• Preventive Nutrition and Food Science
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• v.11 no.3
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• pp.177-183
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• 2006

Methanolic and aqueous extracts of 26 red algae species collected from Jeju Island coast were prepared at a high $(70^{\circ}C)$ and a room temperature $(20^{\circ}C)$ and were examined for their cytotoxic activity against 4 tumor cell lines: U-937 (human monoblastoid leukemia cell line), HL-60 (human promyelocytic leukemia cell line), B-16 (murine melanoma cell line) and HeLa (woman cervical carcinoma cell line). $20^{\circ}C$ methanolic extract of Polysiphonia japonica showed cytotoxic activity of over 50% against U-937, HL-60 and B-16 cells. On the other hand, the $20^{\circ}C$ aqueous extract of Scinaia okamurae and $70^{\circ}C$ aqueous extract of Chondrus crispus showed cell growth inhibition activity of more than 50% against HL-60 and B-16 cells. The highest cytotoxic activity was observed in the $20^{\circ}C$ aqueous extract of Scinaia okamurae against B-16 cells (80.55%).

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.279-282
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• 2016

This is the first report of Lactoria diaphana (Tetraodontiformes: Ostraciide) from Korea. A single specimen (208.0 mm standard length) was collected off the coast of Jejudo Island by gill net on 14 November, 2011. This species is characterized by having a pair of strong spines in front of the eyes, a slightly curved spine on the dorsal ridge, a pair of strong and short spines on the ventro-lateral ridge and various-sized spots on the body. We add L. diaphana to the Korean fish fauna and propose a new Korean name, "So-ppul-bok" for the species.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.434-437
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• 2006

Though numerous drilling has been performed in Jeju Island for development of ground water, the wells are mostly located along the coast lines or at low altitude area, and can hardly be found on the mid-mountain area. Two-dimensional magnetotelluric (MT) surveys have been carried out to cover the lack of geological Informal ion on the mid-mountain area and to figure out any possible structures or evidences for deep geothermal energy remained. Two-dimensional (2-D) inversion of MT data for four survey lines surrounding the Halla mountain show a thick layer having around 10 ohm-m in the depth of a few hundred meters throughout the survey area, which can be considered as the unconsol idated sedimentary layer. And they also show a conductive anomaly extending to more than 2km depth at the central part of each survey lines, which can possibly be related with old volcanic activities during the formation of Halla Mt.. Further seological/geophysical investigations should be followed.

• Journal of Environmental Science International
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• v.31 no.7
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• pp.617-635
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• 2022

The effect of coupled data assimilation (DA) on the meteorological prediction in the west coastal region of Korea was evaluated using a coupled atmosphere-ocean model (e.g., COAWST) in the spring (March 17-26) of 2019. We performed two sets of simulation experiments: (1) with the coupled DA (i.e., COAWST_DA) and (2) without the coupled DA (i.e., COAWST_BASE). Overall, compared with the COAWST_BASE simulation, the COAWST_DA simulation showed good agreement in the spatial and temporal variations of meteorological variables (sea surface temperature, air temperature, wind speed, and relative humidity) with those of the observations. In particular, the effect of the coupled DA on wind speed was greatly improved. This might be primarily due to the prediction improvement of the sea surface temperature resulting from the coupled DA in the study area. In addition, the improvement of meteorological prediction in COAWST_DA simulation was also confirmed by the comparative analysis between SST and other meteorological variables (sea surface wind speed and pressure variation).

• Korean Journal of Plant Taxonomy
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• v.39 no.4
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• pp.264-276
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• 2009

To elucidate the distribution of halophytes in Korea, we surveyed 95 coastal salt marsh and sand dune areas. As a result, 62 halophytes of 57 species, 4 varieties and 1 form belonging to 44 genera and 21 families were recorded from coastal regions and islands of South Korea. Of these, 33 taxa were plants growing on sand dunes and the other 29 in salt marsh. Fifty eight taxa were found on the west coast, which was surveyed at 61 areas. The most common species among them were Suaeda glauca (Bunge) Bunge, Suaeda japonica Makino, Phragmites communis Trin., Zoysia sinica Hance, Carex scabrifolia Steud. in salt marsh, and Salsola komarrovii Iljin, Lathyrus japonicus Willd., Limonium tetragonum (Thunb.) A.A. Bulloc, Calystegia soldanella Roem. & Schult. on sand dunes. On the other hand, only 45 taxa were found on the southern coast, surveyed at 15 areas. On the east coast, surveyed at 13 areas, 44 taxa were found. The most common species were Salsola komarrovii Iljin, Lathyrus japonicus Willd., Calystegia soldanella Roem. & Schult., on sand dunes and Linaria japonica Miq., which on the Korean peninsula is found only on the east coast. On Jeju Island, surveyed at 6 areas, 30 taxa of halophytes were found. Canavalia lineata (Thunb.) DC. is found in Korea only on Jeju Island. About half of the Korean halophytes were members of three families (Chenopodiaceae: 12 species, Poaceae: 12 species and Asteraceae: 7 species).

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.45 no.2
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• pp.77-84
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• 2009

This paper is to investigate the effect of the immersion time in the traditional hairtail hand line for developing the fishing methods and the fishing gear in the coast of jeju. The operating of 32 times was made with each different immersion time of hairtail hand line, and the relations between the catch and the immersion time were examined. As the result, targeted species rate was over 98% of total catch. From about 800 seconds after casting, the hooking rate was decreased and the bite loss rate was increased, it seems to be made by the decreasing factors of predators including the cutting of branch lines etc. In addition, it was supposed that the hooking rate and the bait loss rate had a deep connection with feeding time zone. The level of the correlation coefficient of the bait loss rate according to the immersion time was 0.54 at $p{\leq}0.01$, in the case of the hooking rate, 0.59 was chosen after about 800 seconds. The hooking rate and the bait loss rate according to the hook number were not irrelevant to the fish school layer. Additionally, it was assumed that the bait loss rate was related to the depth of water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.657-663
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• 2009

This paper reports the strandings of sea turtles on Korean shores monitored for the first time in 2008. A total of 19 sea turtles, consisting of 12 greens and 7 loggerheads, were recorded as stranded from the east coast to the south including Jeju Island. Reported strandings reached a peak in July and dominant area was Jeju Island. The curved carapace length of loggerhead sea turtles ranged 65-84.2cm and that of green sea turtles ranged 39.2-90cm, indicating most of them were immature to sub-adult. Out of 19 turtles, 11 were found dead with unknown reasons. Possible causes of death may include drawning by fishing gear, swallowing of marine debris, boat collision, and diseases. An immature green sea turtle tagged with a satellite transmitter spent winter near Jeju Island where it was released, suggesting that the Island provide immature greens a feeding ground. Considering thousands of sea turtles crawl on Japanese shores for nesting every year, the number of sea turtles reported in Korean waters was relatively small. Therefore, it is suggested that an appropriate monitoring system be necessary to protect and conserve endangered sea turtle species in Korean waters.

• Korean Journal of Environmental Biology
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• v.30 no.4
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• pp.339-348
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• 2012

To survey the seagrass distribution in Jeju and Chuja Islands, we directly observed seagrass beds using SCUBA in July, 2011. Distributional area, species composition, morphology, density, and biomass of seagrasses and environmental characteristics were examined in investigation sites. In particular, three protected seagrass species (Zostera marina, Z. caulescens and Z. caespitosa) were found in the investigation areas. While the three species were found in Chuja Island, only Z. marina was distributed in Jeju Island. Z. marina was distributed only north-eastern coast of Jeju Island, and the total coverage was $238,572m^2$. Total seagrass coverage of Chuja Island was $23,584m^2$. In detail, Z. caulescens Z. caespitosa and Z. marina were 21,216, 1,870 and $498m^2$, respectively. Of these, Z. marina was found from the intertidal to subtidal zones of 5m MSL (mean sea level) depth. Z. caespitosa and Z. caulescens were found in subtidal zones of 3~4 m and 4~6m MSL depth, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.6
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• pp.940-946
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• 2015

The Indo-Pacific bottlenose dolphin Tursiops aduncus commonly inhabits the coastal waters of Jeju Island, Korea. An investigation was conducted using data from vessel sightings and point sightings from land. During 40 days of vessel sighting surveys between 2007 and 2010, a total of 18 dolphin groups were encountered. The overall sighting rate was 0.01 group/n.m. Most Indo-Pacific bottlenose dolphins were sighted within 500 m of the northern coast of Jeju Island during surveys. Also, dolphin groups were observed 47 times during 109 days of shore-based surveys conducted between 2011 and 2015. The results of a dolphin distribution survey conducted in 2011 were generally similar to the results of previous surveys. However, there were no dolphin sightings from 2012 in Hanllim-eup, in the north-western part of the island, where dolphins were sighted frequently until 2011, whereas dolphin observations increased in the southern part of the island. The mean group size was 35.4 (SD=18.08) individuals. The most frequently sighted group size was 36-40 individuals. To conserve resident dolphins off Jeju Island, long term sighting surveys and environmental assessment are required to monitor their distribution patterns.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.637-649
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• 2017

Lipid levels and fatty acid compositions of 20 species of subtropical fish caught off the coast of Jeju Island, Korea were determined. The fish were categorized according to total lipid (TL) content as follows; lean fish ($TL=1.19{\pm}0.32%$, n=10 species), low-fat fish ($TL=3.02{\pm}0.44%$, n=6 species) and medium-fat fish ($TL=6.87{\pm}1.23%$, n=4 species). The prominent fatty acids were saturated fatty acids (SFAs), at 16:0 and 18:0 monounsaturated fatty acids (MUFAs), at 18:1n-9 and 16:1n-7, and polyunsaturated fatty acids (PUFAs), at 22:6n-3, 20:5n-3 and/or 20:4n-6. Across all species, the percentages of PUFAs and SFAs were $38.0{\pm}7.89%$ and $34.3{\pm}3.08%$, respectively, with no significant difference between both groups (P<0.05), but showed higher proportions than that of MUFA group ($27.8{\pm}7.23%$) (P<0.05). The proportion of n-3 PUFAs was $27.1{\pm}8.68%$ across all fish species, similar to levels in other fishes from Korea. These results suggest that subtropical fish from Jeju Island are a good source of n-3 PUFAs for humans.