a very complex geological history, along with equatorial warm sea temperature, resulting in diverse types of coral reefs and high diversity of coral reef fish. Many livelihoods of the coastal community are dependent on coral reef fisheries. The present study aimed to determine which region and location in the Indonesian Archipelago has the most diverse and abundant coral reef fish. The archipelago was divided into four regions: the Indian Ocean, Sunda Shelf, Wallacea, and the Pacific Ocean. Data were obtained from a national coral reef monitoring program of the Indonesian Research Center for Oceanography (RCO)-the National Board for Research and Innovation (BRIN). The reef fish data were collected using the underwater visual census method, from 321 belt transects on 24 locations (districts) across the archipelago. The results show that coral reef fish diversity of the Pacific region was the highest across the archipelago for all three trophic levels, i.e., corallivore, herbivore, and carnivore fish. The Pacific Ocean region also had the highest fish abundance for the three trophic levels. Comparison among locations revealed that the best ten locations in reef fish diversity and abundance were Sabang, Mentawai, Makassar, Selayar, Buton, Luwuk, Ternate, Raja Ampat, Biak, and Wakatobi. Wakatobi reefs showed their supremacy in carnivore fish diversity and abundance, while Biak reefs were the best in herbivore fish. The abundance of corallivore fish was also considerably high in Sabang reefs, but it is still lower than in Raja Ampat, Biak, and Wakatobi reefs. These results provide empirical evidence that the coral reefs of Wakatobi and Biak are the hottest hotspots of coral reef fish diversity and abundance in the Indonesian Archipelago.

• Ocean and Polar Research
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• v.30 no.4
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• pp.519-536
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• 2008

The relatively tranquil area within the Gogunsan Archipelago was for the first time investigated preliminarily with respect to modern sedimentological processes in association with the emplacement of the Saemangeum Dyke. Basic sedimentological observations, bathymetry and surface sediments were performed twice during 2006-2008 to compare the results and elaborate changes during that period of time. In addition, sediment dynamical observations were carried out with latest measuring equipment along two transects crossing the entrances of the archipelago, including 12-hour onboard measurements of current, suspended sediments, temperature, and salinity. This dataset was used to reveal hydrodynamic characteristics for spring season April-May and to estimate the direction and relative magnitude of the net flux of suspended sediments. There occurred three depositional areas (A to C) within the archipelago, where sediment texture was also changed. In area A, around Yami Island and the dyke, and area B, in the center of the archipelago, surface sediments became coarsened over the two-year period; sand content increased 5% at the expense of silt content in the former, whereas silt content increased 3% at the expense of clay content in the latter. By comparison, area C in the western entrance of the archipelago shows a textural trend of fining with more silt and clay (combined increase of 5%) at the expense of sand content. The accumulation of sediments in areas A and B is attributable to the sand and silt resuspended from the seabed sediments off sector 4 of the dyke during the winter. The origin of the fine materials depositing on area C is uncertain at present, although suspended sediments moving offshore around the archipelago may be one of the most likely candidates for the source. The temperature of seawater increased rapidly from $9-10^{\circ}C$ in April to $14-16^{\circ}C$ in May, whereas salinity remained more or less constant at 31-32%o during the two months. Both of these parameters showed little variations with depth through a tidal cycle, suggesting good mixing of seawater without any help of significant waves. The consistency of salinity during a tidal cycle also indicates no insignificant effects of freshwater from the rivers Mangyung and Donjin emitting through the opening gap near Sinsi Island. The suspended sediment concentrations were higher at the entrance between Sunyu and Sinsi islands than at the entrance between Hoenggyong and Sinsi islands, ranging from 20 and 30 mg/l and from 5 and 15 mg/l, respectively at the sea surface. Although tidal currents were variable across a transect between Sunyu and Sinsi islands, the currents across the entrance between Hoenggyong and Sinsi islands flowed consistently in the same direction all over the transect during a tidal cycle. The estimation of net flux of suspended sediments indicates that suspended sediments are transferred to the Gogunsan Archipelago mainly through a relatively deep trough adjacent to Sinsi Island toward the shallow area around Yami Island and the dyke.

• Journal of Navigation and Port Research
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• v.30 no.3 s.109
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• pp.253-258
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• 2006

In this paper, we analyse the marine leisure base condition of the archipelago at the southwest sea area which has the natural advantage for marine leisure. We also discuss how to adapt the yacht business on the above area. At first, we analyse the current situation of the domestic marine leisure and draw up a plan to solve its problem. Finally we apply an environment friendly marina establishment to the archipelago at the southwest sea area and evaluate its validity.

• ALGAE
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• v.28 no.3
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• pp.267-280
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• 2013

The marine algal flora of the Keret Archipelago ($66^{\circ}$ N, $33^{\circ}$ E) in the White Sea, Russia was investigated during 2008. Over 250 algal records from more than 15 islands and several sites on the adjoining mainland produced a total of 62 algal species. This raised the total from 56 to 88 species of Chlorophyta (23 species), Phaeophyceae (31 species), Rhodophyta (33 species), and Tribophyceae (1 species) of which seven were new records or verifications of ambiguous records for the White Sea and 11 species are new for the Keret Archipelago. The new or confirmed records included species of Blidingia, Eugomontia, Prasiola, Rosenvingiella, and Ulothrix (Chlorophyta), Acrochaetium, Colaconema (Rhodophyta), and Vaucheria (Tribophyceae). Five species of flowering plants (Aster, Plantago, Triglochin, and Zostera) were associated with the macrophytic algal vegetation of the region. Five fucoid algae in Pelvetia, Fucus, and Ascophyllum provide a picture of a temperate flora. Regardless, the overall species richness is consistent with an arctic nature to the flora. This discrepancy is attributed to the 'filter' provided by the Barents Sea of the Arctic Ocean for post-glacial colonization of the White Sea.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.1
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• pp.23-31
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• 2022

The analysis of seven islands in Gogunsan archipelago, Korea with insect fauna and vascular plant flora was carried out based on a field survey conducted in May, July, and September. As a result, a total of 2,817 insect individuals including 264 species and 315 taxa of vascular plant were recorded. Bangchukdo the largest island among the seven islands showed the largest number both insect species and plant taxa. The similarity analysis suggested that the nearness of each island strongly affected the insect fauna and vascular plant flora on each island. In addition, there was significant correlation between the areas of each island and the numbers of insect species (Spearman's correlation coefficient=0.857, P-value=0.014). In the future, the results of this study can be used as data related to island ecology and conservation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.179-187
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• 2018

In order to understand the flow of currents around Aphae Island and the surrounding Archipelago, the numerical model experiments on tidal currents and tide-induced residual currents were carried out. Dominant semidiurnal tidal currents have a reversing form and flow along the narrow channels of the archipelago. During periods of flood, currents flow from the west of Hwawon Peninsula to the archipelago to the northwest together with the currents flowing from the channels at Palgeum Island to Amtae Island and Amtae Island to Jeung Island. Ebb currents flow from the northwest archipelago to the channel of Amtae Island and Jeung Island as well as Amtae Island to Palgeum Island, further flowing south between Palgeum Island and Hwawon Peninsula. Flood currents are separated from east and west at the southern coast of Aphae Island, but flow south from both the west and east of Aphae Island to the channel found between Palgeum Island and Hwawon Peninsula at ebb. Flow speed is high between Amtae Island and Aphae Island where the flows meet and join. Lee wakes or topographical eddies are formed around the islands due to the high speed of the currents flowing along the narrow channel in the archipelago, manifesting as a tide-induced residual current. A weak cyclonic wake and anti-cyclonic eddy both exist at the west and northwestern coast of Aphae Island individually. The speed of the tide-induced residual current become slow on account of the wide littoral zone at exists around Aphae Island.

• The Korean Journal of Ecology
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• v.13 no.4
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• pp.343-359
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• 1990

Phytosociological investigation of the forest vegeation was carried out in Kumo archipelago at the period of May 21th 1990 to May 29th 1990 by Braun-Blanquet's method. The forest vegetation was classified into 7 communities, Camellia japonica, Castanopsis cuspidata var. sieboldii, Machilus thunbergii, Camellia japonica-Pinus thunbergii, Camellia japonica-Torreya nucifera, Carpinus coreana and Quercus acutissima community. Based on the classification of communities, the actual vegetation maps were drawn in 1 : 50,000 scale.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.197-202
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• 2004

In this paper, we tackled the marine leisure business of the archipelago at the southwest sea area which has the natural advantage for marine leisure. We also discuss how to adapt the yacht business on the above area. At first, we will introduce the predominant case on the marine leisure business of the overseas. Next we will analyze the current situation of the domestic marine leisure and draw up a plan to solve its problem. Finally we apply an environment friendly marina establishment to the archipelago at the southwest sea area and evaluate its validity.

• Molecules and Cells
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• v.21 no.1
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• pp.89-103
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• 2006

Population structure was investigated in Reticulitermes speratus populations in the Korean Peninsula and the Japanese Archipelago. All trees derived from analyses of the combined sequence dataset of two mitochondrial genes, COII and COIII, showed that R. speratus populations cluster into two major clades comprising the Korean/southern Japanese populations and the northern Japanese populations. Analysis of population genetic structure showed strong genetic partitioning between populations of the two clades. To understand historical migration routes and current distributions, the phylogeographic history of R. speratus was inferred from intra-/interspecific phylogeny and divergence times estimated between the clades of the phylogenetic tree. The estimated migration route and divergence time of ancestral R. speratus are congruent with recent paleogeographic hypotheses involving land-bridge connections between the Asian continent and the Japanese Archipelago. We suggest that ancestral R. speratus separated into northern and southern Japanese populations after its migration into the Japanese main islands from East China during the early Pleistocene via the East China Sea basin, which may have been exposed during that period. The Korean populations seem to have diverged recently from southern Japanese populations; this may explain the current distribution of R. speratus in the Japanese Arachipelago, and account for why it is restricted to northern areas of the Tokara Strait.

• The Korean Journal of Ecology
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• v.13 no.3
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• pp.181-190
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• 1990

Chodo Archipelago ($125^{\circ}$45 $-126^{\circ}$13 E and $34^{\circ}$15 $-34^{\circ}$25 N, ca. $56.7km^2$), a part of the Dadohae National Marine Park, largely is covered with substitutional vegetation under various human impact such as grazing, cutting for firewood. However natural vegetation is partially distributed in the tutelary shrine forests, deep valleys and etc. From October 1988 to June 1989, phytosociological investigation of this forest vegetation was carried out by Braun-Blanquet s method. The forest vegetation was classified into 1 association and 7 communities. Ardisio-Castanopsietum sieboldii, Machilus thunbergii, Quercus acuta, Litsea japonca, Eurya japonica-Pinus thunbergii mixed forest, Pinus densiflora, Pinus rigida afforestation. Carpinus coreana community. Based on the classification, the actual vegetation map was drawn in 1 : 50,000 scale.